GB2601613A - A system for covering a roof and a mounting unit therefor - Google Patents

Abstract

The roof covering mounting unit 10 is planar having a roof facing underside14 and a header rail 16. On a side edge is an interlocking feature 22a/22b which is deformable to facilitate expansion and contraction in a lateral direction. A spacing element is disposed on the underneath of the main body and defines a height which is higher at the header end compared to the opposite end to allow water run-off. A second interlocking feature comprises a first male locking component provided on said header rail and a female locking component formed of a slot for receiving the male locking component of another mounting unit. A locating element facilitates the accurate location of the header rail on the mounting unit, the locating element being a deformable protrusion on the header rail. The mounting unit might be part of a system. Also claimed is a mounting component comprising a shank that terminates in a point; a second shank continuing from a corner terminating in a hook shape. The mounting unit may support slates, tiles or PV cells.

Description

A SYSTEM FOR COVERING A ROOF AND A MOUNTING UNIT THEREFOR

FIELD OF THE INVENTION

The present invention relates to a system for covering a roof structure, to a mounting unit and to a covered roof structure. More specifically, but not exclusively, the present invention relates to a system incorporating one or more mounting units which seeks to improve the cost effectiveness, efficiency and quality of installation of natural roofing slates. Beneficially, the mounting units are provided with first and second interlocking features which along with other features of the mounting units provide for a single lap installation-format to be used instead of the traditional double lap, whilst seeking to improve wind-uplift performance. Additional advantages provided by the system and mounting units disclosed herein include the use of slates for example as a roof covering for low-pitch roofs. Further applications for the system disclosed herein include the installation of a variety of roof covering materials, tiles and the like as well as other devices, such as, but not limited to photovoltaic (PV cells).

BACKGROUND OF THE INVENTION

Typically, pitched roofs are constructed using rafters (typically timber) or pre-formed roof trusses. The outer surfaces are designed to shed rain water and optionally may be covered in a roofing membrane over which a plurality of battens (typically timber) is then fixed transversely up and over the roof. The battens provide mounting rails for the outermost roof covering which may be tiles, such as stone, slate or cement.

Single lapping is an economical method of roof covering because there is just one layer of tiles (roof covering elements) over most of the roof and a double layer just where the tiles overlap vertically (head lap).

Typically, where natural, quarried, slates are used as the roof covering, they are located adjacent each other and extend from one edge of the roof to the other in courses. Slates are laid side by side and abut the next adjacent tile and leave an open joint called a 'perp joint' (perpendicular joint). A second course of tiles is installed in such a manner so as to cover the perp joint of the course below; and tiles in the second course are positioned above the centre of the slate below. This method continues up the roof alternating for each course. A third course is installed such that front edges of the slates in this third course extend over the top of the first course in order to prevent any wind driven rain that enters the perp joint from being forced over the top of the slate and causing failure in the waterproof requirement of the roof covering. This method of third course overlapping the first course is called 'double lap' slating and is normally employed when installing slates. The amount of this double 'lap' is typically greater for a lower pitch roof and reduced slightly for a steeper, higher pitch roof.

Such, double lap roofing methods are very well known; are one of the oldest forms of roof covering in the UK and can be used with a range of plain tiles. The term 'double lap' may be used herein and may refer to the manner in which plain tiles are laid onto a roof in order to form an effective waterproof barrier. Plain files are generally uniform in shape and typically have no side interlocks. When laid side by side the gap that exists between the tiles may allow water flow. As described, to drain this water away another file must be present below each joint. This means that at any tile course of the roof there is at least a double overlapping layer of tiles. With such roofing methods, used with a variety of roof covering materials, and in particular with traditional materials such as slate and stone; the off-set overlapping layers give rise to a particular appearance, which may be referred to as "broken bond".

In conservation areas, historic or listed buildings, and some new-build developments, the use of traditional materials such as slate and stone may be mandated or desired. Alternatively, the "broken bond" appearance may be a desirable aesthetic for a traditional "look". However, due to the weight of slate or stone tiles and the quantity of files required in a double lap roofing method roofs covered with such slate tiles can be expensive. Additionally, a high degree of skill is required and such roofs can be time consuming to install, re-cover and/or maintain. A further consideration is the structure of the roof which must have a sufficient weight rating in order to support the weight of double-lapped slate or stone tiles. The extra materials, extra labour and skill-level required to construct such roof structures adds cost and time.

Since the need for traditional roofs with coverings such as slate and stone tiles continues in conservations areas, historic, listed and some new buildings, there is a need and a desire to provide a system to weatherproof a roof, that utilises slate, stone and/or other traditional materials whilst maintaining the aesthetic appearance that is so important to this type of installation without the necessity for the high-quantity, high-weight and high-cost associated with using such materials.

Subsequent to the applicant's development of their own invention, it has been discovered, that in 1990, Brown et al invented a mounting device for natural quarried slates, as disclosed in United Kingdom patent GB 2,249,112. The mounting device disclosed therein is said to enable slates of shorter length to be used and is said to enable the laying of slates in a single-lap arrangement. It is not known whether this mounting device was developed for commercial markets and the applicant is not aware of any such product being available in the marketplace.

Without being limited to any particular theory, it is possible that the reason the mounting device of GB 2,249,112 is not known to have been made widely available commercially, is that there are many flaws in the mounting device disclosed in GB '112. Many crucial requirements for a roofing structure do not seem to have been accounted for in the GB '112 system. For example, the present applicant, in developing the mounting unit roof covering system of the present invention, has considered and addressed problems associated with, for example: waterproofing; speed of installation; breathability of the roof structure; wind-lift, two-dimensional expansion or contraction of the mounting device; and skill-shortages resulting in problems associated with poor-quality installation.

The present invention seeks to provide an improvement in the field of roofing systems, and more particularly, but not exclusively, in the field of slate or stone tile covered roof systems.

The invention may be utilised in applications other than for slate or stone covered roofs and may not be limited in its application to a specific roof covering type, format or arrangement. Indeed, it is envisaged that the system provided by the present invention could be utilised for covering roofs with other items, such as, but not limited to PV (photovoltaic) cells and the like.

SUMMARY OF THE INVENTION

Aspects of the invention provide a roof covering system, a mounting unit, a kit of parts, and a covered roof as claimed in the appended claims.

