GB2314356A

GB2314356A - Method of forming a roof tile

Info

Publication number: GB2314356A
Application number: GB9713969A
Authority: GB
Inventors: Norman Wright; Bernard Curtis
Original assignee: MARLEY BUILDING MATERIALS Ltd
Current assignee: MARLEY BUILDING MATERIALS Ltd
Priority date: 1993-12-10
Filing date: 1994-12-12
Publication date: 1997-12-24
Anticipated expiration: 2014-12-12
Also published as: GB2314356B; GB2298664A; GB9713969D0; GB9612040D0; GB2298664B

Abstract

A method of forming a roof tile comprises extruding a ribbon of material onto a series of pallets which pass under a slipper plate. The pallets define the underside shape of the tiles 1 such that longitudinal features on the underside of the tiles are defined by the pallets to extend transversely of the direction of extrusion. The slipper plate may be flat or profiled to define the transverse profile of the tiles.

Description

Roof Tiles This invention relates to a method of making a roof tile. The method is suitable for making roof tiles for the roof tile system described in co-pending UK Patent Application No. 9612040.7 (Serial No. 2298664).

Conventional roof tiles of concrete and other materials are generally rectangular in plan view. They are usually provided with a top surface interlock region along one side edge, and a bottom surface interlock region along the other side edge. In use, adjacent tiles are interlocked in a relatively watertight manner by means of these regions. On a roof, the lower portions of one row of interlocked tiles overlap the upper portions of the row below. Various means such as clips have been proposed for attaching the tiles to roof battens.

It is sometimes desired for the lower ends of the tiles to have a relatively thin appearance, for example if they are to resemble conventional slates. This presents problems, since a minimum thickness of material is required to provide the interlock regions along the tiles. One proposal has been to form an undercut at the bottom of the lower end of a tile. This provides a shadow effect when the tile is laid on a roof, thus tending to reduce the apparent thickness of the tile.

Another proposal is made in GB-A-2 172 025. In this specification, the upper end of the top surface of the tile is recessed, and the lower end of the interlock region on the top surface is cut away. In use, the recessed portion of a tile receives the interlocked regions of two adjacent tiles in the row above. The remainders of the two tiles project beyond the recessed portion. In this manner, a thin lower edge may be seen.

These solutions are not ideal. In GB-A-2298664 there is proposed a novel type of roof construction using a tile which does not rely upon top and bottom surface interlock regions in order to be joined to other tiles. Such a system has a number of advantages.

The invention disclosed in GB-A-2298664 provides a roof tile system comprising a number of rows of laterally adjacent roof tiles, each tile having a head end and a tail end, the tail ends of tiles in one row overlying the head ends of tiles in the next row down the roof; each tile having on its underside, adjacent each side edge, a longitudinally extending recess; a longitudinally extending weathering member under adjacent side edges of a laterally adjacent pair of tiles in a row, said weathering member having a laterally spaced pair of longitudinally extending upstands which project into the recesses of the respective tiles; attachment means attaching the tail end of the weathering member to a support member which is located beneath the tail ends of the pair of tiles; and locating means passing between the pair of tiles and engaging upper surfaces of the tiles to restrict movement of their tail ends.

Thus, each tile is restricted in terms of lateral movement by engagement of upstands of the weathering member in the tile recesses. Movement of the tiles away from the roof is prevented by the locating means, and the weathering member is attached to a support member such as tiling batten. Any water passing between the tiles is caught by the weathering member and channelled down the roof. The upstands on the weathering member also prevent water moving sideways into the roof space under the tiles.

Accordingly, adjacent tiles in the roof are indirectly interlocked together with adequate weathering. However, there is no need for the conventional interlock regions, and the tile can be less thick, and provide the desired appearance on a roof, without compromising strength requirements. There is no need for a complex tile construction as in GB-A-2172025.

Because the only essential profiles are in the underside of the tile, there is the possibility for improved manufacturing techniques.

Thus, according to the present invention, there is provided a method of forming a roof tile by extruding a ribbon of material onto a series of pallets which define the underside shape of the tiles, wherein longitudinal features on the underside of the tile are defined by the pallets to extend transversely of the direction of extrusion.

