IES20030808A2 - Interlocking roof tile - Google Patents

Abstract

An interlocking roof tile for a pitched roof comprises a substantially rectangular body (10) having a top major surface (12), a bottom major surface (14), a front edge (18), a rear edge (16) which is covered in use by at least one overlapping tile of an adjacent row of tiles, and a pair of opposite side edges (20,22). An underlock (24) extends along one side edge and an overlock (26) extends along the other side edge whereby the tile may be interlocked with its neighbours on each side. In the front-to-rear direction of the tile body the top major surface is convex and the bottom major surface is concave, these convex and concave major surfaces converging towards, and extending substantially fully up to, the front edge. <Figure 1>

Description

TRUE COHY AS LODGED Interlocking Roof Tile IE OS 08 0 8 This invention relates to a roof tile of the type which interlocks with its neighbours on each side.

Natural slate tiles are generally flat rectangles which are laid on the roof double-lapped to guard against rain and wind-driven water entering the roof space between the abutting side edges of the tiles. They typically have a constant thickness of about 10mm. Plain concrete tiles are also known which simulate natural roof tiles and have a thickness of about 12mm. However, these too are plain edged and therefore need to be double lapped.

Flat concrete roof tiles are known which have interlocking formations along opposite side edges so that double-lapping can be avoided, thereby reducing the cost of the roof. However, these tiles have to be manufactured with a thickness of, typically, 20mm to accommodate the interlocking formations. This is aesthetically undesirable, since the exposed front (lower) edge of the tiles has a thickness twice that of natural slate tiles.

EP 0 387 305 BI proposes a solution to th.is problem which involves angling the region of the 'bottom surface including the underlock adjacent to the front edge of the tile upwardly towards the top surface, and making the top surface of the tile convex so that the upwardly angled part of the tile sits squarely on the convex surface.

This admittedly reduces the visible thickness of the front edge of the tiles, but has the disadvantage that the tile sits squarely on the tile below for only a OF OPEN TO PUBUC INSPECTION UNOER SECTION 28 ANL RULE 23 ΙΕΟ3 Ud 0 8 limited range of overlap since, due to the angled front portion of the tile, the front edge of the tile will tend to lift away from the top surface of the underlying tile for large overlaps leaving an unacceptable gap.

It is an object of the invention to mitigate this disadvantage.

According to the present invention there is provided an interlocking roof tile for a pitched roof, the tile comprising a substantially rectangular body having a top major surface, a bottom major surface, a front edge, a rear edge which is covered in use by at least one overlapping tile of an adjacent row of tiles, and a pair of opposite side edges, the tile further including an underlock extending along one side edge and an overlook extending along the other side edge whereby the tile may be interlocked with its neighbours on each side, wherein in the front-to-rear direction of the tile body the top major surface is convex and the bottom major surface is concave, said convex and concave major surfaces converging towards, and extending substantially fully up to, the front edge.

Preferably, the underlock has a substantially uniform thickness along the length thereof.

The invention differs from the solution described in EP 0 387 305 BI by maintaining the concavity of the bottom surface substantially fully up to the front edge of the tile. This allows the degree of overlap of one row of tiles on the next to be adjusted over a relatively large range, with the front edges of the tiles resting with little or no gap on the top surface of the IE b 5 08 0 8 underlying tiles. The preferred embodiment also differs from the disclosure of EP 0 387 305 in that the underlock of the tile of the invention does not taper, i.e. has a substantially uniform thickness along the length thereof.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a top perspective view of an embodiment of an interlocking roof tile according to the invention; Fig. 2 is an underneath perspective view of the roof tile; Fig. 3 is an underneath plan view of the roof tile; Fig. 3A is a cross-section of the underlock of the roof tile taken on the line E-E of Fig. 3; Fig. 4 is a cross-section of the roof tile taken on the line A-A of Fig. 3; Fig. 5 is an edge view of the roof tile looking in the direction C of Fig. 3; Fig. 6 is a cross-section of the roof tile taken on the line B-B of Fig. 3; Fig. 7 is an edge view of the roof tile looking in the direction D of Fig. 3; Fig. 8 is a perspective view of two rows of roof tiles as they might be assembled on a pitched roof, illustrating IEU 08 0 8 the variable degree of overlap of one row of tiles on the next row below; and Fig. 9 is a cross-section of the assembly of Fig. 8 showing the overlap for two positions of the rows of tiles .