According to a first aspect, there is provided a roof covering system comprising: a mounting unit having a generally planar main body having a roof facing underside, an outward facing upper side; the mounting unit having a header rail at a first end of the main body; and a foot-end opposing said first-end. A first interlocking feature provided may be disposed on at least a first side edge of the main body, the first interlocking feature may comprise a deformable portion to facilitate expansion and contraction in a lateral direction. Optionally, at least one spacing element is disposed on the underside of the main body. The spacing element may have a first portion proximate the first end and a second portion proximate the foot end of the main body. The first portion of the spacing element may have a first height proximate said first end; and the second portion of the spacing element may have a second height proximate said foot end. The first height is beneficially sufficiently less than said second height to provide a pitch for enabling water run-off. Optionally the roof covering system may further comprise a second interlocking feature having a first male locking component provided on the header rail and a second female locking component formed as a slot. The slot arranged for receiving said first male locking component of another mounting unit.

Optionally, a locating element is provided to facilitate accurate location of the header rail of one mounting unit and the spacing element of another mounting unit when the second interlocking feature is deployed. The locating element may be provided on the header rail as a deformable protrusion; and said header rail and a portion of the second female locking component together may define an expansion gap.

Optionally, said header rail is solid construct or bar having one or more apertures formed therein for securing the header rail to a structural component of the roof.

Optionally, a first male locking component of the second interlocking feature provided on said header rail is provided as a continuous formation along at least a portion of an end-edge of the header rail.

Said locating element may be provided as a continuous rib or continuous protrusion along the header rail and spaced from said spur, which continuous rib or continuous protrusion is deformable Optionally, said first interlocking feature comprises a first locking member disposed on a first side edge of the main body; and a second locking member disposed on a second side edge of the main body. One or both of the first and second locking members may comprise a deformable portion to facilitate expansion and contraction in a lateral direction. The deformable portion may comprise a material that has a deformable characteristic; and/or said deformable portion may comprise a shaped-structure or configuration that can move into and out of the plane of the mounting unit. Where the deformable portion comprises a shaped-structure or configuration, that may take the form of a corrugated, undulated, "V", "U", folded, creased or rib shape.

Optionally, said mounting unit comprises one or more mounting components disposed on the upper side of the main body by which a roof covering item can be attached to the mounting unit. The mounting components may each be provided as an integrally moulded, protrusion or lug, upwardly standing from the upper side of the main body and disposed closer to the header rail than to the foot-end of the main body. In some arrangements, the mounting unit may be configured to accommodate two roof covering items and may comprise four integrally moulded upwardly standing lugs.

Optionally, the mounting unit comprises one or more mounting features provided at least substantially within said header rail and disposed within the upper side of the main body, the one or more mounting features each comprising at least one of said one or more apertures formed for securing the header rail to a structural component of the roof; and said one or more

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mounting features configured to receive and co-operate with an auxiliary mounting component.

Optionally, the one or more mounting features are provided as grooves, channels or profiled slots within the header rail and are shaped, sized and configured for receiving a portion of the one or more mounting components therein.

Optionally, the system further comprises one or more mounting components and the one or more mounting components each comprise: a first shank which terminates in a point; a corner; a second shank continuing from the corner; and a hook-shaped portion, wherein the second shank terminates in the hooked-shaped portion; and wherein the hook-shaped portion returns relative to the second shank and is positioned in spaced relation above part of the second shank.

The system where, in use, the point and first shank may be inserted into one of said one or more apertures formed for securing the header rail to a structural component of the roof; the second shank may be partially seated within a groove, channel or profiled slot of one of the mounting features; and a portion of the second shank may sits parallel to and spaced above the upper surface of the main body such that a gap 'G' exists between that portion of the second shank and the upper surface of the main body, into which gap a roof covering, such as a tile, slate tile, or PV cell can be fitted.

Optionally, the female locking component of the second interlocking feature comprises a slot or socket, which slot or socket is provided by an extension of the second portion of the spacing element such that said spacing element comprises a slot or socket shaped portion proximate said foot end and such that said first male locking component provided on said header rail is configured and arranged for interlocking with the slot or socket of the spacing element of another mounting unit.

The first portion and the second portion of the spacing element may be contiguously formed as a single tapered rib. In some arrangements the mounting unit comprises six tapered ribs. The six tapered ribs may be arranged with a first along a first side of the main body; two middle ribs disposed side-by-side and substantially centrally of the main body; a fourth rib along the second side of the main body; a fifth rib disposed between said first rib and said two middle ribs; and a sixth rib disposed between said two middle ribs and said fourth rib.

A roof covering system described comprises a plurality of mounting units, which are intended to be laid in a series of courses, with adjacent mounting units of each course being laterally interlocked by said first interlocking feature; and with overlapping mounting units of adjacent courses being longitudinally interlocked by said second interlocking feature.

According to a further aspect of the invention, there is provided a mounting unit having: (i) a generally planar main body haying a roof facing underside, an outward facing upper side; the mounting unit having a header rail at a first end of the main body; and a foot-end opposing said first-end; (ii) a first interlocking feature disposed on at least a first side edge of the main body, the first interlocking feature comprising a deformable portion to facilitate expansion and contraction in a lateral direction; (iii) at least one spacing element disposed on the underside of the main body, said spacing element having a first portion proximate the first end and a second portion proximate the foot end of the main body, the first portion of the spacing element having a first height proximate said first end; and the second portion of the spacing element having a second height proximate said foot end, the first height being sufficiently less than said second height to provide a pitch for enabling water run-off; (iv) a second interlocking feature comprising a first male locking component provided on said header rail and a second female locking component formed as a slot for receiving said first male locking component; and (v) a locating element provided to facilitate accurate location of the header rail of one mounting unit and the spacing element of another mounting unit when the second interlocking feature is deployed; the locating element being provided on said header rail as a deformable protrusion; and said header rail and a portion of the second female locking component together defining an expansion gap.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIGURE 1 is perspective view showing a first, outward-facing, top-side of a mounting unit according to an embodiment of the invention for use in a system for mounting a plurality of roof covering items to a roof; FIGURE 2 is a perspective view of the mounting unit of Figure 1, showing a second, inward-facing or roof-facing back-side; FIGURE 3 is a perspective view of the mounting unit shown in Figure 1 showing a first, outward-facing, top-side of a mounting unit and additionally illustrating the placement of two roof-covering elements, such as a slate roof tiles onto the mounting unit; and the placement of two pairs of optional retaining clips; FIGURE 4 shows the mounting unit of Figure 3 with the two roof-covering elements, located onto the mounting unit and optionally, additionally secured thereto by retaining elements (clips); FIGURE 5 shows a perspective view of two of the mounting units of Figure 1, in an interlocked condition, wherein a first interlocking feature, which is disposed along a first side edge of a main body of the mounting unit is engaged to adjoin the two side-by-side mounting units together; FIGURES 6 and 7 illustrate the first (lateral) interlocking feature, which is disposed along the first side edge of the main body of the mounting unit; FIGURE 8 shows the assembly of a system for mounting a plurality of roof covering items to a roof, wherein a roofing batten is shown; the batten provides a structural rail member to which the mounting units have been attached. Additionally, in this Figure, it can be seen that a first-laid mounting unit is overlapped by a second over-laid mounting unit. The first-laid and overlaid mounting units are interlocked and secured together (as shown in Figures 9 and 10) using a second (longitudinal) interlocking feature; FIGURES 9 and 10 illustrate the second interlocking feature which is provided optionally in part by a header rail and optionally in part by a spacing element; FIGURE 11 is perspective view showing a first, outward-facing, top-side of a mounting unit according to various further embodiments of the invention for use in a system for mounting a plurality of roof covering items to a roof; FIGURE 12 shows a perspective view of two of the mounting units of Figure 11, in an interlocked condition, wherein a first interlocking feature, which is disposed along a first side edge of a main body of the mounting unit is engaged to adjoin, couple or link the two side-byside mounting units together; FIGURE 13 shows the part-assembly of a system for mounting a plurality of roof covering items to a roof, wherein a roofing batten is shown; the batten provides a structural rail member to which a mounting unit of Figure 11 is being attached.

