AU2013203212B2 - A roof tile - Google Patents

Abstract

A roof tile 10 which is of generally square or rectangular shape and which has a top surface 11 and a bottom surface 16. The top and bottom surfaces 11 and 16 are generally parallel. The roof tile 10 has a pair of end edges 12 and 13 and a pair of side edges 14 and 15. The side edges 14 and 15 are formed so that a side edge of one roof tile overlaps the side edge of another roof tile to form an overlapping region when the roof tiles are laid side by side. The roof tile 10 includes a removable batten engaging device 26 suitable for engaging a roof batten 31 for locating the roof tile 10 relative to the roof batten 31. The batten engaging device 26 includes an abutment 43 which projects from the bottom surface 16 of the roof tile 10 for engaging the roof batten 31. <filename>

Description

1 A ROOF TILE Technical Field [0001] The present invention relates to a roof tile, a roof formed with such roof tiles and a method of manufacturing roof tiles. Background of Invention [0002] The following discussion of the background to the invention is intended to facilitate an understanding of the invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge as at the priority date of the application. [0003] Roof tiles generally are formed into complex shapes to ensure appropriate interlocking and overlapping at the ends and sides between laid tiles to ensure integrity of a tiled roof in terms of structural stability and weatherproofing. Roof tiles are generally also formed with an upper or outer facing surface which defines one or more channels that, in an installed condition of the tile, extend downwardly for the shedding of rain water. [0004] The roof tile shape is typically selected to assist location of one tile relative to another (which assists laying) and to maintain the laid position over the life of the roof. The shape is further made to resist penetration of rainwater through the tiling, and this generally means that significant side and end overlap between adjacent tiles must be provided. The end overlap is required to resist "blowback" of rainwater up the pitch of the roof between overlapping tile ends of adjacent tile courses during windy conditions. The side overlap is likewise required to prevent rainwater penetration past the sides of a pair of adjacent tiles. [0005] The channels formed in a roof tile operate as a watercourse to disperse rain water from the roof. The depth of the channels can vary, and it is the case that channels of greater depth capture water more securely than channels of lesser depth. Tiles having channels of lesser depth create a roof surface in which rain water is more able to be blown across the roof by wind, therefore increasing the chance of water <filename> 2 penetrating through overlapping regions of the tiles, particularly the side regions. Where sufficient inundation of overlapping regions occurs, water can penetrate (leak) into the roof space. [0006] Roof tiles are commonly formed to have one or more batten lugs which in use, rest behind a roof batten of a roof structure on the upside of the batten. The batten lugs project from the bottom surface of the tile and assist to locate the tile on the battens when the tiles are being laid and when the tiles are not otherwise fixed on the battens. The batten lugs typically are an integral part of the roof tile and they are typically arranged so that they protrude from one tile into the next tile when packed so as to maximise packaging density. Thus, the tiles have an indent or recess in the top surface to accommodate the batten lugs of another tile that extend from the bottom surface when the tiles are packed. [0007] Some roof tiles have batten lugs moulded into the bottom surface, but this has the disadvantage that the moulding can lead to points of weakness or breakage or add generally to the complexity of the tile shape. [0008] The complex roof tile shapes discussed above require that tiles which are made of terracotta or ceramic, must be pressed, using traditional wet pressing methods, or moulded, rather than employing other, less costly and time consuming manufacturing processes. Also, the material of the roof tile has been restricted largely to terracotta or cement because these are inexpensive and well proven materials, being stable (in UV and weather) and easy to form and handle. [0009] It is an object of the invention to provide a new roof tile that overcomes or at least alleviates disadvantages associated with the prior art, or in the alternative, provides an alternative to prior art roof tiles. Summary of Invention [0010] The present invention provides a roof tile which is of generally square or rectangular shape and which has top and bottom surfaces in which the top surface is generally planar and the top and bottom surfaces are generally parallel, the roof tile further having a pair of end edges and a pair of generally parallel side edges which are formed so that a side edge of one roof tile overlaps the side edge of another roof <filename> 3 tile to form an overlapping region when the roof tiles are laid side-by-side, the roof tile including a removable batten engaging device suitable to engage a roof batten of an inclined roof for locating the roof tile relative to the roof batten against movement down the incline of the roof, wherein the batten engaging device includes an abutment and the roof tile is formed with an opening in the top surface into which one end of the batten engaging device is removably inserted to locate the batten engaging device, the batten engaging device extends behind one edge of the roof tile and extends to the abutment which projects from the bottom surface of the roof tile to rest against the rear side of the roof batten. [0011] The present invention also provides separately, a roof tile and a batten engaging device of the above described