GB2373262A

GB2373262A - Cavity wall structure

Info

Publication number: GB2373262A
Application number: GB0106656A
Authority: GB
Inventors: Hilton Spencer Ingram
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-03-16
Filing date: 2001-03-16
Publication date: 2002-09-18
Anticipated expiration: 2021-03-16
Also published as: GB0106656D0; GB2373262B

Abstract

A cavity wall structure includes a number of cavity wall spacing members (110) each supported on a foundation pad (200) and inner and outer wall members (112-117) provided with wall bars (116, 118) which are bolted to the support member. Preferably wall bars of adjacent wall members are connected by connecting pieces (139, Figure 12) which allow the wall members to be in face to face contact, thus providing corners. A further invention (Figures 17 and 18) includes a coach bolt (162), nut (164) and washer (166) for securing to a beam (160), where the washer has a square aperture (168) for receiving the square shank (170) of the bolt, where the washer has a lateral dimension W which is less than the internal width w of the beam and a maximum dimension L which is greater than the internal width of the beam.

Description

CAVITY WALL STRUCTURE Field of the invention The present invention relates to improvements in construction techniques.

Backaround of the invention Most construction techniques to date involve so-called"wet- trades"involving the mixing and handling of wet cementitious compositions, such as wet cement and concrete.

These techniques tend to require a significant work space which is not always available and/or may involve cutting down of trees, dismantling of other structures and the risk of damage to gardens and other amenities.

Furthermore, wet-trade techniques tend to add to total construction time, since, for example, concrete has to be left for many hours, even days, to set before the next task can begin.

Also, traditional construction techniques tend to employ large scale components, which cannot always be delivered as needed and therefore require storage space on site and require the use of large scale equipment which occupies significant space on site while building work progresses, and require remedial work to rectify any associated damage.

There is therefore a need for construction methods and systems where wet-trade techniques can be minimised, construction times may be minimised, government regulations can be easily met, conventional materials can be used, where relatively small scale components are used, so that the market can be organised on a purchase-as-needed basis, and

where relatively small scale equipment can be used. Three of the initial steps necessary in the construction of a building are the formation of (i) foundations, (ii) internal and external walls, and (iii) flooring.

The present invention is directed primarily at the formation of a cavity wall structure for the building.

SUMMARY OF THE INVENTION According to the invention there is provided a cavity wall structure of a building, comprising a plurality of cavity spacing members supported at a plurality of locations on the discrete foundation pads of the building, and inner and outer wall members provided with wall bars, the wall bars being bolted to the cavity spacing members.

The cavity spacing members may have a C-shaped or rectangular cross-section, and may optionally be bolted to the foundation pads.

The wall bars are preferably embedded in the wall members The wall bars are preferably continuous, i. e. they extend from side edge to side edge of the wall members. The wall bars are ideally formed of a rigid material, such as metal.

Ideally each wall member carries at least two wall bars.

The inner wall member may be formed of cementitious material, wood, plaster, fibrous material, synthetic material or a combination of two or more such materials. In one embodiment, the inner wall member is of sandwich construction, for example comprising a layer of heat insulating material sandwiched between layers of cementitious material.

An alternative embodiment is a double layer structure with a layer of wood on the inside, glued to a layer of insulating material such as polystyrene, the wall bars being attached to the rigid material and embedded in the polystyrene layer.

The outer wall member may be a moulded member comprising a substrate of cementitious material carrying an outer embedded layer of brick slips.

Alternatively, the outer wall member may comprise a metal or concrete wall beam carried on a supporting bracket or resting on the foundation pads, supporting a number of brick courses, the wall bars being constituted by tie bars each positioned between two adjacent brick courses and bolted to the cavity spacing members.

The inner and outer wall members may be cut to any shape, for example to accommodate sloping ground or to avoid obstacles.

The cavity spacing members are preferably formed with apertures to accommodate services for the building, such as electric power and telecommunication cables and/or water and heating and cooling pipes.

An access plate having a generally flat upper surface may rest on the top of the cavity spacing members or on the wall members, to substantially close off the cavity formed between the inner and outer wall members. Windows and other structures may be built on top of the access plate.

Alternatively, a capping plate with sloping upper surfaces may be used, if no further such structure is required.

A plurality of the wall members will generally be provided, in side edge to side edge adjacent relationship to each other, wall bars of adjacent wall members being connected together. Wall bars of adjacent wall members may be connected together by hinged connecting pieces having arms located in the wall bars and secured thereto. Edges of adjacent wall members at corners of the building may be so shaped to enable side edge to side edge face-to-face contact. Adjacent wall members are preferably bonded together with suitable adhesive along their side edges.