Referring to Figs. 1 to 7, an interlocking roof tile comprises a substantially rectangular body 10 having a top major surface 12, a bottom major surface 14, a rear edge 16, a front edge 18, and a pair of opposite side edges 20, 22. As will be described, Figs. 8 and 9, the tiles are laid in rows on a pitched roof so that the rear edge 16 of each tile is covered by at least one overlapping tile of an adjacent row of tiles.

In order to avoid the need to double lap the tiles, each tile includes an underlock 24 extending along one side edge 20 and an overlook 26 extending along the other side edge 22. Referring now to Figure 3A in particular, the underlock 24 has a first surface 25 and a second surface 27, said first and second surfaces 25, 27 being maintained at a substantially uniform distance from each other. The underlock 24 therefore preferably does not taper, and has a substantially uniform thickness Y along the length thereof, as shown in Figure 3A. The first and second surfaces 25, 27, have the same centre of curvature (not shown). It will be appreciated, however, that the underlock 24 may be provided with an indentation on the second surface 27 towards the rear edge 16 of the tile, as also shown in Figure 3A. This indentation is generally provided to accommodate a roof batten 36 used when constructing of a row of tiles, as shown in Figure 9 for example. It will be further appreciated that when the IE 0 3 08 0 8 indentation is present, the underlock 24 still preferably has a substantially uniform thickness as described above.

The first and second surfaces 25, 27 preferably have respective radii of curvature of between 1618 mm and 1625 mm; and between 1626 mm and 1632 mm. Further preferably, the first and second surfaces 25, 27, have respective radii of curvature of between 1619 mm and 1624.5 mm; and between 1627 mm and 1631 mm. Most preferably, the first surface 25 has a radius of curvature of 1620.7 mm, and the second surface 27 has a radius of curvature of 1628.5 mm. Less preferably, whilst still being a preferred form of the roof tile, the first and second surfaces 25, 27, have respective radii of curvature of 1624.1 mm and 1630 mm.

The underlock 24 and overlook 26 are ribbed and grooved in complementary fashion to allow each tile to be interlocked with its neighbours on each side, the underlock 24 on each tile engaging under the overlook 26 on the next laterally adjacent tile. Consequently, the overlook 26 on each tile preferably has a radius of curvature suitable for engagement with the second surface 27 of the underlock 24 of the next adjacent tile, i.e. preferably approximately 1628.1 mm, or, using the alternative version of the roof tile mentioned above, 1630 mm. As seen, the underlock 24 and overlook 26 stop short of the front edge 18 so that they are not visible externally on the laid tiles to maintain the aesthetic appearance of the tiles roof.

As seen in side view, Figs. 4 and 5, in the front-to-rear direction of the tile body 10 the top major surface 12 is convex and the bottom major surface 14 is concave, and IE 0 J 0 8 0 8 these surfaces 12, 14 maintain their convexity and concavity respectively fully up to the front edge 18. However, whereas the top surface 12 has a substantially constant radius of curvature, the radius of curvature of the bottom surface 14 progressively increases from a point X (Fig. 4) to the front edge 18, so that the surfaces 12, 14 converge towards the front edge 18. The distance between the point X and the front edge 18, as measured in the front-to-rear direction of the tile body, is preferably at least one third, and most preferably at least half, the distance between the front and rear edges 16, 18. Between the point X and the rear edge 16 the top and bottom major surfaces 12, 14 are a substantially constant distance apart, except for a minor portion 14A of the bottom surface 14 which is upwardly inclined at a very small angle at the rear. It will be apparent that the bottom major surface 14 may be stepped up towards the front edge 18 of the tile, as shown in Figures 4 and 5 for example. It will, however, be further apparent that the invention is not to be considered to be limited in this way.

Preferred dimensions for the tile are: - Constant radius of curvature of the top surface 12 is from 1500mm to 1700mm.

- The straight line distance between the front and rear edges is from 280mm to 300mm.

The width of the tile is from 320mm to 340mm.

IE 03 0808 - Rearwardly of the point X the constant distance between the top and bottom surfaces 12, 14 is from 16-20mm, preferably about 18mm.

Forwardly of the point X the top and bottom surfaces converge to a separation of from 11-13.5mm, preferably about 12mm, at the front edge.

As previously mentioned herein, the underlock 24 is preferably of uniform thickness Y, and does not taper along the length thereof. An indentation may also be present on the second surface 27, as described above. Furthermore, the radii of curvature of the first and second surfaces 25, 27 are preferably 1620.7 mm and 1628.5 mm (or, alternatively, 1624.1 mm and 1630 mm) respectively.