kind. [0012] In some forms of the invention, one of the side edges of the roof tile includes one or more channels to capture water which drains or penetrates into the overlapping region between adjacent tiles and to feed that water along the side edge for discharge from an end edge of the roof tile. The other of the side edges can also include one or more channels for feeding water in the same manner. In that form of the invention, the channels of the side edges of the roof tile face in the same direction (upwardly for example). [0013] Alternatively, the channels of the opposite side edges can face in different directions so that one side edge will face upwardly when the tile is installed on a roof and the other side will face downwardly. The upwardly facing tile can include one or more channels to capture and drain water while in some forms of the invention, the downwardly facing side edge can also include one or more channels. However, because that side edge will face downwardly when installed on a roof, the channels of that side can have a protective effect such as to operate to protect the flow of water in the upward facing channels, such as by limiting entry of wind into the upward facing channels. Thus, the channels that face downwardly can correspond or mate with the channels that face upwardly to form a convoluted path that frustrates wind and rain entry into the mating area. The profile of the respective channels can be the same, similar or quite different 3a [0014] In some arrangements, each side edge can be shaped so that in an overlapping region between a pair of adjacent roof tiles, facing surfaces of overlapping side edges have complementary profiles and the facing surfaces are in spaced-apart, but close facing relationship throughout a major portion of the overlapping region. Accordingly, one form of this arrangement would have a peak of 4 one side edge being received within the trough of a facing side edge but the surfaces of the respective peak and trough would be spaced from contact. In alternative arrangements, facing surfaces of overlapping side edges have dissimilar profiles, although the facing surfaces are still in spaced-apart, but close facing relationship throughout a major portion of the overlapping region. By this non-contacting relationship, the side edges are not exposed to loading which might otherwise tend to cause the side edges to fail, such as by fracture, given the often brittle nature of the material used for tile manufacture. [0015] In the preferred arrangement, each side edge includes a pair of channels and the relationship between overlapping side edges is that the respective channels of each side edge underlie or receive the peaks between the channels of the facing side edge, although the profile of the side edges is not required to be the same. In this arrangement, water which enters the overlapping region is captured in a first channel and any leakage past this first channel over an intermediate peak is captured in the second channel. Testing has shown that it is rare for water which enters the overlapping region to move beyond the second channel so that this arrangement has successfully passed testing conditions which relate to the prevention of water entering into the roof space beneath the roof tiles. In particular, roof tiles according to the present invention perform at least to the same level as prior art roof tiles. [0016] In a preferred arrangement, a surface of one side edge is co-extensive and/or co-planar with the top surface of the tile, with the channels of that side edge being formed on the opposite surface of the side edge. Preferably the side edges are formed so that the top surfaces of a pair of adjacent tiles which have respective side edges thereof in overlapping relationship, are substantially co-planar. In this arrangement, the entire upper surface of the roof tile can be disposed in substantially a single plane. [0017] While the top surface of the roof tile is generally planar, the underneath or bottom surface of the roof tile can either also be planar, or can be profiled. In some forms of the invention, the bottom surface is profiled with strengthening ribs that are formed in a grid or matrix type of pattern. That profiled surface can extend fully across the bottom surface of the tile, or can terminate between opposite side edges. The profiled pattern can also terminate at one or both of the end edges. In one <filename> 5 particular form of the invention, the profiled bottom surface terminates at each of the side edges, and at an end edge, which is a bottom edge of the tile when the tile is laid. [0018] A tile according to the invention can include an end edge which is profiled, in order to provide resistance to blowback of water under the end edge. The end edge can be a front, leading or bottom edge of the tile, which is the end of the tile which is lower than the opposite end when the tile is laid on an inclined roof structure. Typically the profiled end edge would rest upon the opposite end of an adjacent tile, although supports can be provided on the end of the adjacent tile on which the profiled end edge rests. Alternatively, as will be discussed later herein, the profiled end edge can rest on the batten engaging device or devices of an adjacent tile. [0019] The batten engaging device of a roof tile according to the invention is provided to engage a roof batten for the purpose of locating the roof tile relative to the roof batten. The batten engaging device includes an abutment which projects from the bottom surface of the tile for engaging behind the rear of a roof batten so as to prevent the tile from movement down the incline of the roof. The batten engaging device of a roof tile according to the invention can take any suitable form. For example, the device can include a pin which extends through an opening in the roof tile to project from