A plurality of the wall members may be provided, in top edge to bottom edge adjacent relationship, the top and bottom edges of the wall members being correspondingly shaped to engage each other.

Each cavity spacing member may extend to the height of the access plate or top most wall member, or alternatively they may be of a lower height, such as the height of the associated wall members, with extension pieces being provided to enable the fitting of the inner wall members to continue without the need to complete the construction of the outer wall members at the same time. This could be of particular advantage, if the outer wall member comprises a brick wall, which may need to be constructed by a skilled labourer. Such a cavity wall extension piece may include a downwardly extending portion, having slots therein by means of which the extension piece may be bolted to a cavity spacing member at the top thereof, with an outwardly extending portion extending over the line of the exterior wall of the building. The outwardly extending portion may be capable of supporting, for example a sill, without the need to build the outer wall up to this level in advance.

A damp proof membrane may be provided to extend under the inner wall member and to be coupled to a damp proof course provided in the inner wall member or the outer wall member.

The cavity defined between the wall members is usefully filled with heat insulating material, such as polystyrene pieces or foam, although such filling may be unnecessary if the wall members are sufficiently insulating in themselves.

The inner and outer wall members have their lower edges resting on the foundation pads, the upper surface of which are preferably just below ground level. In such a case it will be necessary to form shallow trenches extending between the foundation pads to accommodate the lower edges of the wall members.

While the inner and outer walls may have their lower edges resting on the same foundation pad, it is also possible that the outer wall rests on a foundation pad which is at a lower level than the foundation pad on which the inner wall rests.

Where the wall members are positioned adjacent a door or window opening, an end member may be provided to close off the cavity between the wall members and to which the door or window frame is attached. The outer surface of the end member may be finished to match the adjacent inner and outer wall members.

The cavity wall structure of the invention may be used with a method of forming foundations for a building, comprising forming a plurality of discrete holes in the ground, and forming a foundation pad in each of the holes by: providing a layer of cementitious material at the

bottom of the hole ; lowering a base plate into the hole to rest upon the cementitious material layer; lowering a stack of interlocking hollow pile rings into the hole to rest upon the base plate; and positioning a top plate to rest upon the top one of the pile rings.

The holes in the ground may be formed using an auger or other digging tool.

The base plate, pile rings and top plate are preferably formed of a material selected from concrete (optionally reinforced) and synthetic (i. e. plastics) materials, the latter being especially suitable in damp environments.

The base of the hole is preferably flattened with a pounder before the cementitious material is added. The latter is preferably a dry mix of cementitious ingredients, such as a mixture of sand and cement, the top surface of which is ideally flattened before the base plate and the pile rings are lowered into the hole.

In one embodiment, the pile rings are provided with annular ribs and grooves so positioned that the annular rib of one pile ring is capable of being engaged in the annular groove of an adjacent ring. The base plate and top plate are similarly provided with ribs and grooves as appropriate, on their upper and lower surfaces respectively.

The number of the pile rings in the stack is preferably such that the top surface of the foundation pad is adjacent (e. g. just below) ground level. Furthermore, the number of rings

can be selected such that all foundation pads are at the same or similar level, irrespective of any undulations in the ground surface.

Although the pile rings may be solid, it is preferred that they are hollow so as to define a hollow space within the stack of rings. Hollow pile rings have the advantage of weight and cost and also enable back-filling with the solid removed during formation of the hole. Thus, after the pile rings are lowered into the hole, the hollow space within the pile rings, and any annular space around the rings, may be back-filled with the soil removed during formation of the hole or with wet cementitious material, such as wet concrete.

A lowering tool may be used to lower at least the base plate and the pile rings into the hole, the lowering tool being capable of being releasably engaged with the base plate or pile rings. For this purpose it is useful for the base plate to have an aperture formed there-through.

By forming the hole before the pile rings are inserted, the foundation becomes an end-bearing pile, in contrast to the friction piles conventionally used to date.

The foundation pad ideally has a plane top surface, has an anchorage bar embedded in a groove therein or has an aperture there-through, the latter embodiment being especially useful if the pile rings are hollow and the hollow space within the pile rings is to be filled with wet concrete. Although it is an object of this invention to avoid the use of wet-trade techniques so far as possible, the use of wet concrete in this context may be acceptable,

especially since subsequent building work may continue, even while the concrete in the hollow pile is setting.

