TECHNICAL FIELD

This disclosure relates to roofing elements for cladding roof structures. In particular, this disclosure relates to roofing elements formed of composite materials or synthetic materials such as those comprising e.g. thermoset plastics.

BACKGROUND ART

Roof elements, or roof tiles, are used to clad roof structures so as to prevent the ingress of water, dust, etc. into a building. Such tiles are manufactured from a range of materials including terracotta, slate, concrete, and plastic (the latter often referred to as composite roof tiles, as they can comprise a fibre-reinforced polymer resin).

Composite roof tiles are lightweight (e.g. in comparison to concrete tiles). This can make them easier to handle, but can also result in them being susceptible to being lifted by high winds. Hence, some composite tiles have been configured to be mounted to the roof structure in such a way that prevents or reduces this lifting. However, such mounting arrangements can result in installation being

complicated and time consuming.

It is to be understood that, if any prior art is referred to herein, such reference does not constitute an admission that the prior art forms a part of the common general knowledge in the art, in Australia or any other country.

SUMMARY

Disclosed herein is a polymer composite roofing element for cladding a roof structure. The element comprises a body having a leading edge and an opposing trailing edge. For example, in a sloping roof, the leading edge can be the in-use lower edge of the body, and can overlap a trailing edge of an adjacent lower roofing element. The trailing edge can be the in-use higher edge of the body.

The element further comprises a mounting region for securing the element to the roof structure. A retainer extends from the body proximate to the leading edge so as to define a recess. In use, this recess is able to receive the trailing edge of a like-element so as to restrict movement of the leading edge of the element away from the roof structure.

In other words, the like-element may interlock with the first mentioned element (i.e. by way of its receipt in the recess). The like-element may be further interlocked (e.g. in the same way) to one or more further elements, and/or may be secured to the roof structure. In this way, receipt of the like-element in the recess may restrict movement of the leading edge of the element away from the roof structure.

The element, because of the retainer, is simple and quick for an installer to install. This is especially beneficial when multiple elements must be secured to a roof structure. The retainer is not reliant on the roof structure being of any particular type, shape or dimension, because it connects to the like-element and not the roof structure via a roof batten system. This provides flexibility in the use of the system and may avoid roof compatibility issues. The retainer can also provide adjustability (i.e. in regards to the placement of an element relative to the roof structure, or relative to other like-elements). In this regard, the recess may be such that the extent to which the like-element extends into the recess may be varied. So, for example, where a greater overlap is required between the element and the like-element, the like-element may be positioned so that it extends fully (or substantially fully) into the recess. On the other hand, where less overlap is required, the like-element may be positioned only partially into the recess. The amount of overlap may be adapted to suit, for example, the slope of the roof structure (greater overlap may be required for shallower slopes for waterproofing reasons). The overlap may also be adjusted (e.g. during installation) where there is some variance in the positioning of roof members of the roof structure. A higher degree of overlap (i.e. extent of positioning into the recess) may be employed in higher wind areas, for better securement of each roofing element.

In one embodiment, the retainer may extend from the body so as to abut the underside surface of the like-element, in use. This abutment may provide for restriction of movement of the element away from the structure (and away from the like-element).

In one embodiment, the roofing element may further comprise an abutment portion for abutting a roof member of the roof structure, in use, so as to restrict movement of the element in at least one direction relative to the roof structure.

In one embodiment abutment of the abutment portion against the roof member may restrict movement of the element in a downward direction along a slope of the roof structure. In this way, the element may hook over the roof member. The roof member may, for example, be a batten. The roof element may be supported on an upper side of the batten and the abutment portion may abut against a side of the batten to restrict movement of the element.

In one embodiment the abutment portion may protrude from an underside of the element.

In one embodiment the abutment portion may be positioned proximate to the trailing edge.

In one embodiment the roofing element may comprise a plurality of discrete abutment portions spaced along, and proximate to, the trailing edge. The roofing element may also comprise a plurality of retainers spaced along, and proximate to, the leading edge. The spacing of the abutment portions and retainers may be such that the retainers can extend between the adjacent abutment portions of the like- element in use. In one embodiment the spacing of the abutment portions and retainers may be such that the retainers extend between the adjacent abutment portions of the like- element when the elements are arranged in both a brick pattern and a stack pattern. A brick pattern is where rows of tiles are offset laterally to adjacent rows (e.g. by half a tile). A stack or straight pattern is where the rows of tiles are not offset (i.e. such that the sides of the tiles are aligned).