the bottom surface of the tile and the abutment is formed by a portion of the pin which extends from the bottom surface. The pin can extend from an opening formed in the bottom surface of the tile or from an opening that extends fully through the tile from the top surface to the bottom surface. The pin preferably extends substantially perpendicular to the bottom surface. In a basic form, the pin can be a nail for example. [0020] Alternatively, the batten engaging device can extend behind one end edge of the roof tile and a portion of the device can project from the bottom surface of the tile and again the abutment is formed by the portion which extends from the bottom surface. While the entire portion that extends from the bottom surface can form the abutment, a lesser section of that portion can form the abutment. This applies to any form of batten engaging device according to the invention. <filename> 6 [0021] In the latter arrangement discussed above, in which the batten engaging device extends behind one end edge of the roof tile, the device can be connected to the tile in any suitable manner and in some forms, the batten engaging device includes a pin which is connected to the abutment of the device and which extends into an opening of the tile. For example, the tile can include an opening extending into or through the tile from the upper surface and the pin can extend into that opening to locate the batten engaging device. The pin can be connected to the abutment by a member, such as a finger that bridges between the pin and the abutment. The abutment can extend from a portion of the batten engaging device that extends closely about an end edge of the tile, the end edge being that edge that is located further up the incline of the roof than the opposite end edge. [0022] Alternatively, the batten engaging device can be a clip, such as a wire clip can be used in which only a small indent is formed in the top surface of the tile and the clip engages within that indent to locate on the tile. This form of batten engaging device can also be used with an opening in the tile of the forms described above. The clip will extend from the indent to behind one edge of the roof tile and will project from the bottom surface of the roof tile to form an abutment for engaging a roof batten. The wire clip is similar to the batten engaging device that includes the pin described above in terms of operation, but is different in terms of structure. [0023] An advantage of the above arrangement is that the traditional batten lug described as part of the prior art above, in which the lug is formed integrally with the roof tile, can be eliminated as part of the tile and instead, the function of the lug is formed by a separate component being the batten engaging device. This has advantages in terms of storage and transport roof tiles because the density of packing of the tiles can be increased. Moreover, the tiles are more easily formed without integral lugs or protrusions and the likelihood of fracture of the roof tile is lessened by the absence of integral lugs or protrusions. [0024] The batten lug of the above described kind can be formed from any suitable material such as metal or plastic and in plastic, the batten lug can be easily moulded. <filename> 7 [0025] Where the batten lug is formed alternatively as a pin, the pin can be press fitted into an opening in the tile which is of a diameter that enables the pin to be held by friction. The pin can be formed as a nail and held by friction in this manner or it can be formed as a screw and be screwed into an opening. The pin can be ribbed (when not formed as a screw) to increase the grip between the pin and the surface of the opening. The pin can include a head of greater diameter than the opening to terminate the passage of the pin through the roof tile. The pin can be of metal or plastic and in plastic the pin can be easily moulded. [0026] Advantageously, the use of batten engaging devices according to the invention requires no particular skill beyond that already possessed by roofing personnel. [0027] In a preferred arrangement, a pair of the batten engaging devices is provided for use with the roof tile. Preferably the abutments of the devices are spaced apart towards opposite side edges of the roof tile, and preferably they are positioned at substantially the same distance away from the side edge they are closest to. The batten engaging devices can be supplied with the roof tiles in an installed condition, or they can be provided separately and installed on site when the roof tiles are being laid. [0028] The present invention also extends to an inclined roof formed with a plurality of roof tiles that rest on a plurality of roof battens, each roof tile being generally square or rectangular and having top and bottom surfaces in which the top surface is generally planar and the top and bottom surfaces are generally parallel, each roof tile further having a pair of end edges and a pair of generally parallel side edges which are formed so that a side edge of one roof tile overlaps the side edge of another roof tile to form an overlapping region between a pair of tiles which are laid side-by-side, each tile being secured in place at least in part by a removable batten engaging device which includes an abutment and the roof tiles are formed with an opening in the top surface into which one end of the batten engaging device is removably inserted to locate the batten engaging device, the batten engaging devices extend behind one edge of the roof tiles and extend to the abutment which projects from the bottom surface of the respective roof tiles and rests against the rear side of a roof batten of said plurality of roof battens. Such a roof would typically include a 7a plurality of courses of roof tiles which are laid side-by-side. Each course is laid across the incline of the roof