GB2576830A

GB2576830A - Masonry unit and structures made thereof

Info

Publication number: GB2576830A
Application number: GB1912532.7A
Authority: GB
Inventors: Alfred Hoad Matthew
Original assignee: Matt Hoad Ltd
Current assignee: Matt Hoad Ltd
Priority date: 2018-09-03
Filing date: 2019-08-30
Publication date: 2020-03-04
Also published as: GB201912532D0; GB201814269D0

Abstract

The masonry unit 100 comprises a main body 110 extending in a first direction from a header end 101 to a trailing end 102. The body comprises an outer surface 111 defining a stretcher face 104. A main leg 130 and a narrower header leg 120 extend from an inner surface 112 in a second direction perpendicular to the first direction. The legs extend from the body, the header leg at the header end and the main leg spaced in the first direction from both header leg and trailing end. The legs define a main recess 140 between them that can accommodate either one main leg or two header legs of identical masonry units. The masonry unit may be F-shape or E-shape. The spacing between inner surfaces of interlocked masonry units may be variable in the second direction. The inner surface may be keyed to retain a binding agent. Also claimed are a system or wall comprising a plurality of the masonry units, and a method of building such a wall.

Description

MASONRY UNIT AND STRUCTURES MADE THEREOF

FIELD OF INVENTION

Embodiments of the present invention relate generally to masonry units such as bricks, stone blocks and concrete masonry units, and structures composed of and incorporating masonry units. More particularly, an improved masonry unit is provided which allows architects, engineers, and builders to create increasingly complex and structurally efficient walls, buildings and other structures.

BACKGROUND

Masonry is the building of structures from a plurality of individual units. Historically, these methods have employed both irregular units such as uncut stone, and more regular units, such as: cut stone blocks; clay or adobe bricks; concrete masonry units (including breeze blocks, cinder blocks, concrete blocks and clinker blocks); and blocks and bricks made of other materials. These individual units are typically laid in and joined by mortar, cement or another binding material. However, so-called ‘dry set masonry’ which is laid without mortar is also known.

Historically, the majority of masonry structures are constructed using regular, substantially cuboid masonry units which are easily transported, manipulated and laid. Examples of such masonry units include the British Standard brick has dimensions 215mm x 102.5 x 65 mm excluding mortar joints (and is defined in BS EN 771-1:2003 (‘Specification for Clay Masonry Units’, National Annex (informative), 2011) and British concrete blocks which have a face with dimensions of 440 x 215 mm or 390 x 190 mm and are commonly supplied in a variety of widths. Such bricks and blocks, which have a significant depth relative to their length and height, are often termed ‘hand laid masonry’.

However, structures constructed using masonry units such as bricks and blocks are necessarily limited in their geometry. To avoid a wall (or other structure) collapsing its centre of gravity of the wall must be substantially vertically over its base. If masonry units are laid such that they project laterally from a wall, the centre of gravity of the wall is moved outwards the more the wall projects and the wall is unstable and likely to fall down. To avoid this issue, commonly each ‘course’ (i.e. row) of masonry units is commonly laid (i.e. stacked) directly above the course of masonry units below them to create a strong wall with flat, vertical faces.

Equally, the ‘bond’ of a masonry structure - the arrangement of the masonry units across a wall - is also restricted when using traditional cuboidal masonry units. In the majority of structures bricks and blocks are typically ‘lapped’, such that each course of masonry units is offset from the course below in a direction along the length of a wall. In these structures, each vertical joint between two adjacent of masonry units in any given course is overlaid by a masonry unit in the course above. As such, where walls are lapped there are no continuous vertical joints extending through multiple courses in the wall. This creates a strong join between each course of masonry units and enables builders to achieve a strong and durable wall. Common bonds which exhibit this lapping between courses of masonry units include the so-called stretcher bond, English bond, and Flemish bond. There are numerous variations of bonds in use, however, all are derived from a standard rectilinear unit or the use of cut units (i.e. bats).

In contrast, if the masonry units in a wall or other structure are not lapped - such that masonry units are arranged in vertical columns in a so-called ‘stack bond’ the structure is significantly weaker. The columns of masonry units in the structure may be easily separated from each other, and the structure may collapse under relatively low loads. Such a collapse can occur regardless of whether the masonry units are bonded using mortar or not, since mortar is significantly weaker under tensile stress than under compressive stress. This issue is especially problematic where continuous vertical joints extend vertically between courses and through the depth of a wall. Indeed, in view of these issues BS 5628-3:2001, ‘Code of practice for use of masonry¹, (now superseded by BS EN 1996-2:2006) teaches that “the horizontal distance between crossjoints in successive courses (of bricks) should normally be not less than one quarter of the length of the bricks but in no case less than 50 mm”.

Therefore, it will be understood that structures built using traditional hand laid rectilinear bricks (and other similar masonry units) are limited in their geometry.

More recently, thinner alternatives to masonry units, such as brick tiles and brick slips, have been developed which may be applied as a non-structural veneer over secondary substrates fixed to the building structure. These thinner products are lightweight and may be applied to structures as a surface in order to achieve the effect or appearance of a wide range of geometries (e.g. curves or stepped walls), bonds and other visual finishes. Equally, curtain walling - thin walls typically comprising a single layer of half or full size bricks or other masonry units which do not bear any structural load and are suspended from the structural portions of a building - has been used to create similar effects. However, fagades constructed via these methods are significantly less durable than structures utilising more traditional bricks and blocks in part because they are reliant on the underlying carrier system. As such, buildings constructed using brick tiles, brick slips, curtain walls or other similar methods may be subject to increased maintenance costs during their lifetime and/or provide a shorter lifespan in service. Furthermore, providing both a structural portion of a building and a separate aesthetic fagade or veneer increases the complexity of construction, necessitates additional material and will incur additional costs during construction. In addition, due to the difference in construction technique, walls formed of brick slips or brick tiles can look can appear significantly different from walls manufactured using more traditional hand-laid bricks, even where this is not intended.

Therefore, there is a need for improved masonry units which can be used to construct walls with a wide variety of geometries (including geometries which were previously unknown) which are safe, durable and inexpensive.

SUMMARY OF INVENTION

According to an aspect of the invention, there is provided a masonry unit comprising: a main body extending in a first direction from a header end of the masonry unit to a trailing end of the masonry unit, the main body comprising opposed outer and inner surfaces, said outer surface defining a stretcher face of the masonry unit; a header leg extending from the inner surface of the main body at the header end of the masonry unit in a second direction which is substantially perpendicular to the first direction; and a main leg extending from the inner surface of the main body in the second direction, the main leg being spaced from the header leg in the first direction so as to define a main recess between the header leg and the main leg, and spaced from the trailing end ofthe masonry unit; wherein the header leg is narrower than the main leg in the first direction; the main recess being configured such that it can, at least in the first direction, alternately: (i) accommodate one main leg of an identical masonry unit; and (ii) accommodate two header legs of two respective identical masonry units.

By configuring the main leg, header leg and main recess of first masonry unit in this manner the main recess can receive both of the header legs of identical second and third masonry units, or the main leg of an identical second masonry unit, but not at the same time. By configuring the geometry of the masonry units in this manner, the units can arranged to interlock or mate (where the main recess of each masonry unit accommodates one or more legs of other masonry units) in multiple orientations or arrangements.

These different orientations or arrangements can be achieved by rotating a masonry unit by 180 degrees about an axis extending in the first direction or third direction. In each configuration the distance between the main bodies of the interlocked masonry units in the second direction may be varied (i.e. the masonry units may be translated relative to one another). As such, the profile of a wall constructed using two interlocked columns of masonry units may be varied across the face of the wall.

By interlock it is understood that the legs of a first masonry unit are inserted in the second direction into the recesses of a second masonry unit by any amount (i.e. such that the legs of the interlocked masonry units are overlapped or interdigitated). Having said this in practice, to create walls and other structures with sufficient structural strength masonry units may be required to be interlocked by a minimum amount. Preferably a recess of a first masonry unit is configured to receive (and preferably in use does receive) at least 10% of a main leg of a second identical masonry unit by length in the second direction, more preferably at least 20%, more preferably still at least 30%. Nevertheless it will be appreciated that the minimum acceptable amount of overlap may vary considerably depending on a variety of factors including the materials of the masonry units, the use of any binding agent (e.g. mortar), the weight of any overlying structure, the expected loading which will be applied to the wall, the desired strength of the wall and the desired wall relief.

In addition, masonry units of the present invention may also be interlocked with non-identical masonry units which have similar distributions of legs in the first direction. For instance, masonry units with different leg dimensions in the second direction and/or different leg dimensions in a third direction substantially perpendicular to the first and second directions may still be interlocked with one another such that the legs of one masonry unit are received in the recesses of the other and vice versa.

Advantageously, these interlocking masonry units may be combined to create strong and durable walls or structures with a wider variety of wall profiles, geometries and bonds than can be achieved with conventional cuboidal bricks and blocks. For instance, walls with significant surface reliefs and/or stack bonds may be created with considerable structural strength. In addition these masonry units may be arranged in new bond patterns which are unachievable with traditional rectilinear masonry units.

As discussed above, the main recess of a masonry unit must alternately accommodate (i.e. be configured to receive non-simultaneously) a main leg or two header legs of identical masonry units. Advantageously the main leg is as large as possible to reduce voids or gaps between interlocked masonry units which would reduce the strength of a structure constructed using the interlocked masonry units. In addition as the width of the main leg is increased the centre of gravity of the masonry unit is moved further away from the stretcher face in the second direction. This change in the centre of gravity increases the range of distances between the main bodies of two interlocked masonry units which can be achieved without negatively impacting the strength of a wall comprising these units. This increases the variety of wall geometries, bonds and surface reliefs that can be economically and safely constructed using the masonry unit.

In preferred embodiments the maximum width of the main leg in the first direction is approximately equal to, or greater than, twice the maximum width of the header leg in the first direction. Preferably the masonry units are modular and may combine or co-ordinate with conventional rectilinear brick and block sizes in a variety of different bonds.

The maximum width of the main leg may be greater than twice the maximum of the header leg, so as to accommodate mortar, cement, grout, cement, adhesive or other binding agent between the two header legs of a pair of masonry units when received within the main recess of a third masonry unit in use. When cured, the binding agent will increase the strength of join between the masonry units and avoid gaps between adjacent units. Alternatively, the maximum width of the main leg may be equal to or smaller than the twice the maximum width of the header leg in the first direction.

In preferred embodiments, the maximum width of the main recess in the first direction is greater than the maximum width of the main leg in the first direction so as to accommodate binding agent (e.g. mortar or grout) between the main recess of a first masonry unit and a main leg of a second masonry unit received within it. Alternatively, the maximum width of the main recess in the first direction may be substantially equal to the maximum width of the main leg in the first direction. In this case the masonry units may be interlocked or combined using an interference, press or friction fit.

More preferably, the minimum width of the main recess in the first direction is greater than the maximum width of the main leg in the first direction. Therefore, the main recess of a first masonry unit may receive the main leg of a second masonry unit (and vice versa) by sliding the two units together in either the second direction or the third direction. This simplifies construction of a wall using the masonry units.

In particularly preferred embodiments the main recess and main leg are configured such that the main leg of an identical masonry unit can be accommodated within the main recess of the masonry unit at a plurality of different positions in the second direction, the spacing between the distal end of the main leg of the identical masonry unit and the inner surface of the masonry unit it the second direction being different at each respective position.

In summary, in such an embodiment the masonry unit and the identical masonry unit may be interlocked at different relative positions in the second direction. This can be achieved, for example, by selecting different dimensions and/or shapes for the main recess and the main leg respectively such that when the main leg is placed within the main recess sufficient space remains for the main leg to be moved in the second direction within the recess. Consequently, the distance between the opposing stretcher faces of interlocked masonry units can be varied. This is especially beneficial when constructing walls and other masonry structures formed of two columns of interlocked masonry units. The distance between the stretcher faces of the interlocked masonry units may be varied across the wall so as to create variations in surface relief in one or more sides of the wall.

Equally the main recess and header leg of the masonry unit may be configured such that the header legs of two identical masonry units can be accommodated within the main recess of the masonry unit at a plurality of different positions in the second direction, the spacing between the distal end of the header legs of the identical masonry units and the inner surface of the masonry unit it the second direction being different at each respective position. This may be achieved where the maximum width of the header leg in the first direction is equal to or less than half the maximum width of the main leg of the masonry unit. The spacing between the distal end of the header leg of each identical masonry unit and the inner surface of the masonry unit may also be varied as necessary (e.g. to create variation in surface relief across a wall or course of masonry units). The variation in the width of a wall needed to create such a surface relief does not significantly affect the strength of a wall due to the interlocking between the columns of masonry units.

In preferred embodiments the width of the main recess in the first direction is greater than or equal to the maximum width of the main leg in the first direction along at least a portion of the length of the main recess in the second direction, the portion being longer than the part of the main leg which has the maximum width. By “longer” it is understood that the portion is substantially longer than the part of the main leg which has the maximum width (e.g. a more significant difference than would be required to avoid interference between interlocked masonry units or would typically be provided to receive a binding agent between masonry units). For instance, the width of the main recess in the first direction may be greater than or equal to the maximum width of the main leg in the first direction along at least 10% of the length of the main recess in the second direction, preferably along at least 50% of the length of the main recess in the second direction, more preferably along at least 90% of the length of the main recess in the second direction.

Additionally, or alternatively the width of the main recess in the first direction may be greater than or equal to twice the maximum width of the header leg in the first direction along at least a portion of the length of the main recess in the second direction, the portion being longer than the part of the header leg which has the maximum width. As such, the width of the main recess in the first direction may be greater than or equal to twice the maximum width of the header leg in the first direction along at least 10% of the length of the main recess in the second direction, preferably along at least 50% of the length of the main recess in the second direction, more preferably along at least 90% of the length of the main recess in the second direction.

Preferably the width of the trailing recess in the first direction is greater than or equal to the width of the header leg in the first direction along at least a portion of the length of the trailing recess in the second direction, the portion being longer than the part of the header leg which has the maximum width. For instance, the width of the trailing recess in the first direction may be greater than or equal to the maximum width of the header leg in the first direction along at least 10% of the length of the main recess in the second direction, preferably along at least 50% ofthe length ofthe main recess in the second direction, more preferably along at least 90% of the length of the trailing recess in the second direction.

These features enable the distance between the distal end of the main leg of a first masonry unit and the inner surface of a second identical interlocking masonry unit to be varied continuously in the second direction along at least part of the length of the recess/main leg. In other words, the distance between opposed stretcher faces of interlocked and identical masonry units may be varied continuously between a point where the distal end of the main leg and/or header leg of the first masonry unit contact the inner surface of the second masonry unit (and vice versa), and a point at which the main leg and header leg of the first masonry unit are no longer accommodated in the recesses of the second masonry unit (and vice versa). Therefore, the range of surface reliefs and range of widths which may be created using a wall formed of two interlocked columns of masonry units are increased. Again these variations in the width of interlocked masonry units or a wall formed of these units will not significantly affect the strength of a structure due to the interlocked connection between the masonry units.

Alternatively, the main recess of a masonry unit may dovetail with the main leg of an identical masonry unit. This may occur when the entrance to the main recess is narrower in the first direction than the base of the recess and/or the distal end of the main leg is wider in the first direction than the base of the main leg. This can assist in interlocking multiple masonry units together. This is discussed further below.

Advantageously, if the maximum width of the main leg is greater than the width of the entrance to the main recess, the masonry units can be interlocked and separated only by relative movement of the masonry units in a third direction which is substantially perpendicular to the first and second directions. In addition, unlike traditional rectilinear bricks or blocks, the binding or coupling between masonry units no longer reliant on the adhesion of mortar, cement, grout or another binding agent alone. Therefore, the strength and lifespan of a wall constructed using the masonry units is increased.

In preferred embodiments an interior surface of the main recess is an interlocking surface configured to retain binding agent applied thereto in use so as to retain an identical masonry unit within the main recess (e.g. where a leg of an identical masonry unit is received by or inserted into the main recess). That is, the interior surface includes feature(s) which will engage with mortar (or other binding agent) applied thereto and, once the mortar is cured, resist relative movement between the mortar and the masonry unit. Since this will occur where the mortar will contact both of two interlocked and/or adjoining masonry units this also causes those masonry units to be fixed relative to each other. In other words, this interlocking surface is configured to retain binding agent applied thereto in use so as to mechanically retain an identical masonry unit within the main recess.

Additionally or alternatively, a surface of the trailing recess may be an interlocking surface configured to retain binding agent applied thereto so as to retain an identical masonry unit within the main recess (e.g. where a leg of an identical masonry unit is received by or inserted into the trailing recess). Such interlocking surfaces of the trailing recess may comprise any of the features discussed with reference to the interlocking surfaces of the main recess.

In practice it is unlikely that binding agent (e.g. mortar or grout) will be applied directly to the full extent of the interior surface of either the main recess or the trailing recess due to their uneven geometry. Instead, uncured mortar or grout will be first applied to the free bedding face of the underlying course of masonry units (i.e. the underlying surface of the wall). A masonry unit will then be laid into this layer of uncured mortar, grout or other binding agent such that the mortar, grout or binding agent is squeezed or pushed up into the main and trailing recesses. As such, the mortar, grout or other binding agent is indirectly applied to the internal surfaces of the main and trailing recesses. Once cured the mortar, grout or other binding agent which is applied to (i.e. in contact with) the interior surfaces of the recesses will be strongly retained by interlocking surface(s) of the main and/or trailing recess.

Nevertheless, when a plurality of masonry units according to the present invention are laid in a bed of mortar or grout (or another binding agent) such that the masonry units are interlocked cavities between adjacent bricks may exist which are not filled by mortar or grout (or another binding agent). In traditional rectilinear masonry and brickwork such cavities would be unacceptable because they would result cause a significant reduction in strength of a wall. However, when using masonry units according to the present invention sufficient strength is provided by the mechanical interlocking of the masonry units without the need for all cavities to be completely filled. Positively, this simplifies construction of buildings using masonry units.