Where the top plate has an aperture there-through, this may be subsequently closed off with a separate cap, thereby to generate a plane top surface.

A further alternative embodiment of the foundation pad is to provide an annular metal insert having a number of downwardly extending bolts to anchor it to the foundation pad and a number of upstanding bolts to which components of the building may be attached.

A layout sheet may be used to define the location of the holes, the layout sheet having a peripheral portion which extends beyond the building area defined by the holes to define a work area and thereby avoid the risk of the work area spreading uncontrollably and to reduce remedial work.

The pile rings, base plate and top plate may have a crosssectional shape which is circular, D-shaped or quadrant shaped. D-shaped pile rings, a D-shaped base plate and a Dshaped top plate are useful where the building is to be butted up to another structure or, used in pairs for forming a split level foundation pad. Quadrant shaped pile rings, a quadrant shaped base plate and a quadrant shaped top plate are useful where the building is to be butted into a corner of another structure.

After the foundation pads are positioned, a damp-proof membrane is ideally positioned there-over. Also, resilient protective mats may be placed over the top surface of the top plate, and over the damp-proof membrane where present,

to cushion any component resting on the foundation pad. The protective mat will also provide useful heat insulation between the top plate and the components resting thereon.

In an embodiment of the invention suitable for forming foundations underwater or in ground where the water table is high, the pile rings are hollow, a flexible water impermeable tube may be provided extending upwardly from the base plate through the pile rings, and the tube is progressively filled with cementitious material as the stack of hollow pile rings are lowered into the hole. For example, after each pile ring is lowered into the hole, the tube is filled with wet concrete up to the level of that pile ring to expand the tube into the hollow space within the pile ring and thereby expel any water therefrom. The flexible tube may be connected to the base plate in a number of ways, for example by passing the tube through a hole in the base plate and providing a knot in the tube or other obstruction to hold the tube in the base plate.

The cavity wall structure of the invention may be used with a flooring structure of a building, comprising a support frame formed of a plurality of rigid beams connected at their ends by beam connecting members which rest at a plurality of locations on discrete foundation pads of the building, flooring material, and optionally also insulating material, being supported by the support frame.

The beam connecting members preferably allow the beams to be positioned at a selected angle relative to each other. Such a beam connecting member may comprise first and second parts each having a beam end engaging portion and a disc, the disc of the first part being connected to the disc of the second

part, to rotate in face-to-face contact therewith, foundation contacting members extending away from the discs to contact the associated foundation member. The beam connecting member may further comprise locking means for locking the discs together. The locking means may be constituted by at least one bolt passing through a hole in one of the discs and through a slot in the other of the discs, nuts being provided on the bolt on either side of the discs, the tightening of the nuts causing the discs to be clamped together. The bolt advantageously additionally constitutes the foundation contacting member and has a head to contact the associated foundation member while the position of the nuts on the bolt determines the spacing between the ends of the beams and the associated foundation member, and enables this space to be adjusted to ensure that the flooring surface is level. Guide markings may be provided on the discs to indicate the angle set between the beams.

The beam end engaging portions may be U-shaped, defined by a base and two upstanding wings, fixing holes being provided in the wings, or in the base, to enable fixing to the beams.

When the beams are fixed to these U-shaped portions by the use of through bolts, tube-shaped washers are preferably inserted to prevent the tightening of these bolts distorting the upstanding wings.

A number of methods can be employed for securing the flooring material to the support frame. In one embodiment, the support frame additionally comprises joists extending between the beams, the flooring material resting on the joists. The joists typically each comprise a C-shaped metal member which may embrace a wooden infill, the flooring

material being connected to the wooden infill, by screws or nails, or to which wooden joists carrying runner rails may be attached.

Conventional single or double joist hangers bolted or otherwise secured to the beams may be used. Alternatively, one or more single or double universal joist hangers may be used, which allow the joists each to be positioned at a selected angle relative to the beams.

Where the upper surface of the joists supported by joist hangers is above the level of the upper surface of the beams, beam extensions may be secured to the beams at various locations between the joist hangers, the beam extensions having an upper surface level with the upper surface of the joists.

An alternative construction is to provide joists which rest upon the upper surface of the beams, the joists being secured to the top of the beams. In some applications it may be desirable to position the joists at an angle other than 900 to the support beam. For this purpose, a universal joist holder may be used.