FIGURE 14 shows the further assembly of the system of Figure 13, wherein a second batten provides a further structural rail member to which a further course of mounting units is being attached. Additionally, in this Figure, it can be seen that a first-laid course of mounting units is being overlapped by a second over-laid course of mounting units. The first-laid and second over-laid courses of mounting units are interlocked and secured together using a second (longitudinal) interlocking feature. Furthermore, the placement of off-set (broken-bond) roof-covering elements, such as slate roof tiles onto the mounting units can be seen along with the placement of hooked securing means for enabling the header rail to be securely attached to the roof structure, which hooked securing means also provides retaining clips for the slate tiles disposed thereon; and FIGURE 15 shows the positioning of the hooked securing means of Figure 14 being located on a mounting unit of Figure 11.

DETAILED DESCRIPTION OF EMBODIMENTS

Detailed descriptions of specific embodiments of the roof covering system, mounting units, kits of parts and covered roofs of the present invention are disclosed herein. It will be understood that the disclosed embodiments are merely examples of the way in which certain aspects of the invention can be implemented and do not represent an exhaustive list of all of the ways the invention may be embodied. Indeed, it will be understood that the roof covering system, mounting units, kits of parts and covered roofs described herein may be embodied in various and alternative forms. The figures are not necessarily to scale and some features may be exaggerated or minimised to show details of particular components. Well-known components, materials or methods are not necessarily described in great detail in order to avoid obscuring the present disclosure. Any specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the invention.

In the roofing covering system of the present invention, a series of mounting boards, or mounting units are first installed and then an outermost covering of material, which optionally may be provided by a plurality of slates, is affixed to the mounting units. The mounting units disclosed herein may provide for the easy and accurate installation of roof covering elements; interlock with one another in two-dimensions; allow for expansion in at least two-dimensions; and allow airflow within the roof structure. It will be appreciated that as a large roofing area to be covered by the roofing covering system disclosed herein is being assembled, in some methods of installation a number of mounting units 10 may be installed; followed by some tiles, such as slates, and the process repeated course by course until the roof is covered. As such in certain applications, the roof structure is not necessarily first covered by a plurality of mounting units 10; but rather, progressively courses of mounting units and tiles may be laid in a sequential manner.

In Figure 1 a mounting unit 10 according to various embodiments is shown. In Figure 1, a first, outward-facing, uppermost or top-side 12 of the mounting unit can be seen. In Figure 2, a second, inward-facing (roof-facing), lowermost or back-side 14 of the mounting unit 10 is shown. The mounting unit 10 has a first end 17; and a second-end 19; and generally planar, substantially rectangular main body 15. A header rail 16 is provided in the region of the first end 17 of the mounting unit 10; and a foot-portion 18 is provided in the region of the second-end 19 of the mounting unit 10 (opposite to the first-end 17).

The main body 15 provides a supporting area onto which slates, tiles, or other roof covering items 30a, 30b, (hereinafter referred to as "roof covering items" or "slates" 30a, 30b) can be safely, securely, accurately and easily, located and secured. Optionally, the mounting unit 10 comprises one or more mounting components 20a, 20b, 20c, 20d, disposed on the upper side 12 of the main body 15, by which a roof covering item 30a, 30b can be located onto the mounting unit 10.

The header rail 16 may be formed as a moulded, stepped band across the top of the main body 15. Referring to Figures 1 and 2 it can be seen that the first, outward-facing, uppermost or top-side 12b of the header rail 16 rests in a plane disposed above the plane of the first, outward-facing, uppermost or top-side 12 of the main body 15. The header rail 16 may have a substantially similar thickness to the thickness of the main body 15, and as such, when viewed from the back-side 14 (see Figure 2), the second, inward-facing, lowermost or backside 14 of the main body 15 may rest in a plane that is disposed above the plane of the second, inward-facing, lowermost or back-side 14b of the header rail 16. This stepped-formation allows the mounting unit 10 to be placed onto and affixed to a batten 'B' of a roof structure for secure attachment thereto. Additionally, this formation also allows a male portion 34 of the header rail 16 of one mounting unit 10 to engage with a female locking portion located proximate the foot-end 18 of another (overlapping) mounting unit 10c as is described further below and illustrated in Figures 8 and 10.

The header rail 16 may be formed with or otherwise provided with securing means for enabling the header rail 16 (and thus the mounting unit 10) to be securely attached to the roof structure. More specifically, but not exclusively, the header rail 16 may be provided with a series of apertures or holes 11a, 11 b, 11c, lid that are used to correctly position and locate fixings (such as nails, screws or other suitable fixings) that can be used to securely attach the mounting unit 10 to roof battens 'B' or boards. Optionally, the apertures or holes 11a, 11b, 11 c, lid may be elongated to allow for a degree of movement, adjustment or expansion of the mounting unit 10.

As is best shown in Figures 3 and 4, the illustrated embodiment of mounting unit 10 has been sized and configured to accommodate two complete slates 30a, 30b. Whereas certain sizes of slate 30a, 30b may be standard in the industry, the mounting unit 10 is not limited to being any specific size (and the illustrations are not necessarily to scale). The slates 30a, 30b are each provided with two apertures 21a/21b, 21c/21d, which is typical of some roof covering elements 30a, 30b used in the industry. In the present invention one or more mounting components 20a, 20b, 20c, 20d are optionally provided; and further optionally, in the first illustrated embodiment, four mounting components 20a, 20b, 20c, 20d are optionally provided. As such in the present and other embodiments two mounting components 20a/20b, 20c/20d are provided for each of the two apertures 21a/21b, 21c/21d in each of the two slates 30a, 30b being received on the mounting unit 10. In various other arrangements roof covering elements 30a, 30b may not comprise apertures and the mounting components 20a, 20b, 20c, 20d, may take a variety of suitable formats, for example, the format shown in Figures 11 to 15. Additionally, because the present invention allows for the "broken bond" staggered or offset arrangement of placed files 30a, 30b, the number, size and format of mounting components 20a, 20b, 20c, 20d optionally allows for the placement and securing of half tiles, and/or tiles 30a, 30b that span more than one mounting unit 10.