and the bottom end of one course would overlap with the top or head end of an immediately adjacent course. In accordance with normal roofing techniques, the side edge overlaps are staggered or half bonded from one course to the next, to that they are not aligned from course to course. [0029] In a tile according to the invention, advantageously the surface of an individual course can be substantially planar across its length. Apart from various advantages described earlier in relation to roof tiles according to the invention, tile courses which are generally or extremely planar provide an aesthetic appeal. Additionally, with the provision of a water course in the overlapping region between 8 adjacent tiles, any rain water that enters the overlapping region can be dispersed through the watercourse without entering the roof space. [0030] In addition to the batten engaging device discussed earlier, a roof according to the present invention can include hold-down members which are employed to engage both the roof tile and the roof batten in a manner to urge the roof tile to remain seated on the roof batten. In one form, the hold-down members comprise a resilient clip which is arranged to engage the upper surface of a tile and either the under surface of a roof batten, or the downwardly facing surface of the batten, or both. A resilient clip is preferred as it can easily be fitted into place quickly and without expert skill. [0031] The batten engaging device of the invention advantageously can be arranged to provide a hold-down capacity of the kind discussed above. Thus, a batten engaging device of the invention can extend to a position to engage the under surface of a roof batten for example and can eliminate the need for a separate hold down member. [0032] In some forms of the invention, the batten engaging device can project proud of the upper surface of the roof tile to which it is applied. In this arrangement, in the overlap between end edges of adjacent courses of roof tiles, the bottom end of one tile course can rest upon the batten engaging device or devices of the immediately adjacent course. In the forms of batten engaging devices discussed above, one or more of the pin or finger can have a surface that projects proud of the upper tile surface. By this arrangement, overlapping tiles do not engage each other, but rather, they are spaced apart by the depth of the portion of the batten engaging device that projects above the upper surface of the tile to which it is fixed. [0033] In preferred arrangements, batten engagement for each roof tile is provided by two batten engaging devices at two spaced apart positions, and in overlapping courses of roof tiles having that arrangement, each tile of one course can be supported at its lower or bottom end by a portion of the batten engaging devices that projects proud of the upper surface of roof tiles of a lower and adjacent course at the two spaced apart positions. This arrangement tends to provide stable support for the bottom ends of the roof tiles by providing two points of support and in particular <filename> 9 tends, to resist wobbling movement of the tiles under wind load. This arrangement also can accommodate the use of a separate hold-down clip and in the preferred arrangement, the portion of the clip which engages the upper surface of the tile sits between the points at which the batten engaging devices engage the roof tiles and the battens and the height of the clip away from the upper surface of the tile is less than that of the batten engaging devices, so that there is no engagement between the bottom surfaces of the lower or bottom ends of one course of tiles and the hold-down clip. Brief Description of Drawings [0034] For a better understanding of the invention and to show how it may be performed, embodiments thereof will now be described, by way of non-limiting example only, with reference to the accompanying drawings. [0035] Figure 1 is a top isometric view of a roof tile according to one embodiment of the invention. [0036] Figure 2 is a bottom isometric view of the roof tile of Figure 1. [0037] Figure 3 is a cross-sectional view showing a side edge overlapping region between a pair of roof tiles according to one embodiment of the invention. [0038] Figure 4 illustrates in end view, two roof tiles according to one embodiment of the invention assembled together. [0039] Figure 5 illustrates in side elevation view, two roof tiles according to one embodiment of the invention assembled together. [0040] Figure 6 is a perspective view of a batten engaging device according to one embodiment of the invention. [0041] Figure 7 is a perspective view of a batten engaging device according to another embodiment of the invention. [0042] Figure 8 is a side view of the batten engaging device of Figure 7. <filename> 10 [0043] Figure 9 shows three courses of tiles according to one embodiment of the invention supported on roof battens. Detailed Description [0044] Figure 1 is a top isometric view of a roof tile 10 according to one embodiment of the invention. The roof tile 10 includes a relatively planar or flat top surface 11, end edges 12 and 13, and side edges 14 and 15. The tile 10 is rectangular although it could alternatively be square. [0045] Figure 2 is a bottom isometric view of the tile 10 and this figure shows that the tile 10 includes a bottom surface 16 which has a ribbed profile, although it is nevertheless still generally parallel to the top surface 11. The ribs comprise intersecting ribs 17a and 17b which extend perpendicular to each other and form a grid or matrix pattern. [0046] Each of the side edges 14 and 15 are profiled for overlying relationship as illustrated in Figure 3. While the profiles of the side edges 14 and 15 can be generally complementary, it can be seen that the profiles illustrated are not identical. [0047] The side edge 14 is shown including