An embodiment of such a universal joist holder comprises a plate which is capable of being bolted to the support beam in one of a plurality of rotational orientations about a vertical axis, the plate having an upstanding first jaw, a second jaw being formed by a separate member which can be bolted to the plate in adjustable manner towards and away from the first jaw, the joist end being positioned and clamped, and optionally bolted, screwed or nailed, between the two jaw members.

Where the joist is to be positioned with its floor-engaging surface substantially in the plane of the upper surface of the beams, and where again it is desired to position the joist at an angle other than 90'to the support beam, a universal joist hanger may be used. The present invention provides such a universal joist hanger, comprising a receptacle for receiving one end of a joist, a fixing plate positioned above the receptacle and extending away therefrom, means for fixing the fixing plate to the upper surface of a support beam in one of a plurality of rotational orientations about a vertical axis, and a curved cam surface for making contact with the adjacent lateral surface of the support beam.

Insulation support members may be carried by the joists to support sheets of thermal insulation material, such as polystyrene, below the flooring material. The insulation support members may be constituted by clips which are a press fit onto the lower face of the joists, or are plates which are connected to the lower face of the joists.

The flooring material is typically in the form of tongued and grooved sheets, for example formed of wood or cementitious material. Means for providing underfloor heating may be incorporated in the flooring material.

The present invention is applicable not only to buildings in the strict sense of that term, i. e. occupied constructions having walls, one or more floors and a roof, but also to any built construction requiring foundations and walls, such as for example out-buildings, warehouses, factory units, stands, perimeter walls, towers, bridges, monuments, domes, and any other built structure having walls supported by a

foundation requiring secure retention in the ground and being expected to be able to withstand significant forces.

The term"building"as used in the description and claims herein is to be interpreted accordingly.

The invention will now be further described, purely by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic representation illustrating a method of forming foundations of a building; Figure 2 is a detailed representation of a pile ring used in the foundations illustrated in Figure 1; Figure 3 is a schematic representation of part of the flooring structure of a building which makes use of the foundations illustrated in Figure 1 and 2; Figure 4 is a top view of a bottom beam connector or floor leg used in the flooring structure illustrated in Figure 3; Figure 4A is an exploded view of the floor leg shown in Figure 4 ; Figure 5 is a view of a top beam connector used in the flooring structure illustrated in Figure 3; Figure 6 illustrates one embodiment for positioning joists in the support frame of the flooring structure illustrated in Figure 3; Figure 7 shows one embodiment for supporting insulating

sheets in part of the flooring structure illustrated in Figure 3 ; Figure 8 shows another embodiment for supporting insulating sheets in part of the flooring structure illustrated in Figures 3; Figure 9 is a schematic illustration of a cavity wall structure of a building; Figure 10 is a view taken in the direction X-X in Figure 9; Figure 11 shows an embodiment of a wall connector upon which the lower edge corners of wall members rest; Figure 11A shows an alternative embodiment for constructing the outer wall of a cavity wall structure; Figure 12 illustrates, in partly exploded condition, the connection of two horizontally adjacent wall members of the cavity wall structure illustrated in Figures 9 and 10; Figure 13 illustrates the connection of two vertically adjacent wall members of the cavity wall structure illustrated in Figures 9 and 10; Figure 14 illustrates an embodiment for a universal joist holder; Figures 15 and 16 illustrate an embodiment for a single universal joist hanger for use with the flooring structure illustrated in Figure 3, as viewed from above and from the

side respectively ; Figures 17 and 18 show an embodiment of a washer used with a beam such as may be incorporated in the flooring structure illustrated in Figure 3; and Figure 19 illustrates a cavity wall extension for use with a cavity spacing member as illustrated, for example, in Figures 9 and 10.

Referring to the Figures, there is shown a building which includes a foundation structure, a flooring structure and a walling structure.

The method of forming the foundations for the building, include forming a plurality of discrete holes 10 in the ground 12, as shown in Figure 1. The holes are formed with an auger and have a depth of about 1 m. A layout sheet 34 is used to define the location of the holes 10, the layout sheet 34 having a peripheral portion 38 which extends beyond the building area defined by the holes 10.

The bottom of each hole 10 is flattened with a pounder and then a layer 14 of dry mixed sand and cement is provided at the bottom of the hole 10. The top surface 21 of the dry mix layer is flattened with a pounder and a concrete base plate 16 is lowered into the hole 10 by use of a lowering tool (not shown) inserted into the central hole 17, to rest upon the cementitious material. A stack of interlocking hollow concrete pile rings 18 are then lowered into the hole 10 to rest upon the base plate 16. The base plate 16 and each of the pile rings 18 can be lowered into the hole 10 using a lowering tool which is capable of being releasably

engaged with the base plate 16 or pile rings 18.