Tiles of concrete are formed by extruding a ribbon of concrete onto a moving line of pallets. The pallets serve as moulds which define the underneath profile of the tile. The extrusion process provides any upper surface profiling but it is of course limited to longitudinally extending features such as the interlocks or a regular profile for the tiles. The tiles move in the direction of such features. In accordance with the present invention, recesses in the underneath of the tile can be formed by the pallet, and thus it is irrelevant whether they extend parallel or transversely to the direction of movement. Thus, the tiles can be formed such that their normal longitudinal direction is perpendicular to the direction of movement. This means that it is now possible to form transverse upper surface features in the extrusion process. Thus, a transverse groove or upstand can be provided in the upper surface.

During extrusion this will extend in the direction of extrusion, but when the tile is turned the right way round the feature will extend transversely. The same applies to profiling the front (lower) edge of the tile.

During extrusion a curved profile can be applied on one side of the concrete ribbon, but this will be the front edge in use. In general of course, the upper surface will not be provided with any longitudinal features which would require subsequent treatment after extrusion.

Extruding the tiles perpendicular to the normal direction also speeds up the process. Most conventional tiles are longer than they are wide. By extruding perpendicular to the normal direction, more tiles are fitted in per unit length. Thus for the same linear speed of the tile extruding apparatus, more tile per minute will be produced.

Preferably, the roof tiles are usable in conjunction with a weathering member as described in GB A-2298664, which is in the form of a channel with upwardly projecting side flanges which form the upstands. Preferably, the attachment means is integral with the weathering member, for example being in the form of one or more extensions from the underside of the member, towards its tail end. The attachment means may be in the form of a clip to clip under or over a roof batten, from either direction as desired. In the preferred embodiment the attachment means comprises an extension which passes under the batten and engages against the underside of the batten. The extension comprises a first portion which projects away from the under surface of the weathering member and a second portion which then projects down the roof.

There is preferably some resilience so that the second portion can be moved resiliently away from the body of the weathering member, so as to receive and then clamp against the roof batten. The free end of the second portion may be rounded and may be provided with raised portions, serrations or the like to assist in engagement with the roof batten. The extension could be profiled so as to latch under the batten and engage the other side of the batten, so as to provide more secure attachment. In practice a clip arrangement of the type described above will be sufficient. The extension may be provided with reinforcing ribs, flanges or the like.

In an alternative arrangement the extension does not act as a clip but is provided with means for receiving a nail or like fastener which is used to secure the weathering member to the roof batten.

Preferably, the attachment means comprises a pair of such extensions, one adjacent each side of the weathering member. The two extensions preferably diverge outwardly from each other. Using a pair of spaced extensions means that it is possible for the weathering member to be located above a roof rafter, with the extensions straddling the rafter. Preferably, the legs can be removed - e.g. by snapping or cutting.

This means that where the weathering member has to be attached in a difficult location such as close up to a rafter, one of the extensions can be removed. Which one is removed depends upon whether the weathering member is to the left or right of the rafter.

The use of a pair of extensions which clip under the roof battens, adjacent the tail of the weathering member, provides a simple and effective way of attaching the weathering member to a roof. At the eaves of the roof there will be no batten and the weathering member will be attached in an alternative way. For example, a nail could be used, passing through the base of the channel. The extensions would be removed. Indeed, such a method of attachment could be used over the entire roof, and a channel without extensions nailed in place.

In such an embodiment, where there is used a fastening member such as a nail or other suitable element, the weathering member channel preferably further includes a raised portion whose width is slightly greater than the fastener. Preferably this portion extends generally centrally along the length of the weathering strip. Alternatively the raised portion can be simply located in those regions where the fastening member is expected to be passed through. The centrally raised portion has the effect of substantially preventing water, which has passed between the edges of the tiles, accumulating in the region where the fastener penetrates the weathering member. This reduces the likelihood of the fastener corroding or the tiling batten going rotten. The weathering member may be made from any suitable material such as metal or plastics.

It may be made in colours such as grey to simulate slate.

The functions of the attachment means and the locating means could be combined in single element such as a clip or a fastener such as a nail. Thus, a clip could be nailed to a roof rafter and have a first portion which engages the weathering member and a second portion which passes between the pair of tiles and has a head engaging their upper surfaces. Alternatively, in an embodiment using a nail to fix the weathering member, the nail may pass between the tiles and its head may engage their upper surfaces.