two peaks 18, 19 and two troughs 20, 21. The troughs 20 and 21 constitute channels for capturing and discharging rainwater. [0048] The side edge 15 is shown including two peaks 22, 23 and two troughs 24, 25. The peak 22 enters the trough 20 and the peak 23 enters the trough 21. There is no contact between the overlapping side edges. Rather, there is a close fit between the surfaces of the side edges as illustrated, although the surfaces are separated. The separation between the side edges 14 and 15 is such to ensure that there is no pressure loading on either side edge. A sufficient pressure loading could result in failure of either side edge such as by cracking or fracture. Additionally, the separation allows for natural expansion and contraction of the roof on which the tiles are mounted such as might be caused by temperature variations or variations in batten angles on a typical roof structure. Still further, the separation allows for movement in the roof structure, for example shrinkage of timber or metal roof members or settlement of those members over time. <filename> 11 [0049] Despite the side edges 14 and 15 being separated from contact, the mating arrangement as illustrated has the effect described earlier that water which enters the overlapping region between the tiles 10 will firstly enter the channel formed by the trough 21 and will tend to flow within that trough down the pitch of the roof through the tile course and then onto the next course of tiles. Rainwater which enters the trough 21 has difficulty moving past the peak 19, but during heavy rain or wind, water may leak over the peak 19 and into the channel formed by the trough 20. However, that water will then flow down the tile course within that trough. Any rainwater that does move past the peak 19 and which enters the trough 20 has difficulty moving past the peak 18. The arrangement is thus effective in preventing passage of almost all rainwater past the overlapping side edges 14 and 15. [0050] While it is theoretically possible for water to leak over the peak 18 and thus into the roof cavity, tests have shown that such leakage rarely, if ever, occurs. Testing has shown that tiles formed according to the arrangement shown in the figures satisfy Australian Standard AS 4046.9-2002, concerning determination of dynamic weather resistance. [0051] Figure 4 illustrates in end view, two tiles 10 assembled together with an overlapping region being formed by overlying side edges 14 and 15. The view is taken from the opposite direction to that shown in Figure 3 and is taken from the upper end of a pair of laid tiles. Figure 4 illustrates batten engaging devices in the form of batten lugs 26 in rear view and these will be described in more detail later herein. [0052] Figure 4 also illustrates that the flat top surface 11 of one tile 10 extends generally coplanar with the top surface 11 of the adjacent tile 10. [0053] Figure 5 illustrates a side elevation view of tiles according to the invention installed to form a roof. Figure 5 shows a rafter 30 and in cross-section, two battens 31, 32 which extend perpendicular to the lengthwise extent of the rafter 30. Two tiles 33, 34 are shown supported on the rafter 30/battens 31, 32. The tiles 33, 34 are identical to the tile 10 described and illustrated in the earlier drawings. The tile 34 is shown supported at the upper end 34a thereof between the batten 32 and the tile 33, so that the lower end 33b of the tile 33 is supported in overlapping relationship with <filename> 12 the upper end 34a of the tile 34. It can be seen that the facing surfaces in the overlap between the tiles 34 and 33 are very close and while not evident in Figure 5, the preferred arrangement of the overlap is that the facing surfaces are closer toward the rear of the overlap than toward the front (when the rear of the overlap is taken to be that section which is closer to the batten lug 26). Testing has shown that overlapping tiles according to the invention resist water inundation through the overlapping region to an extent that meets standards for that aspect of a tiled roof. [0054] The resistance to water inundation is improved by the use of the profiled front end 35 of the tiles 33 and 34, which is also shown in Figures 1 and 2. The profiled end 35 comprises a pair of elongate troughs or grooves 36 that extend across the tiles 10, 33 and 34 and which are intended to be in close facing relationship with the adjacent and lower tile in a roof installation. This is shown in Figure 5, in which the front end 35 of the tile 33 is in close facing relationship with the upper and facing surface of the tile 34. [0055] Figure 6 illustrates a batten engaging device, or as hereinafter called, a batten lug 26 in isolation and it can be seen that the batten lug 26 includes a pin 40 which is provided to extend into an opening of a tile. Figure 1 shows two openings 41 towards the rear end of the tile 10 into which the pin 40 can extend. The pin 40 is connected by a member in the form of a finger or bridge 42 to a batten engaging member 43. The batten engaging member 43 extends closely about an end edge 44 of a tile (see Figure 4), the end edge being that edge that is located further up the incline of the roof than the opposite end edge or front end 35. As will be clearly evident from Figure 5, the batten lugs 26 maintain the position of the tiles 33, 34 on the underlying roof structure. Moreover, the batten lugs 26 are easy to install, simply requiring the pin 40 to by pushed into the opening 41 (see Figure 1) by finger pressure. The pin 40 can include a plurality of concentric barbs 45 which operate to resist release of the pin 40 from the opening 41. The pin can alternatively be formed as a nail or a screw and thus be of significantly different construction to that illustrated in Figure 6. [0056] With the pin 40 inserted into the opening 41, as