After the pile rings 18 are lowered into the hole 10, the hollow space 28 within the pile rings 18 and the annular space surrounding the pile rings is back-filled with the soil removed during formation of the hole 10 or with concrete or other particulate material. Finally a top plate 20 of concrete reinforced with a mild steel cage is positioned to rest upon the top one of the pile rings 18.

The top plate 20 has a plane top surface 22. The number and size of pile rings 18 in the stack is such that the top surface 22 of the so formed foundation pad 200 is just below ground level. The base plate 16, pile rings 18 and top plate 20 are formed of pre-cast concrete.

After the top plate 20 is positioned, a damp-proof membrane 36 is positioned there-over.

In the illustrated embodiment, the pile rings 18 have a circular or D-shaped cross-section. As shown in Figure 2, the pile rings 18 are provided with annular ribs 24 and grooves 26 so positioned that, in the stack, the annular rib 24 of one pile ring is engaged in the annular groove 26 of the adjacent ring. The base plate 16 and top plate 20 are similarly provided with ribs and grooves, on their upper and lower surfaces respectively.

Referring to Figure 3, the flooring structure of the building includes a support frame 40 formed of a plurality of rigid C-cross-section beams 42 connected at their ends by top and bottom beam connecting members 43,44. The bottom beam connecting members rest on the discrete foundation pads 200 of the building, formed as described above. Brackets 41

are provided to couple the frame to an existing structure, such as to the sidewall of a house where the new building is, for example, a conservatory.

The flooring material 48 is in the form of tongued and grooved wooden or concrete sheets, supported by joists 90.

As shown in Figures 4 and 4A, the bottom beam connecting members 44 are so designed to allow the beams 42 (shown in phantom lines) to be positioned at a selected angle relative to each other. Each bottom beam connecting member 44 includes first and second parts 50,52 each having a beam end engaging portion 54,56 and a disc 58,60. The disc 58 of the first part 50 is rivetted to the disc 60 of the second part 52 by a rivet 59, to rotate in face-to-face contact therewith. Notches 80 are provided on the edges of the discs 58,60 to indicate the angle set between the beams 42.

The beam end engaging portions 54,56 are U-shaped, defined by a base 82 and two upstanding wings 84,86. Fixing holes 88 are provided in the wings 84,86.

A bolt 68 passes through a slot 73 in the lower disc 60 and through a hole 69 in the upper disc 58, while another bolt 70 passes through a hole 71 in the lower disc 60 and through a slot 75 in the upper disc 58. Nuts 72,74, 76,78 are provided on the bolts 68,70 on either side of the discs 58, 60, so that the tightening of the nuts 72,74, 76,78 causing the discs 58,60 to be clamped together to lock the discs 58,60 together.

The bolts 68,70 also pass through holes in the beams 42,

adjacent the ends thereof, to secure the beams to the bottom beam connecting member.

Heads 81,83 of the bolts 68,70 contact the associated foundation pad 200. The position of the nuts 72,74, 76,78 on the bolts 68,70 determines the spacing between the beam 42 ends and the foundation pad 200.

Figure 4A also shows a preferred option in which a rubber protective mat 19, corresponding in shape to the top plate 20, is placed over the top surface of the top plate over the damp proof membrane 36 to cushion the components resting on the foundation pad 200 and to provide useful heat insulation there-between.

As shown in Figure 5, the top beam connecting member 43 includes first and second parts 51,53 each having an arm 55,57 and a disc 61,62. The disc 61 of the first part 51 is rivetted to the disc 62 of the second part 53 by a rivet 63 to rotate in face to face contact therewith. The arms 55,57 are U-shaped defined by a base 64 and two downwardly extending wings 65 including bolt holes 66 to line up with the fixing holes 88 in the bottom beam connecting member and with holes appropriately positioned in the beam end.