In the preferred embodiment, using the integral extension to attach the weathering member to the roof batten, the weathering member is provided with integral locating means. This is preferably in the form of a generally "T"-shaped projection on the upper surface of the weathering member, the leg of the T passing between the files and the arms engaging on the upper surfaces of the tiles. Preferably the arms possess a degree of resilience so as to engage the tiles firmly. The projection should be positioned so as to hold down the tail ends of the tiles. In a practical embodiment this may mean positioning it within 100 mm of the tail end of the weathering member. Preferably the complete weathering member is injection moulded plastics and to ease moulding the projection is close to the tail end of the weathering member. An alternative method of manufacture would be to die cast aluminium.

The roof tile may have an upper surface which is flat, curved or profiled to give rolls or the like; an important factor is that no interlock region is necessary in the upper surface. The underside will be provided with the longitudinal recesses and such other configurations as are required, such as a nib to locate the upper end of the tile over a roof batten. There may be provided stiffening portions to improve the rigidity of the tile. A line could be moulded to act as a guide when aligning the weathering member with the tile. The recesses will generally be parallel and of constant width and depth although this may not be essential in all circumstances. Preferably, the recesses will extend substantially the entire length of the tile. However, in a preferred arrangement the ends of the recesses are closed off at the bottom end of the tile, i.e. they stop short of the lower end face of the tile. This not only provides a better appearance for the end face but also prevents movement of the weathering member downwards relative to the tiles.

In such an arrangement, and using a simple channel as the weathering member, it may not be necessary to provide any other means for preventing longitudinal movement of the weathering member. However, it could be provided with a flange to hook over a roof batten or the like. In the embodiments where the attachment means comprises a clip, additionally or alternatively the weathering member could be nailed or screwed to a batten although there may then be need to provide weathering for the nail or screw hole, such as a wall around the hole. A clamp, clip or the like could be used to secure the weathering strip to the batten, in addition to the clip already mentioned. The upper end of the weathering member could be closed off, if desired.

The recesses and weathering member are preferably so arranged that the upstands can engage the innermost walls of the recesses to restrict lateral movement.

There should be provision for a certain amount of movement, for example a maximum of lOmm and preferably 5-6mm. The recesses may be of unequal widths. There will generally be a gap between the tiles along the join between them.

In a preferred embodiment, a portion of the locating means will pass between the tiles.

Additionally, there may be a notch in one or both tiles, in its side edge, to permit passage of part e.g. of a clip. Apart for the question of appearance, such a notch will also impose a fixed position as regards the tile relative to the clip. Preferably, if a separate clip is used it will have variable possible positions relative to the tile in the longitudinal direction, thus allowing for various gauges. In such an arrangement the clip may snap onto or otherwise engage one or both upstands on the weathering member, at a number of positions along its length. It may simply be engaged over an upstand but as mentioned there is preferably a snap fit. To this end an upstand may have an enlarged portion at its upper end, which a channel on the clip may snap over.

In a relatively simple embodiment, an arm of the clip is nailed, screwed or otherwise fastened to a roof batten. A channel portion engages over an upstand, a lateral portion extends to the join between the tiles, and a locating portion extends up between the tiles, terminating in a head which engages the top surface of each tile. In a modification, each upstand has an enlarged upper portion. In this case, the lateral portion of the clip may extend past the join, and locate under the enlarged upper portion on the other upstand.

In normal use, such a clip will not be screwed or nailed directly to the roof batten. Instead, it will be positioned on the upper surface of a tile in the row below and then a fastener such as a screw or nail passed through the clip and a conventional aperture in the tile. Thus a single clip holds down the head of a tile, the tails of two tiles in the row above, and the weathering strip. The clip is preferably resilient to assist forming snap fits, and may be made of plastics e.g. by injection moulding - metal or any other suitable material.

To accommodate the clip, at the bottom of the tile there is preferably an additional recess extending laterally of the main longitudinal recess. The additional recess should preferably extend over a sufficient longitudinal distance to permit variation of position of the clip relative to the tile. The recess should also preferably be open in the laterally outwards direction to accommodate the clip. In one arrangement an additional recess is provided on each side of the tile. This gives a choice of the side on which the clip will be positioned and therefore a choice as to whether to tile from left to right or from right to left.