The retention of a binding agent and the retention of the identical masonry unit increase the force required to separate interlocked masonry units (i.e. where a leg of a first masonry unit is received in the main recess of the second masonry unit). Since the force required to separate interlocked or mated masonry units is greater, walls and other structures constructed using the masonry units will be stronger and have longer lifespans. Equally, this increase in strength enables builders and architects to develop walls with greater variety of geometries, surfaces reliefs and bonds.

A variety of features can be used to make the interior surface of the main recess an interlocking surface. In some embodiments the width of the main leg in the first direction is greater at the distal end of the main leg than adjacent to the main body and/or the width of the header leg in the first direction is greater at the distal end of the header leg than adjacent to the main body.

For instance, the main leg and/or the header leg may be tapered on at least one side thereof, such that the width of the main leg or the header leg in the first direction increases away from the main body along the second direction. Alternatively the variation in width may be non-continuous along the length of the respective leg.

These variations in width along the length of one or more legs of the masonry unit will mean that cured mortar, grout or another binding agent applied between the interlocked masonry units will create a mechanical obstruction which restricts movement of the masonry units relative to each other. In other words, binding agent retained between the legs of multiple masonry units which have the variations in widths discussed above will lock the masonry units together. Overcoming this mechanical obstruction is difficult and requires a large amount of force because attempting to separate the masonry units once the received binding agent has cured will apply compressive forces to the cured binding agent and the interlocking surface(s) of the masonry unit, which have high compressive strength.

Additionally or alternatively, one interior surface of the main leg and/or the header leg is keyed so as to retain binding agent (e.g. mortar or grout) applied thereto in use so as to retain an identical masonry unit within the main recess. By keyed it is understood that the surface is roughened, irregular or serrated. Such keyed surfaces have a greater surface area to adhere to a bonding agent such as mortar or grout and will therefore provide a stronger bond to the binding agent and the interlocking surface(s) than a smooth surface thus increasing the force required to separate interlocked masonry units.

Additionally or alternatively the masonry unit may comprise at least one locking cavity in an interior surface of the main leg and/or the header leg, the or each locking cavity configured to retain binding agent applied thereto in use so as to retain an identical masonry unit within the main recess. Preferably, the locking cavity is a groove extending through the masonry unit in a third direction which is substantially perpendicular to the first and second directions since these grooves are relatively simple to manufacture. Alternatively the locking cavity may be blind hole or other cavity extending into a surface of the main leg or the header leg.

In use these locking cavities will receive binding agent which, when cured, is a solid mechanical obstruction which restricts the relative movement of interlocked masonry units. Therefore, the binding agent received by the locking cavity increases the force required to separate interlocked masonry units in use.

Preferably the at least one locking cavity is configured to receive a reinforcement pin (.g. “rebar” - a reinforcing bar which is typically made of steel). For instance, the locking pin may extend through multiple courses (i.e. rows) of masonry units within a wall restricting relative movement of masonry units in adjacent courses. In addition a locking pin received in a pair of locking cavities of two identical and interlocked masonry units may provide a mechanical obstruction to relative motion of the interlocked masonry units.

In each of the examples of interlocking surfaces discussed above, the surfaces are provided with a shape or surface relief which increases the force required to separate interlocked or mated masonry units which are joined using binding agent. This increase in the strength of the join between masonry units will increase the strength and lifespan of a wall or structure constructed using these masonry units and, as a result increase the variety of walls and structures which can be safely and durably constructed using the masonry units.

Equally, in practice substantially any surface of the masonry unit may be made an interlocking surface using the features discussed above so as to increase the adhesion between adjacent or interlocking masonry units.

The interlocking surfaces discussed above cause a pair of interlocked or mated masonry units to act as a single combined unit. This is because the interlocked masonry units are mechanically restricted from moving relative to one another by their shape and/or surface finish. This differs from conventional brickwork or corbelling or masonry where bricks are retained in a wall through adhesion of mortar with surrounding masonry units.

Preferably the masonry unit comprises a guide notch in a surface of the masonry unit which identifies a predetermined cutting position on the masonry unit. This can simplify construction of walls since the guide notch can (for instance) identify common locations a mason or bricklayer may wish to split the masonry unit. For instance, the masonry unit may be split at the predetermined cutting position identified by the guide notch for inclusion in a bond. This may be necessary at comers or ends of a wall - i.e. when closing a wall. For example, a guide notch may be located at a point halfway along the length masonry unit in any direction, at a point a third of the distance along the masonry unit in a given direction, and/or a quarter of the distance along the masonry unit in a given direction. Preferably the guide notch is a groove across the surface of the masonry unit. This groove may concentrate stress at the pre-determined cutting location, thereby increases the likelihood that the masonry unit will split cleanly and in the correct location. Preferably the masonry unit comprises a plurality of guide notches defining predetermined cutting positions in at least one of the first direction and second direction of the masonry unit. Alternatively, the masonry unit may also comprise one or more guide notches defining predetermined cutting positions in the third direction of the masonry unit.

In preferred embodiments the masonry unit comprises perforations extending into or through the masonry unit in a third direction which is substantially perpendicular to the first and second directions. Advantageously these perforations can receive binding agent when a masonry unit is laid in a wall. This binding agent, when cured, will lock each masonry unit in place such that its movement relative to the courses of masonry units above and below it is restricted. Therefore, the perforations can increase the strength and lifespan of a masonry structure constructed using the masonry units.

Perforations also reduce the material required to manufacture a masonry unit. Additionally, perforations can ensure that the masonry units manufactured using aggregates (e.g. clay or concrete) dry evenly during manufacture and preventing the cracking, deformation, or failure of the masonry units during manufacture.

In further embodiments, the masonry unit may have perforations extending into or through the masonry unit in different directions. Alternatively or in addition, the masonry unit may comprise a so-called ‘frog’ - an indentation or depression in one or more of the faces of the masonry unit (e.g. in the bedding face, such that the frog extends into the main body, the main leg and/or header leg). In use this frog can receive mortar, grout or another binding agent when the masonry unit is laid down. The binding agent received in a frog when laying masonry units will, when cured, mechanically lock adjacent masonry units (e.g. masonry units in adjacent courses) together.

The masonry unit may comprise a spacer protrusion which extends in the second direction from the inner surface of the main body, wherein the protrusion is shorter in the second direction than the header leg and the main leg. The size of the spacer protrusion defines a pre-determined minimum spacing or clearance between the inner surface of the main body and an adjacent masonry unit. This minimum spacing or clearance may be selected such that an appropriate amount of binding agent may be received between interlocked (i.e. mated or “top and tailed”) or adjacent masonry units.

Since the spacer protrusion provides a minimum separation between two or more interlocked masonry units the dimensions of interlocked masonry units are more predictable for those designing and constructing building and other structures using masonry units. For instance, in preferred embodiments the spacer protrusion may extend a distance of approximately 10 mm from the masonry unit to allow for approximately 10 mm of mortar to be received between interlocked masonry units.

In addition, the spacer protrusion can simply the transport and storage of the masonry units since the spacer protrusion can be used to define a specific spacing between interlocked masonry units such that the interlocked units correspond in size to existing bricks or blocks (e.g. the British standard brick). As such, the interlocked masonry units may be easily stored or transported on pre-existing pallets and other equipment designed for pre-existing masonry units.

The spacer protrusions may be resized by a manufacturer or designer based on a pre-determined width or length of adjacent or interlocked masonry units. The spacer protrusions can reduce the need for a mason to measure or assess the spacing between adjacent or interlocked masonry units. Therefore, the masonry units are simple to lay.

Preferably the spacer protrusion is positioned between the main leg and the header leg and extends into the main recess such that it is protected from accidental damage. However, it can be located at substantially any point on the inner surface of the main body of a masonry unit. Alternatively, a spacer protrusion may be omitted to provide builders increased flexibility when positioning each masonry unit or where a masonry unit is intended to be laid without binding agent.

In preferred embodiments of the masonry unit the length of the main leg in the second direction and the length of the header leg in the second direction are substantially the same. Advantageously, placing and aligning masonry units is simplified.

Nevertheless, in alternative embodiments the header and main legs may be of different lengths. For instance, if the masonry unit comprises a spacer protrusion of a given length extending in the second direction from the inner surface within the main recess, the header leg may be longer than the main leg by approximately the same length. Therefore, when a pair of these masonry units are interlocked such that the main leg of each masonry unit is received in the main recess of the opposing recess such that the main leg is adjacent to the spacer protrusion, the header leg of each brick will be adjacent to the inner surface of the opposing masonry unit within the trailing recess. This may increase the strength of the interlocking since the width of the joint between the header leg and inner surface is reduced.

In preferred examples, the inner surface ofthe main body within the main recess and the inner surface of the main body within the trailing recess are substantially co-planar. This means that the main and header legs may be received to the same depth in each recess, meaning that it is easier to lay and align masonry units which are interlocking or adjacent. However, this is not essential.

Preferably, the main recess is configured such that it cannot (in the first direction) accommodate a main leg and a header leg of two respective identical masonry units simultaneously, or accommodate three header legs of three respective identical masonry units simultaneously.

In other words, the masonry unit is configured such that the main leg and/or header leg are sufficiently large that the main recess cannot (in the first direction) accommodate a main leg and a header leg of two respective identical masonry units simultaneously, or accommodate three header legs of three respective identical masonry units simultaneously. This minimises the voids or gaps between adjacent masonry units (which may or may not be filled with binding agent) when a plurality of masonry units are mated or interlocked, thereby increasing the strength of a structure built using the masonry units. In addition placing and aligning such masonry units is simplified since gaps or voids between units are minimised. In addition, when masonry units have larger main legs and header legs length the centre of mass of the masonry unit is further from the outer surface (i.e. the stretcher face) of the masonry unit in the second direction. This increases the range of structures which may be built simply and safely using the masonry units.

In preferred embodiments the space between the main leg and the trailing end of the masonry unit in the first direction is greater than the maximum width of the header leg in the first direction, and preferably less than the maximum width of the main leg in the first direction. Advantageously this means that the interlocked masonry units can be laid or tessellated without leaving significant gaps or voids between them. The strength of a wall containing such gaps or voids between units is reduced.

Equally, in such embodiments regular gaps may be left between units for the use of a binding agent (e.g. mortar, grout, etc) or reinforcement (e.g. reinforcement pins extending between courses of masonry units)

In particularly preferred embodiments: the space between the header leg and the trailing end of the masonry unit defines an open trailing recess; the open trailing recess being configured such that it can accommodate a header leg of an identical masonry unit at least in the first direction; and more preferably a cross section through the masonry unit on a plane containing the first direction and the second direction is approximately ‘F’-shaped.

Advantageously, a plurality of these ‘F’ shaped masonry units with open trailing recesses may be combined and interlocked to create a variety of strong and durable walls or structures with complex wall profiles and a variety of unit geometries or bonds. In preferred examples, the surfaces of the open trailing recess may be an interlocking surface as discussed above with reference to the main recess. In addition, individual units or multiple interlocked units may be orientated or rotated in substantially any direction (e.g. with the stretcher face is substantially vertical, horizontal or at another angle) in order to create novel bonding effects visible on the surface of a wall.

In preferred embodiments the sum of the widths of the header leg and the main recess in the first direction is greater than or equal to the sum of the widths of the main leg and the trailing recess in the first direction. This minimises voids or gaps between interlocked masonry units, thereby maximising the strength of structures constructed using interlocked masonry units. In use, any voids or gaps between interlocked masonry units may be filled with a binding agent. For instance, any conventional brick mortar may be used between masonry units.

It is particularly preferred that the sum of the widths of the header leg and the main recess in the first direction is substantially equal to the sum of the widths of the main leg and the trailing recess in the first direction. In these embodiments two identical masonry units can be combined or interlocked such that the main recess of a first masonry unit accommodates the main leg of a second masonry unit (and vice versa) and the open trailing recess of the first masonry unit accommodates the header leg of the second masonry unit (and vice versa) so as to form a substantially rectangular cuboid combined unit. This combined unit acts as a single conventional masonry unit when laid, and is therefore easy to work with (requiring the same knowledge, equipment and training as conventional bricks and blocks) and can simplify the construction of walls and buildings. This substantially cuboid combined unit formed by a pair of identical masonry units may be positioned and sized to correspond to the dimensions of standard rectilinear bricks and blocks (e.g. the British standard brick which has dimensions of 102.5 mm x 140 mm x215 mm excluding mortar).

In alternative embodiments the masonry unit may comprise:

a trailing leg extending from the inner surface of the main body at the trailing end of the masonry unit in the second direction, the trailing leg being spaced from the main leg so as to define a closed trailing recess between the trailing leg and the main leg;

wherein the trailing leg is narrower than the main leg in the first direction and substantially the same width as the header leg in the first direction;

the closed trailing recess being configured such that it can, at least in the first direction, alternately: (i) accommodate one main leg of an identical masonry unit; and (ii) accommodate a header leg and a trailing leg of two respective identical masonry units; and wherein preferably a cross section through the masonry unit on a plane containing the first direction and the second direction is approximately Έ’-shaped.

Advantageously, a plurality of these Έ shaped masonry units with closed trailing recesses may be combined and interlocked to create a variety of strong and durable walls or structures with complex wall profiles and a variety of unit geometries or bonds. As discussed further below, Έ’ shaped masonry units may be used to create a continuous “locked chain” where all of the mortar joints in a course of mated masonry units are mechanically interlocked.

Preferably these examples of masonry units with a trailing leg are substantially symmetric about a plane extending in the second direction through the centreline of its main leg. As such, the trailing leg may share any or all of the features and/or geometry of the header leg and the closed trailing recess may share any of the features and/or geometry of the main recess. This increases the number of orientations the masonry units can be interlocked in.

The trailing leg and trailing recess may comprise any of the features discussed above in relation to the main leg or header leg and the main recess, respectively. For instance, the trailing leg may be provided with an interlocking surface or a spacer protrusion.

It should also be noted that masonry units with a trailing leg (Έ shaped units) can in some embodiments be mated or interlocked with masonry units without a trailing leg (‘F’ shaped units). As such, these different units in combination form a masonry unit system in which the most appropriate unit may be easily selected and laid with other units in the system by a mason or bricklayer.

Equally, in preferred embodiments a masonry unit may further comprise:

a plurality of main legs extending from the inner surface or the masonry unit in the second direction;

wherein the main leg nearest to the header end of the masonry unit is spaced from the header leg in the first direction so as to define a first main recess between the header leg and the main leg nearest to the header end of the masonry unit;

wherein the main leg nearest to the trailing end of the masonry unit is spaced from the trailing end of the masonry unit each main leg being spaced from any adjacent main legs by a main recess;

the main recesses being configured such that they can, at least in the first direction, alternately: (i) accommodate one main leg of an identical masonry unit; and (ii) accommodate two header legs of two respective identical masonry units.

Preferably, in such masonry units with multiple main legs wherein the space between the header leg and the trailing end of the masonry unit defines an open trailing recess, the open trailing recess being configured such that it can accommodate a header leg of an identical masonry unit at least in the first direction.

Such masonry units are analogous to the F shaped masonry units discussed above, having an open trailing recess but additional main legs. These masonry units share the advantages of the F shaped masonry units but may be made longer without negatively impacting the strength or handling of the unit.

Alternatively these features discussed above may be applied to masonry units with a larger number of legs. Masonry units comprising a plurality of main and/or header legs along their length are envisioned. These masonry units may comprise a symmetric or repeating pattern of legs.

For instance, a masonry unit with multiple main legs may further comprise:

a trailing leg extending from the inner surface of the main body at the trailing end of the masonry unit in the second direction, the trailing leg being spaced from the main leg nearest to the trailing end of the masonry unit so as to define a closed trailing recess between the trailing leg and the main leg nearest to the trailing end of the masonry unit;

wherein the trailing leg is narrower than the main legs in the first direction and substantially the same width as the header leg in the first direction;

the closed trailing recess being configured such that it can, at least in the first direction, alternately: (i) accommodate one main leg of an identical masonry unit; and (ii) accommodate a header leg and a trailing leg of two respective identical masonry units.

These masonry units are analogous to the Έ’ shaped bricks discussed above, having a closed trailing recess but additional main legs. These masonry units share the advantages of the Έ’ shaped masonry units but may be made longer without negatively impacting the strength or handling of the unit.

In preferred embodiments at least one face of the masonry unit is a finished face. These finished faces are faces of the masonry unit which are intended to be visible in use, i.e. facing externally from a wall or structure. These finished faces may be treated or manufactured to provide an attractive or aesthetically pleasing appearance.

Therefore, such finished faces may be contrasted with (i.e. are different from) the interlocking surfaces discussed above which may be keyed, roughed or serrated, or comprise locking cavities in order to adhere or retain binding agent when in use.

In particularly preferred examples of masonry units the stretcher face is a finished face. Equally, the masonry unit may comprise a header face defined by the header end of the main body and a surface of the header leg, wherein the header face is a finished face. Alternatively, or additionally, the masonry unit may comprise a trailing face defined by the trailing end of the main body, wherein the trailing face is a finished face. Where the masonry unit has a trailing leg, the masonry unit may comprise a trailing face defined by the trailing end of the main body and a surface of a trailing leg, wherein the trailing face is a finished face.

The finished faces could be of consistent appearance, or exhibit variations in at least one of colour, texture, surface relief, and surface coating or any other property. These variations could be applied to the surface of the masonry unit using any suitable technique including extrusion, pressing, embossing, 3D printing, or any combination of these techniques. Alternatively these variations could be created by variations in materials or coatings of the masonry unit.

In preferred embodiments the masonry unit has the following dimensions:

• the maximum length of the masonry unit in the first direction is approximately 215 mm;

• the maximum width of the masonry unit in the second direction is approximately 102.5 mm and the maximum with of the main body of the masonry unit in the second direction is approximately 27.5 mm; and/or, • the maximum height of the masonry unit in a third direction which is a third direction which is substantially perpendicular to the first and second directions is approximately 65 mm.