As shown in Figure 3, joists 90 extend between the beams 42, to support the flooring material 48. As shown in Figure 6, a conventional single joist hanger 98 is bolted to one of the beams 42, to support a joist 90, which stretches across the support frame 40, the joist hanger having slots 92 in the side faces thereof to enable the joist to be screwed to the joist hanger. One end of a beam extension 176 secured to the beam 42 between adjacent joist hangers can be seen in

Figure 6, the upper surface of the beam extension 176 being on the same level as the upper surface of the joist 90. As shown in Figure 7, the joists 90 each comprise a C-shaped metal member which embraces a wooden infill 94, the flooring material 48 being connected to the wooden infill 94, by screws 97. Clips 100 which are a press fit onto the lower face of the joists 90, support sheets 104 of thermal insulation material (which may of course be thicker than shown in the Figures) below the flooring material 48.

Figure 8 shows an alternative embodiment, where plates 102 are connected to the lower face of wooden joists 101 to support the sheets 104 of insulating material, the flooring material 48 being connected to the wooden joists 101, by screws 97.

Referring to Figures 9 and 10, a cavity wall structure of the building, includes a number of cavity spacing members 110 each supported on the foundation pad 200 of one of the foundations. The cavity spacing members 110 have a C-shaped cross-section.

Inner wall member 112 is provided with metal wall bars 116 embedded therein. The wall bars 116, which may be formed in one piece, using a Dutch fold technique which provides particular strength, are bolted to one of the short arms of the cavity spacing member 110. At least two such wall bars are provided on each of the wall members. For the sake of simplicity, only one such wall bar is shown on each wall member in Figure 9.

In the illustrated embodiment, the inner wall member 112 is

of co-extruded sandwich construction having a layer 120 of heat insulating material sandwiched between two layers 122, 124 of cementitious material. An outer wall member 115 is in the form of a concrete substrate 126 carrying an outer layer 128 of embedded brick slips. A wall bar 118 is embedded in the concrete substrate and is bolted to the other short arm of the cavity spacing member 110. Typical heights for the wall members are 400,500 and 600 mm, while a typical thickness will be 50 mm for an inner wall member and 50 mm for an outer wall member.

A concrete access plate 136 having a flat upper surface 138 rests on the top of the cavity spacing member 110, to substantially close off the cavity 140 formed between the inner and outer wall members 112,115.

The damp proof membrane 36 extends under the inner wall member 112 and is coupled to a damp proof course 156 provided in the inner wall member 112 or, as shown by broken lines, to a damp proof course 158 provided in the outer wall member 115. For this purpose, the lowest inner or outer wall member as appropriate may be provided with a damp proof course on its upper face, enabling the damp proof membrane to be clamped between this wall member and the next higher wall member. For this reason the lowest wall members may have a height such as 160 mm or 240 mm which is less than that of other wall members.

The cavity spacing members 110 are formed with apertures 134 to accommodate services for the building, such as electric power and telecommunication cables and/or water and heating and cooling pipes. Electrical and other services may be prefabricated into the wall members, especially the inner

wall members, to save construction time on site.

The lower edge corners of adjacent bottom-most wall members 112,113 rest on wall connectors as shown in Figure 11, which comprise base portions 180, and wing portions 182 arranged at an angle a matching the angle subtended by the adjacent walls, such as 90 .

If the foundation pads are not at the same level, with the result that the lower edges of adjacent wall members are not at the same level, packing members may be inserted between the bases of the U-shaped wall engaging portions of the wall connectors and the lower edge of one or both of the walls.

The cavity 140 defined between the wall members 112,115 is filled with heat insulating material (not shown), such as polystyrene pieces or foam.

In the alternative embodiment shown in Figure 11A, the outer wall member 117 includes a wall beam 130 which rests on brackets 129 connected to the cavity spacing members and rests on foundation pads 200. The wall beam 130 supports a number of brick courses 132, tie bars 131 being positioned within the mortar between two adjacent brick courses 132 to constitute wall bars to be bolted to the cavity spacing member 110.

A still further alternative is to use a reinforced concrete beam in place of the metal wall beam 130.

In Figure 12, two adjacent wall members 112,113 at corners of the building are shown, in side edge to side edge adjacent relationship to each other, the wall bars 116,119

of the adjacent wall members 112, 113 being connected together by hinged connecting pieces 139 having arms 142, 144 located in the wall bars 116,119 and bolted thereto.

Edges of adjacent wall members 112,113 are so shaped to enable side edge 146 to side edge 148 face-to-face contact while the adjacent wall members 112,113 are bonded together with cementitious or other suitable adhesive 150 along their side edges 146,148.

As shown in Figure 13, two wall members 112,114, incorporating wall bars 116, are provided, in top edge 152 to bottom edge 154 adjacent relationship. The top and bottom edges 152,154 of the wall members 112,114 are provided with a dog-leg shape to engage each other, the edge-to-edge contact being higher on the cavity side of the wall member than on its other side to prevent possible ingress of moisture.