In one embodiment the roofing element may be configured so as to be mounted to a roof structure with a plurality of like -elements in both a brick pattern and a stack pattern. In one embodiment the roof member of the roof structure may comprise a transversely extending batten against which abuts the or each abutment portion (or which is abutted by the or each abutment portion). The batten may be secured to rafters of the roof structure.

In one embodiment the retainer may comprise a resilient projection that abuts the underside of the like-element.

In one embodiment a portion of the resilient projection may be spaced from an underside of the body, so as to define the recess for receipt of the trailing edge of the like-element.

In one embodiment the resilient projection may be arranged to be biased against the underside of the like-element when received in the recess. In this way, the resilient projection may flex around the edge of the like-element as it is received in the recess. The biased nature of the projection may provide some resistance to movement of the element relative to the like-element (i.e. it may restrict sliding of the like-element in the recess). It may also further restrict movement of the element away from the roof structure.

In one embodiment the resilient projection may be formed of stainless steel strip (for example, in the form of a clip). That is, the projection may be formed separately to the body, and may then be mounted to the body. In an alternative embodiment the resilient projection may be integral with the body (e.g. it may form a moulded portion of the body).

In one embodiment the body may further comprise a boss to which an end of the resilient projection is arranged to be mounted. The boss may be integrally formed with the body of the element. The boss may space the retainer from an underside of the body.

In one embodiment the resilient projection may be removably secured to the boss. For example, a clip may be used to secure the projection to the boss. In practice, the resilient projection (and e.g. clips) may be supplied to a roofing element installer (e.g. a roofing contractor) separately from the body. The installer may then have the choice of installing only the necessary number of resilient projections to each roofing element.

In one embodiment the mounting region may be positioned proximate the trailing edge.

In one embodiment the mounting region may comprise two spaced mounting holes for receipt of fasteners to fasten the element to the roof structure. The mounting holes may generally be positioned at opposing corners of the body.

In one embodiment the mounting region may further comprise a frangible portion for optional receipt of a fastener therethrough to fasten the element to the roof structure. The frangible portion may, for example, be a thinner portion of the body and may be marked so as to be visible to an installer.

In one embodiment the frangible portion may be disposed generally centrally between the mounting holes. That is, the frangible portion may provide one or more further intermediate mounting points between the mounting holes and may be in the form of a thinner and/or weaker portion of the body. In one embodiment the roofing element may further comprise a spacer, such as a ridge, that projects from an underside of the body. The spacer may rest on the roof structure, in use, so as to space the underside of the body from the roof structure. This spacing may provide a gap (i.e. between the body and the roof structure) for receipt of the retainer of a like-element.

In one embodiment the body may further comprise opposing side edges extending between the leading and trailing edges, the roofing element further comprising a tab extending from one of the side edges, the tab arranged to locate beneath a laterally adjacent like-element when secured to the roof structure in use. The tab may resist movement of the element away from the structure along the side of the element.

In one embodiment the tab may comprise a mounting hole that aligns with a mounting hole of the like-element, in use.

In one embodiment the leading edge may be at least 700 mm long. In this regard, the roofing element may be of the type that is considered to be a "large format" roofing element or tile.

In one embodiment the shape and dimensions of each roofing element may be such that it covers an area of at least 0.45 m ² of the roof structure when mounted thereto. Again, in this regard, the roofing element may be of the type that is considered to be a "large format" roofing element or tile

In one embodiment the shape and dimensions of each roofing element may be such that it covers an area of at least 0.9 m ² of the roof structure when mounted thereto.

In one embodiment the roofing element may comprise a guide surface configured to guide the roofing element into side-by-side relation with a like-element such that the trailing and leading edges of the elements are generally aligned. Also disclosed is a roofing system. The system comprises a roof structure and a plurality of roofing elements as set forth above. Each roofing element is secured to the roof structure at the mounting region and retained against movement away from the roof structure by its respective retainer. In one embodiment, when secured to the roof structure, at least some of the plurality of roofing elements may define a plurality of edge roofing elements. The retainers of each roofing element that is not an edge roofing element may extend under an adjacent roofing element to retain the first-mentioned roofing element against movement away from the roof structure. Thus, the edge of the system of roofing elements comprises a number of edge elements, with each edge element having a free edge that comprises at least one retainer (i.e. which retainer is not engaged with any further element).