Advantageously, a pair of masonry units according to the dimensions above which are interlocked such that the main leg of each unit extends into the main recess of the other unit allowing for a nominal 10mm spacing for mortar between the two masonry units corresponds to the working dimensions of the UK standard metric brick - 215 x 102.5 x 65 mm - as defined in BS-EN-771-1 (‘Specification for Clay Masonry Units’, National Annex (informative), 2011) and BS 4725: 2005. Alternatively, the masonry units may be sized to correspond to any other standardised type of masonry unit. Masonry units sized to correspond to existing standards are easily handled and laid using existing equipment and techniques and can be simply integrated into structures which also use standardised brick.

Equally, the masonry unit may be sized to correspond to any masonry unit which complies with the European BS EN 771-1 standard or any other national or international standard.

It will be understood that the dimensions of a specific masonry unit intended to be manufactured to these nominal dimensions may still vary from the nominal dimensions depending on the manufacturing conditions. In other words, two bricks manufactured to the same method may still vary in size. Therefore, the term approximately used above is in part intended to reflect variations from the nominal size of a brick caused by manufacturing conditions.

For instance, in the preferred embodiment of a masonry unit discussed above which corresponds to the working dimensions British standard metric brick (the size a manufacturer will attempt to make a brick): the maximum length in the first direction of any individual masonry unit may be between 200 and 230 mm, more preferably between 210 and 220 mm; the maximum width of a masonry unit in the second direction may be between 85 mm and 120 mm, more preferably between 95 mm and 110 mm; the maximum with of the main body of a masonry unit in the second direction may be between 20 mm and 40 mm, more preferably between 25 mm and 30 mm; and the maximum height of a masonry unit in the third direction may be between 50 mm and 80 mm, more preferably between 60 and 70 mm.

It should be noted that these working dimensions differ from the coordinating dimensions of a British Standard brick - 225 x 112.5 x 75 mm. This nominal size includes 10 mm of mortar applied to a bedding face, header face and stretcher face of the masonry unit which is used to bind multiple adjacent bricks or masonry units together in a conventional wall.

Alternatively, one or more of the dimensions of the masonry unit may be varied from the size of a standard masonry unit. For instance, a masonry unit which conforms to the standard width and length dimensions of a standard British brick unit may be varied in height (e.g. such that each masonry unit of 215 x 102.5 mm may be manufactured to be less than or greater than 65 mm in the third direction). Equally, the maximum width of the main body in the second direction may be increased and the maximum width of the legs in the second direction may be decreased by a corresponding amount (or vice versa). As such, the total width of the masonry unit in the second dimension will remain constant whilst the relative proportions of the main body and legs are varied. For instance, a wider main body may be preferred where the masonry unit is to be use in walls with large steps between adjacent bricks in a lateral direction (i.e. perpendicular to the height of the wall) in the coursing or bonding of the masonry units.

In preferred examples the height of the masonry unit in the third direction is less than the minimum width of the main recess, and/or less than twice the width of an open trailing recess, and/or less than the minimum width of a closed trailing recess (where present). Therefore, a masonry unit may be received within the respective recess of an identical masonry unit when the two masonry units are oriented substantially perpendicular to one another. This enables the production of a wider variety of bonding patterns and walls of increased strength.

As an alternative, the masonry unit may be sized such that it does not conform to the dimensions of previous standardised bricks or blocks. This may be for a structural, design or aesthetic reason.

In preferred embodiments the masonry unit may be extruded (i.e. manufactured to the so-called stiff mud process), moulded (i.e. manufactured to the soft-mud process), wet or dry pressed, 3D-printed, or a combination of these methods. Alternatively, a combination of two or more of these techniques may be used to produce the masonry unit. Alternatively, the masonry units may be formed or manufactured using any other suitable method or a combination of these methods.

Where the masonry unit is extruded, it is preferable that the third dimension (along which the masonry unit has a constant cross section) shall be the extrusion dimension. The height of the masonry unit in the extrusion direction may be easily varied during manufacture as required.

In accordance with a further aspect of the invention there is provided a masonry unit system comprising a plurality of masonry units in accordance with the first aspect of the invention. Each masonry unit may comprise any of the features discussed above with reference to the first aspect of the invention and their corresponding advantages.

In particular, the masonry unit system may further comprise at least one reinforcement pin, wherein preferably the length of the at least one reinforcement pin is at least the height of the masonry unit in a third direction which is a substantially perpendicular to the first and second directions, more preferably at least twice the height of the masonry unit in the third direction, more preferably still at least the height of the masonry unit in the third direction.

The locking pin may extend through multiple courses (i.e. rows) of masonry units within a wall, thereby restricting relative movement of masonry units in adjacent courses. In addition a locking pin received in a pair of locking cavities of two identical and interlocked masonry units may provide a mechanical obstruction to relative motion of the interlocked masonry units. Therefore, the reinforcement pins increase the strength of a wall or structure constructed using the system.

Construction of a wall may be further simplified using a system which further comprises a lintel (i.e. a foundation or other support structure) from which extend a line or series of reinforcing pins. The line of reinforcing pins may extend in the direction of the length of the wall, whereas the reinforcing pins may extend in the direction of the height of the wall. The reinforcing pins may be arranged such that courses of masonry units can be laid around these reinforcing pins such that the pin extend through multiple courses of masonry units, for instance, through the channels or perforations discussed herein.

Therefore, the reinforcing pins fix the location of channels and the locations of masonry units in the wall in a direction along the length of the wall. By restricting the positions of a masonry unit the process of laying a wall is simplified as the number of measurements which must be made by a mason or bricklayer are reduced. Not all channels may be provided with a reinforcement member (e.g. a reinforcement member may be provided periodically, for instance every two, three or five channels or every two, or five masonry units).

The lintel may be pre-drilled with holes to accommodate reinforcing pins at appropriate positions (i.e. positions which correspond to the location of channels extending through a wall) based on the dimensions of the masonry units and any joints present.

In accordance with a further aspect of the invention there is provided a wall comprising a plurality of masonry units according to the first aspect of the invention. Each masonry unit may comprise any of the features discussed above with reference to the first aspect of the invention and their corresponding advantages. These walls may safely and robustly be formed in an increased variety of geometries, bonds and surface reliefs in comparison to existing structures. The wall may be structural (e.g. load-bearing), or not. The ability to construct walls of increased strength means that walls may be constructed with no foundation or foundations of reduced size. This may result in reduced construction time and reduced construction costs.

Preferably all of the masonry units of a wall are masonry units according to the first aspect of the invention. However, this is not essential. Walls according to the invention may also comprise further masonry units which do not correspond to the first aspect of the invention. For instance, the wall may further comprise a plurality of conventional or traditional masonry units (e.g. substantially cuboidal masonry units). Additionally, or alternatively, the wall may further comprise bats (i.e. cut portions) of the masonry units according to the first aspect.

In preferred embodiments the wall comprises a plurality of masonry units arranged in a front column and a rear column such that the stretcher faces of the masonry units in the front column define a front side of the wall and the stretcher faces of the masonry units in the rear column define a rear side of the wall, the legs of the masonry units in the front column extending at least partly into the recesses of the masonry units in the rear column, and vice versa. As such, the masonry units of the front column are interlocked with the masonry units of the rear column. These interlocked masonry units increase the strength and lifespan ofthewall.

Preferably, the legs of all (or substantially all) of the masonry units in the front column extend at least partly into the recesses of all (or substantially all) of the masonry units in the rear column and vice versa. However, it should be noted that the wall could optionally additionally include some masonry units which do not interlock in this matter. In some embodiments, the legs of at least 25%, more preferably 50%, more preferably still 75% of the masonry units in the front column may extend at least partly into the recesses of a plurality of the masonry units in the rear column and vice versa.

In further examples, the legs of all (or substantially all) of the masonry units of at least one course of the front column may extend at least partly into the recesses of a plurality of the masonry units in the rear column and vice versa.

The masonry units in the opposing columns are interlocked where one or more legs of a first masonry unit are inserted one or more respective recesses in a second masonry unit in the second direction. In practice there will be minimum acceptable interlocking or overlap between the masonry units in the opposing columns (and equally a maximum spacing between the masonry units in the opposing columns) in order to achieve sufficient structural strength. Preferably a recess of a masonry unit in the first column receives at least 10% of a main leg of a second masonry unit by length in the second direction, more preferably at least 20%, more preferably still at least 30%. However, it will be appreciated that the minimum acceptable amount of a leg received in a recess may vary considerably depending on a wide variety of factors including but not limited to the materials of the masonry units, the use of any binding agent (e.g. mortar), the weight of any overlying structure, the expected loading which will be applied to the wall, the desired strength of the wall and the desired wall relief.

Walls with increased interlocking between the front and rear column have increased strength. However, the variety of structures which may be safely constructed may be increased if only a portion of the masonry units in each column are interlocked.

Walls according to the invention may further comprise additional masonry units (which may or may not be in accordance with the first aspect of the invention) which are not arranged in the columns described above. For instance, the wall may comprise masonry units which extend across both columns (e.g. at an exposed edge of the wall). Equally, walls according to the invention may comprise additional masonry units according to the first aspect of the invention which are arranged in a different manner (i.e. are not part of the plurality of masonry units discussed above).

For instance, the walls may comprise masonry units according to the first aspect of the invention which do not form part of the front or rear column described above. For instance, the stretcher faces of these masonry units according to the first aspect of the invention may not define the front or rear faces of the wall. Instead the bedding faces, header faces, or trailing faces of these masonry units may be aligned with the front or rear faces of the walls. Alternatively, or additionally the wall may comprise further masonry units according to the first aspect of the invention that are arranged such that their legs extend outwards from a centreline of the wall (e.g. where the legs of the masonry units project outwards from a face of the wall).

In preferred embodiments the spacing between the masonry units in the front column and the masonry units in the rear column varies such that the wall thickness varies in accordance with a desired wall profile. Consequently, an increased variety of wall geometries and appearances can be constructed, examples of which will be given below. For instance, ‘parametric walls’ (walls which exhibits a highly controlled and mathematical arrangement of masonry units and wall profile) with a variety of geometric patterns may be constructed. These geometric patterns may be formed using variations in wall profile (i.e. a geometric surface relief may be created) by varying the relative positioning of the masonry units. Alternatively, each masonry unit in a column may be arranged at a substantially random or pseudo-random spacing from the unit in the opposing column to provide a ‘free-form’ or random wall profile or surface relief. Equally, during construction each of the interlocking or adjacent masonry units may be positioned to accommodate variations in the terrain, foundation, underlying courses of bricks or discrepancies in the size and shape of specific individual masonry units. In addition, bricks according to the present invention may be combined with conventional substantially cuboidal bricks and blocks to create a wider variety of wall structures, designs and geometries.

In this manner walls may be created which are plumb or vertical on one side, but exhibit either: traditional corbels (i.e. corbels of specific sizes as shown in the British standards for bricks discussed above); or non-conventional corbels which may be achieved through the infinite variability in relative position of interlocked masonry units according to the present invention (between the minimum constraint of contact between the masonry units, and the maximum constraint wherein the legs of a given masonry unit are no longer received in the recesses of a second masonry unit).

In preferred embodiments the stretcher faces of the masonry units of either the front or rear column are substantially co-planar. As such, at least one side of the wall is provided without a varying surface relief. This may be suitable where a flat wall is desired structurally (e.g. to support objects or equipment) or aesthetically (e.g. to provide rooms with even or flat walls). In other examples both sides of the wall may exhibit a non-planar relief.

Where the masonry units extends in a third direction between a first bedding face and an opposed second bedding face, wherein the third direction is substantially perpendicular to the first and second directions the masonry units of the front column and the rear column may each be arranged in at least one course, such that the bedding faces of the masonry units in each course of the respective column are substantially coplanar. Alternatively, the masonry units may be arranged in a variety of other geometries without strict courses (e.g. solider bonds or herringbone patterns).

Preferably a course of masonry units in the front column and/or the rear column overlaps two courses of the masonry units in the opposing column in a direction substantially parallel to the stretcher faces and substantially perpendicular to bedding faces of the masonry units of the front and rear columns. Consequently, there is no joint extending continuously through the thickness of the wall. This increases the strength of the wall as there is no single failure plane.

In other words, the bedding faces of the masonry units in a given course of the front column may be interlocked with two courses in the rear column (and vice versa). Thus the bedding faces of courses of masonry units in the front and rear columns are offset from one another. The strength increase is maximised where the overlap or offset is approximately half the height of a masonry unit and any binding agent present in the third direction (i.e. a direction normal to the bedding plane). Due to the offset or overlap between the courses of the recesses of the masonry units may accommodate or receive the legs of multiple masonry units in the third direction simultaneously. This does not affect the interlocking between masonry units discussed above which occurs in a plane formed by the first and second directions

In some embodiments of walls, the masonry units define a channel them, wherein the channel extends in a direction substantially parallel to the stretcher faces and substantially perpendicular to bedding faces of the masonry units of the front and rear columns, and wherein preferably the channel extends through a distance which is at least twice the height of the masonry unit in the third direction, more preferably at least three times the height of the masonry unit in the third direction, more preferably still at least five times the height of the masonry unit in the third direction. These continuous channels, which can extend through multiple courses of masonry units, may accommodate reinforcement pins. Alternatively, the masonry units in the wall may be arranged such that no continuous channel is created which extends between multiple courses of masonry units. In which case reinforcement pins may still be provided within the wall and between courses of masonry units by using gaps between adjacent masonry units and/or any perforations extending through the masonry units in the third direction.

These channels are spaces or voids within a wall which are not obstructed by masonry units within the wall, i.e. they are defined by the interface or boundary between adjacent and/or interlocked masonry units. Such channels are typically rectilinear or substantially rectilinear parallel to the third direction, but this is not essential. In preferred embodiments these channels are provided or filled with a binding agent such as mortar but can also receive or accommodate reinforcing pins which extend through the wall to provide increased strength and durability.

These channels may be open channels, such that they extend to the exterior of the wall, or closed such that they are internal within the wall and are enclosed by surrounding masonry units. For instance, where a wall is formed of two columns of masonry units, an open channel may be defined by a spacing or gap between two adjacent masonry units in the same column (e.g. between the header leg(s) and/or trailing leg(s) of adjacent masonry units). Equally, a closed channel may defined between the inner surfaces of interlocked masonry units (e.g. between the main leg of a first masonry unit and the main recess, header leg or main leg of an interlocked second masonry unit). Alternatively, where a channel extends through multiple courses of masonry it may comprise a combination of external and internal channels defined by the arrangement of masonry units in each course.

Preferably the masonry units define a channel between the inner surfaces of the masonry units in the front column and the inner surfaces of the masonry units in the second column.

Furthermore, it will be understood that channels may extend continuously in the third direction (i.e. in the direction of the height of a typical wall) through multiple courses of masonry units in different arrangements. For instance, a channel may extend continuously in the third direction through a first section of wall in which the courses of masonry units are lapped (i.e. offset in the first direction) and a second section of wall which overlies or underlies the first in the third direction in which the masonry units are stack bonded.

As discussed above, in preferred embodiments the wall comprises at least one reinforcement pin which provides the wall with increased strength and these reinforcement pins may, in further embodiments, be provided within the channel extending through the wall.. However, this is not essential. Preferably the length of the at least one reinforcement pin is at least the height of the masonry unit in a third direction which is a substantially perpendicular to the first and second directions, more preferably at least twice the height of the masonry unit in the third direction, more preferably still at least five times the height of the masonry unit in the third direction.

In preferred embodiments of the wall the masonry units of the rear column are lapped, whilst the masonry units of the front column are arranged in a stack bond, or vice versa. As such, the lapped column of masonry units which may be arranged in a stretcher bond secures the stack bonded column of masonry units.

In more detail, each masonry unit of the stack bonded column of masonry units is interlocked with at least one masonry unit in the column of lapped masonry units such that the legs of stack bonded masonry units are accommodated and retained within the recesses of the lapped masonry units (and vice versa). This interlocking, which can be increased through the use of a binding agent and/or interlocking units prevents movement of masonry units in the stack bonded column relative to the lapped masonry units in the opposing column. Thus this embodiment achieves a wall with high strength and a long lifespan which exhibits a stack bond appearance from one side and a lapped appearance (e.g. a stretcher bond) from the other. This cannot be achieved using traditional cuboidal bricks.

In preferred embodiments a plurality of masonry units of the front column are arranged in a stack bond and wherein at least a portion of each of masonry units of the front column arranged in the stack bond is lapped by a masonry unit of the rear column, and/or wherein a plurality of masonry units of the rear column are arranged in a stack bond and wherein at least a portion of each of masonry units of the rear column arranged in the stack bond is lapped by a masonry unit of the front column.

Therefore, advantageously masonry units according to the first aspect of the invention may be constructed in a wall which exhibits a stack bond (possibly on both sides) - where the bricks are arranged in vertical lines with a continuous vertical joint extending between multiple courses of masonry units - without the disadvantages of walls with stack bonds constructed using conventional cuboidal bricks or blocks. Since a portion of each of the masonry units forming the stack bond is overlapped by a masonry unit in the opposing column its movement is restricted. The adjacent stacks or columns of masonry units cannot be easily separated and the wall retains its strength.

Preferably the wall comprises mortar, grout or another binding agent to adhere adjacent masonry units together. Such binding agents (especially mortar) will increase the strength of a wall. In addition binding agents will fill and seal holes or gaps between adjacent masonry units. Preferably the wall comprises cement mortar. However, any other suitable mortar or binding component may also be used. Alternatively, the wall may be constructed without a binding agent.

As is known in the art, mortar, grout and cement are workable aggregate pastes used to bind masonry units together as an adhesive and fill or seal gaps and cavities between them. Once cured mortar, grout or an alternative binding agent form a solid join or bond between masonry units. A wide variety of compositions of both mortar and grout are known and substantially any suitable composition may be used to bind masonry unit of the present invention together. Additionally or alternatively, any further suitable binding agents such as adhesives may also be used.