In order to accommodate industry norms, it is anticipated that in various embodiments, the mounting unit 10 will be sized such that two slates 30a, 30b can be located, side by side, on a single mounting unit 10. Additionally, or alternatively, it is anticipated that in various embodiments, the mounting unit 10 will be formed such that two mounting components 20a/20b, 20c/20d are provided for each of the two apertures 21a/21b, 21c/21d in the two slates 30a, 30b.

A mounting unit 10 in other arrangements may be sized, arranged and configured to hold a greater or fewer number of slates (roof covering items), than two. Beneficially, a mounting unit 10 sized to hold two slates 30a, 30b is considered to be a manageable size for manufacture, storage and distribution. Furthermore, a mounting unit 10 sized to hold two slates 30a, 30b is considered a manageable size and weight for being carried and lifted up to a roof and for being handled by the installer. Additionally, the number of mounting units 10 required and the interlocking-installation time is reduced with a ratio of 1 mounting unit 10 for two slates 30a, 30b (compared to one mounting unit 10 for one slate 30a). In various embodiments a mounting board 10 is configured and arranged to accommodate three slates 30a, 30b; thus, even further reducing the number of mounting units 10 required. The interlocking-installation time is further reduced with a ratio of one mounting unit 10 for three slates 30a, 30b. As explained above, where a broken bond aesthetic is required, the tiles in one course may be misaligned, off-set or staggered in relation to files in neighbouring courses and to achieve this a single mounting board 10 may house or support a portion, e.g. a first half of a tile 30a, 30b, whilst a neighbouring mounting board 10 may house or support another portion, e.g. a second half of a tile 30a, 30b.

Beneficially, the mounting unit 10 may be formed from one or more, or a combination of synthetic materials such that a plurality of mounting units 10 can be uniformly constructed (within normal manufacturing tolerances) to allow for consistent and accurate installation of the mounting units 10. Additionally, being manufactured from a synthetic material allows for a high-quality mounting unit 10 of suitable durability to be made from a weather resistant (optionally mould resistant) material in large scale production. For example, the mounting unit may be moulded from plastics material. Optionally, the mounting unit may be formed from a single material; alternatively, the mounting unit may comprise two or more materials. Accordingly, some or all of the various features of the mounting unit 10, described herein may be integrally and unitarily formed (by moulding) with the main body portion 15 to create a single-piece mounting unit 10. Advantageously, features such as the mounting components 20a, 20b, 20c, 20d may be moulded as unitary elements of the main body 15, which may contribute to their strength and robustness. Furthermore, the inclusion of integrally formed mounting components 20a, 20b, 20c, 20d may ensure that the system provided herein has a low number of parts, is simple to use and therefore requires a reduced skill requirement for installation. Furthermore, each mounting unit 10 being a single-piece construct may require a small inventory of parts, which, beneficially may avoid problems associated with systems that require a larger number and type of components to be assembled and mated together because any such systems would require an increase in the time, labour, skill and effort of installation; may suffer from delays in installation if the correct parts or correct number of parts are not provided to the fitter; and/or can lead to errors and inaccurate installation.

Referring again to Figure 2, it can be seen that the underside (back-side) 14 of the mounting unit 10 comprises spacing elements 23a, 23b, 23c, 23d, 23e, 23f. Optionally, a series of two or more, for example six spacing elements 23a, 23b, 23c, 23d, 23e, 23f, is disposed on the underside 14 of the mounting unit 10. The spacing elements 23a, 23b, 23c, 23d, 23e, 23f may have a first portion 23f that is disposed proximate to the first end 17 of the mounting unit 10; and a second portion 23s that is disposed proximate to the second-end 19 of the mounting unit 10.

In respect of a first example of a spacing element, numbered 23a in Figure 2, a first arrow 23f denotes the first portion 23f of the spacing element 23; and a second arrow 23s denotes the second portion 23s of the spacing element 23. As can be seen the first and second portions 23f, 23s are optionally provided as a single, contiguously moulded formation that is at least substantially co-extensive with the main body 15 of the mounting unit 10, and which depends or projects downwardly from the lowermost or back-side 14 of the mounting unit 10.

The depths (thicknesses) of the first and second portions 23f, 23s are not uniform along their length; and depths (thicknesses) of the first and second portions 23f, 23s are not the same as each other. The first portion 23f is tapered from a narrower depth proximate to the first end 17 of the mounting unit 10 to a greater depth as the first portion 23f approaches the second portion 23s. The second portion 23s is tapered from a narrower depth proximate to the first portion 23f to a greater depth at the second end 19 of the mounting unit 10. Optionally, between the narrowest part of the first portion 23f of the spacing element 23, to the greatest depth part of the second portion 23s of the spacing element 23, the change in thickness or depth may provide a degree of taper, which may be between about 2° and about 15°. The taper or pitch of the spacing elements 23 is sufficient to enable water run-off; and preferably sufficient to provide for air-flow beneath the mounting unit 10.

In various embodiments the first and second portions 23f, 23s are not provided by a continuous strip and as such may not be adjoined or contiguous with one another. In such embodiments the first portion 23f is not joined to the second portion 23s and they are interrupted or separated from each other by a space, gap or other feature.

Figure 5 illustrates first and a second mounting units 10a, 10b, each shown without slates 30a, 30b, disposed side-by-side and affixed to a roofing batten E'. The axis across the roof structure, from one side edge to the opposite side edge On parallel with the courses and battens 'B1') is considered to be a lateral direction. A first interlocking feature may be considered as a lateral locking feature. A first (lateral) interconnecting feature is shown in Figure 5 in a deployed condition, locating, coupling or connecting, the first and second mounting units 10a, 10b together in a lateral direction.

Referring back to Figures 1 and 2, it can be seen that the first interlocking feature 22a/22b comprises a first locking member 22a disposed on a first side edge of the main body 12; and a second locking member 22b disposed on a second side edge of the main body 12. In Figure 1, the first side edge is (optionally) the right-hand side of the mounting-unit 10; and the second side edge is (optionally) the left-hand side of the mounting-unit 10. The first and second locking members 22a, 22b of one mounting unit 10 are inter-engageable with second and first locking members 22b, 22a of other such mounting units 10. In this way, the roofing system has a modular facet and a series of mounting units 10 can be interlocked in a (side-by-side) lateral direction, across a roof structure. Due to the first interlocking feature 22a/22b a barrier to water ingress is provided, and water is thereby prevented from flowing in-between adjacently positioned mounting units 10a, 10b. In providing this waterproofing aspect, the requirement for typical slate tiles to be laid in a double-lapped arrangement to ensure weatherproofing at the perp joint is addressed.