In one embodiment a leading edge of the non-edge roofing element may be adjacent to said adjacent roofing element. That is, the roofing elements are arranged such that the retainers are positioned at the leading edge of each element so as to engage a trailing edge of the adjacent elements.

In one embodiment the edge roofing elements may be secured at a leading edge of the roof structure. The retainers of the edge roofing elements may extend beneath a portion of the roof structure so as to abut an underside surface of the portion of the roof structure, in use, to restrict movement of the edge roofing elements away from the roof structure.

In one embodiment the portion of the roof structure may comprise a bracket secured to a roof member of the roof structure. The bracket may be in the form of an angle. A recess may be defined between the bracket and the roof member for receipt of the retainer of a respective edge roofing element. In this way, the bracket effectively acts as a dummy roof element.

In one embodiment the bracket may comprise a first portion for securing the bracket to the roof member, and a second portion for defining the recess for receipt of a respective retainer. The first and second portions may extend generally perpendicularly to one another to define a bracket having a generally L- shaped profile. In some embodiments, the bracket may be an angle strip, or a channel section.

In one embodiment a respective bracket may be provided for each retainer.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described by way of example only, with reference to the accompanying drawings in which

Figures 1A, IB, 1C and ID are views of a first embodiment of a roofing element;

Figure IE is a detailed view of the underside of two adjacent roofing elements of the first embodiment engaged with one another;

Figure IF is a detailed view of a retainer of one of a roofing element of the first embodiment;

Figures 2A and 2B are perspective views of a roofing system formed of roofing elements similar to that shown in Figures 1A to IF;

Figure 2C is a section view of one roofing element engaging another, adjacent roofing element in the roofing system;

Figure 3 is section view showing a variation of the leading edge of the roofing element of the first embodiment.

Figure 4A is a perspective view of a bracket for use as part of the roofing system shown in Figures 3A, 3B and 3C;

Figure 4B is a side view of the bracket of Figure 4A;

Figure 4C is a perspective section view of the bracket of figure 4A and 4B, when used in a roofing system; Figure 5A is a perspective view of the underside of a second embodiment of a roofing element;

Figure 5B is a top view of the second embodiment of the roofing element;

Figures 5C and 5D are detailed perspective views of guide surfaces of the second embodiment;

Figure 5E is a detailed perspective view of a mounting hole of the second embodiment; and

Figure 5F is a detailed perspective view of a rebate of the second embodiment.

DETAILED DESCRIPTION

In the following detailed description, reference is made to accompanying drawings which form a part of the detailed description. The illustrative embodiments described in the detailed description, depicted in the drawings and defined in the claims, are not intended to be limiting. Other embodiments may be utilised and other changes may be made without departing from the spirit or scope of the subject matter presented. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings can be arranged, substituted, combined, separated and designed in a wide variety of different configurations, all of which are contemplated in this disclosure.

A composite roofing element for cladding a roof structure is illustrated in Figures 1A, IB, 1C and ID in the form of a large format roof tile 100. The roof tile 100 is, for the most part, an integrally formed thermoset resin polymer structure that is reinforced with fine glass fibres (i.e. a glass fibre reinforced composite). In the illustrated embodiment, the large format roof tile 100 has dimensions of approximately 750 mm x 1500 mm. This type of tile is generally larger than other tiles, especially non-composite roof tiles that are typically used to clad roof structures.

The roof tile 100 comprises a generally planar rectangular body 102 (of thermoset composite resin) having a leading edge 104 and an opposing trailing edge 106, and two opposing side edges 108 extending between the leading 104 and trailing edges 106. In use, the roof tile 100 is oriented such that the side edges 108 are parallel to the slope of the roof, the trailing edge 106 is positioned on the upward side (towards the apex of the roof), and the leading edge 104 is positioned on the lower side (towards the lower edge of the roof). The body 102 comprises an upper surface 1 10 that is visible when mounted to a roof structure 101 (see Figure 2A), and an underside surface 1 12 that rests on the roof structure 101 when mounted thereto. The upper surface 1 10 may have a texture, pattern, colouring, surface coating, etc. applied thereto in order to alter the appearance of the roof tile 100. For example, the upper surface 1 10 may be shaped so as to resemble a non-composite roofing element (e.g. a concrete, slate, or terracotta roofing element).