The top surface 12 is substantially flat across the width of the tile, Figs. 6 and 7. However, to lighten the tile the bottom surface 14 of the tile body may have one or more recesses 28. Also, the top surface 12 may have a cosmetic groove 30 parallel to the side edges 20, 22 to give the tile the appearance of two tiles side-by-side.

A pair of dependent nibs 32 is disposed on the bottom surface 14 alongside the rear edge 16, and a nail hole 34 provided through the body 10.

The tile may be cast, moulded or extruded from a cement mixture using known techniques.

In use, Figs. 8 and 9, the tiles are laid on a pitched roof in overlapping rows, with the rear edge 16 of each tile in a given row being covered by at least one overlapping tile of the row above. The tiles are ¢0 3 08 β s retained in position in their rows by their nibs 32 engaging behind roof battens 36 in conventional manner. As previously mentioned herein, the underlock 24 of each of the tiles may include an indentation adapted to accommodate a respective roof batten 26. Selected tiles may also be nailed to the battens through the nail holes 34 .

The features marked 38 and 40 are very shallow loadbearing protrusions of about 0.5mm thickness. The protrusion 38 located in the centre towards the rear of the tile sits, in use, on the batten 36, as shown. The protrusions 40 located at both sides towards the front of the tile sit on the top surface 12 of the tile which it overlaps. The protrusions are present in order to provide pressure points for the tile. The underlock and overlock are quite weak in comparison with the rest of the tile, due to their thinness. The protrusions enable the tile to rest on these pressure points, rather than resting on and placing pressure on the thin underlock and overlook, which may undesirably cause the breakage of same .

Due to the substantially constant curvature of the top and concave bottom surface which converges towards the top surface at the front edge of the tiles, the degree of overlap of one row of tiles on the next can be adjusted over a relatively large range, Fig. 9, with the front edges 18 of the tiles resting with little or no gap on the top surface of the underlying tiles. Furthermore, the positioning of the protrusions 40 also enables the tiles to conveniently overlap over a range of positions. This contrasts with the design of tile shown in IE Ο 5 08 Ο 8 ΕΡ Ο 387 305 BI where, due to the upwardly inclined front portion of the bottom surface of the tile, the front edge of the tile will tend to lift away from the top surface of the underlying tile for large overlaps.

It will be appreciated that the bottom surface 14 of the tile may be adapted as desired. For example, the size and/or the positioning of the recesses 28 present on the bottom surface 14 of the tile body 10 may be amended as desired. It will be further appreciated that the size and/or positioning of the nail holes 34 and the loadbearing protrusions 38, 40, may be modified as necessary. It will also be apparent that both the width of the tile, and the distance between the front and the rear edges of the tile may be amended as desired, so as to form any suitably sized tile.

The invention is not limited to the embodiment described herein which may be modified or varied without departing from the scope of the invention.

Claims (5)

Claims

1. An interlocking roof tile for a pitched roof, the tile comprising a substantially rectangular body having a top major surface, a bottom major surface, a front edge, a rear edge which is covered in use by at least one overlapping tile of an adjacent row of tiles, and a pair of opposite side edges, the tile further including an underlock extending along one side edge and an overlook extending along the other side edge whereby the tile may be interlocked with its neighbours on each side, wherein in the front-to-rear direction of the tile body the top major surface is convex and the bottom major surface is concave, said convex and concave major surfaces converging towards, and extending substantially fully up to, the front edge.

2. A roof tile as claimed in claim 1, wherein the top and bottom major surfaces converge along at least the front third of the tile, as measured in the front-to-rear direction, and preferably at least the front half of the tile .

3. A roof tile as claimed in claim 1 or claim 2, wherein the underlock has a substantially uniform thickness along the length thereof .

4. A roof tile as claimed in claim 2 or claim 3, wherein the top and bottom major surfaces are a substantially constant distance apart rearwardly of their convergent portions; and, wherein, the substantially constant distance is from 16-20mm, preferably about 18mm, and the top and bottom major surfaces converge to a IE Ο 3 0808 separation of from 11-13.5mm, preferably about 12mm, at the front edge.

5. A roof tile as claimed in claim 1, 2, 3 or 4, 5 wherein the top major surface has a substantially constant radius of curvature of from 1500mm to 1700mm, wherein the straight line distance between the front and rear edges is from 280mm to 300mm, and wherein the width of the tile is from 320mm to 340mm.