As shown in Figures 1 and 2, the first locking member 22a may not be fully co-extensive with the mounting unit 10. In other words, the first locking member 22a may not span the complete distance from the top of the header rail 16 at the first end 17 to the bottom of the footer 18 at the second end 19 of the mounting unit 10. Rather, the first locking member 22a may extend from a location disposed below the first end 17 and proximate to a lower edge of the header rail 16; to a location disposed above the second end 19 of the mounting unit 10 and proximate to an upper area of the footer 18.

As shown in Figures 1 and 2, the second locking member 22b may also not be fully co-extensive with the mounting unit 10. In other words, the second locking member 22b may not span the complete distance from the top of the header rail 16 at the first end 17 to the bottom of the footer 18 at the second end 19 of the mounting unit 10. Rather, the second locking member 22b in the present arrangement extends from a location proximate to the first end 17; to a location disposed above the second end 19 of the mounting unit 10 and proximate to an upper area of the footer 18.

The first interlocking feature 22a/22b comprises a deformable portion to facilitate expansion and contraction in a lateral direction. The term "lateral direction" is used to refer to the side-toside direction, which is indicated by arrow 'L' in Figure 5. The deformable portion optionally may comprise a material that has a deformable characteristic. Additionally, or alternatively, the deformable portion may comprise a shaped-structure or configuration that can move (in the lateral direction) into and out of the plane of the mounting unit 10. For example, a corrugated, undulated, "V", "U", folded, creased or otherwise formed shaping may be provided within the first interlocking feature 22a/22b, wherein portions of the first interlocking feature 22a/22b can be moved towards one another or away from one another in response to and in dependence upon slight changes or adjustment in the size and/or position of the mounting units 10a, 10b (optionally due to changes in temperature). It is advantageous to provide a mechanism to accommodate the effects of thermal expansion and contraction and in doing so the system of the present invention mitigates against one of many of the shortcomings of known systems such as that of GB 2,249,112.

In Figures 6 and 7 the interlocking of the first, lateral, interlocking feature 22a/22b can be seen. As shown in Figures 6 and 7, two panels 10a, 10b are brought together such that the first locking member 22a of the first panel 10a is located and abuts, is coupled to, or otherwise fits or seats with the second locking member 22b of the second panel 10b.

Referring now to Figure 8, it can be seen that a mounting unit 10b in a first course of mounting units 10a/10b, is overlapped by a mounting unit 10c from a second course. The mounting units 10a, 10b in the first course are affixed to a first roofing batten Bl, whereas the mounting units 10c of the second course are affixed to a second roofing batten B2. As shown in Figure 8, the foot-portion 18 of the mounting unit 10c of the second course overlaps (optionally the entirety of) the header rail 16 of the mounting unit 10b. This (longitudinal) overlap contributes to the waterproof quality of the roof covering provided by the system of the present disclosure.

Further beneficially, the mounting units 10a, 10b, 10c of the roof covering system of the present disclosure are each provided with a second interlocking feature 34/23S/38 which enables a first mounting unit 10b of a first course to be interlocked with a second, overlapping mounting unit 10c of an adjacent (and up-pitch) mounting unit 10c of a second course.

If the axis of the roof between the ridge at the top and an eave at the bottom is considered as a longitudinal direction, then the second interlocking feature 34/38 may be described as a "longitudinal locking feature" 34/38. The longitudinal locking feature 34/38 is provided by first and second co-operative elements 34, 38. Whereas a single mounting unit 10a, 10b, 10c is provided with both the first and second co-operative elements 34 38, it will be understood that the first locking element 34 of one mounting unit 10b is intended to co-operate with, interlock and engage with a second locking element 38 of a second mounting unit 10c. In this way, a plurality of mounting units 10a, 10b, 10c are interlocked and the roofing system provided herein comprises a contiguous, two-dimensionally interlocked series of mounting units covering the surface of the roof.

In an illustrated embodiment the first element 34 of the second interlocking feature comprises at least a portion of said header rail 16. The first element 34 of the second interlocking feature 34, 38 may be considered as a male part, and may be referred to as comprising a "male spur" 34. This male spur 34 may be provided by an integrally moulded and shaped portion of the top edge of the header rail 16 at the first end 17 of the mounting unit 10a, 10b, 10c. This is shown in Figures 9 and 10. Optionally, the male spur 34 may have a slightly up-turned end or protrusion which can securely locate and engage with a female locking part 38 provided by the second element 38.

The second element 38 of the second interlocking feature 34/38 may comprise or be formed by a portion of said spacing element 23s. As shown in Figure 9, the spacing element 23s may comprise a shaped portion (proximate said foot end 18). The shaped portion 38 forms or provides a slot, a clip or female socket 38 into which the shaped male portion 34 of the header rail 16 can be located and locked. In Figure 9 it can be seen that the spacing element 23s is formed flush with and connects directly to the underside 14 of the main body 15 apart from in the region where the spacing element 23s comprises the shaped portion 38. Though it will be understood that the mounting units 10a, 10b, 10c are optionally formed by moulding as a single unitary construct such that the start and termination of labelled features may not be well defined; it can nevertheless be understood from Figure 9 that the first element 34 of the second interlocking feature 34/38 locates in and fits within the shaped slot 38 provided by a female clip 36 extending from the spacing element 23s of another mounting unit 10c. the female socket 36 is formed where that spacing element 23s ceases to be formed flush with and in direct connection to the underside 14 of the main body 15. The termination of the spacing element 23s, and the start of the female socket 36 (and thus slot 38) has been denoted by reference numeral 38e in Figure 9. In this side view of Figure 9 the side of the first locking member 22a of the first interlocking feature 22a/22b can be seen, but this is not in the same plane as the spacing element 23s. The gap or slot 38 is disposed between the underside 14 of the main body 15 and the socket or female clip 36. In Figure 9, the second interlocking feature 34/36 has not yet been deployed. In Figure 10 the second interlocking feature 34/36 is in use. The inter-engagement of the header rail 16 of one mounting unit 10b with the spacing element 23s of an up-pitch mounting unit 10c can be seen. When connecting the upper mounting device 10c to the already installed lowermost mounting unit 10b, the female clip 34/38/38e is manipulated and locates onto the male spur 34. The second end 19 and footer region 18 of the upper mounting device 10c extends beyond the second interlocking feature 34/36 of the lower mounting device 10b and over an installed slate (not shown in Figures 9 and 10). Advantageously this not only locks the mounting devices 10b, 10c together (in a longitudinal direction) but further beneficially serves to trap the underlying slate (that is affixed to the lower mounting unit 10b) in position whereby all three: the lower and upper mounting units 10b, 10b and the slate 30a; are securely held in place.