Mortar is particularly preferred to structurally bind adjacent masonry units together and is typically laid with a thickness of approximately 10 mm. In addition, mortar is visually preferred and provides a good aesthetic appearance. However, if cavities or gaps between masonry units are greater than 20 to 30 mm grout is preferred. For instance, where the inner surfaces of interlocked masonry units are relatively far from one another grout may be applied to fill gaps between the main and trailing recesses and the legs received within the recesses. Alternatively any other suitable binding agent may be used for structural performance or visual appearance (i.e. the appearance or visual effect of exposed or external joints).

The mortar in which the masonry units are laid may be finished (e.g. smoothed) where the joints are exposed. Alternatively, or additionally pointing may be applied to external or exposed joints. This pointing is typically weather resistant and/or sacrificial. The pointing may also provide further visual effects.

In particularly advantageous embodiments the plurality of masonry units are arranged in a front column and a rear column such that the stretcher faces of the masonry units in the front column define a front side of the wall and the stretcher faces of the masonry units in the rear column define a rear side of the wall, wherein the wall comprises an internal cavity between the front column and the rear column, and wherein preferably the wall comprises insulation, concrete, reinforced concrete, grout and/or another material within the internal cavity. Advantageously, such walls offer improved strength and improved thermal properties respectively. Filing the internal cavity with concrete is especially advantageous since when poured the concrete is received with the recesses in each masonry unit and keys or locks the masonry units to the structure, thereby increasing the strength and lifespan of the structure in comparison to structures constructed using traditional bricks or blocks.

In alternative embodiments a wall may comprise a single column of masonry units. For instance the stretcher faces of a plurality of masonry units may be aligned with the length of the wall and define a continuous side of the wall. Such walls are cheaper and quicker to manufacture but can support reduced loads. Equally, the stretcher faces of masonry units can be laid substantially perpendicular to the wall such that adjacent masonry units are interlocked.

In accordance with a further aspect of the invention there is provided a method of building a wall using a plurality of masonry units in accordance with the first aspect of the invention. The masonry units may comprise any of the features discussed above with reference to the first aspect of the invention and their corresponding advantages. Equally, the wall may comprise any of the features of the walls discussed above and the corresponding advantages.

In some examples the method may include the step of arranging the plurality of masonry units in a front column and a rear column such that the stretcher faces of the masonry units in the front column define a front side of the wall and the stretcher faces of the masonry units in the rear column define a rear side of the wall, the legs of the masonry units in the front column extending at least partly into the recesses of the masonry units in the second column, and vice versa.

Preferably the method includes arranging the masonry units such that the spacing between the masonry units in the front column and the masonry units in the rear column varies such that the wall thickness varies in accordance with a desired wall profile.

The variation in spacing between two or more interlocked masonry units is not restricted between a minimum spacing (where the legs of a first masonry unit are fully inserted into the recesses of an interlocking second masonry unit such that they abut the inner surface of the second masonry unit (and vice versa)) and a maximum spacing (where the legs of the first masonry unit are no longer received in the recesses of the interlocking second masonry unit (and vice versa). In other words, there is infinite adjustability in the positioning of interlocked masonry units relative to each other and therefore infinite variation in the width of a course of bricks.

Outside the maximum limit discussed above concrete or grout may be provided between opposing (but not interlocked) masonry units to bind the separate units together. In other words, the cavity between masonry unit columns which are not interlocked - or only partially interlocked - may be filled with concrete, grout or an alternative binding agent with sufficient strength to bind the columns together. This may be especially useful when constructing piers and other structures filled with a binding agent since the interlocking surfaces of a masonry unit will bind strongly to the binding agent used to fill the structure.

In preferred examples the method includes arranging the masonry units such that the stretcher faces of the masonry units of either the front or rear column are arranged to be substantially co-planar.

Advantageously the method comprises building the wall such that the masonry units of the rear column are lapped, whilst the masonry units of the front column are arranged in a stack bond, or vice versa.

Preferably the method comprises building the wall such that a plurality of masonry units of the front column are arranged in a stack bond and wherein at least a portion of each of masonry units of the front column arranged in the stack bond is lapped by a masonry unit of the rear column, and/or wherein a plurality of masonry units of the rear column are arranged in a stack bond and wherein at least a portion of each of masonry units of the rear column arranged in the stack bond is lapped by a masonry unit of the front column.

In further examples the method further comprises applying mortar between adjacent masonry units to bind said adjacent masonry units together. The adjacent masonry units may be adjacent units in the same course (including the units in the same column or the opposing column) or adjacent courses (i.e. the courses above and below any given masonry unit).

Preferably the method comprises the step of:

arranging the plurality of masonry units in a front column and a rear column such that the stretcher faces of the masonry units in the front column define a front side of the wall and the stretcher faces of the masonry units in the rear column define a rear side of the wall, and such that the front column and rear column define an internal cavity between the front column, and wherein preferably the method comprises the further step of providing insulation, concrete reinforced concrete and/or grout within the internal cavity.

BRIEF DESCRIPTION OF DRAWINGS

Figures 1a and 1b respectively show an isometric view and cross section of an embodiment of a masonry unit in accordance with the present invention.

Figures 2a and 2b show cross sections of two alternative interlocking arrangements of a plurality ofthe masonry units shown in Figures 1a and 1b.

Figures 3a and 3b respectively show an isometric view and cross section of a further embodiment of a masonry unit in accordance with the present invention.

Figures 4a and 4b show cross sections of two alternative interlocking arrangements of a plurality of the masonry units shown in Figures 3a and 3b.

Figures 5a to 5h show cross sections of alternative arrangements of a plurality of the masonry units shown in Figures 3a and 3b.

Figures 6a and 6b show cross sections of an embodiment of a wall in accordance with the present invention constructed of the masonry units shown in

Figures 3a and 3b; Figure 6c shows said wall in isometric view.

Figure 7a shows a cross section of an embodiment of a wall in accordance with the present invention constructed of the masonry units shown in Figures 3a and 3b; Figure 7b shows said wall in isometric view.

Figure 8a shows an isometric view of a wall constructed using masonry units according to the present invention; Figure 8b shows an isometric view of this wall from the reverse angle.

Figures 9a and 9b show elevation views of the front and rear of a wall in accordance with the present invention manufactured using the masonry units shown in Figures 3a and 3b; Figure 9c shows three cross sections through said wall.

Figures 10a and 10b show an elevation view and a cross section respectively of a wall in accordance with the present invention.

Figure 11a shows an isometric view of a pier constructed using the masonry units shown in Figures 3a and 3b; Figure 11b shows an isometric view of a pier constructed using the masonry units shown in Figure 3a and 3b incorporated into a wall formed of traditional rectilinear masonry units.

Figure 12 shows isometric views of eight masonry units in accordance with the present invention with alternative surface decorations.

Figure 13 shows a cross section of interlocking arrangements of masonry units of a further embodiment of the present invention.

Figure 14a and 14b show cross sections of two alternative interlocking arrangements of masonry units of a further embodiment of the present invention.

DETAILED DESCRIPTION OF DRAWINGS

Figure 1a shows an isometric view of an embodiment of an ‘F’ shaped masonry unit 100 in accordance with the present invention. Figure 1b shows a cross section through the masonry unit 100 in a plane parallel to its bedding faces 103a and 103b.

Geometrically, the masonry unit shown in Figure 1a is a Tight prism’ - i.e. it is a solid having two substantially identical polygonal bases (bedding faces 103a and 103b) arranged parallel and in register with one another such that the solid extends in a direction (direction z) which is perpendicular to the bases (plane x-y). The cross section of the masonry unit is identical in all planes which are parallel to the bedding faces 103a and 103b.

The masonry unit 100 comprises a cuboidal main body 110 extending in the x direction from a header end 101 of the masonry unit 100 to a trailing end 102 of the masonry unit 100. The extent of the main body is indicated by dashed lines in Figure 1b. The main body 110 comprises opposed outer and inner surfaces 111, 112. The outer surface 111 defines a stretcher face 104 of the masonry unit 100.

From the inner surface 112 of the main body 110 extends a header leg 120 and a main leg 130. The header leg 120 and the main leg 130 extend in the y direction i.e. the header leg 120 and main leg 130 extend in a perpendicular direction from the inner surface 112 of the main body 110.

The header leg 120 extends from the inner surface 112 of the main body 110 at the header end 101 of the masonry unit 100. The header leg 120 and the main leg 130 are spaced from one another in the x direction such that the masonry unit 100 comprises a main recess 140 between the header leg 120 and main leg 130. In addition, the main leg 130 is spaced from the trailing end 102 of the masonry unit. This spacing defines a trailing recess 150 between the main leg

130 and the trailing end 102 of the masonry unit.

In this example the header leg 120 and main leg 130 are substantially cuboidal and of a constant width in the x direction. In addition, the header leg 120 and main leg 130 are of substantially equal length in the y direction.

The header end 101 of the masonry unit and a header face 121 of the header leg 120 are coplanar and together define a header face of the masonry unit 400. The trailing end 102 of the masonry unit defines a trailing face of the masonry unit.

It will be seen that the header face 121 and trailing face 122 of the header leg 120 are parallel to each other and perpendicular to the inner surface 112 of the main body 110. Equally, the header face 131 and trailing face 132 of the main leg 130 are parallel to each other and perpendicular to the inner surface 112 of the main body 110. The distal faces 123, 133 of the header leg 120 and main leg 130 are parallel to the inner surface 112 of the main body 110.

The main recess 140 is substantially the same width as the main leg 130 in the x direction, and substantially twice the width of the header leg 120 in the x direction. The trailing recess 150 is substantially the same width as the header leg 120 in the x direction and substantially half the width of the main leg 130 in the x direction. Equally, the main leg 130 is substantially twice the width of the header leg 120 in the x direction.

By substantially the same width it will be understood that the main recess 140 remains large enough to receive the main leg 130 or two header legs 130 even if this is in an interference fit or friction fit. In practice, the width of the main recess 140 in the second direction is preferably slightly wider than the width of the main leg 130 in the second direction and twice the width of the header leg 120 so that it is easy to mate or interlock two or more identical masonry units 100.

A plurality of the masonry units 100 discussed above may be interlocked in a variety of arrangements. The main recess 140 of the masonry unit 100 is configured (i.e. sized) such that it can receive one main leg 130 of an identical masonry unit 100, or two header legs 120 of a pair of identical masonry units 100 (but not both of these options at the same time). The trailing recess 150 of the masonry unit 100 is configured (i.e. sized) such that it may receive a header leg 120 or half of a main leg 130 of an identical masonry unit 100.

Of particular interest are arrangements where a plurality of masonry units 100 are interlocked or mated in a single course or row which offer bricklayers and masons the ability to construct walls of increased design freedom and strength using a simple masonry unit. In preferred courses of interlocked masonry units 100 the bedding faces 103a, 103b are substantially coplanar. Cross-sections of two of these interlocking arrangements are shown in Figures 2a and 2b.

Figure 2a shows a pair of the masonry units 100a, 100b discussed above with reference to Figure 1 which are mated or interlocked. The masonry units 100a, 100b are opposed and interlocked such that the header leg 120a and main leg 130a of the first masonry unit 100a are respectively received in the trailing recess 150b and main recess 140b of the second masonry unit 100b, and vice versa.

In this example, the masonry units 100a, 100b have been interlocked such that the legs 120a-b, 130a-b of each masonry unit 100a, 100b are fully inserted into the corresponding recesses 140a-b, 150a-b. Specifically, the distal faces 123a, 133a of the first masonry unit 100a abut the inner surface 112 of the second masonry unit 100b and vice versa. However, this is not essential and as explained below, in many cases a spacing will be left between the units 100a, 100b in the y direction such that the legs 120a-b, 130a-b are partially inserted into the corresponding recess.

Consequently, the pair of ‘F’ shaped masonry units 100a, 100b have been combined to form a single rectilinear (i.e. cuboidal) unit. As discussed further below, while the dimensions of this combined rectilinear unit are fixed in the x direction, its dimension in the y direction is variable and dependent on the spacing between the two units 100a, 100b. This single, combined unit may be used in place of traditional rectilinear masonry units (e.g. bricks or concrete blocks) used to construct walls and other structures. As an aside the relative positioning of the masonry units in the z direction may be varied to achieve overlapping between masonry units in adjacent courses or rows of masonry units and to provide further strength (as will be discussed in detail with reference to Figures 8a and 8b).

When arranging the masonry units 100a, 100b in this opposed manner, it will be seen that it is necessary to rotate the second masonry unit 100b by 180° about either the y axis or z axis relative to the first masonry unit 100a. This rotation is easily performed by a mason or bricklayer.

Figure 2b shows an alternative arrangement of ‘F’-shaped masonry units 200a-c, 300a-c that is formed of two opposing, interlocked columns 200, 300 of masonry units 100. As defined, the columns 200, 300 extend in the x direction (the same direction that the main body of each masonry unit 200a-c, 300a-c extends in)

The stretcher faces of the masonry units 200a-c, 300a-c in each column 200, 300 are coplanar. Furthermore, in both columns 200, 300, each masonry unit 200a-c, 300a-c is rotated by 180° about the y axis relative to the respective adjacent (i.e. neighbouring) masonry units 200a-c, 300a-c in the same column. The masonry units 300a-c of the second column 300 are rotated by 180° about either the x or z axes relative to the masonry units 200a-c of the first column 200, such that the masonry units 200a-c, 300a-c of the two columns 200, 300 are opposed.

Furthermore, in comparison to the interlocking effect shown in Figure 2a (where a pair of masonry units 100 are combined to form a single cuboidal unit), in the arrangement shown in Figure 2b the two columns 200, 300 are displaced relative to one another in the x direction.

Hence, it will be seen that: the main leg of masonry unit 200a is received by the trailing leg of masonry unit 300a; the header legs of masonry units 200a and 200b are received by the main recess of masonry unit 300a; the main leg of masonry unit 200b is received by the main recess of masonry unit 300b; the main leg of masonry unit 200c is received by the trailing recesses of masonry units 300b and 300c; the header leg of masonry unit 200c is received in the main recess of masonry unit 300c; and so on.

Equally, it will be seen that: the main leg of masonry unit 300a is received in the main recess of masonry unit 200a; the header legs of masonry units 300a and 300b are received in the main recess of masonry unit 200b; the main leg of masonry unit 300b is received in the trailing recesses of masonry units 200b and 300c; the main leg of masonry unit 300c is received in the main recess of masonry unit 200c; and so on.

As with the arrangement shown in Figure 2a, in Figure 2b the legs of the masonry units 200a-c, 300a-c are fully inserted into the recesses of the masonry units 200a-c, 300a-c in the opposing column 300, 200, such that the distal face of each leg abuts or is adjacent to the inner surface of a masonry unit in the opposing column 300, 200. Again this is not essential and, as discussed below, can be varied in order to produce walls of varying thickness and appearance.

As shown, this interlocking arrangement of ‘F’ shaped masonry units 200, 300 achieves courses of masonry units without vertical joints (interfaces between adjacent masonry units 200, 300) extending through the whole course in the horizontal direction. In other words there are no joints extending continuously in a single direction through the course of masonry units 200, 300 in the y-z plane from a first side of the course 201 to the second side of the course 301. Avoiding such vertical joints can increase the strength of courses, walls and other structures since the structures do not contain a single failure plane.

As will be seen from each of Figures 1 and 2, the masonry units 100, 200, 300 discussed are configured such that the main recess 140 is substantially the same width as the main leg 130 in the first direction across the entire length (i.e. 100% of the length) of the main recess 140 in the second direction, and substantially the same width as twice the width of the header leg 120 in the first direction across the entire length (i.e. 100% of the length) of the main recess 140 in the second direction.

In practice, preferably the width of the main recess 140 is slightly larger than width of the main leg 130 and slightly larger twice the width of the header leg 120 in the first direction. In this case the two or more masonry units 100, 200, 300 may be slid into and out of each other in the second direction so as to interlock them (such that the legs 120, 130 of one masonry unit 100, 200, 300 are received in the recesses 140, 150 of the other, and vice versa).

This ability to slide masonry units 100, 200, 300 together enables easy construction. However, masonry units 100, 200, 300 may additionally be interlocked in a plurality of different positions in the second direction relative to one another. This can be used to create walls and courses of masonry units 100 with variations in surface relief (as will be discussed further below). In other words, the main recess 140 and main leg 130 are configured such that the main leg 130 of an identical masonry unit can be accommodated within the main recess 140 of the masonry unit 100 at a plurality of different positions in the second direction, the spacing between the distal end or distal surface 132 of the main leg 130 of the identical masonry unit 100 and the inner surface of the masonry unit 100 it the second direction being different at each respective position.

While a masonry unit in which the main recess is substantially the same width or greater than the maximum width of the main leg or twice the maximum width of the header leg over 100% of the length of the main recess is preferred, this is not essential. Rather, it is preferred that the components of the masonry unit are configured - i.e. shaped or sized - such that a given masonry unit can be interlocked with a second identical masonry unit in multiple positions relative to one another. In the masonry unitslOO, 200, 300 shown in Figures 1 and 2 the width of the main recess 140 in the first direction is substantially equal to the maximum width of the main leg 130 in the first direction along at least a portion of the length of the main recess 140 in the second direction, the portion being longer than the part of the main leg 140 which has the maximum width.

As discussed above, the ‘F’ shaped masonry units 100, 200, 300 shown in Figures 1 and 2 may be interlocked in multiple arrangements to form strong, stable walls and structures using traditional construction methods. However, further benefits may be achieved using the ‘F’ shaped masonry units shown in Figures 3 and 4. The masonry units 400 of Figures 3 and 4 share the general ‘F’ shaped geometry of the masonry units 100, 200, 300 but comprise a variety of additional features and modification, as will be discussed below.

Figure 3a shows an isometric view of an embodiment of this second ‘F’ shaped masonry unit 400 in accordance with the present invention. Figure 3b shows a cross section through the masonry unit 400 in a plane parallel to its bedding faces 403a and 403b.