A mounting region 1 14, which is configured for securing the roof tile 100 to the roof structure 101, is positioned proximate to the trailing edge 106 of the body 102. In use, and as will be described in more detail below, the roof tile 100 is mounted to the roof structure 101 at the mounting region 1 14.

The mounting region 1 14 comprises two spaced mounting holes 116 for receipt of fasteners (e.g. screws, bolts, rivets, nails etc.) to fasten the roof tile 100 to the roof structure 101. One of these mounting holes 1 16 is positioned proximate the intersection of a side edge 108 and the trailing edge 106 of the body 102, and the other is positioned proximate the intersection between the opposing side edge 104 and the trailing edge 106 of the body 102 (i.e. one at each of the trailing edge 106 corners).

The mounting region 1 14 also comprises three frangible portions 118 (which in other embodiments could instead be further mounting holes) which are spaced generally evenly between the mounting holes 1 16. The frangible portions 1 18 provide further points on the body 102 where fasteners may be used to fasten the roof tile 100 to the roof structure 101. Although the frangible portions 118 are not perforated, they can be formed in such a way that they define an area of weakness, where a fastener can be forced through the body 102 with relative ease, and without causing damage to other parts of the element. In other words, each frangible portion 1 18 provides an optional further point of fastening that may or may not be used depending on the restrictions of a particular environment. For example, areas that are prone to high winds may require extra fastening of the roof tile 100 to the roof.

The roof tile 100 is further retained against movement away from the roof structure 101 by a plurality of spaced retainers, each in the form of a clip. These clips have been removed from the roof tile 100 shown in Figures 1A, IB, 1C and ID. Figure IE depicts the roof tile 100 (of the type described above) engaged with a like-roof tile 100' . This engagement is by way of retainers, again, in the form of clips 120. Each clip 120 extends from an underside surface 1 12 of the body 100 and proximate the leading edge 104. The extension is such that, in use, the clip abuts the underside surface 1 12' of the like-roof tile 100' (i.e. that is also secured to the roof structure 101).

One such clip 120 is shown in more detail in Figure IF. This clip 120 is representative of all of the clips 120 of the roof tile 100. The clip 120 takes the form of a resilient strip (e.g. stainless steel strip) and is able to abut the underside 1 12' of a like-roof tile 100' in use. In other embodiments, the clip may include strengthening gussets. This clip 120 is spaced from the underside 1 12 of the roof tile 100 by a boss 122 that protrudes from the underside 1 12 of the body 102. The boss 122 is integral with the underside 112 of the body 102 (i.e. so as to form part of the body 102). A distal end (i.e. distal from the generally planar surface of the underside of the body 112) of the boss 122 comprises a generally flat support surface 124 for receipt of a mounting end 126 of the clip 120. This support surface 124 is recessed into the end of the boss 122, and sidewalls of the recess extend either side of the flat support surface 124 to laterally support the mounting end 126 of the clip 120. The clip 120 curves (or hooks) around a rear side of the boss 122 at its mounting end 126 and extends from the boss 122 to a remote end 128. The remote end 128 of the clip 120 (or a region thereof) abuts the underside 1 12' of the like-roof tile 100' in use. As set forth above, the mounting of the clip 120 to the boss 122 is such that the clip 120 is spaced from the underside 1 12 of the body 102, and is such that the trailing edge 106' of a like-roof tile 100' can be received in a recess defined between the clip 120 and the underside 1 12 of the body 102 of the roof tile 100. To facilitate this, the remote end 128 of the clip 120 is bent in a curved manner so as to comprise a bump 130 that extends away from the underside 1 12 of the body 102. This bump 130 can help to guide the like-roof tile 100' between the clip 120 and the body 102, and/or can help to guide the clip 120 past the trailing edge 106' of the like-roof tile 100' .

Receipt of the like-roof tile 100' is further facilitated by ramps 131 that extend between the underside 1 12 of the body 102 and a laterally extending rib 150 that projects from the underside 1 12 of the body 102. In use, and as will be described in further detail with respect to the embodiment of Figure 2C, the trailing edge 106' of the like-roof tile 100' locates between the laterally extending rib 150 and the clip 120. As the trailing edge 106' of the like-roof tile moves into this position, it engages the ramps 131 and is guided by the ramps so as to be located in position between the clip 120 and the laterally extending rib 150. As set forth above, the clip 120 helps to retain the roof tile 100 against movement away from a roof structure. As should be apparent, the clip 120 performs this function by retaining the roof tile 100 against the like-roof tile 100' . This arrangement also helps to minimise gaps between the underside of the roof tile 100 and the upper surface 1 10' of the like-roof tile 100' (e.g. which could open up due to wind loading). These gaps are also minimised by the clip 120 being biased so as to press against the underside 112' of the like-roof tile 100' when it is received between the clip 120 and the body 102 of the roof tile 100. That is, the gap between the remote end 128 (or bump 130) of the clip 120 and the underside 112 of the body 102 is marginally smaller than the thickness of the trailing edge 106' of the like-roof tile 100'. In this way, when the like-roof tile 100' is received through the gap, the clip 120 is forced to flex against the bias and is consequently urged against the underside 112' of the like-roof tile 100'.