Referring to Figure 14, a universal joist holder is provided which allows the timber joists 87 each to be positioned at a selected angle relative to the beams 42. The universal joist holder comprises a plate 67 bolted to the support beam 42 in one of a plurality of rotational orientations about a vertical axis. The plate has an upstanding first jaw 77. A second jaw is formed by a separate member 79 bolted through a curved slot 85 through the plate 67 in such a manner as to be adjustable towards and away from the first jaw 77. Both jaw members are provided with screw holes. The end 89 of the joist 87 is positioned, clamped between the two jaw members and screwed thereto.

Referring to Figures 15 and 16, a single universal joist hanger for supporting a joist from a support beam is shown.

This universal joist hanger comprises a receptacle 91 for receiving one end 93 of the joist, the receptacle having slots 103 in the side faces thereof to enable the joist to be bolted or screwed to the joist hanger. A fixing plate 95 is positioned above the receptacle and extends away therefrom. A slot 96 is provided for bolting the fixing plate 95 to the upper surface of the support beam 42 in one of a plurality of rotational orientations about a vertical axis.

A curved cam surface 99 is provided for making contact with the adjacent lateral surface of the support beam, the cam surface and the slot 96 having approximately the same centre of curvature,"C".

Where in any of the embodiments of the invention illustrated herein, a component is to be bolted to a wall bar or beam, it is convenient to use coach bolts, i. e. bolts where that part of the shank adjacent the bolt head has a square crosssection. The use of such bolts avoids the risk of rotation once the associated nuts are secured thereto. To aid in the tightening of such bolts, washers may be used having a correspondingly square-shaped aperture which are so sized and shaped as to be unable to rotate in the wall bar or beam.

To illustrate this, Figures 17 and 18 show the combination of a beam 160, a coach bolt 162, a nut 164 for the coach bolt and a washer 166, wherein in order to assist in securing the coach bolt and nut to the beam, the washer has a square aperture 168 for receiving the square shank 170 of the coach bolt, a lateral dimension W less than the internal width w of the beam and a maximum dimension L greater than the internal width of the beam. By this arrangement, when the washer 166 is placed on the coach bolt 162 and the two

are inserted into the beam 160, with the threaded end 172 of the coach bolt extending through the beam slot 174, and the nut 164 is placed thereon, rotation of the nut 164 initially causes the coach bolt 162 and washer 166 to rotate until a jammed position is reached. Further rotation of the nut 164 will then tighten the nut on the bolt. The dimension of the washer 166 in a direction lateral to the square aperture 168 corresponds to the internal width w of the beam, so that in the jammed position of the washer the aperture 168 lines up with the beam slot 174.

Referring to Figure 19, a cavity wall extension piece 190 is shown for use with a cavity spacing member 110 as illustrated, for example, in Figures 9 and 10. The extension piece 190 includes a downwardly extending portion 191, having slots 192,193 therein by means of which the extension piece 190 may be bolted to a cavity spacing member 110, at the top thereof with an outwardly extending portion 194 extending over the line of the exterior wall of the building. the outwardly extending portion 194 is capable of supporting, for example a sill, without the need to build the outer wall up to this level in advance. This can be of advantage, if the building of the outer wall needs to be delayed.

Wherever components described herein are bolted together, suitably shaped gaskets can be incorporated to act as a thermal break.