Like the masonry units 100, 200, 300 discussed above, the masonry unit 400 shown in Figure 3 is a right prism, such that its cross section is constant in all planes parallel to the bedding faces 403a and 403b. The masonry unit 400 further comprises a cuboidal main body 410 extending in the x direction from a header end 401 of the masonry unit 400 to a trailing end 402 of the masonry unit 400. The extent of the main body is indicated by dashed lines in Figure 3b. The main body 410 comprises opposed outer and inner surfaces 411, 412. The outer surface 411 defines a stretcher face 404 of the masonry unit 400.

From the inner surface 412 of the main body 410 extends a header leg 420 and a main leg 430. The header leg 420 and the main leg 430 extend in the y direction i.e. the header leg 420 and main leg 430 extend in a perpendicular direction from the inner surface 412 of the main body 410.

The header leg 420 extends from the inner surface 412 of the main body 410 at the header end 401 of the masonry unit 400. The header leg 420 and the main leg 430 are spaced from one another in the x direction such that the masonry unit 400 comprises a main recess 440 between the header leg 420 and main leg 430. In addition, the main leg 430 is spaced from the trailing end 402 of the masonry unit. This spacing defines a trailing recess 450 between the main leg 430 and the trailing end 402 of the masonry unit.

The main leg 430 is approximately twice the width of the header leg 420 in the x direction. Whilst the main recess 440 is approximately twice the width of the trailing recess 450 in the x direction.

Unlike the masonry units 100, 200, 300 discussed above with reference to Figures 1 and 2, the header leg 420 and main leg 430 are tapered such that they are wider in the x direction at their distal ends than at their bases.

In the embodiment shown in Figure 3, the trailing face 422 of the header leg 420, the header face 431 of the main leg 430 and the trailing face of the main leg each respectively form an acute angle A of 87.71° with the inner surface 412 of the masonry unit 420. This angle is preferable where the masonry unit 400 is based on the dimensions of the British standard brick. However, this is not essential and in alternative embodiments the trailing face 422 of the header leg 420, the header face 431 of the main leg 430 and the trailing face of the main leg each respectively form an acute angle A of between 80° and 90° with the inner surface 412 of the masonry unit 420.

The header face 421 of the header leg 420 is perpendicular to the inner surface 412 of the main body 410. The distal faces 423, 433 of the header leg 420 and main leg 430 extend in the x direction and are parallel to the inner surface 412 of the main body. The header end 401 of the masonry unit and the header face 421 of the header leg 420 are coplanar and together define a header face of the masonry unit 400. The trailing end 402 of the masonry unit 400 defines a trailing face of the masonry unit 400.

As with the masonry units 100, 200, 300 of Figures 1 and 2, the main recess 450 of the masonry unit 400 shown in Figure 3a and 3b is configured to receive or accommodate a main leg 430 of an identical masonry unit 400 or two header legs 430 of a pair of identical masonry units 400 (but not both of these options at the same time).

However, in this example the minimum width of the main recess 440 in the x direction (which occurs at the mouth or entrance of the main recess 440 due to the taper of the legs 420, 430) is greater than the maximum width of the main leg 430 and greater than twice the maximum width of the header leg 420 (which occurs at the distal end of the respective leg) in the x direction. Equally, the minimum width of the trailing recess 450 is greater than half the maximum width of the main leg 430 and greater than the maximum width of the header leg 420 in the x direction.

As a result, the recesses 440, 450 are configured to receive the legs 420, 430 of an interlocking identical masonry unit and a binding agent such as mortar or grout therebetween. In use this binding agent will fill the cavity between the masonry units 400 caused by the differences in widths of the recesses 440, 430 and legs 420, 430, and will bind or adhere the masonry units 400 together.

In addition, as will be seen from the figures the width of the main recess 440 in the first direction is greater than the maximum width of the main leg 430 in the first direction along the entire length of the main recess 440 in the second direction. Equally, the width of the main recess 440 in the first direction is greater than twice the maximum width of the header leg 420 in the first direction along the entire length of the main recess 440. Consequently, masonry units 400 may be slid together long the second direction such that one or more legs of a first masonry unit 400 are received in a recess of a second masonry unit 400 so as to interlock. In addition, these interlocked masonry units may be positioned at a plurality of different relative positions in the second direction, so that the spacing or distance between the distal face 433 of the main leg of the identical masonry unit and the inner surface 412 of the masonry unit is different at each respective position.

While a masonry unit in which the main recess is substantially greater than the maximum width of the main leg or twice the maximum width of the header leg over the entire length of the main recess is preferred, this is not essential. Rather, it is preferred that the components of the masonry unit are configured i.e. shaped or sized - such that a given masonry unit can be interlocked with a second identical masonry unit in multiple positions relative to one another. Indeed, in the masonry unit 400 shown in Figure 3 the maximum width of the main recess 440 in the first direction is greater than the maximum width of the main leg 430 in the first direction along at least a portion of the length of the main recess 440 in the second direction, the portion being longer than the part of the main leg 440 which has the maximum width.

Additionally, the masonry unit 400 further comprises locking cavities 460 extending into the main body 410, the header leg 420 and the main leg 430. The locking cavities 460 are substantially semi-circular notches or grooves extending through the masonry unit 400 in the z direction between the bedding faces 403a and 403b. When the masonry unit 400 is laid in a binding agent (e.g. mortar or grout), the binding agent will be pushed or squeezed into these locking cavities 460. When the binding agent is cured, the locking cavities 460 and the binding agent received in the locking cavities 460 will together form a mechanical obstruction to the movement ofthe masonry unit 400.

A primary locking cavity 460a extends into each of the trailing face 422 of the header leg and the header face 431 and trailing face 432 of the main leg 430. Smaller locking cavities extend into the distal faces 423, 433 of the header leg 420 and main leg 430, into the trailing face 422 of the header leg, the header face 431 and trailing face 432 of the main leg 430 and the inner surface 412 of the main body 410 in the trailing recess 450. The primary locking cavity 460a is preferably sized to accommodate or partially accommodate a reinforcement pin extending through the recesses 440, 450.

The tapered faces 422, 431, 432 of the header leg 429 and main leg 430, and the locking cavities 460 are examples of how to provide an interlocking surface which in use retains a binding agent such as mortar or grout applied thereto. In the example shown in Figures 3a and 3b these features are used in combination such that trailing face 422 and distal face 423 of the header leg 420, inner surface 412 of the main body 410, and the header face 431, trailing face 432 and distal face 433 of the main leg 430 are all interlocking surfaces. Thus all of the working surfaces of the masonry unit 400 (i.e. all surfaces of the masonry 400 unit which, when the masonry unit 400 is interlocked with at least one identical masonry unit, are adjacent to the interlocked masonry unit and are therefore not externally visible) are interlocking surfaces.

In alternative embodiments tapered faces and locking cavities may be applied separately or in combination to one or more of the surfaces of a masonry unit. Alternatively, or in addition one or more surfaces of a masonry unit may be a keyed surface (i.e. a surface which is roughened, irregular or serrated).

The masonry unit 400 further comprises a series of guide notches 470. These guide notches 470 extend indicate predetermined cutting positions to simplify construction using the masonry unit 400. The guide notches 470 are substantially semi-circular notches extending into the working surfaces of the masonry unit 400 (i.e. the surfaces of the masonry unit 400 which are not externally visible when the masonry 400 is interlocked or mated with an identical masonry unit 400).

The masonry unit 400 may be easily divided approximately in half in the y direction using three guide notches 470a which extend into the trailing face 422 of the header leg 420 and the header face 422 and trailing face 432 of the main leg. The masonry unit 400 may be divided approximately in half in the x direction using a guide notch 470b extending into the inner surface 412 of the main body 410 within the main recess 440. The masonry unit 400 may further be divided approximately into quarters in the x direction using a guide notch 470c located on the inner surface 412 of the main body 410 at substantially the centreline of the main recess 440 and a guide notch 470d extending into the distal face 433 of the main leg 430 at approximately the centreline of the main leg 430.

The masonry unit further comprises four cylindrical perforations 480 extending through the masonry unit in the z direction between the two bedding faces 403a, 403b. These perforations 480 reduce the weight of the masonry unit 400 (thus simplifying handling of the masonry unit 400), reduce the risk that the masonry unit 400 splits or cracks during manufacture and, in use, may receive a binding agent (thereby restricting movement of the masonry unit 400).

Two relatively large perforations 480a are located along the centreline of the main leg 430 of the masonry unit 400. Two smaller perforations 480b are located symmetrically about the centreline of the main leg 430 where the main leg 430 meets the inner surface 412 of the main body 410. It is noted that although it is preferable to provide the main leg with at least one perforation the number and positioning of perforation shown in Figures 3a and 3b are not essential.

Radii are provided to the comers of the masonry unit 400 which are not typically seen in use when the masonry unit 400 is interlocked with an identical masonry unit. Specifically, a radius is provided: between the trailing face 422 of the header leg 420 and the inner surface 412 of the main body 410; between the header face 431 of the main leg 430 and the inner surface 412 of the main body

410; between the trailing face 432 of the main leg 430 and the inner surface 412 of the main body 410; between the distal face 423 and trailing face 422 of the header leg 420; between the distal face 433 and the header face 431 of the main leg 430; and distal face 433 and trailing face 432 of the main leg 430

The smooth, rounded comers created by these radii simplify the manufacture of the masonry unit 400 and reduce the stress concentration reducing the chance that the masonry unit 400 will crack or split at these points.

The masonry unit 400 further comprises a spacer protrusion 490 which extends into the main recess 440 from the inner surface 412 of the main body. This spacer protrusion 490 defines a pre-determined minimum spacing or clearance between the inner surface 412 of the main body 410 and an interlocking masonry unit 412.

An alignment datum 490a is provided at the distal end of the spacer protrusion 490 to aid bricklayers and masons using the masonry units identify the centre of the main recess 440. This alignment datum 490a is formed as a semi-circular notch in the surface of the spacer protrusion 490 and is sized and shaped similarly to the guide notches 470 discussed above.

It should be appreciated that the tapering of the legs 420, 430, the provision of locking cavities 460, guide notches 470, perforations 480, corner radii, spacer protrusion 490 and alignment datum 490a are each preferred features and not essential to the invention. Furthermore, whilst all of these have been presented together in this embodiment, each feature could be deployed separately or in combination with any one or more of the other preferred features since they are not interdependent on one another.

A plurality of the masonry units 400 shown in Figures 3a and 3b may be combined or interlocked in a variety of arrangements in a similar manner to the masonry units 100, 200, 300 shown in Figures 1 and 2. Two exemplary interlocking arrangements which may be formed using these masonry units 400 are shown in Figures 4a and 4b. These arrangements correspond to the arrangements shown in Figures 2a and 2b respectively.

Figure 4a shows a pair of the ‘F’ shaped masonry units 400a, 400b discussed above with reference to Figure 3 which are mated or interlocked. This arrangement of masonry units 400a, 400b is constructed using a similar interlocking pattern and similar techniques as discussed above in reference to Figure 2a.

The masonry units 400a, 400b are opposed and interlocked such that the header leg 420a and main leg 430a of the first masonry unit 400a are respectively received in the trailing recess 450b and main recess 440b of the second masonry unit 400b, and vice versa. Together, the masonry units 400a, 400b form a single combined unit.

As shown, the masonry units 400a, 400b are interlocked such that the distal face 433 of the main leg 430 of the first masonry unit 400a abuts the spacer protrusion 490 of the second masonry unit 490, and vice versa.

A cavity 400c exists between the masonry units 400a, 400b which will receive mortar, grout or an alternative binding agent in use (not shown). As discussed with reference to Figures 3a and 3b, the minimum width of the cavity in the y direction is defined by the size of the spacer protrusion 490 of each masonry unit 400b, 400c. The width of the cavities in the x direction are defined by the difference in width between the recesses 440, 450 and the legs 420, 430 of the masonry units 400a, 400b and the relative positions of the masonry units 400a, 400b. However, in alternative examples of a masonry unit a spacer protrusion may be provided to at least one of the trailing or header faces of the legs 420, 430 so as to define a desired spacing between masonry units in the x direction.

Figure 4b shows an alternative arrangement of ‘F’-shaped masonry units 500ab, 600a-b that is formed of two opposing, interlocked columns 500, 600 of masonry units 100. As shown, the columns 500, 600 extend in the x direction (the same direction that the main body of each masonry unit 500a-b, 600a-b extends in).

As will be seen, this arrangement of masonry units 500a-b, 600a-b is constructed using a similar interlocking pattern and similar techniques as discussed above in reference to Figure 2b.

In a similar fashion to Figure 4a, the masonry units 500a-b, 600a-b are interlocked such that the distal face each the main leg of each of the masonry units 500a-b in the first column 500 abuts the spacer protrusion 490 of the respective masonry unit 600a-b in the second column 600 in which it is received, and vice versa.

As such, a cavity 700 exists between the masonry units 500a-b, 600a-b which will receive mortar, grout or an alternative binding agent in use (not shown). In line with the arrangement of Figure 4a, the minimum width of the cavity in the y direction is defined by the size of the spacer protrusion 490 of each masonry unit 500a-b, 600a-b. The width of the cavity in the x direction is defined by the difference in width between the recesses 440, 450 and the legs 420, 430 of the masonry units 500a-b, 600a-b.

Despite the discussion provided above, the masonry units 400 need not be “fully interlocked” such that the main leg of a first masonry unit 400 abuts the main body or spacer protrusion (if present) of a second masonry unit 400. Instead, two or more masonry units 400 may be interlocked at substantially any distance from one other so long as the legs of one masonry unit are at least partially received in the recesses of another (i.e. the masonry units may be placed at an infinite number of locations relative to one another in the y direction defined in Figures 3 and 4).

For instance, Figures 5a to 5g show seven modifications of the interlocking pattern of masonry units 400a, 400b shown in Figure 4a with regular gradually increasing separation between the masonry units.

Each of these figures show a pair of opposed masonry units 400a, 400b which are interlocked such that the header leg 420a and main leg 430a of the first masonry unit 400a are respectively received in the trailing recess 450b and main recess 440b of the second masonry unit 400b, and vice versa. In each case, the masonry units 400a, 400b form a single combined unit.

Figure 5a is a reproduction of Figure 4a, wherein the distal face 433 of the main leg 440 of the first masonry unit 400a abuts the spacer protrusion 490 of the second masonry unit, and vice versa.

In contrast, in Figure 5b the masonry units are separated from one another in the y direction such that the main leg 440 of the first masonry unit 400a no longer abuts the spacer protrusion 490 of the second masonry unit, and vice versa. This separation between the masonry units 400a, 400b in the y direction is increased with each subsequent figure until Figure 5g, wherein only a very small portion of the legs of the first masonry unit 400a are received by the recesses of the second masonry unit 400b, and vice versa.

As a comparison, Figure 5h shows a pair of masonry units 400a, 400b which are not interlocked (i.e. the legs of the opposing masonry units are not overlapped in the y direction). In this figure the masonry units are separated in the y direction by a sufficient distance that the legs of the first masonry unit 400a are no longer received by the recesses of the second masonry unit 400b, and vice versa.

Despite the increasing size of the cavity between masonry units 400a, 400b in Figures 5a to 5g, the combined unit retains significant strength due to the interlocking between the opposing masonry units 400a, 400b. Therefore walls of high strength may be created using masonry units interlocked in this manner. Having said this, masonry units which are not interlocked (such as the masonry units 400a, 400b shown in Figure 5h) may still be used in some examples of walls, especially where the wall comprises further masonry units interlocked as shown in Figures 5a to 5g. For example, in some embodiments the wall could include some regions in which the legs of the front and rear units do not interlock (as in Figure 5h) in addition to other regions in which the legs of the front and rear units do interlock (as in any of Figures 5a to 5g).

As will be appreciated from Figures 5a to 5g the main recess and main leg of the opposed masonry units 400a, 400b are configured such that the main leg of an identical masonry unit can be accommodated within the main recess of the masonry unit at a plurality of different positions in the second direction, the spacing between the distal end or distal surface of the main leg of the identical masonry unit and the inner surface of the masonry unit in the second direction being different at each respective position.

In addition, although Figures 5a to 5h show variations of two masonry units 400a, 400b interlocked in the manner shown in Figure 4a (such that the main recess of each masonry unit receives the main leg of an opposed masonry unit), it will be appreciated that similar variations in the relative position of masonry units may be achieved where the masonry units are interlocked in the pattern shown in Figure 4b (where the main recess of each masonry unit receives either the main leg of an opposed masonry unit or the header legs of two opposed masonry units).

An example of a wall 700 constructed using these techniques is shown in cross section in Figure 6a, a portion of this figure (as indicated by a circle in the figure) is shown in greater detail in Figure 6b. The wall 700 is further shown in isometric view in Figure 6c.

The wall 700 is provided with a surface relief on a first side 710 of the wall 700. Specifically the first side 710 of the wall 700 comprises a series of corbels 700a formed by masonry units 400 projecting from the wall 700 in the shape of a rhombus. The second side of the wall 720 does not have a surface relief. This has technical advantages when forming the inner surface to a wall cavity or the interior face of a building wall.

For simplicity no binding agent (e.g. mortar or grout) is shown between the masonry units 400 in these figures. However, it is preferred to add binding agent in practice.

The wall 700 is formed of multiple courses 730 of identical masonry units 400. The masonry units are arranged in two columns 740, 750 such that each masonry unit 400 in the first column 740 is interlocked with a single corresponding masonry unit 400 in the second column 750. In other words, the masonry units are interlocked using the pattern shown in Figures 2a and 4a.

The wall 700 exhibits a half lap bond, whereby each course 730 of masonry units 400 is offset from the course 730 of masonry units 400 above and below it in the x direction (i.e. along the length of the wall 700) by a distance equal to half the length of a masonry unit 400 in the x direction plus the width of the separation between adjacent bricks in the x direction (e.g. the width of a mortar or grout joint, where present).