The clip 120 as depicted is removably secured to the boss 122. To enable this removable mounting, the boss 122 comprises a threaded bore and the clip comprises a corresponding aperture. For mounting of the clip 120 to the boss 122, the aperture and bore are aligned and a fastener can be received therethrough. The clip can be secured by e.g. the head of the fastener or a circlip received between a fastener and the clip 120. The mounting is such that a roofing contractor can secure one or more clips to a given roof tile 100 on site.

In addition to the clips 120, the roof tile 100 also comprises a plurality of abutment portions in the form of ridges or protrusions 132 that each protrude from the underside surface 112. The protrusions 132 are disposed so as to be proximate to, and spaced along, the trailing edge 106 of the roof tile 100. In-use, each protrusion 132 is configured to abut a roof member (typically a batten - see Figure 2A) of the roof structure so as to restrict movement of the roof tile 100. In the illustrated embodiment, the protrusions 132 are configured to abut a trailing side (i.e. facing the apex of the roof structure) of the batten so that movement of the roof tile 100 is restricted in a downward direction along a slope of the roof structure. In this way, each protrusion 132 may be considered a hook that hooks over a batten and prevents the roof tile 100 from sliding down the roof structure (i.e. towards a bottom or leading edge of the roof structure).

Located at either side (in the lateral direction) of each protrusion 132 is a pair of spacers in the form of ribs 134 that are integral with the protrusion 132. The spacer ribs 134 are angled relative to the protrusion 132 (which is generally parallel to the leading and trailing edges). Each spacer rib 134 joins a further spacer rib 136 that extends laterally across the body 102. The spacer ribs 134 do not protrude from the underside of the body 102 to the same extent as the protrusions , such that a distal edge of each rib 134 rests on top of the batten (which the protrusions 132 hook over) so as to space the underside 1 12 of the body 102 from the roof structure.

As set forth above, the protrusions 132 are spaced along, and proximate, to the trailing edge 106 of the roof tile 100. As is also described above (and as is apparent from the figures), the plurality of clips 120 are spaced along, and proximate to, the leading edge of the roof tile 100. The spacing of both the abutment protrusions 132 and the clips 120 is such that, when the clips 120 of the roof tile 100 engage the trailing edge 106 of a like-roof tile 100', the clips 120 are able to locate between the protrusions 132 (and the spacer ribs 134). In addition to engaging a like- roof tile 100' positioned down-slope from the roof tile 100, the roof tile 100 is adapted to engage a laterally adjacent like-roof tile 100" (see Figure 2A). This engagement is by way of a tab 138, shown in Figures 1A, IB, 1C and ID, which extends from one of the side edges 108 of the body 102. An upper surface 140 of the tab 138 is set back from the upper surface 1 10 of the body 102 of the roof tile 100 such that the tab 138 is able to locate beneath the laterally adjacent like-roof tile 100". This further restricts movement of the roof tile 100 away from the roof structure (i.e. when the laterally adjacent like- roof tile is also secured to the roof structure). Receipt of the tab 138"' of a laterally adjacent like-roof tile 100"' at the opposing (i.e. non-tab) edge 108 of the roof tile 100 is somewhat permitted by presence of the spacer ribs 134, 136 on the underside 1 12 of the roof tile 100. The space between the body 102 and the roof structure, which is provided by the spacer ribs 134, 136, allows the tab 138 to be received under the laterally adjacent like -roof tile 100"' . Some spacing of the body 102 from the roof structure is also provided by a plurality of intermediate spacer ribs 142 disposed on the underside 1 12 of the body 102. The ribs 142 are spaced evenly along a line that extends between the side edges 108, the line generally being centrally located between the leading 104 and trailing 106 edges. The positioning of the ribs 142 is such that they are able to rest on an intermediate batten of the roof structure (i.e. between the battens at the leading 104 and trailing edges 106). This may provide further support to the body 102 and may be especially beneficial where the tile 100 is particularly large.