An advantage of such a tiling system, is that when laying a roof it is possible to tile from either the left or the right. With a system using interlocks, tiling has to be carried out in one direction and this may not be natural when hammering fastening members such as nails or clips in, depending upon whether the operator is left or right handed. Indeed, the conventional arrangement is inconvenient for right handed people. A further advantage is that by avoiding the use of overlapped interlocked regions there is more roof coverage per tile. Thus fewer tiles are required per roof. As compared to e.g. the systems of GB-A2172025 there is less head lap, which is also advantageous.

The weathering member may be provided with one or more additional upstands, parallel to the first two, extending along its length. This may be of use in coping with driven water.

An advantage of the preferred system is that the upper surface of the tile needs no special configurations such as an interlock. However, as noted above the side could be notched to permit the engaging means to pass between the tiles without any appreciable space between them. It would also be possible to provide a recess in the upper surface of each tile so that the locating means could be flush with the upper surface of the tile rather than rest upon it. A recess would generally mean that fixed gauge tiling only would be possible. It would also be possible to have a completely recessed locating means which extends into a groove in the side of the tile. However, these possibilities complicate manufacture of the tile.

Visible fixing clips and flat head nails are already known for conventional slate systems and should be acceptable.

In its broadest sense the tile requires only the two recesses in its underneath. In one of the preferred embodiments an additional recess is provided and thus preferably the roof tile has on its underside, adjacent each side edge, a longitudinally extending recess extending substantially the length of the tile, and wherein at least one of the recesses being provided at a lower end region of the tile with a laterally inwardly directed additional recess, and being open laterally in the outwards direction in this region.

It will be appreciated that the expression "tile" used herein encompasses a number of roof covering elements such as slates, shingles and so forth.

Preferred embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a schematic view of part of a roof; Figure 2 is a side elevation of a weathering member described in GB-A-2298554; Figure 3 is a top plan of the weathering member; Figure 4 is an end view of the weathering member; Figure 5 is a view of part of the weathering member showing in schematic outline a pair of tiles; Figure 6 is a view of one end of the weathering member showing in schematic outline a tile and a roofing batten; Figure 7 is a view of one end of an alternative weathering member described in GB-A-2298554; Figure 8 is a schematic view of tiles in the process of manufacture in accordance with a preferred embodiment of the present invention; Figure 9 is an underneath view of a preferred tile; Figure 10 is a top perspective view of an alternative weathering member described in GB-A-2298554; Figure 11 is a section showing the weathering member of Figure 10 in conjunction with a pair of tiles and a fastening nail; Figure 12 is a top perspective view of a further alternative weathering member described in GB-A-2298554; Figure 13 is a section showing the weathering member of Figure 12 in conjunction with a pair of tiles and a clip; and Figure 14 is an underneath view of a tile for use with the system of Figures 12 and 13.

In Figure 1 there is shown schematically part of a roof with a number of rows of tiles 1. The tiles in each row overlap the tiles in the row below and the joins between adjacent tiles are offset. The upper ends 2 of the tiles are referred to as the head ends and the lower ends are the tail ends.

Figures 2, 3 and 4 show an injection moulded plastics weathering member 3 which is positioned beneath the join between adjacent tiles 1. The elongate member 3 comprises a channel portion 4, attachment means 5 for attaching the member to a roof batten beneath the tiles 1, and locating means 6 for engaging a pair of adjacent tiles 1. The locating means and attachment means are at the tail end of the member. The channel portion 4 comprises a base 7, a pair of longitudinally extending upstands 8 along its edges and a central longitudinally extending flange 9 which terminates at the tail end in the locating means 6.

As shown in Figure 5 and in more detail in Figure 9, each tile has a longitudinally extending recess 10 adjacent each edge. The upstands 8 of the weathering member extend into these recesses. The locating means 6 comprise a central web 11 extending integrally from the flange 9, terminating in an enlarged, rectangular head portion 12 which extends on both sides to engage the upper surfaces of tiles 1. The head portion 12 is resilient and is angled downwardly to improve engagement with the tiles 1. In Figure 5 the tiles are indicated schematically only.