It will be recognised that the interaction between the female clip 38 and the male spur 34 can be varied in so far as how deep the spur 34 is engaged with the clip 38. This inherent and deliberately configured degree of variation is very useful during installation of the roof system.

Further advantageously, the male spur 34 provides a locating element which facilitates accurate location of the header rail 16 of one mounting unit 10b within the female locking part 36/38 of another mounting unit 10c. The locating element may be provided on the header rail 16 or male spur 34 as a deformable protrusion. The slot 38 provides an expansion gap such that the second interlocking feature 34/36,38 provides a secure longitudinal connection between the overlapping mounting units 10a, 10c and beneficially, simultaneously provides for a degree of relative adjustment to accommodate thermal expansion and contraction of the mounting units 10b, 10c.

Turning now to the method of installation of the roof system described herein, it may be appreciated that a variety of features are provided to encourage the correct, quick and accurate assembly of the system. However, whilst the foregoing describes an optimum method of installation, it is recognised that this may not be the only method of installation; and indeed, in other embodiments of mounting unit, having various first and second interlocking features, other suitable methods of installation of the roof system may be deployed.

To being installation, an optional starter strip (not shown) may be installed, which may have characteristics of the header rail 16 of a mounting unit 10, such that a series of male spurs are provided that imitate the header rail 16 portion of a full-sized mounting unit 10a, 10b, 10c. A first mounting unit 10a is then installed by locating the female clip(s) 34 of the first mounting unit 10a onto the male spurs 34 provided by the starter strip. The series of apertures or holes 11a, 11b, 11c, 1 id that are provided within the header rail 16 are then used to correctly position and locate fixings (such as nails, screws or other suitable fixings) to securely attach the mounting unit 10a onto a roof batten '1311 or board. (In the end views of Figures 9 and 10, the apertures 11a-11d cannot be seen). In this way the mounting unit 10a is permanently and resiliently fixed The next adjacent mounting unit 10b of the first course is then mounted onto the spurs of the starter unit and set alongside the already installed mounting unit 10a. The two mounting units 10a, 10b are connected along their perpendicular joint by means of the first interlocking feature 22a/22b as described above (with reference to Figures 5, 6 and 7). The first interlocking feature 22a/22b forms a waterproof and permanently resilient join which allows for a degree of lateral adjustment. Subsequent mounting units are then installed along the first course in the same way. This process continues along the course until the edge of the roof is reached. Next, and preferably before the second course of mounting units 10c is installed, roof coverings 30a, 30b are installed or affixed onto the course of mounting units 10a, 10b that have been laid. In alternative methods of installation, the roof covering items for a mounting unit 10a, may be laid onto and (optionally) affixed thereto before the entire first course of mounting units 10a, 10b has been laid.

Optionally, the roof coverings 30a, 30b are simply located onto the one or more mounting components 20a, 20b, 20c, 20d. In other envisaged arrangements an additional (third) locking feature may be provided in the form of a fastener or clip, which may be slotted onto the footer region 18 of a mounting unit 10 and slate 30a, in order to further secure the slate or roof covering 30a to the mounting unit 10. Once the roof coverings 30a, 30b or slates 30a, 30b have been installed (on at least some if not all of the mounting units 10a, 10b in the first course), then installation of the second course of mounting units 10c may commence. Again, the mounting units 10c are installed by manipulating the female slots 38 of each mounting unit 10c about and onto the installed male spurs 34 of the header units 16 of the mounting units 10a, 10b of the first course. The method of fixing is repeated, and adjacent devices installed to again complete the course. The whole process is repeated to until the whole roof is fully covered.

Once installed the roof covering system of the present invention can proved a waterproof covering, which can if desired have an arrangement of slates in a broken bond effect. The waterproof covering provided by the interconnected modular mounting boards 10a, 10b, 10c, in having lateral interconnections and lateral deformation; and longitudinal interconnections with expansion gaps for longitudinal adjustment provides a successful solution that addresses the failings of GB 2,249,112.

Referring now to Figures 11 to 15, there is shown a further embodiment of the present invention. In the second embodiment, like numerals have, where possible, been used to denote like parts, albeit with the addition of the prefix "100" to indicate that these features belong to the second embodiment. The further illustrated embodiment shares many common features with the first embodiment and therefore only the differences from the embodiment illustrated in Figures 1 to 10 will be described in significant detail.

In Figure 11 a mounting unit 110 according to a further illustrated embodiment is shown. In Figure 11, a first, outward-facing, uppermost or top-side 112 of the mounting unit can be seen.

The mounting unit 110 is very similar to the mounting unit 10 of the first illustrated embodiment and also comprises: a first end 117; a second-end 119; a generally planar, substantially rectangular main body 115; a header rail 116 provided in the region of the first end 117 of the mounting unit 110; and a foot-portion 118 provided in the region of the second-end 119 of the mounting unit 110 (opposite to the first-end 117).

The main body 115 again provides an appropriately sized supporting area onto which slates, files, or other roof covering items, (hereinafter referred to as "roof covering items" or "slates" 130a, 130b) can be safely, securely, accurately and easily, located and secured. In this arrangement the mounting unit 110 comprises one or more mounting features 120a, 120b, 120c, 120d, provided at least substantially within the header rail 116 and disposed on the upper side 112 of the main body 115. The one or more mounting features 120a, 120b, 120c, 120d each co-operate with a mounting component 123a, 123b, 123c, 123' (see Figures 13, 14 and 15). A roof covering item 130a, 130b can be located onto the mounting unit 110 and affixed thereto by means of one or more mounting components123a, 123b, 123c, 123' secured to the mounting unit 110 head rail 116 by the one or more mounting features 120a, 120b, 120c, 120d.

As shown in Figure 15, the one or more mounting features 120a, 120b, 120c, 120d are provided as grooves, channels or profiled slots within the header rail 116 and are shaped, sized and configured for receiving a portion of the one or more mounting components123a, 123b, 123c, 123' therein.