The tab 138 can also be secured to the roof structure by way of a fastener. This fastening is made possible by one of the mounting holes 1 16 (for receipt of the fastener therethrough) that forms part of the mounting region 1 14 and that is disposed proximate the trailing edge 106 of the body 102. In use, when the tab 138 is received under the body 102" of a laterally adjacent like-roof tile 100", this mounting hole 1 16 aligns with the other of the mounting holes 1 16" in the body 102" of the laterally adjacent like-roof tile 100". In this way, a single fastener can be received through the two aligned holes 1 16, 1 16", thereby allowing both the roof tile 100 and the laterally adjacent like-roof tile 100" to be fastened to the roof structure with that fastener.

Figures 2A, 2B and 2C depict a roofing system 244 formed of a plurality of roof tiles 200, 200', 200", 200"' similar to that described above, and a roof structure 201 (i.e. in the form of a roof framework). The roof structure comprises rafters 246 and transverse, spaced battens 203, as is known. Figure 2A shows the upper side of the roofing system 244, with each roof tile 200 being secured to the roof structure 201 at its respective mounting region 214, through its respective mounting holes 216.

A majority of the roof tiles 200 (i.e. except for edge tiles 200a at the leading edge of the structure 201) are also restricted against movement away from the roof structure 201 by abutment of their respective clips 220 against the undersides of adjacent tiles 210' . The tiles located at the leading edge (i.e. edge tiles 200a) have no adjacent roof tiles 200' at their respective leading edges 204, but are also retained against movement away from the structure 201 by way of abutment of their respective clips 220. However, this is not in the same manner as the other (non-edge) tiles 200. Instead, a plurality of brackets 248 are secured to the roof structure 201 and the clips 220 of each edge tile 200a abut an underside of these brackets (not shown). In this respect, the brackets replicate the trailing edge 206 of an adjacent roof tile 200' . One of these brackets is shown in Figures 4A and 4B, and will be described in further detail below. Figure 2C shows, in greater detail, the connection between a leading edge of a roof tile 200, a trailing edge of a like-roof tile 200', and a roof member in the form of a batten 203 of a roof structure 201. As is apparent from this figure, the roof tile 200 comprises first 248a, second 248b and third 248c spaced ridges that protrude from an underside 212 of the body 202 and extend laterally across the body 202 so as to be parallel to the leading edge 204. The first ridge 248a extends at the leading edge 204 so as to define a front face of the leading edge 204 and the second 248b and third 248c ridges are spaced back (i.e. inset) from the leading edge 204. These ridges 248a, 248b, 248c provide a barrier to water entering the space between the roof tile 200 and the like-roof tile 200' (and into the roof structure/roof space).

An alternative leading edge 304 arrangement is shown in Figure 3. This arrangement comprises a minor adjustment in that the upper surface 310 slopes downwards at the leading edge 304 to form a larger transition zone between the upper surface 310 and the front face of the leading edge 304. This means that the distal end of the first ridge 348a extends below the distal end of the second 348b and third 348c ridges. In general, this arrangement may provide a more aerodynamic profile.

Returning to Figure 2C, the underside 212 of the roof tile 200, that is proximate to the clips 220, comprises a laterally extending rib 250 that rests on an upper surface 210 of the like-roof tile 200' in use. This rib 250 spaces the underside 212 of the roof tile 200 from the upper surface 210 of the like-roof tile 200' at the leading edge 204. In the illustrated embodiment, this rib 250 is located so as to rest on a primary ridge 252' that generally extends laterally across the upper surface 210 of the like-roof tile 200' at a location that is proximate to the trailing edge 206' . A plurality of secondary ridges 254' extend between the primary ridge 252' and the trailing edge 206' of the like-roof tile 200' .