The corbels 700a (i.e. the surface relief) are formed using the techniques discussed above with relation to Figures 5a to 5g. The separation between the masonry units 400 in the y direction (i.e. in a direction through the wall 700) is varied by changing the positions masonry units 400 of the first column 740 in accordance with the desired surface relief.

Despite these variations in surface relief the wall 700 is still able to resist high loads and retains a high level of structural strength since each of the masonry units 400 of the first column 740 are rigidly interlocked with a masonry unit 400 in the second column 750. This second column is arranged vertically in a similar manner to traditional rectilinear brickwork and masonry and retains high strength. This is because since the masonry units 400 in each course 730 are directly overlaid the masonry units 400 in the courses above.

In each of the walls 600, 700 shown in Figures 6 and 7 and discussed above reinforcement may be provided between the opposing columns 740, 750 & 840,

850 in the z direction (i.e. substantially vertically) which extends over multiple courses 630, 730 of masonry units. This reinforcement may tie the adjacent courses 630, 730 of masonry units together, preventing movement of masonry units relative to the masonry units above and below.

A further example of a wall 800 having a surface relief which constructed using the masonry units 400 and techniques discussed above is shown in Figures 7a and 7b. Figure 7a shows a plan view of a course of masonry units 400 within the wall, whereas Figure 7b shows an isometric view of the wall 800. As with Figures 6a and 6b, no binding agent is shown in these figures for simplicity. However, it is preferred to use binding agent between masonry units 400 in practice.

The wall 800 is formed of two opposed columns 840, 850 of masonry units 400 which are interlocked in the manner shown in Figures 2b and 4b. As such, each masonry unit 400 is rotated by 180° about the y direction (an axis perpendicular to the length and height of the wall) relative to the two adjacent masonry units 400 in the same column 840, 850 and course 830 (i.e. the masonry units 400 adjacent in the x direction).

The first side 810 of the wall 800 exhibits a repeating “saw-tooth” surface relief. As shown, the separation between the masonry units 400 in the first and second columns 840, 850 is decreased in steps along the length of the wall 800 from a relatively large separation at the start of the wall (the left of Figures 7a and 7b) is gradually decreased until the legs of the masonry units 400 in the first column 840 abut the spacer protrusion 490 of the masonry units 400 in the second column, at which point the separation is increased to the original separation and the pattern repeated along the wall. The second side 820 of the wall 800 does not exhibit variations in surface relief as all of the stretcher faces 411 of the masonry units in the second column 850 are coplanar.

Unlike the wall 700 shown in Figures 6a and 6b, the wall 800 shown in Figures

7a and 7b is stack bonded, such that there is no offset between courses 830 of masonry units 400 and each masonry unit 400 is positioned directly above a corresponding masonry unit 400 in the underlying course 830.

A wall with these surface reliefs and bond could not be safely constructed using traditional rectilinear bricks without further reinforcement. However, the interlocking between the masonry units 400 in the two columns 840, 850 provides increased strength to the wall 800 shown in Figures 7a and 7b.

In the embodiments of walls 700, 800 discussed above cavities are left between the masonry units 400 of the first column 740, 840 and second column 750, 850. These cavities are particularly large where the separation between the masonry units 400 of the two columns is large. These cavities may be filled with a binding agent (e.g. mortar, grout, cement, adhesive), concrete or reinforced concrete (which can provide increased strength to the wall 700, 800), insulation, or any other suitable filling material.

It will be appreciated that the walls 700, 800 are simple examples of the surface reliefs which may be achieved using masonry units 400 according to the present invention. A wide variety of alternative surface reliefs and patterns (including random or pseudo-random patterns) may be created using the masonry units 400 of the present invention without sacrificing the structural performance of a wall. In some preferred examples a wall may comprise surface reliefs on either or both of its surfaces.

In addition, further reinforcement such as reinforcement members may be provided to the walls 700, 800 shown in Figures 6 and 7. For instance, substantially vertical pins or rods (i.e. pins or rods extending in the z direction) which extend through multiple courses of masonry units may be placed within cavities between the masonry units 400 and/or columns of masonry units 400. Alternatively, these reinforcement members may be located such that they extend through a perforation in at least one masonry units 400 (for instance, through the perforations 480 which extend between the bedding faces 403a, 403b of the masonry unit shown in Figures 3 and 4).

In the embodiment discussed above the masonry units 400 of opposing columns in a given course have had coplanar bedding faces 403a & 403b. Figures 8a and 8b show a section of a wall in a further embodiment where this is not the case. Instead, in Figures 8a and 8b the courses of masonry units in each column are offset in the z direction (in the direction of the height of the wall). This provides increased structural strength and increase resistance to lateral loads (e.g. wind loading).

Figure 8a shows an isometric view of a wall section constructed using two types of interlocked ‘F’ shaped masonry units 900a and 900b. Figure 8b shows an isometric view of the same wall section from the reverse angle. No binding agent is shown in these figures for simplicity. In addition, detail of the radii and edges on the working faces of the masonry unit (e.g. the inner surface of the main body, the header face, trailing face and distal end of the main leg and the distal end and trailing face of the header leg) has been omitted for clarity.

The two types of masonry unit 900a, 900b have identical cross sections. However, the nominal height of the first type of masonry unit 900a in the z direction (i.e. the height of the masonry unit 900a including an adjacent binding agent joint) is approximately twice the nominal height of the second type of masonry unit 900b in the z direction.

The wall section comprises two opposed columns 1000, 1100 of interlocked masonry units 900a, 900b. The bases 1001, 1101 of each column 1000, 1100 (i.e. the lower bedding faces of the lowest course of masonry units in the z direction) are coplanar.

The first column 1000 comprises two courses 1000a, 1000b of masonry units, each of which is formed of a plurality of the taller first type of masonry units 900a. The bedding faces of the masonry units 900a in each course 1000a, 1000b are coplanar.

The second column 1100 comprises three courses 1100a, 1100b, 1100c of masonry units 900a, 900b. The lowest course 1100a in the z direction comprises a plurality of the shorter second type of second masonry units 900b. The two overlying courses 1100b, 1100c are each constructed using plurality of the taller first type of masonry unit 900a. Again, the bedding faces of the masonry units 900a, 900b within each course 1100a, 1100b, 1100c are again coplanar.

Since the masonry units of the lowest course 1100a of the second column 1100 is a row of the half-height second type of masonry units 900b, the masonry units of the overlying courses 1100b, 1100c are not coplanar with the courses 1000a, 1000b of the first column 1000 . Instead, they are offset by half of the height of the first type of masonry unit 900a in the z direction. Each of the courses 1000a, 1000b of the first column 1000 overlap two courses 1100a, 1100b & 1100b, 1100c (respectively) in the second column 1100 in the z direction (a direction substantially parallel to the stretcher faces and substantially perpendicular to the bedding faces of all of the masonry units 900a, 900b). Equally the middle course 1100b of the second column 1100 overlaps both courses 1000a, 1000b of the first column 1000 in the z direction.

As will be seen from the figures, the legs of the masonry units 900a in the second course 1100a of the second column are received by the recesses of the first and second courses 1000a, 1000b of the first column 1000. Equally, the legs of the masonry units 900a in the second course 1000a of the first column are received by the recesses of the first and second courses 1100a, 1100b of the second column 1100.

Such an offset or overlapping arrangement of interlocking masonry units 900a, 900b is advantageous because the wall section shown in Figures 8a and 8b has no joints extending continuously through the wall from the first side 1001 of the wall section to the second side 1101. This has the effect of locking adjacent courses 1000a-b, 1100a-c of masonry units 900a, 900b together and avoids a single failure plane through the wall. This provides the wall with increased rigidity and strength.

It should be noted that substantially any overlap between the masonry units 900a in the opposing (i.e. any offset greater than the thickness of binding agent between the adjacent courses 1000a-b, 1100a-c) will achieve this benefit. However, the greatest increases of strength are achieved when the masonry units 900a are offset by approximately half of the combined height of a masonry unit and binding agent (if present) in the z direction.

In other words, due to the offset between the courses 1000a-b, 1100a-c of masonry units 900a, the recesses of the masonry units 900a, 900b may accommodate or receive the legs of masonry units 900a, 900b in multiple courses 1000a-b, 1100a-c. In effect the recesses of the masonry units 900a, 900b accommodate the legs of multiple masonry units in the z direction.

Having said this, it will be recognised that any cross section through a x-y plane will reveal a pattern or arrangement which is similar to those shown in Figures 1b and 3b. In effect, although masonry units 900a, 900b in these figures receive or mate with a plurality of masonry units in the z direction, the main recess of each masonry unit 900a, 900b is configured such that in the x direction it may alternately (i.e. either, but not at the same time) accommodate one main leg of an identical masonry unit; and (ii) accommodate two header legs of two respective identical masonry units.

As an additional point, it will be seen that the wall section of Figures 8a and 8b exhibits different bonds from each side (which is optional). The first column 1000 of masonry units 900a is arranged in a stack bond, such that at the first face of the wall 1002 joints extend continuously in the z direction (i.e. the direction of the height of the wall section) through multiple courses of masonry units 900a. This is formed since each masonry unit 900a is positioned directly above or below a corresponding masonry unit 900a with the same orientation (i.e. the masonry units 900a are not rotated relative to one another) in the underlying or overlying courses. In contrast, the second column 1100 of masonry units 900a, 900b is arranged in a stretcher bond with a 1/3 lap between courses, such that each course of masonry units 900a, 900b is offset from the underlying course of masonry units in the y direction by a distance which is approximately a third of the length of the masonry units 900a, 900b.

A wall or wall section which exhibits different bonds from each side cannot be easily or cheaply constructed using traditional masonry units. It will be appreciated that a wide variety of alternative bonding patterns may be constructed using the two types of masonry units 900a, 900b discussed above depending on design, aesthetic or structural reasons.

In more detail, although the cross sections of the masonry units 900, 900a shown in Figures 8a and 8b are similar to the cross section of the masonry unit 400 discussed above with reference to Figures 3 they are not identical.

Like the masonry units 400 of Figure 3, the masonry units 900, 900a of Figures 8a and 8b comprise a main body extending in the x direction and a header leg and main leg extending from the main body in the y direction. However, the main and header legs of masonry units 900 and 900a are shorter in the y direction relative to the width of the main body in the y direction than is the case in the masonry units 400 described previous.

Specifically, it will be seen that the cross section of the masonry units 900a, 900b of Figure 8 is substantially identical to the cross section of the masonry units 400 of Figure 3 except that the header and main legs are truncated. The truncation is at a distance halfway along the legs in the y direction. Therefore, the header and main legs of the masonry units 900a, 900b of Figure 8 are approximately half the length in the y direction of the header leg 240 and main leg 340 of the masonry unit of Figure 3. This truncation or shortening may be achieved during manufacture (e.g. by use of a different mold or die) or after manufacture (e.g. by splitting the ends of the main and trailing legs 420, 430 from masonry unit 400).

Figure 9a and 9b show front and rear elevation views of another embodiment of a wall 1200 formed of two interlocked columns 1240, 1250 of the masonry units

400 shown in Figure 3.

The wall comprises a plurality of courses 1230 of ‘F’ shaped masonry units 400, wherein the bedding faces 403a, 403b of the masonry units 400 in each course 1230 are coplanar.

The front face 1210 of the wall 1200 (as seen in Figure 9a) and the rear face 1220 of the wall 1200 (as shown in Figure 9b) both exhibit a stack bond. In this stack bond substantially vertical joints extend continuously in the z direction up and down the each face 1210, 1220 of the wall 1200.

Walls constructed in stack bonds using traditional rectilinear masonry units are relatively weak since continuous vertical joints extend through the wall, meaning that individual stacks of masonry units may be easily separated. In contrast, the wall 1200 shown in Figures 9a and 9b is significantly stronger due to its interlocked internal structure. This interlocking may be seen in Figure 9C which shows cross sections in an x-y plane through three successive courses 1230a, 1230b, 1230c.

Each course 1230 is interlocked in the manner shown in Figure 4b, such that the main recess of any given masonry unit receives either the main leg of a single masonry unit 400 in the opposing column 1240, 1250, or two header legs of two masonry units 400 in the opposing column. Therefore the masonry units 400 within each course 1230 are restricted from moving relative to one another.

The stack bond exhibited by both sides of the wall 1200 is formed since the extent of each masonry unit 400 in the x direction (along the length of the wall 1200) is substantially identical to the extent of corresponding masonry units 400 in the overlying and underlying courses 1230 of the same column 1240, 1250. However, unlike in the stack bonded column 1000 of masonry units 900a shown in Figures 8a and 8b (where each masonry unit has the same orientation and has not been rotated relative to the underlying and overlying masonry units) in the wall 1200 of Figure 9 each masonry unit 400 is rotated by 180° about the y axis (the direction of the width of the wall or through the wall) relative to the corresponding masonry units 400 in the courses 1230 adjacent directly above and below it in the same column 1240, 1250.

As an aside, it is noted that this arrangement is simple for a mason or bricklayer to create. After laying a course 1230 of interlocked masonry units 400 as shown in Figure 4b they may create a subsequent course 1230 by laying a further masonry unit 400 to overlie over each of the masonry units 400 in the original course 1230 such that: the stretcher face 405 of the overlying masonry unit 400 is substantially coplanar with the stretcher face 405 of the original masonry unit 400; the trailing end of the overlying masonry unit 400 is substantially coplanar with the header end of the original masonry unit 400; and the header face of the overlying masonry unit 400 is substantially coplanar with the trailing face of the original masonry unit 400.

The increased strength of wall 1200 is caused by this rotation or flipping of the orientation of the masonry units 400 between adjacent courses 1230 since masonry units 400 in the first column 1240 overlap and retain masonry units 400 in the second column 1250 (and vice versa). This will now be discussed with reference to lines A-A and B-B which are substantially vertical lines in the y-z plane through three adjacent courses 1230a, 1230b, and 1230c.

Starting with line A-A, it will be seen that the lowest course 1230a in the z direction comprises a masonry unit 400d in the second column 1250. The main leg of this masonry unit 400d is partially overlapped by the main leg of a masonry unit 400e in the first column 1240 of the directly overlying second course 1230b. Equally, the main leg of this masonry unit 400e in the second column 1250 and second course 1230b is partially overlapped by the main leg of a masonry unit 400f in the third course 1230c and first column 1240. The overlapping of the legs means that forces (such the weight of the overlying masonry units 400) are transmitted down through the wall 1200 in the z direction. As a result, the masonry units 400 in the wall 1200 are restricted from moving relative to masonry units 400 in the overlying and underlying courses

1230.

Equally, considering line B-B it will be seen that the main leg of a masonry unit 400g in the first column 1240 and first course 1230a is partially overlapped by the header legs of masonry units 400i and 400h in the second column 1250 and directly overlaying second course 1230b. In turn, the header legs of these masonry units 400i and 400h in the second column 1250 and second course 1230b are overlapped by the main leg of a masonry unit 400j in the opposing first column 1240 and in the overlying third course 1230c.

As will be seen from the figures, these patterns are repeated throughout the wall 1200. The legs of any given masonry unit 400 in wall 1200 are overlapped and secured by the legs of masonry units in the directly overlying course and opposing column. In effect the masonry units 400 of the opposing columns 1240, 1250 are interleaved or interdigitated in the z direction. The overlapping between masonry units 400 in the opposing columns 1240, 1250 and overlying courses 1230 restricts movement of a masonry unit 400 relative to overlying and underlying masonry units 400.

The combination of interlocking between masonry units 400 in each course 1230 (which restricts movement of each masonry unit 400 relative to the other masonry units 400 in the same course 1230) and the overlapping of masonry units 400 in opposing columns 1240, 1250 (which restricts movement of each masonry unit 400 relative to overlying and underlying courses 1230 of masonry units 400) results in a wall 1200 which is able to withstand high stresses and has high structural strength despite exhibiting a stack bond from each face 1210, 1220.

In addition, this arrangement of masonry units 400 (i.e. the bonding pattern) defines a plurality of continuous closed (i.e. internal) channels 1260 extending through the wall 1200 and across multiple courses of masonry units 400. Such closed channels 1260 are most easily seen when considering line C-C. As will be observed the internal channel 1260, which is not visible from the exterior of the wall 1200, extends in the z direction (i.e. vertically) between the opposed inner surfaces of the masonry units 400 in the first and second columns 1240, 1250 and between the interdigitated (i.e. interlocked) legs of the masonry units 400.

Furthermore, the wall 1200 also exhibits open (i.e. external) channels 1270 between the header legs of adjacent masonry units 400. These open channels extend between the masonry units 400 to the external front and rear faces 1210 and 1220 of the wall. However, as will be seen when comparing the courses 1230a, 1230b, 1230c shown in Figure 9c, in this arrangement the open channels 1270 do not extend through multiple courses of the wall 1200 across their entire width in the y direction.

As will be appreciated, these channels 1260, 1270 are substantially rectilinear. Additionally, in further embodiments of walls these channels 1260, 1270 may be provided with reinforcement (e.g. using reinforcement pins such as steel rebar, or pins made of an alternative material). However, these features are not essential.

The wall section 1300 also includes a pier formed from bats 900d (i.e. sections of the larger masonry unit 900a) which may be easily formed by a mason or bricklayer splitting the masonry units 900a into smaller portions. This pier provides lateral support for the wall section 1300, thereby increasing the strength and lifespan of the wall section 1300.

In the examples discussed above each wall or wall section has comprised two columns of interlocked masonry units. However, this is not essential and Figures 10a and 10b show an elevation view of the front face 1310 and cross section of a wall 1300 formed using a single column of masonry units 900a. No binding agent is shown in this figure for simplicity. However, a binding agent such as mortar, grout or cement would be preferred in practice.

The wall 1300 is formed of a mix of: half lapped stretcher bond, where the respective bedding faces of each masonry unit in a given course are coplanar and where the masonry units in each course are offset from the underlying and overlying masonry units in the x direction by half the nominal width of a masonry unit in the x direction (along the length of the wall); and soldier bond, where masonry units 900a are laid such that their bedding faces are parallel to the z direction or height of the wall such that (as shown) the bedding faces are substantially vertical.