shown in Figure 5, the batten engaging member 43 forms an abutment which projects from the bottom surface 16 of the roof tile 10 so as to rest against the rear side or upside 46 of the <filename> 13 battens 31 and 32. By that engagement, the tiles 33 and 34 are prevented from movement down the inclined pitch of the roof. [0057] Figures 7 and 8 illustrate a different type of baton engaging device compared to the arrangement of Figures 4 to 6. In Figures 7 and 8, a tile 50 is illustrated, supported at one end on a roof baton 51 and a pair of baton engaging devices in the form of wire clips 52 engage the upper surface of the tile 50 and wrap about the roof batten 51 to secure the tile 50 to the batten 51. [0058] The tile 50 includes a pair of recesses or indents 53, to accommodate an upper portion of the clip 52. With reference to Figure 8, it can be seen that the clip 52 has a locating end part 54 which extends into the deep end portion 55 of the indent 53, while a bridging portion 56 extends from the portion 55 through the indent 53 to the rear surface 57 of the tile 50. [0059] An extension portion 58 extends behind the rear surface 57 of the tile 50 and the rear surface 59 of the batten 51, while a locating portion 60 extends beneath the bottom surface 61 and leads to a distal lip 62. The lip 62 can engage against the forward face 63 of the baton 51, or can be spaced slightly from it. In fact, movement of the clip 52 under normal loading conditions can bring the lip 62 into and out of engagement with the surface 63. [0060] It will be appreciated that the clip 52 could terminate at the bottom end of the extension portion 58, so as not to include the locating portion 60 or the lip 62. In that form, the clip would be an alternative version to the batten lug 26 of Figure 6. However, the clip 52 provides both a hold down function, as well as a batten engaging function in the form illustrated. [0061] Moreover, the use of indents 53 in the upper surface of the tile 50 permits the clip 52 to be installed without projecting from the upper surface of the tile 50. This is in contrast to the use of the batten lug 26 which, as shown in Figures 4 and 5, projects from the top surface 11 of the tiles 10. [0062] Figure 9 shows three courses of tiles 10 supported on battens 48 and from that figure it will be seen that the tile 10 of one course overlaps the junction between the tiles 10 of an immediately adjacent course. The arrangement can be such that <filename> 14 the overlapping end of a tile 10 is supported on the bridge 42 of each of two batten lugs 26 of the aforedescribed kind. This provides each tile 10 with a two point support at the lower end thereof. [0063] The tiles 10 according to the invention have no lugs protruding from the bottom surface 16 out of the plane of the bottom surface. As described earlier, it is typical for roof tiles to have lugs projecting from a bottom or underneath surface for abutting engagement with the roof battens. That engagement secures the position of the tiles on the roof. However, the lugs provide disadvantages as discussed earlier herein. Absence of such lugs in the present invention is thus an advantage, even more so, because tiles according to the invention can be stored and transported flush against each other, so reducing the volume for storage and transport. Moreover, manufacture of a tile without lugs is less complex. [0064] It can also be seen from Figures 4 and 5, that tiles according to the invention do not necessarily require interlocking heads. Interlocking heads are a requirement of prior art terracotta roof tiles because the heads allow for distortion during manufacturing, but they can be eliminated in terracotta roof tiles of the present invention because of the relatively low degree of distortion which is experienced in the manufacture of a terracotta roof tile according to the invention. Accordingly, there is no requirement to treat the underside of the nose (the front end 35 of the tile 10) of the roof tile to prevent water blowback through the overlap between adjacent courses of tiles. Again, the employment of the batten lugs 26 is sufficient to properly locate the tiles 10, so that interlocking heads have been found to be unnecessary. The absence of interlocking heads provides similar advantages as those discussed above in relation to the absence of lugs extending from the bottom surface. Thus, the absence of interlocking heads facilitates cost advantages in manufacture, storage, transport and handling. This is achieved without a reduction in performance of the tiles and without a loss of aesthetic appeal. [0065] A tile according to the invention can have any suitable dimensions, although in a preferred arrangement, the tile can have a width of 335 mm and a depth in the pitch direction of 480 mm. The weight of such a tile is anticipated to be in the region of 4 to 5kg. The thickness of the tile can be about 20 to 30mm. <filename> 15 [0066] Apart from the water testing outlined earlier, tiles according to the invention can also satisfy the requirements of the following Australian Standards: [0067] AS 4046.3-2002 - Determination of transverse strength [0068] AS 4046.4-2002 - Determination of water absorption [0069] AS 4046.5-2002 - Determination of permeability [0070] AS 4046.7-2002 - Determination of resistance to salt attach [0071] The invention described herein is susceptible to variations, modifications and/or additions other than those specifically described and it is to be understood that the invention includes all such variations, modifications and/or additions which fall within the spirit and scope of the above description. [0072] Throughout the description and claims of this specification the word "comprise" and variations of that word, such as "comprises" and "comprising", are not intended to exclude other additives, components, integers or steps. <filename>