The primary 252' and secondary 254' ridges cooperate to provide a raised surface upon which the laterally extending rib 250 of the roof tile 200 can rest, even when the degree of overlap of the tiles 200, 200' is reduced in comparison to that illustrated. This highlights a further advantage of the present embodiment - that the overlap of the roof tile 200 with a like-tile 200' is able to be adjusted without loss of spacing. Additionally, the ridges 252', 254' can serve as a water control feature. This adjustment is of a continuous, rather than a discrete nature. In other words, the degree of roof tile overlap can be of any size within a minimum and maximum distance (generally determined by the size of the clip). The continuous nature of the adjustment is somewhat made possible by the configuration of the clips 220, which generally only restrict movement of the roof tiles 200 in a single direction (i.e. away from the roof structure 201 and the adjacent like-tile 200'). Each clip 220, for its length, provides minimal restriction to movement in the direction along the slope of the roof structure 201 (i.e. the trailing edge 206' of a like-tile 200' can slide in and out of the recess defined by each clip 220 as required). This means adjustment of the overlap of the tiles 200 over a continuous, rather than a discrete, range (in the direction of the slope) is not restricted by the clips 220.

As such, each roof tile 200 is configured so as to accommodate slight misalignment or inaccurate spacing (i.e. gauge) of the underlying roof supporting member (typically the battens 203). For example, where the spacing of two battens 203 is smaller than intended, the trailing edge 206 of one tile 200 can be slid further into the recess of the clips 220 of another adjacent like-tile 200' in order to increase the overlap. In this way, the abutment protrusions 232 of both roof tiles 200, 200' will still abut against respective battens 203, and the mounting holes 216 will still align with the battens 203. Similarly, such an adjustment of the overlap may be required based on the geometry of the roof structure 201. For example, a shallower slope may require more overlap (e.g. 100 mm), in order to ensure that moisture is unable to enter the roof structure 201 between the tiles 200. On the other hand, a greater slope (which increases the amount of moisture run-off) may not require such a large overlap (e.g. 80 mm). The minimum and maximum overlaps capable with the illustrated roof tile 200 may, for example, be between 80 mm and 100 mm.

As discussed above, the roof system 244 comprises a bracket which enables the edge tiles 200a to be secured to the roof structure 201. An exemplary bracket is shown in Figure 4 in the form of an angle bracket 456. The angle bracket 456 comprises a first portion 458 for securing the angle bracket to the roof member (which is a fascia 405) of the roof structure 401, and a second portion 460 that defines the recess for receipt therein of a clip 420. The first 458 and second 460 portions extend approximately or somewhat perpendicular to one another such that the angle bracket 456 has an approximately L-shaped profile. The first portion 458 comprises two apertures 462 for receipt of a fastener such that, in use, the first portion 458 is able to be secured to a leading edge of the roof structure 401. The second portion 460 extends over this leading edge of the roof structure 401 so as to be generally parallel to the slope of the roof structure 401. The mounting is such that the second portion 460 is spaced from the roof structure 401 so as to define a recess for receipt of a clip 420 of a leading edge 404 of an (edge) roof tile 400a.

In this way, the edge tiles 400a are retained against movement away from the roof structure 401. As with the connection between roof tiles 400 and like-roof tiles 400', this resistance to movement is facilitated by the bias in the clips 420, which hold the roof tile 400a against the laterally extending rib 450 on the underside of the tile 400a.

The roof tile 500 of Figures 5A to 5F is a variation of that shown in Figures 1 A to IF. For that reason, only major differences have been discussed below, and corresponding references numerals have been used for features that exist in both roof tile embodiments 100, 500.

One difference present in the roof tile 500 is the inclusion of two further clips (not shown) and corresponding bosses 522 (such that the roof tile 500 includes a total of five clips and five bosses 522). The addition of the extra bosses 522 and clips may provide further uplift resistance (i.e. of the roof tile 500 away from the roof structure, and/or a like-roof tile 500') and may provide a closer fit between the roof tiles 500, 500' . Each set of new clips 522 and bosses 522 also comprises a set of ramps 531 that facilitate engagement of the trailing edge 506 like-element.

The locations of the ribs 534, 536 and protrusions 532 at the trailing edge 506 are modified (from the roof tile 100) so as to accommodate the additional clips and bosses 522. The protrusions 532 and ribs 534, 536 are also arranged such that the roof tile 500 can be arranged with like-roof tiles 500' in both a brick bonding pattern (i.e. offset rows) and a straight or stack pattern (i.e. aligned rows). A straight pattern may be suited, for example, to roofing structure including solar tiles.