Claims

CLAIMS 1. A cavity wall structure of a building, comprising a plurality of cavity spacing members (110) supported at a plurality of locations on discrete foundation pads (200) of the building, and inner and outer wall members (112,113, 114,115, 117) provided with wall bars (116,118, 119), said wall bars (116,118, 119) being bolted to said cavity spacing members (110).
2. A cavity wall structure according to claim 1, wherein said cavity spacing members (110) have a C-shaped or rectangular cross-section.
3. A cavity wall structure according to claim 1 or 2, wherein said wall bars (116,118, 119) are embedded in said wall members (112,113, 114,115, 117).
4. A cavity wall structure according to any preceding claim, wherein said wall bars (116,118, 119) are formed of a rigid material.
5. A cavity wall structure according to any preceding claim, wherein said inner wall member (112,113, 114) is formed of cementitious material, wood, plaster, fibrous material, synthetic material or a combination of two or more such materials.
6. A cavity wall structure according to any preceding claim wherein said inner wall member (112,113, 114) is of sandwich construction.
7. A cavity wall structure according to claim 6, wherein a layer (120) of heat insulating material is sandwiched between layers (122,124) of cementitious material.
8. A cavity wall structure according to any preceding claim, wherein said outer wall member (115,117) comprises a substrate (126) of cementitious material carrying an outer embedded layer (128) of brick slips.
9. A cavity wall structure according to any preceding claim, wherein said outer wall member (115,117) comprises a wall beam (130) supporting a number of brick courses (132), said wall bars being constituted by tie bars (131) each positioned between two adjacent brick courses (132).
10. A cavity wall structure according to any preceding claim, wherein said cavity spacing members (110) are formed with apertures (134) to accommodate services for the building, such as electric power and telecommunication cables and/or water and heating and cooling pipes.
11. A cavity wall structure according to any preceding claim, wherein an access plate (136) having a generally flat upper surface (138) rests on the top of said cavity spacing members (110), or on the top of said wall members (112,113, 114,115, 117) to substantially close off the cavity (140) formed between said inner and outer wall members (112,113, 114,115, 117).
12. A cavity wall structure according to any preceding claim, wherein a plurality of said wall members (112,113) are provided, in side edge to side edge adjacent

relationship to each other, wall bars (116, 119) of adjacent wall members (112, 113) being connected together.
13. A cavity wall structure according to claim 12, wherein wall bars (116,119) of adjacent wall members (112, 113) are connected together by connecting pieces (139) having arms (142,144) located in said wall bars (116,119) and secured thereto.
14. A cavity wall structure according to claim 12 or 13, wherein edges of adjacent said wall member (112,113) at corners of the building are so shaped to enable side edge (146) to side edge (148) face-to-face contact.
15. A cavity wall structure according to any one of claims 12 to 14, wherein said adjacent wall members (112, 113) are bonded together with adhesive (150) along their side edges (146,148).
16. A cavity wall structure according to any preceding claim, wherein a plurality of said wall members (112,114) are provided, in top edge (152) to bottom edge (154) adjacent relationship, the top and bottom edges (152,154) of said wall members (112,114) being correspondingly shaped to engage each other.
17. A cavity wall structure according to any preceding claim, wherein a damp proof membrane (36) extends under said inner wall member (112, 113,114,) and is coupled to a damp proof course (156,158) provided in said inner wall member (112,113, 114) or said outer wall member (115,117).
18. A cavity wall structure according to any preceding

claim, wherein the cavity (140) defined between said wall members (112, 113, 114, 115, 117) is filled with heat insulating material (160).
19. A cavity wall structure according to any preceding claim, wherein said foundation pads (200) each comprise a discrete hole (10) in the ground (12), a layer (14) of cementitious material at the bottom of the hole (10); a base plate (16) in the hole (10) resting upon said cementitious material layer (14), a stack of interlocking pile rings (18) in the hole (10) resting upon said base plate (16) ; and a top plate (20) resting upon the top one of said pile rings (18).
20. A cavity wall structure according to any preceding claim, together with a flooring structure of the building, comprising a support frame (40) comprising a plurality of rigid beams (42) connected at their ends by beam connecting members (44) which rest at a plurality of locations on said discrete foundation pads (200), flooring material (48) being supported by said support frame (40).
21. A cavity wall structure of a building, substantially as hereinbefore described, with reference to the accompanying drawings.
22. A method of forming a cavity wall structure of a building, comprising supporting a plurality of cavity spacing members (110) at a plurality of locations on discrete foundation pads (200) of the building, providing inner and outer wall members (112,113, 114,115, 117) with wall bars (116,118, 119), and bolting said wall bars (116, 118,119) to said cavity spacing members (110).
23. The combination of a wall bar or beam (160), a coach bolt (162), a nut (164) for the coach bolt and a washer (166), wherein in order to assist in securing the coach bolt (162) and nut (164) to the wall bar or beam (160), the washer (166) has a square aperture (168) for receiving the square shank (170) of the coach bolt (162), a lateral dimension (W) less than the internal width (w) of the wall bar or beam (160) and a maximum dimension (L) greater than the internal width (w) of the wall bar or beam (160).
24. The combination according to claim 23, wherein the dimension of the washer (166) in a direction lateral to the square aperture (168) corresponds to the internal width (w) of the wall bar or beam (160), so that in the jammed position of the washer (166) the aperture (168) lines up with the wall bar or beam slot (174).