Claims (20)

1. A roof tile, the roof tile being of generally square or rectangular shape and having top and bottom surfaces in which the top surface is generally planar and the top and bottom surfaces are generally parallel, the roof tile further having a pair of end edges and a pair of generally parallel side edges which are formed so that a side edge of one roof tile overlaps the side edge of another roof tile to form an overlapping region when the roof tiles are laid side-by-side, the roof tile including a removable batten engaging device suitable to engage a roof batten of an inclined roof for locating the roof tile relative to the roof batten against movement down the incline of the roof, wherein the batten engaging device includes an abutment and the roof tile is formed with an opening in the top surface into which one end of the batten engaging device is removably inserted to locate the batten engaging device, the batten engaging device extends behind one edge of the roof tile and extends to the abutment which projects from the bottom surface of the roof tile to rest against the rear side of the roof batten.

2. A roof tile according to claim 1, wherein the each of the side edges includes one or more channels to capture water which drains into the overlapping region and to feed that water along the side edge for discharge from an end edge of the roof tile.

3. A roof tile according to claim 1, wherein each of the side edges includes one or more channels and wherein each channel of the respective side edges opens in opposite directions which are generally perpendicular to the plane of the top surface.

4. A roof tile according to claim 2 or 3, wherein the channels of each side edge are shaped so that in an overlapping region between a pair of roof tiles, facing surfaces of overlapping side edges have complementary profiles and the facing surfaces are in spaced-apart but close facing relationship throughout a major portion of the overlapping region.