The roof tile 500 also further includes a plurality of intermediate fixing arrangements that (in the illustrated embodiment) are each in the form of a ring- shaped boss 564 shape that is raised from the underside surface 1 12. Each boss 564 has a corresponding markings (e.g. indentations, indicia, etc.), which are not shown in the figures, on the upper surface 510 of the tile 500 to indicate the location of the boss 564 to a user. In some forms a frangible or weakened region may be disposed in the centre of each boss to facilitate receipt of e.g. a screw, nail, etc. therethrough. The bosses 564 are arranged along a line that extends generally parallel to, and generally centrally between, the leading 504 and trailing 506 edges of the tile 500. In use, a fixing member (such as a screw or a nail) may be received through the centre of each boss and into a batten of a roofing structure, so as to fix the central portion of the tile 500 to the batten. When fixed in this manner, the distal end of each boss 564 abuts the batten, so as to space the underside surface 512 of the tile 500 from the batten. This intermediate fixing may only be necessary in circumstances where high wind loading is experienced (e.g. high wind/cyclonic areas). The roof tile 500 also tear-drop shaped fixing supports 568 spaced along the leading edge 504 of the roof tile 500, and that are raised from the underside surface 512 of the tile 500. Again, these supports 568 each have a corresponding marking (again, not shown) on the opposite upper surface 510 of the tile 500. In use, these can align with mounting holes 516 at the trailing edge 506 of a like-roof tile 500' and a fastener (such as a screw) can be received through both tiles 500, 500' and into a batten of a roofing structure. In this way, the supports 568 abut or rest on the upper surface 510' of the like-roof tile 500' . Again, this arrangement may be particularly suited to areas where high wind loading is experienced.

Further supports 576 are provided at the trailing edge 506 and are raised from the underside surface 512. These define a generally elongate (in the direction perpendicular to the leading 504 and trailing 506 edges) recess that can provide some tolerance with regards to the positioning of the roof tile 500 on a roof structure. These supports 576 align with the mounting holes 516 formed in the upper surface 510. As is apparent from Figures 5C and 5D, the upper surface 510 of the roof tile 500 further comprises first 572 and second 574 guide surfaces 572 at each of the opposing corners at the trailing edge 506 of the roof tile 500. The guide surfaces 572, 574 are angled relative to the leading 504 and trailing 506 edges of the roof tile 500 and are arranged so as to face one another when the tile roof 500 is in side-by-side relation with a like-roof tile 500' . In this way, the guide surfaces 572, 574 engage one another as the roof tile 500 is moved into side-by-side relation with the like-roof tile 500' and act to align the roof tile 500 and like-roof tile 500' such that the leading 504, 504' and trailing 506, 506' edges of the roof tiles 500, 500' are aligned.

As shown in figures 5E and 5F, roof tile 500 further differs from the previously described embodiments in that is suitable for use with dome-head screws (or other types of fasteners with a head projecting above the adjacent surface and that could otherwise interfere with assembly). For example, the roof tile includes rebates formed at the mounting holes 516 and frangible portions 518 (at the trailing edge 506) to accommodate the head of a fastener.

Similarly, an elongate rebate 578 is disposed on the underside surface 512 of the roof tile 500 at the side edge 508 that does not include the tab 538. This elongate rebate 578 accommodates the head of a fastener passing through the tab 538 of a laterally adjacent like-roof tile and the trailing edge 506 of a lower adjacent like- roof tile (and into a batten of a roof structure).

Variations and modifications may be made to the parts previously described without departing from the spirit or ambit of the disclosure.

For example, the roof tile may instead comprise retainers (e.g. clips) that extend from its upper surface. These retainers may abut an upper side (e.g. at the leading edge) of an adjacent like-roof tile so as to retain the like-roof tile against movement away from the roof structure. However such an arrangement may not be preferred over the illustrated embodiment, because the retainers would be visible, and would be exposed to the external environment. The roof tile may have more or less mounting holes, which may be positioned at various locations on the roof tile. Alternatively, the roof tile may not comprise any mounting holes and may instead only comprise frangible portions but that still allow mounting of the roof tile to the roof structure. The retainers (e.g. clips) may be integrally formed with the body of the roof tile (i.e. the clip may be integrally formed or integrally mounted with or incorporated into the boss). In this case, the retainers may be formed of plastic and the roof tile may then be moulded as a single piece. The retainers may have various shapes. Where the retainer is of a removable type, it may be interchanged with various shaped retainers (e.g. other clip types) depending on the requirements of the roof tile.

Whilst an element in the form of a large format roof tile has been described, the element may take other forms such as: small format roof tiles, elongate plank-like roof elements, roof sheets, etc.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or

"comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the roofing element and system.