As shown, the header rail 116 is formed as a moulded, stepped band across the top of the main body 115. As shown in Figure 11, the outward-facing, uppermost or top-side 112b of the header rail 116 rests in a plane disposed above the plane of the first, outward-facing, uppermost or top-side 112 of the main body 115. The header rail 116 may have a substantially similar thickness to the thickness of the main body 115, and as such, when viewed from the back-side (not shown, but similar to Figure 2), the second, inward-facing, lowermost or backside of the main body 115 may rest in a plane that is disposed above the plane of the second, inward-facing, lowermost or back-side of the header rail 116. As with the first embodiment, this stepped-formation allows the mounting unit 110 to be placed onto and affixed to a batten B101', 'B102' of a roof structure (see Figures 13 and 14) and provides for a large mounting area of interconnected mounting units 110 to be provided rapidly and accurately onto which slates 130a, 130b or other roof tiles can be quickly and securely affixed. The inter-connecting formation provided by the use of the mounting units 110 allows a male portion 134 of the header rail 116 of one mounting unit 110a to engage with a female locking portion located proximate the foot-end 118 of another (overlapping) mounting unit 110b as is described further below and illustrated in Figure 14.

To allow for the mounting units 110to be quickly attached to a roof batten 'B101', 'B102' the header rail 116 is formed with or otherwise provided with securing means. More specifically, but not exclusively, the header rail 16 may be provided with a series of apertures or holes 111a, 111b, 111c, 111d that are used to correctly position and locate fixings, which in this embodiment are provided as mounting components 123a, 123b, 123c, 123'. Optionally, the apertures or holes 111a, 111b, 111c, 111d may be provided within the grooves, channels or profiled slots that form the one or more mounting features 120a, 120b, 120c, 120d. This is perhaps best shown in Figures 13 and 15. The apertures or holes 111a, 111b, 111c, 111d may be elongated to allow for a degree of expansion of the mounting unit 10. Where the grooves, channels or profiled slots that form the one or more mounting features 120a, 120b, 120c, 120d are narrow, the apertures or holes 111a, 111b, 111c, 111d may be circular.

Referring to Figure 13, the part-assembly of a system for mounting a plurality of roof covering items to a roof is shown. A batten "B101" provides a rail to which the mounting unit 110 of Figure 11 is being attached by means of the mounting components123a, 123b, 123c, 123'. As shown, the mounting components 123a, 123b, 123c, 123' are optionally each the same and will be described in relation to a single mounting component 123a. The mounting component 123a comprises a first shank 126 which terminates in a point 125. The first shank 126 terminates at a corner, which is optionally about a 900 corner. The corner continues into second shank 127 which terminates in a hooked-end 128. The hooked-end 128 returns relative to the second shank 127 and is positioned in spaced relation above part of the second shank 127. In use, the point 125 and first shank 126 are inserted into an aperture or hole 111a, 111b, 111c, 111d in the header rail 116, which aperture or hole 111a, 111b, 111c, 111d is provided within a groove, channel or profiled slot of one of the mounting features 120a, 120b, 120c, 120d. The second shank 127 is partially seated within groove, channel or profiled slot of one of the mounting features 120a, 120b, 120c, 120d and as shown in Figure 15, a portion of the second shank 127 sits parallel to and spaced above the upper surface 112 of the main body 115. A space or gap 'G' therefore exists between that portion of the second shank 127 and the upper surface 112 of the main body 115. The gap 'G' is sized for the roof covering, for example slate tile 130a, 130b that is to be held on the mounting unit 110 (see Figure 15).

Referring to Figure 14, the further assembly of the system of Figure 13 is depicted. A second batten 'B102' provides another structural rail to which a further course of mounting units 110b is being attached. Additionally, in this Figure, it can be seen that the roof coverings 130a, 130b on the first-laid course of mounting units 110a are being overlapped by a second over-laid course of roof coverings 130c being located and secured to the mounting units 110b. The first-laid 110a and second over-laid 110b mounting units are interlocked and secured together using the second (longitudinal) interlocking feature as described above. Furthermore, the placement of off-set (broken-bond) roof-covering elements 130a, 130b, such as a slate roof tiles 130a, 130b onto the mounting units 110a, 100b can be seen along with the placement of the hook-shaped mounting components 123', 123c. The hook-shaped mounting components 123', 123c enabling the header rail 116 to be securely attached to the batten '101', '102' of the roof structure; clamp a roof covering tile 130c onto the mounting unit 110 and serve as a retaining clip for a bottom edge of a roof covering tile on an overlaid course.

Advantageously, the mounting board system taught herein may be used in applications where a lighter weight roof structure would be desirable or required, for example, in a lower-cost housing project, or conservatory; and where for aesthetic and other reasons, a slate-tiled covering, optionally with a broken bond layering pattern is desirable. The mounting unit system, as shown in Figure 14 allows for the systematic, weatherproof, accurate, quick and easy installation of slate files. Beneficially the system allows the tiles to be arranged on those mounting units 110, in a broken bond layering (if required) whilst being securely held at both their top end and bottom end. At the top end, the tiles 130a, 130b are clamped, in the gap 'G' between a portion of the second shank 127 of a mounting component 123' and the upper surface 112 of the main body 115. At the top end, the files 130a, 130b are retained by the hooked-end 128 of a mounting component 123' that affixes the header rail 116 of a mounting board 110a of a lower course to a batten 'B101' for that lower course.

Referring back to Figure 11, it can be seen that in this illustrated embodiment the first interlocking feature 122a comprises only a first locking member 122a disposed on a first side edge of the main body 112; and that a second locking member is not necessarily disposed on an opposite second side edge of the main body 112. In such an arrangement, a first interlocking feature 122a, disposed on a first side edge of the main body and comprising a deformable portion to facilitate expansion and contraction in a lateral direction, is coupled to, overlaps, abuts, is juxtaposed or otherwise fits or site adjacent to a free-second side edge of the main body 112.

It can be appreciated that various changes may be made within the scope of the present invention, for example, it can be appreciated that within the scope of the present invention, the roofing systems disclosed herein are not necessarily limited in their application to slate tiles or plain tiles. Indeed, it is envisaged that the mounting units and systems disclosed herein may have beneficial application and utility with a wide range of styles, sizes and types of roof structure and roof covering not necessarily limited to that shown and described herein.

It will be recognised that as used herein, directional references such as "top", "bottom", "front", "back", "end", "side", "inner", "outer", "upper" and "lower" do not necessarily limit the respective components to such orientation, but may merely serve to distinguish components from one another.