5. A roof tile according to claim 2 or 3, wherein the channels of each side edge are shaped so that in an overlapping region between a pair of roof tiles, peaks between adjacent channels of one side edge overlie facing channels of the other side edge <filename> 17 and whereby the facing surfaces of the overlapping region are in spaced-apart but close facing relationship throughout a major portion of the overlapping region.

6. A roof tile according to claim 5, wherein the peaks between adjacent channels of one side edge overlie and extend into facing channels of the other side edge.

7. A roof tile according to any one of claims 1 to 6, wherein the end of the batten engaging device that is removably inserted into the opening is a pin which is connected to the abutment, wherein the pin is formed as a nail or a screw, wherein the pin is connected to the abutment by a bridging member, a portion of which overlies the top surface of the tile.

8. A roof tile according to any one of claims 1 to 7, wherein the batten engaging device is a wire clip and the opening of the top surface of the tile is an indent in which one end of the clip is received and the clip extends behind one edge of the roof tile to an abutment of the clip and extends to a position to engage against the rear side of a roof batten.

9. A roof tile according to claim 8, the clip extending to a position underneath the roof batten to provide a hold-down effect on the roof tile relative to a batten.

10. An inclined roof formed with a plurality of roof tiles that rest on a plurality of roof battens, each roof tile being generally square or rectangular and having top and bottom surfaces in which the top surface is generally planar and the top and bottom surfaces are generally parallel, each roof tile further having a pair of end edges and a pair of generally parallel side edges which are formed so that a side edge of one roof tile overlaps the side edge of another roof tile to form an overlapping region between a pair of tiles which are laid side-by-side, each tile being secured in place at least in part by a removable batten engaging device which includes an abutment and the roof tiles are formed with an opening in the top surface into which one end of the batten engaging device is removably inserted to locate the batten engaging device, the batten engaging devices extend behind one edge of the roof tiles and extend to the abutment which projects from the bottom surface of the respective roof tiles and rests against the rear side of a roof batten of said plurality of roof battens. <filename> 18

11. A roof according to claim 10, wherein the top surfaces of a plurality of the roof tiles which are laid side-by-side are substantially co-planar, wherein the overlapping region forms a watercourse to capture water which drains into the overlapping region and to feed that water along the overlapping region for discharge from the end edge of the tiles.

12. A roof according to claim 11, wherein the watercourse is formed by one or more channels formed at least in the lowermost side edge of the overlapping region, the or each channel extending generally lengthwise of the side edge.

13. A roof according to claim 11 or 12, wherein the watercourse is formed by one or more channels formed in each side edge of the overlapping region, and wherein the facing surfaces of the side edges are in spaced-apart but close facing relationship throughout a major portion of the overlapping region.

14. A roof according to claim 13, wherein the channels of each side edge are shaped so that in the overlapping region between a pair of said roof tiles, facing surfaces of overlapping side edges have complementary profiles.

15. A roof according to claim 13, wherein the channels of each side edge are shaped so that in the overlapping region between a pair of said roof tiles, peaks between adjacent channels of one side edge overlie facing channels of the other side edge.

16. A roof according to claim 15, wherein peaks between adjacent channels of one side edge overlie and extend into facing channels of the other side edge.

17. A roof according to any one of claims 10 to 16, wherein the end of the batten engaging device that is removably inserted into the opening is a pin which is connected to the abutment. <filename> 19

18. A roof according to any one of claims 10 to 16, wherein the batten engaging device is a wire clip and the opening of the top surface of each roof tile is an indent in which one end of the clip is received and each clip extends behind one edge of each roof tile to an abutment of each clip and extends to a position to engage against the rear side of a roof batten.

19. A roof according to any one of claims 10 to 18, the batten engaging device extending above the upper surface of each roof tile and the roof tile of an immediately adjacent course of tiles located further up the incline of the roof rests on the batten engaging device.

20. A roof according to claim 19, wherein adjacent batten engaging devices of a pair of adjacent roof tiles of one tile course support the end of a tile of an immediately adjacent course of tiles located further up the incline of the roof.. <filename>