The masonry units 900a are identical in cross section and share the features of the taller masonry units 900a discussed above with reference to Figure 8. These masonry units 900a are similar to the masonry units 400 of Figure 3, except that they have shorter legs relative the width of the main body.

Despite being formed of a single column of masonry units 900a, the wall 1300 remains structurally stable. This is in part since the legs of the masonry units 900a in the portion of the wall arranged as a stretcher bond (shown in the cross section of Figure 10b) extend away from the front face 1310 of the wall. This moves the centre of gravity of the wall further from the front face 1320 of the wall (formed by the coplanar stretcher faces of the masonry units 900a), thereby increasing stability. Furthermore, the legs of masonry units 900a arranged in the stretcher bond are partially overlapped, such that the legs of the masonry units 900a in the higher courses partially overlap the legs of the underling masonry units 900a. This overlapping transmits forces through the wall in the z direction (i.e. vertically) and restricting movement of masonry units 900a relative to masonry units 900a in underlying and overlying courses.

In addition, it will be seen that the half lapped stretcher bond results in provides continuous channels 1320 in the z direction (i.e. continuous substantially vertical channels 1320 between the legs of the masonry units 900a). Such vertical channels 1320 may be created between the legs of a column of masonry units

900a arranged in both half lapped and third lapped stretcher bonds.

The wall 1300 is provided with reinforcement pins 1330 extending in the z direction (i.e. vertically in the direction of the height of the wall) within the channels. The reinforcement pins 1330 restrict movement of the masonry units 900a relative to one another. Therefore, individual masonry units 900a are retained in the wall 1300 and the wall 1300 has increased strength. The reinforcement pins 1330 are formed of steel. However, any suitable material (e.g. metal, alloys, composites) may be used. In addition, the increase in the increase in strength of a wall 1300 may be further increased where masonry units 900a and reinforcement pins 1330 are laid in a binding agent such as mortar or grout (not shown) which adheres or binds them together. As shown, the reinforcement pins 1330 are provided in alternate channels 1320 (i.e. in every other channel 1320). However, in further embodiments reinforcing pins 1330 may be provided at other intervals (e.g. in every channel 1320, in every third channel 1320, in every fourth channel 1320, etc.).

Figures 11a and 11b show further examples of structures constructed using single columns of masonry units.

Figure 11a shows an isometric view of a free standing or isolated pier 1300 (a pillar of brickwork or masonry) constructed using a plurality of identical masonry units 400 as shown in Figure 3. Again, this figure does not show any binding agent for simplicity, but in preferred embodiments a binding agent would be used.

The pier 1300, which has a cuboidal shape, is formed of a plurality of courses 1310 of masonry units 400. In each course four masonry units 400 are laid in a ring such that the stretcher face of each masonry unit 400 is coplanar and adjacent to the header face of an adjacent masonry unit 400 in the same course. It will be seen that the pier exhibits a half lapped stretcher bond. In effect, the arrangement of masonry units in each course is rotated by 180° about any of the x, y or z axes relative to the arrangement of the directly overlying and underlying courses 1310.

As shown the width of the header leg of the masonry unit 400 is approximately equal to the width of the main body the masonry unit 400 such that there is not a significant variation in wall thickness at the joint between masonry units 400. This avoids any regions which are significantly weaker than other units. The nominal length of the stretcher face (i.e. the length of the stretcher face accounting for the width of joints between masonry units 400) is approximately twice the nominal length of the header face of each masonry unit 400.

The pier 1300 is hollow, having an internal cavity 1320. This internal cavity 1320 may be filed with (for instance) mortar, cement, grout, concrete, reinforced concrete, insulation or any other suitable material. Where the internal cavity 1320 is filled with a binding agent such as mortar, cement, grout, concrete or reinforced concrete the interlocking surfaces of the masonry units 400 will engage and retain the binding agent. This will result in a pier 1300 of increased strength relative to hollow piers constructed using conventional rectilinear masonry units which do not comprise the interlocking surfaces discussed herein. Preferably the internal cavity 1320 is filled in a single step (e.g. a single pour of concrete) ensure homogeneity throughout the internal cavity 1320.

The cavity may be provided with reinforcement pins (not shown) extending past two or more courses of masonry units in the z direction. These reinforcing pins may be located in channels formed between the legs of the masonry units 400 as discussed above with reference to Figure 10b.

Figure 11b shows an isometric view of a similar pier 1400 formed of masonry units 400 in accordance with the present invention which has been incorporated into a wall 1450 of traditional rectilinear masonry units 1455. This combination of traditional masonry rectilinear masonry units 1455 and the masonry units 400 according to the present invention is simple since both types of masonry units 400, 1455 have the same external dimensions - i.e. the working dimensions of the stretcher face and header face of both types of masonry unit 400, 1455 are identical.

It will be seen that the pier 1400 itself shares many of the features and advantages ofthe pier shown in Figure 11a.

Figure 12 shows eight masonry units 1501 to 1508 with a variety of surface decorations on their stretcher faces. All of these masonry units 1501 to 1508 have similar cross sections to the masonry unit of Figure 3. The nominal height (i.e. dimension in the z direction as shown in Figure 3) of the first three masonry units 1501 to 1503 is half the nominal height of the remaining masonry units 1504 to 1508.

The surface decorations applied to the stretcher faces (i.e. finished faces) of the masonry units 1501 to 1508 include variations in colour, texture, surface relief and surface coating or any other property. These variations may be applied to the surface of the masonry unit using any suitable technique including extrusion, pressing, embossing or 3D printing. Alternatively, these variations could be created by variations in materials or coatings of the masonry unit.

In further embodiments such surface decorations or finishes may be applied to any face of a masonry unit according to the present invention. However, it is preferred to apply these finishes to surfaces that will be visible when the masonry units are in use within a wall. As such, surface decorations or finishes are typically applied to one or more of the header face, stretcher face or trailing face of a masonry unit, rather than the “working surfaces” which are not typically visible in use (i.e. the bedding faces, the distal ends or side faces of the legs or the inner surface ofthe main body).

The figures discussed above have focused on ‘F’ shaped masonry units. That is masonry units with two legs. However, the teachings of the present invention may be extended to masonry units with substantially any number of legs. Two examples of such masonry units will now be discussed with reference to Figures and 14.

Figure 13 shows an Έ’ shaped masonry unit 1600 with three legs 1620, 1630, 1660 separated by two recesses 1640, 1650.

In more detail, the masonry unit 1600 comprises a cuboidal main body 1610 extending in the x direction from a header end 1601 of the masonry unit 1600 to a trailing end 102 of the masonry unit 1600. The extent of the main body 1610 is indicated by dashed lines in the figure. The main body 110 comprises opposed outer and inner surfaces 1611, 1612.

From the inner surface 112 of the main body 110 extend a header leg 1620, a main leg 1630 and a trailing leg 1660. The header leg 1620 and main leg 1630 are spaced from one another in the x direction by a main recess 1640, whereas the main leg 1630 and the trailing leg are spaced in the x direction by a trailing recess 1660. The trailing recess 1660 is “closed” in that it is bounded by legs on both sides in the x direction.

The outer surface 1611 defines a stretcher face of the masonry unit 1600. The header end 1601 of the masonry unit and the header leg 1620 together define a header face of the masonry unit 1600. The trailing end 1602 and the trailing leg 1660 together define a trailing face of the masonry unit 1600.

The header leg 1620, main leg 1630 and main recess 1640 share the features, relative dimensions and advantages of the corresponding header leg 420, main leg 430 and main recess 440 of the masonry unit shown in Figure 3. These include: that the header leg 1620 and main leg 1630 are tapered and comprise locking cavities extending into the respective legs 1620, 1630; that the header leg 1620, main leg 1630 and main recess 1640 comprise guide notches; that the main leg comprises a plurality of perforations extending through the masonry unit 1600 in the z direction; that corner radii have been provided to intersections of working faces; and a spacer protrusion with alignment datum is provided to the inner surface 1602 of the masonry unit 1600 in the main recess 1640.

Having said this, it will be appreciated that in further embodiments each of these features may be provided separately or in combination with any one or more of the other preferred features since they are not interdependent on one another.

Unlike the masonry unit 400 shown in Figure 3, it will be seen that the masonry unit 1600 is symmetric about an axis extending in the y direction through the centreline of the main leg 1630. As such, the trailing leg 1660 comprises all of the features of the header leg 1620 and the closed trailing recess 1650 comprises all of the features of the main recess 1640.

The width of the main recess 1640 and trailing recess 1650 in the x direction is greater than the maximum width of the main leg 1630 in the x direction. Furthermore, the width of the main recess 1640 and trailing recess 1650 in the x direction is greater than twice the maximum width of the header leg 1620 and the trailing leg 1660 in in the x direction. Equally, the main leg 1630 is substantially twice the width of the header leg 1620 and the trailing leg 1660 in the x direction.

Therefore, the main recess 1640 and trailing recess 1660 are configured to accommodate the legs 1620, 1630, 1660 of an interlocking identical masonry unit and a binding agent such as mortar or grout therebetween. In use this binding agent will fill the cavity between the masonry units 1600 caused by the differences in widths of the recesses 1640, 1650 and legs 1620, 1630, 1660 and will bind or adhere the masonry units 1600 together.

Specifically, the main recess 1640 and the trailing recess 1660 are each configured to at least in the x direction alternately receive (i.e. receive both, but not at the same time): a main leg of an identical Έ’ shaped masonry unit; or the header leg of a first identical masonry unit and the trailing leg of a second identical masonry unit.

Figure 13 illustrates such an interlocking arrangement using the dashed outline of further masonry units 1600a, 1600b, 1600c, 1660d which are arranged in two interlocking columns. For instance, the main recess 1640 of the original masonry unit 1600 receives the trailing leg of a first opposed masonry unit 1600a and the trailing recess 1650 of the first masonry unit 1600a receives the main leg of this first opposed masonry unit 1600a. Equally, the trailing recess of the first opposed masonry unit 1600a received the main leg 1630 of the original masonry unit 1600, whilst the main recess of the first opposed masonry unit 1600a receives the trailing leg 1660 of the original masonry unit 1600 and the header leg of a further masonry unit 1600b. As shown, this interlocking pattern will continue down a course of such Έ shaped masonry units 1600.

Figures 14a and 14b show cross sections of interlocking arrangements of identical masonry units 1700 with two main legs 1730 and two main recesses 1740. As detailed in Figure 14a the masonry unit 1700 is again similar to the masonry unit 400 shown in Figure 3. This masonry unit 1700 comprises a main body 1710 extending in the x direction from a header end 1701 to a trailing end 1702. The masonry unit further comprises legs 1720, 1730 which extend from an inner surface 1712 of the main body in a y direction.

Like the masonry unit 400 of Figure 3, this masonry unit comprises a header leg 1720 and an open trailing recess 1750 (i.e. a trailing recess which is not bounded by a leg on one side in the x direction). However, the masonry unit 1700 comprises two main legs 1730a, 1730b.

The first main leg 1730a is spaced from the header leg 1720 in the x direction by a first main recess 1740a. The first main leg 1730a and second main leg 1730b are spaced in the x direction by a second main recess 1740b. The second main leg 1730b is spaced from the trailing end 1702 of the masonry unit 1700 by the open trailing recess 1750.

Each of these features shares similar properties and relative dimensions of the corresponding features in Figure 3. In particular, each of the main legs 1730a,

1730b and each of the main recesses 1740a, 1740b share similar relative dimensions, properties and features as the main leg 430 and main recess 440 shown Figure 3, respectively.

Therefore, each of the main recesses 1740a, 1740b is configured (i.e. sized) such that it can at least in the x direction alternately accommodate one main leg 1730 of an identical masonry unit or two header legs 1720 of two respective identical masonry units (but not at the same time). The trailing recess 1750 is sized to accommodate the header leg 1720 of an identical masonry unit 1700 or a portion of a main leg 1730 of an identical masonry unit 1700. In alterative embodiments the trailing recess 1750 may be extended or reduced in length in the x direction (i.e. the main body 1710 may be lengthened or shortened) as required.

Figures 14a and 14b show examples of interlocking patterns which may be created with these masonry units 1700 with multiple main legs.

Specifically, Figure 14a shows how a combined single rectilinear unit may be formed using two opposed and interlocked masonry units 1700a, 1700b with two main legs 1730. The main legs 1730 of each masonry unit 1700a, 1700b are received in a respective main recess 1740 of the opposed masonry unit 1700b, 1700a, whilst the header leg of each masonry unit 1700a, 1700b are received in the trailing recess of the opposing masonry unit 1700b, 1700a. This arrangement of masonry units 1700a, 1700b corresponds to the arrangement of ‘F’ shaped masonry units 400 shown in Figure 4a.

Figure 14b corresponds to Figure 4b and shows an interlocked pattern of two opposed columns 1800, 1900 of masonry units 1700c-f with two main legs wherein the masonry units 1700a, 1700b in the first column 1800 are offset in the y direction relative to the masonry units 1700e, 1700f in the second column 1900. In this pattern a main recess 1730 of a masonry unit 1700 may receive two header legs 1720 of opposed masonry units 1700 and a main leg 1730 of a masonry unit 1700 may be received by the trailing recesses 1750 of two adjacent masonry units 1700.

In view of Figures 13 and 14 and the discussion provided above it will be appreciated with masonry units with more than two legs may be interlocked in similar fashions to the ‘F’ shaped masonry units 400, 900a, 900b discussed above. As such, the masonry units of Figures 13 and 14 may be used to construct walls and wall sections with similar features and properties as the structures using ‘F’ shaped masonry units discussed above with reference to Figures 5 to 11. Equally the masonry units of Figures 13 and 14 may be provided with surface decorations in line with the examples of ‘F’ shaped bricks shown in Figure 12.

Furthermore, masonry units in accordance with the present invention with different numbers of legs may be combined and interlocked within a single wall or other structure so long as the dimensions of the legs and recesses of each type of masonry units are compatible. For example, if the dimensions of the main legs, main recesses, header legs are identical an ‘F’ shaped masonry unit shown in Figure 3 may be interlocked or mated with the masonry units shown in Figures 13 and 14 to create regular or repeating courses of masonry units. Thus the invention enables the construction of increasingly complex walls of high strength without the need to split masonry units at the extreme ends of the walls (i.e. without the need for bats or closures as is necessary when using traditional rectilinear masonry units).

As mentioned above, construction of a wall may be further simplified through the use of a lintel, foundation or other support structure from which extend a line or series of reinforcing pins. The line of reinforcing pins may extend in the direction of the length of the wall, whereas the reinforcing pins may extend in the direction of the height of the wall. Courses of masonry units may be laid around these reinforcing pins. For instance, the reinforcing pins may extend through multiple courses of masonry units in the direction of the height of the wall. The reinforcing pins may preferably extend through the continuous channels between masonry units discussed above.

The reinforcing pins may extend through multiple courses of masonry units arranged in different bonds. For instance, where a wall is constructed of the masonry units 400 shown in Figure 3, channels may extend continuously in a vertical direction (i.e. in the z direction as discussed above, parallel to the face of a wall and perpendicular to the direction the courses of masonry units extend in) through a section of wall comprising multiple courses of lapped masonry units, and through an underlying or overlying section of wall where the masonry units are arranged in a stack bond.

Therefore, the reinforcing pins fix the location of the channels and the locations of masonry units in the wall in a direction along the length of the wall (e.g. by fixing the locations of the channels or interfaces between masonry units). By restricting the positions of a masonry unit the process of laying a wall is simplified as the number of measurements which must be made by a mason or bricklayer are reduced. Not all channels may be provided with a reinforcement member (e.g. a reinforcement member may be provided periodically, every two channels or every three channels).

The lintel may be attached to reinforcing pins, or be pre-drilled with a series of holes or provided with a series of sockets so as to accommodate reinforcing pins at appropriate positions (i.e. positions which correspond to the location of channels extending through a wall) based on the dimensions of the masonry units and any joints present. Alternatively any other suitable means of attaching reinforcing pins to a lintel at the appropriate locations may be used. The lintel may be formed of any suitable material (e.g. steel, concrete, stone, brickwork, etc.), and is preferably a steel or masonry lintel.

In further embodiments the reinforcing pins may extend into or through perforations in the masonry unit (as discussed above with reference to Figures

3a and 3b), especially where these perforations extend through the masonry unit. However, this is not essential.

As a final point it will be appreciated that many of the dimensions of the masonry units discussed above may be varied without significantly affecting the performance of the masonry units or the structures created with them.

To conclude, the masonry units described above offer a simple and inexpensive means to construct strong and durable walls with a wide variety of geometries. Therefore, the present invention offers significant benefit to the art.

Further aspects of the invention are provided in the following numbered clauses:

Clause 1. A masonry unit comprising:

a main body extending in a first direction from a header end of the masonry unit to a trailing end of the masonry unit, the main body comprising opposed outer and inner surfaces, said outer surface defining a stretcher face of the masonry unit;

a header leg extending from the inner surface of the main body at the header end of the masonry unit in a second direction which is substantially perpendicular to the first direction; and, a main leg extending from the inner surface of the main body in the second direction, the main leg being spaced from the header leg in the first direction so as to define a main recess between the header leg and the main leg, and spaced from the trailing end of the masonry unit;

wherein the header leg is narrower than the main leg in the first direction;

the main recess being configured such that it can, at least in the first direction, alternately: (i) accommodate one main leg of an identical masonry unit; and (ii) accommodate two header legs of two respective identical masonry units.

Clause 2. A masonry unit according to any preceding clause, wherein the maximum width of the main leg in the first direction is approximately equal to, or greater than, twice the maximum width of the header leg in the first direction.

Clause 3. A masonry unit according to any preceding clause, wherein the main recess and main leg are configured such that the main leg of an identical masonry unit can be accommodated within the main recess of the masonry unit at a plurality of different positions in the second direction, the spacing between the distal end of the main leg of the identical masonry unit and the inner surface of the masonry unit it the second direction being different at each respective position.