Claims (27)

1. CLAIMSA roof covering system comprising: i) a mounting unit having a generally planar main body having a roof facing underside, an outward facing upper side; the mounting unit having a header rail at a first end of the main body; and a foot-end opposing said first-end; ii) a first interlocking feature disposed on at least a first side edge of the main body, the first interlocking feature comprising a deformable portion to facilitate expansion and contraction in a lateral direction; Hi) at least one spacing element disposed on the underside of the main body, said spacing element having a first portion proximate the first end and a second portion proximate the foot end of the main body, the first portion of the spacing element having a first height proximate said first end; and the second portion of the spacing element having a second height proximate said foot end, the first height being sufficiently less than said second height to provide a pitch for enabling water runoff; iv) a second interlocking feature comprising a first male locking component provided on said header rail and a second female locking component formed as a slot for receiving a first male locking component of another mounting unit when the second interlocking feature is deployed to interlock the said mounting unit to said another mounting unit; and v) a locating element provided to facilitate accurate location of the header rail of one mounting unit and the spacing element of another mounting unit when the second interlocking feature is deployed; the locating element being provided on said header rail as a deformable protrusion; and said header rail and a portion of the second female locking component together defining an expansion gap.
2. A system according to claim 1 wherein said header rail is a generally solid construct having one or more apertures formed therein for securing the header rail to a structural component of a roof.
3. 3. A system according to claim 2 wherein a first male locking component of the second interlocking feature provided on said header rail is provided as a formation along an end-edge of the header rail.
4. 4. A system according to claim 3 wherein said locating element is provided as a continuous rib or continuous protrusion along the header rail and is spaced from said first male locking component.
5. A system according to any preceding claim wherein said first interlocking feature comprises a first locking member disposed on a first side edge of the main body; and a second locking member disposed on a second side edge of the main body.
6. 6. A system according to claim 5 wherein one or both of the first and second locking members comprise a deformable portion to facilitate expansion and contraction in a lateral direction.
7. A system according to claim 6 wherein said deformable portion comprises a material that has a deformable characteristic; and/or said deformable portion comprises a shaped-structure or configuration that can move into and out of the plane of the mounting unit in a lateral direction.
8. 8. A system according to claim 7 wherein said deformable portion comprises a shaped-structure comprising one or more of: corrugated, undulated, "V", "U", folded, creased and/or rib shapes.
9. A system according to any preceding claim wherein said mounting unit comprises one or more mounting components disposed on the upper side of the main body by which a roof covering item can be attached to the mounting unit.
10. 10. A system according to claim 9 wherein said mounting components are each provided as an integrally moulded, protrusion or lug, upwardly standing from the upper side of the main body and disposed closer to the header rail than to the foot-end of the main body.
11. 11. A system according to claim 10 wherein the mounting unit is configured to accommodate two roof covering items and comprises four integrally moulded upwardly standing lugs.
12. 12. A system according to any preceding claim 1 to 9 wherein the mounting unit comprises one or more mounting features provided at least substantially within said header rail and disposed within the upper side of the main body, the one or more mounting features each comprising at least one of said one or more apertures formed for securing the header rail to a structural component of the roof; and said one or more mounting features configured to receive and co-operate with an one or more mounting components.
13. 13. A system according to claim 12 wherein the one or more mounting features are provided as grooves, channels or profiled slots within the header rail and are shaped, sized and configured for receiving a portion of the one or more mounting components therein.
14. 14. A system according to claim 13 further comprising one or more mounting components and wherein the one or more mounting components each comprises: a first shank which terminates in a point; a corner; a second shank continuing from the corner; and a hook-shaped portion, wherein the second shank terminates in the hooked-shaped portion; and wherein the hook-shaped portion returns relative to the second shank and is positioned in spaced relation above part of the second shank.
15. 15. A system according to claim 14 where, in use, the point and first shank are inserted into one of said one or more apertures formed for securing the header rail to a structural component of the roof; the second shank is partially seated within a groove, channel or profiled slot of one of the mounting features; and a portion of the second shank sits parallel to and spaced above the upper surface of the main body such that a gap 'G' exists between that portion of the second shank and the upper surface of the main body, into which gap a roof covering can be fitted.
16. 16. A system according to any preceding claim wherein the female locking component of the second interlocking feature comprises a slot or socket, which slot or socket is provided by an extension of the second portion of the spacing element such that said spacing element comprises a slot or socket shaped portion proximate said foot end and such that said first male locking component provided on said header rail is configured and arranged for interlocking with the slot or socket of the spacing element of another mounting unit.
17. 17. A system according to any preceding claim wherein said first portion and said second portion of the spacing element are contiguously formed as a single tapered rib.
18. 18. A system according to claim 17 wherein the mounting unit comprises six tapered ribs.
19. 19. A system according to claim 18 wherein the six tapered ribs are arranged with a first along a first side of the main body; two middle ribs disposed side-by-side and substantially centrally of the main body; a fourth rib along the second side of the main body; a fifth rib disposed between said first rib and said two middle ribs; and a sixth rib disposed between said two middle ribs and said fourth rib.
20. 20. A roof covering system according to any preceding claim wherein the system comprises a plurality of mounting units.
21. 21. A roof covering system according to claim 16 wherein said mounting units are laid in a series of courses, with adjacent mounting units of each course being laterally interlocked by said first interlocking feature; and with overlapping mounting units of adjacent courses being longitudinally interlocked by said second interlocking feature.
22. 22. A roof covering system according to any preceding claim comprising a starter strip or a series of starter units.
23. 23. A covered roof comprising: a roof structure; a roof covering system according to any of claims 1 to 22 provided thereon; and a plurality of roof covering items selected from: slates, files, PV cells, stone tiles, and plain files.
24. 24. A mounting unit for use in the roof covering system according to any preceding claim, 1 to 22, the mounting unit having: CO a generally planar main body having a roof facing underside, an outward facing upper side; the mounting unit having a header rail at a first end of the main body; and a foot-end opposing said first-end; CIO a first interlocking feature disposed on at least a first side edge of the main body, the first interlocking feature comprising a deformable portion to facilitate expansion and contraction in a lateral direction; (iii) at least one spacing element disposed on the underside of the main body, said spacing element having a first portion proximate the first end and a second portion proximate the foot end of the main body, the first portion of the spacing element having a first height proximate said first end; and the second portion of the spacing element having a second height proximate said foot end, the first height being sufficiently less than said second height to provide a pitch for enabling water run-off; (iv) a second interlocking feature comprising a first male locking component provided on said header rail and a second female locking component formed as a slot for receiving said first male locking component; and (v) a locating element provided to facilitate accurate location of the header rail of one mounting unit and the spacing element of another mounting unit when the second interlocking feature is deployed; the locating element being provided on said header rail as a deformable protrusion; and said header rail and a portion of the second female locking component together defining an expansion gap.
25. 25. A mounting component comprising: a first shank which terminates in a point; a corner; a second shank continuing from the corner; and a hook-shaped portion, wherein the second shank terminates in the hooked-shaped portion; and wherein the hook-shaped portion returns relative to the second shank and is positioned in spaced relation above part of the second shank.
26. 26. A kit of parts for forming a covered roof, the kit comprising a plurality of mounting units according to claim 24 when dependent upon any of claims 12, 13 and 14; and a plurality of mounting components according to claim 25.
27. 27. A kit of parts according to claim 26 further comprising one or more starter units.