Thus, in use the weathering member 3 will be beneath the join between two tiles 1 and will engage in the recesses 10. The locating means will hold the tail ends of the tiles down. The weathering member 3 will collect any rainwater passing between the tiles and will channel it down onto the upper surface of a tile in the row below.

The weathering member itself is secured to the roof structure by means of the attachment means 5 engaging a conventional wooden roof batten 13, as shown in Figure 6. Located over the roof batten by means of a nib 14 at its head end is a roof tile 1' from the row below. The weathering member channel portion 4 with upstands 8 extends to over the upper surface of the tile 1' so that the water will be channelled onto this tile. Thus, the weathering member 3, being secured to the roof batten 13, holds down the tail ends of the tiles 1 by the locating means 6 as described earlier, and also holds down the head end of the tile 1' in the row below. The combined functions of the weathering member in terms of locating the tiles, holding them down and providing weathering for the join between them, lead to an effective construction.

The attachment means in the preferred embodiment comprises a pair of legs 15. As shown in Figure 4, the legs extend downwardly from the edges of the channel portion 4 and diverge in the lateral direction. Their spacing is such that they can, if necessary, straddle a conventional wooden roof rafter. Each leg 15 comprises a downwardly extending portion 16 and a forwardly extending portion 17, both being provided with flanges to improve strength. An additional reinforcing flange 18 is also provided. The forwardly extending portion 17 terminates in an upwardly convex portion 19 which engages the underneath of the roof batten 13. The portion 17 possesses resilience so that the portion 19 is clamped against the roof batten. Sharp projections 20 are also provided on the portion 19 to improve the engagement with batten 13.

In awkward portions, such as up against a rafter, one of the legs 15 can be snapped or cut off.

Figure 7 shows schematically part of a modified weathering member 3' with alternative attachment means.

Each leg now has only a downwardly extending portion 21 terminating in a cylindrical portion 22 provided with a bore through which passes a nail 23 to secure the member to a roof batten. As before, the portions diverge.

Figure 8 shows the passage of tiles 1 in a manufacturing process. The tiles are conveyed in the direction of arrow A in a conventional type of extrusion system using pallets, a slipper plate, a roller, a hopper of concrete and so forth (not shown). However the tiles extend across the direction of movement. The features such as the recesses 10 are formed in the lower surface perpendicular to the arrow A. In this manner, upper surface features, such as grooves 24 which will pass across the tiles at their head ends will extend in the longitudinal direction during manufacture. This means that they can be made by extrusion, thus simplifying production. The tiles have a plain profile and in general the process will not be applicable to tiles having a transverse profile such as a roll. A profile from top to bottom could be provided, however.

Figure 9 shows the underside of a preferred embodiment of a tile 1. There is provided a nib 14 at the head end of the tile 1 for locating over a roof batten, this being split into the spaced portion.

Extending parallel and adjacent to each edge of the tile 1 are the longitudinal grooves or recesses 10. These are open at their head ends and closed at the tail ends 25.

The tile is relatively thin, with a thin front edge. To increase the strength of the tile 1, regions 26 of greater thickness are incorporated into the underside of the tile design in areas where in use they will not interfere with battens or other tiles.

Generally these are formed as substantially rectangular longitudinal regions with chamfered edges as shown in the figure. A lateral groove 27 is provided at the tail end of tile 1 to prevent capillary action drawing up water between the overlapping regions of the tiles.

Figure 10 shows a further embodiment of a weathering member 28 which is in the form of a single channel like strip. In addition to having upstands 29 and 30 the member has a central raised portion 31 running the length of the member. At a predetermined distance along the raised portion 31 is a hole 32 for a nail or other fastener.

As shown in Figure 11, the upstands 29,30 of the member 28 project into longitudinal grooves or recesses 33,34 which extend along the edge of the underside of adjacent tiles 35. As before, water which passes down between these tiles 35 will be directed by the weathering strip 28 onto the upper surface of a tile 35' in the row below.

In this embodiment, the tiles 35 are secured by a nail 36 which is driven into a tiling batten 37. At the same time the nail passes through the hole 32 of the weathering member 28 and a pre-formed or drilled hole 38 in tile 35, securing both of these to the tiling batten 37. The centrally raised portion 31 of the weathering member is intended to have a width only slightly greater that of the nail 36. This prevents water which passes down between the tiles collecting around the junction of the weathering member and the nail.