Clause 4. A masonry unit according to any preceding clause, wherein the maximum width of the main recess in the first direction is greater than the maximum width of the main leg in the first direction.

Clause 5. A masonry unit according to any preceding clause, wherein the width of the main recess in the first direction is greater than or equal to the maximum width of the main leg in the first direction along at least a portion of the length of the main recess in the second direction, the portion being longer than the part of the main leg which has the maximum width.

Clause 6. A masonry unit according to any preceding clause, wherein the minimum width of the main recess in the first direction is greater than the maximum width of the main leg in the first direction.

Clause 7. A masonry unit according to any preceding clause, wherein an interior surface of the main recess is an interlocking surface configured to retain a binding agent applied thereto in use so as to retain an identical masonry unit within the main recess.

Clause 8. A masonry unit according to any preceding clause, wherein the width of the main leg in the first direction is greater at the distal end of the main leg than adjacent to the main body and/or the width of the header leg in the first direction is greater at the distal end of the header leg than adjacent to the main body.

Clause 9. A masonry unit according to any preceding clause, wherein the main leg and/or the header leg is tapered on at least one side thereof, such that the width of the main leg or the header leg in the first direction increases away from the main body along the second direction.

Clause 10. A masonry unit according to any preceding clause, wherein at least one interior surface of the main leg and/or the header leg is keyed so as to retain a binding agent applied thereto in use so as to retain an identical masonry unit within the main recess.

Clause 11. A masonry unit according to any preceding clause, comprising at least one locking cavity in an interior surface of the main leg and/or the header leg, the or each locking cavity configured to retain a binding agent applied thereto in use so as to retain an identical masonry unit within the main recess.

Clause 12. A masonry unit according to any preceding clause, wherein the at least one locking cavity is configured to receive a reinforcement pin.

Clause 13. A masonry unit according to any preceding clause, comprising a guide notch in a surface of the masonry unit which identifies a predetermined cutting position on the masonry unit.

Clause 14. A masonry unit according to any preceding clause, comprising perforations extending into or through the masonry unit in a third direction which is substantially perpendicular to the first and second directions.

Clause 15. A masonry unit according to any preceding clause, comprising a spacer protrusion which extends in the second direction from the inner surface of the main body, wherein the protrusion is shorter in the second direction than the header leg and the main leg.

Clause 16. A masonry unit according to clause 15, wherein the spacer protrusion is positioned between the main leg and the header leg and extends into the main recess.

Clause 17. A masonry unit according to any preceding clause, wherein the length of the main leg in the second direction and the length of the header leg in the second direction are substantially the same.

Clause 18. A masonry unit according to any preceding clause, wherein the inner surface of the main body within the main recess and the inner surface of the main body within the trailing recess are substantially co-planar.

Clause 19. A masonry unit according to any preceding clause, the main recess being configured such that it cannot accommodate a main leg and a header leg of two respective identical masonry units simultaneously, or accommodate three header legs of three respective identical masonry units simultaneously.

Clause 20. A masonry unit according to any preceding clause, wherein the space between the main leg and the trailing end of the masonry unit in the first direction is greater than the maximum width of the header leg in the first direction, and preferably less than the maximum width of the main leg in the first direction.

Clause 21. A masonry unit according to any preceding clause, wherein:

the space between the header leg and the trailing end of the masonry unit defines an open trailing recess;

the open trailing recess being configured such that it can accommodate a header leg of an identical masonry unit at least in the first direction; and wherein preferably a cross section through the masonry unit on a plane containing the first direction and the second direction is approximately ‘F’-shaped.

Clause 22. A masonry unit according to any preceding clause, wherein the sum of the widths of the header leg and the main recess in the first direction is greater than or equal to the sum of the widths of the main leg and the trailing recess in the first direction.

Clause 23. A masonry unit according to any of clauses 1 to 20, further comprising:

Clause 24. A masonry unit according to any of clauses 1 to 20, further comprising:

two or more main legs extending from the inner surface of the masonry unit in the second direction;

wherein the main leg nearest to the trailing end of the masonry unit is spaced from the trailing end of the masonry unit;

each main leg being spaced from any adjacent main legs by a main recess;

the main recesses being configured such that they can, at least in the first direction, alternately: (i) accommodate one main leg of an identical masonry unit;

and (ii) accommodate two header legs of two respective identical masonry units.

Clause 25. The masonry unit according to clause 24, wherein the space between the header leg and the trailing end of the masonry unit defines an open trailing recess, the open trailing recess being configured such that it can accommodate a header leg of an identical masonry unit at least in the first direction.

Clause 26. The masonry unit according to clause 24, further comprising:

Clause 27. A masonry unit according to any preceding clause, comprising one or more finished face.

Clause 28. A masonry unit according to any preceding clause, wherein:

the stretcher face is a finished face;

the masonry unit comprises a header face defined by the header end of the main body and a surface of the header leg and wherein the header face is a finished face; and/or the masonry unit comprises a trailing face defined by the trailing end of the main body and wherein the trailing face is a finished face.

Clause 29. A masonry unit according to at least clause 23, comprising a trailing face defined by the trailing end of the main body and a surface of a trailing leg, wherein the trailing face is a finished face.

Clause 30. A masonry unit according to any of clauses 27 to 29 wherein the finished face(s) exhibit variations in at least one of colour, texture, surface relief and surface coating.

Clause 31. A masonry unit according to any preceding clause, wherein:

• the maximum width of the masonry unit in the second direction is approximately 102.5 mm, and the maximum width of the main body of the masonry unit in the second direction is approximately 27.5 mm; and/or, • the maximum height of the masonry unit in a third direction which is a substantially perpendicular to the first and second directions is approximately 65 mm.

Clause 32. A masonry unit according to any preceding clause, wherein the masonry unit is extruded, moulded, wet or dry pressed, or 3D-printed.

Clause 33. A masonry unit according to any of clauses 7, 10 and 11, wherein the binding agent is a mortar, grout, cement or adhesive.

Clause 34. A masonry unit system comprising:

a plurality of masonry units each according to any of clauses 1 to 33.

Clause 35. A masonry unit system according to clause 34, further comprising at least one reinforcement pin;

wherein preferably the length of the at least one reinforcement pin is at least the height of the masonry unit in a third direction which is a substantially perpendicular to the first and second directions, more preferably at least twice the height of the masonry unit in the third direction, more preferably still at least the height of the masonry unit in the third direction.

Clause 36. A wall comprising a plurality of masonry units each according to any of clauses 1 to 33.

Clause 37. A wall according to clause 36, wherein the plurality of masonry units are arranged in a front column and a rear column such that the stretcher faces of the masonry units in the front column define a front side of the wall and the stretcher faces of the masonry units in the rear column define a rear side of the wall, the legs of the masonry units in the front column extending at least partly into the recesses of the masonry units in the rear column, and vice versa.

Clause 38. A wall according to clause 37, wherein the spacing between the masonry units in the front column and the masonry units in the rear column varies such that the wall thickness varies in accordance with a desired wall profile.

Clause 39. A wall according to any of clauses 37 to 38, wherein the stretcher faces of the masonry units of either the front or rear column are substantially coplanar.

Clause 40. A wall according to any of clauses 37 to 39, wherein each of the masonry units extends in a third direction between a first bedding face and an opposed second bedding face, wherein the third direction is substantially perpendicular to the first and second directions;

wherein the masonry units of the front column and the rear column are each arranged in at least one course, such that the bedding faces of the masonry units in each course of the respective column are substantially coplanar.

Clause 41. A wall according to clause 40, wherein a course of masonry units in the front column and/or the rear column overlaps two courses of the masonry units in the opposing column in a direction substantially parallel to the stretcher faces and substantially perpendicular to bedding faces of the masonry units of the front and rear columns;

Clause 42. A wall according to any of clauses 37 to 41, wherein the masonry units define a channel between them;

wherein the channel extends in a direction substantially parallel to the stretcher faces and substantially perpendicular to bedding faces of the masonry units of the front and rear columns;

and wherein preferably the channel extends through a distance which is at least twice the height of the masonry unit in the third direction, more preferably at least three times the height of the masonry unit in the third direction, more preferably still at least five times the height of the masonry unit in the third direction.

Clause 43. A wall according to any of clauses 36 to 42, further comprising at least one reinforcement pin;

wherein preferably the length of the at least one reinforcement pin is at least the height of the masonry unit in a third direction which is a substantially perpendicular to the first and second directions, more preferably at least twice the height of the masonry unit in the third direction, more preferably still at least five times the height of the masonry unit in the third direction.

Clause 44. A wall according to clause 43, when dependent on clause 42, wherein the at least one reinforcement pin is provided within the channel.

Clause 45. A wall according to any of clauses 37 to 44, wherein the masonry units of the rear column are lapped, whilst the masonry units of the front column are arranged in a stack bond, or vice versa.

Clause 46. A wall according to any of clauses 47 to 45, wherein a plurality of masonry units of the front column are arranged in a stack bond and wherein at least a portion of each of masonry units of the front column arranged in the stack bond is lapped by a masonry unit of the rear column, and/or wherein a plurality of masonry units of the rear column are arranged in a stack bond and wherein at least a portion of each of masonry units of the rear column arranged in the stack bond is lapped by a masonry unit of the front column.

Clause 47. A wall according to any of clauses 36 to 46, comprising a binding agent binding adjacent masonry units together.

Clause 48. A wall according to clause 47, wherein the binding agent is a mortar, grout, cement or adhesive.

Clause 49. A wall according to any of clauses 36 to 48, wherein the plurality of masonry units are arranged in a front column and a rear column such that the stretcher faces of the masonry units in the front column define a front side of the wall and the stretcher faces of the masonry units in the rear column define a rear side of the wall, wherein the wall comprises an internal cavity between the front column and the rear column, and wherein preferably the wall comprises insulation, concrete, reinforced concrete and/or grout within the internal cavity.

Clause 50. A method of building a wall using a plurality of masonry units each according to any of clauses 1 to 33.

Clause 51. A method of building a wall according to clause 50, comprising the step of:

arranging the plurality of masonry units in a front column and a rear column such that the stretcher faces of the masonry units in the front column define a front side of the wall and the stretcher faces of the masonry units in the rear column define a rear side of the wall, the legs of the masonry units in the front column extending at least partly into the recesses of the masonry units in the second column, and vice versa.

Clause 52. A method of building a wall according to clause 51, wherein the spacing between the masonry units in the front column and the masonry units in the rear column varies such that the wall thickness varies in accordance with a desired wall profile.

Clause 53. A method according to any of clauses 51 to 52, wherein the stretcher faces of the masonry units of either the front or rear column are arranged to be substantially co-planar.

Clause 54. A method according to any of clauses 51 to 53, wherein each of the masonry units extends in a third direction between a first bedding face and an opposed second bedding face, wherein the third direction is substantially perpendicular to the first and second directions;

Clause 55. A method according to clause 54, wherein a course of masonry units in the front column and/or the rear column overlaps two courses of the masonry units in the opposing column in a direction substantially parallel to the stretcher faces and substantially perpendicular to bedding faces of the masonry units of the front and rear columns;

Clause 56. A method according to any of clauses 51 to 55, wherein the masonry units define a channel between them;

Clause 57. A method according to any of clauses 50 to 56, further comprising providing at least one reinforcement pin;

Clause 58. A method according to clause 59, when dependent on clause 56, wherein the at least one reinforcement pin is provided within the channel.

Clause 59. A method of building a wall according to any of clauses 51 to 58, wherein the masonry units of the rear column are lapped, whilst the masonry units of the front column are arranged in a stack bond, or vice versa.

Clause 60. A method of building a wall according to any of clauses 51 to 59, wherein a plurality of masonry units of the front column are arranged in a stack bond and wherein at least a portion of each of masonry units of the front column arranged in the stack bond is lapped by a masonry unit of the rear column, and/or wherein a plurality of masonry units of the rear column are arranged in a stack bond and wherein at least a portion of each of masonry units of the rear column arranged in the stack bond is lapped by a masonry unit of the front column.

Clause 61. A method of building a wall according to any of clauses 50 to 60, further comprising applying a binding agent between adjacent masonry units to bind said adjacent masonry units together.

Clause 62. A method of building a wall according to clause 61, wherein the binding agent is a mortar, grout, cement or adhesive.

Clause 63. A method of building a wall according to any of clauses 50 to 62, comprising the step of:

arranging the plurality of masonry units in a front column and a rear column such that the stretcher faces of the masonry units in the front column define a front side of the wall and the stretcher faces of the masonry units in the rear column define a rear side of the wall, and such that the front column and 5 rear column define an internal cavity between the front column, and wherein preferably the method comprises the further step of providing insulation, concrete reinforced concrete and/or grout within the internal cavity.

Claims

1. A masonry unit comprising:

wherein the header leg is narrower than the main leg in the first direction;

2. A masonry unit according to any preceding claim, wherein the main recess and main leg are configured such that the main leg of an identical masonry unit can be accommodated within the main recess of the masonry unit at a plurality of different positions in the second direction, the spacing between the distal end of the main leg of the identical masonry unit and the inner surface of the masonry unit it the second direction being different at each respective position.

3. A masonry unit according to any preceding claim, wherein the width of the main recess in the first direction is greater than or equal to the maximum width of the main leg in the first direction along at least a portion of the length of the main recess in the second direction, the portion being longer than the part of the main leg which has the maximum width.

4. A masonry unit according to any preceding claim, wherein an interior surface of the main recess is an interlocking surface configured to retain a binding agent applied thereto in use so as to retain an identical masonry unit within the main recess.

5. A masonry unit according to any preceding claim, wherein the width of the main leg in the first direction is greater at the distal end of the main leg than adjacent to the main body and/or the width of the header leg in the first direction is greater at the distal end of the header leg than adjacent to the main body.

6. A masonry unit according to any preceding claim, wherein the main leg and/or the header leg is tapered on at least one side thereof, such that the width of the main leg or the header leg in the first direction increases away from the main body along the second direction.

7. A masonry unit according to any preceding claim, wherein at least one interior surface of the main leg and/or the header leg is keyed so as to retain a binding agent applied thereto in use so as to retain an identical masonry unit within the main recess.

8. A masonry unit according to any preceding claim, comprising at least one locking cavity in an interior surface of the main leg and/or the header leg, the or each locking cavity configured to retain a binding agent applied thereto in use so as to retain an identical masonry unit within the main recess.

9. A masonry unit according to any preceding claim, wherein the length of the main leg in the second direction and the length of the header leg in the second direction are substantially the same.

10. A masonry unit according to any preceding claim, the main recess being configured such that it cannot accommodate a main leg and a header leg of two respective identical masonry units simultaneously, or accommodate three header legs of three respective identical masonry units simultaneously.

11. A masonry unit according to any preceding claim, wherein the space between the main leg and the trailing end of the masonry unit in the first direction is greater than the maximum width of the header leg in the first direction, and preferably less than the maximum width of the main leg in the first direction.

12. A masonry unit according to any preceding claim, wherein:

13. A masonry unit according to any of claims 1 to 11, further comprising:

the closed trailing recess being configured such that it can, at least in the first direction, alternately: (i) accommodate one main leg of an identical masonry unit; and (ii) accommodate a header leg and a trailing leg of two respective identical masonry units; and wherein preferably a cross section through the masonry unit on a plane containing the first direction and the second direction is approximately

Έ’-shaped.

14. A masonry unit according to any of claims 1 to 11, further comprising:

each main leg being spaced from any adjacent main legs by a main recess;

15. A masonry unit according to any preceding claim, wherein:

the stretcher face is a finished face;

16. A masonry unit system comprising:

a plurality of masonry units each according to any of claims 1 to 15.

17. A wall comprising a plurality of masonry units each according to any of claims 1 to 15.

18. A wall according to claim 17, wherein the plurality of masonry units are arranged in a front column and a rear column such that the stretcher faces of the masonry units in the front column define a front side of the wall and the stretcher faces of the masonry units in the rear column define a rear side of the wall, the legs of the masonry units in the front column extending at least partly into the recesses of the masonry units in the rear column, and vice versa.

19. A wall according to claim 18, wherein the spacing between the masonry units in the front column and the masonry units in the rear column varies such that the wall thickness varies in accordance with a desired wall profile.

20. A wall according to any of claims 18 to 19, wherein each of the masonry units extends in a third direction between a first bedding face and an opposed second bedding face, wherein the third direction is substantially perpendicular to the first and second directions;

21. A wall according to claim 20, wherein a course of masonry units in the front column and/or the rear column overlaps two courses of the masonry units in the opposing column in a direction substantially parallel to the stretcher faces and substantially perpendicular to bedding faces of the masonry units of the front and rear columns.

22. A wall according to any of claims 18 to 21, wherein the masonry units define a channel between them;

23. A wall according to any of claims 18 to 22, wherein the masonry units of the rear column are lapped, whilst the masonry units of the front column are arranged in a stack bond, or vice versa.

24. A method of building a wall using a plurality of masonry units each according to any of claims 1 to 15.

25. A method of building a wall according to claim 24, comprising the step of:

26. A method of building a wall according to claim 25, wherein the spacing between the masonry units in the front column and the masonry units in the rear column varies such that the wall thickness varies in accordance with a desired wall profile.

27. A method according to any of claims 25 to 26, wherein each of the masonry units extends in a third direction between a first bedding face and an opposed second bedding face, wherein the third direction is substantially perpendicular to the first and second directions;

28. A method according to claim 27, wherein a course of masonry units in the front column and/or the rear column overlaps two courses of the masonry units in the opposing column in a direction substantially parallel to the stretcher faces and substantially perpendicular to bedding faces of the masonry units of the front and rear columns;

29. A method according to any of claims 25 to 28, wherein the masonry units define a channel between them;

30. A method of building a wall according to any of claims 25 to 29, wherein the masonry units of the rear column are lapped, whilst the masonry units of the front column are arranged in a stack bond, or vice versa.