Figures 12, 13 and 14 show a further alternative embodiment of a weathering member.

Figure 14 shows an extruded concrete roof tile 39, from the underneath. The tile 1 has a nib 40 at its head end for location over a roof batten, and a tail end. Extending parallel and adjacent to each edge of the tile is a longitudinal groove or recess 41,42. Each groove 41,42 is open at its head end and terminates short of the tail end of the tile so that it is closed off by portions 43,44.

The recess 41 is laterally outwardly open over a region 45 towards the tail end of the tile, by means of a cut-away portion of the tile forming a wall of the recess and is provided with an additional inwardly extending rectangular recess 46. This recess is rectangular.

As before, the tile has a relatively thin front edge, ie. the visible portion at the tail end of the tile, has a substantially flat and plain upper surface.

The tile is not provided with interlocks.

Figure 12 shows a weathering member 47 which is in the form of an extruded channel of e.g. aluminium or plastics and has upstands 48,49 along its edges. As can be seen more clearly in Figure 13, the upstands have inwardly projecting lugs 50,51 at their upper ends.

Figure 13 shows the tile 39, a second tile 39', the weathering member 13 and a clip 52, all engaged together. The clip 52 is of e.g. injection moulded (preferably somewhat resilient) plastics material. The clip has a first portion 53, an upwardly extending portion 54, a laterally extending portion 55, a second upwardly extending portion 56, and a head 57. The portions 54 and 55 are joined by a portion defining a nib 58 which is designed to clip over the upstand 48 of the weathering member 47, with the nib 58 engaging with the lug 50. Thus, the clip can form a snap fit with the upstand. The clip portion 53 is provided with a hole 59 to receive a fastener such as a nail or screw. The clip portion 56 passes between tiles 39' with the head 57 engaging their upper surfaces.

The clip is fastened by means of a nail 60 which passes through the hole 59 in the clip, through a hole 61 in a tile 39' in the row below, and then into a wooden batten 62.

It will be appreciated that the portions 45 and 46 of the tiles 39, seen more clearly in Figure 14, are necessary to accommodate the clip 52.

In a modification of this embodiment, which involves slight modification of the tile design, the clip has an extension of portion 55 which extends across to the other upstand 49 and engages with it in a like manner forming a snap fit with the lug 51.

Claims

1. A method of forming a roof tile by extruding a ribbon of material onto a series of pallets which define the underside shape of the tiles, wherein longitudinal features on the underside of the tile are defined by the pallets to extend transversely of the direction of extrusion.

2. A method as claimed in claim 1 wherein the longitudinal features on the underside of each tile include a recess extending along each side.

3. A method as claimed in claim 2, wherein the pallets are configured so that at least one of the recesses is provided at a lower end region of the tile with a laterally inwardly directed additional recess which is open laterally in the outwards direction in this region.

4. A method as claimed in claim 1, 2 or 3, wherein the pallets are configured to provide a nib extending in the lateral direction on the underside of the tile at the tile's head end.

5. A method as claimed in any preceding claim, wherein the pallets are configured to provide a recess extending in the lateral direction on the underside of the tile at the tile's tail end.

6. A method as claimed in any preceding claim, wherein the pallets are configured to provide a region of greater thickness on the underside of the tile located towards the middle of the tile.

7. A method as claimed in any preceding claim, wherein during the extrusion process, a slipper plate is used to define the upper surface of the tiles.

8. A method as claimed in claim 7, wherein the slipper plate has a flat edge to define a planar upper surface on the tiles.

9. A method as claimed in claim 8, wherein the slipper plate has a profiled edge to define a transverse profile on the upper surface of the tiles.

10. A method as claimed in claim 7, 8 or 9, wherein the edge of the slipper plate which defines the upper surface of the tiles has a feature for defining a transverse feature on the upper surface of the tiles.

11. A method as claimed in claim 10, wherein said feature comprises a groove extending in the lateral direction on the upper surface of the tiles.

12. A roof tile made by a method as claimed in any preceding claim.

13. A method substantially as hereinbefore described with reference to Figure 8, Figure 9 and Figure 14 of the accompanying drawings.

14. A roof tile substantially as hereinbefore described with reference to Figure 8, Figure 9 and Figure 14 of the accompanying drawings.