GB2323865A

GB2323865A - Insulating roof tile

Info

Publication number: GB2323865A
Application number: GB9806775A
Authority: GB
Inventors: Robert Conroy
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-04-04
Filing date: 1998-03-31
Publication date: 1998-10-07
Also published as: GB9806775D0

Abstract

A roofing tile comprises a first lower layer of insulating material (1) bonded to a second upper layer of metallic sheet (2). The tile has four edges; one upper, one lower and two lateral and is adapted to be laid on a pitched roof. The first layer (1) may be a foam plastic material. The second layer (2) may be steel and may have a coating (3) eg of resin bonded grit. A third layer, of steel sheet, may be located below the first insulating layer (1 ).The tile may be formed with projections and or flanges to facilitate the interengagement of two or more tiles.

Description

ROOFING TILE This invention relates to a roofing tile, in particular an insulated roofing tile. Prior art tiles are generally made of concrete or clay. They have the advantage of strength and simplicity of laying but they have the disadvantage that they are relatively heavy and can break easily. A roof coated with tiles of concrete or clay requires an additional coating of insulation beneath the tiles. The density of concrete and clay means that tiles are limited in size because they must be able to be lifted by a single person and carried to the position on the roof on which they are to be laid. Typically a pitched roof construction will require the following layers to be assembled on top of the rafter forming the pitched roof: sarking board, felt layer, battens, counterbattens and finally tiles.

It is an object of the present invention to provide a roofing tile which is easier to use, provides an improved level of insulation, provides sufficient strength and toughness for use on a roof, may be cut to shape on site easily, and may easily be provided in different shapes and sizes.

According to a first aspect of the invention, there is provided a roofing tile comprising a first lower layer of insulating material and a second upper layer of metallic sheet bonded to the first layer, the tile having an upper edge, a lower edge and two lateral edges and being adapted to be laid on a pitched roof such that the upper edge is above the lower edge.

Preferably the second layer is steel sheet, most preferably coated with an anti-corrosion coating.

Preferably the coating is a plastisol (TM) colour coating. Preferably the first layer is of foam plastic, most preferably a closed cell rigid polystyrene layer. The steel sheet may be galvanised.

Preferably the second layer extends at the lower edge of the tile in a substantially U-shaped flange which comprises a generally planar first return flange extending beneath the first layer. Preferably the first return flange is spaced apart from the first layer.

Preferably the first return flange is provided at its free end with a first lip portion which extends at an angle towards the top of the tile. Preferably the first lip portion extends to the lower surface of the first layer.

Preferably the second layer extends at the upper edge of the tile in a substantially U-shaped flange which comprises a generally planar second return flange extending above the second layer. Preferably the second return flange is spaced apart from the second layer.

Preferably the second return flange is provided at its free end with a second lip portion which extends at an angle away from the second layer. Preferably the first and second lip portions are adapted such that the first lip portion of a first tile engages with the second lip portion of a second tile when the first tile is lapped on the second tile. Preferably the second return flange of the second tile is adapted to be inserted between the first return flange and the first layer of the first tile. Preferably the first and second return flanges are resilient. Preferably the second return flange is longer than the first return flange.

Preferably the second return flange is provided with one or more fixing holes adjacent to the bend of the Ushape.

Preferably the first layer has a recess of generally rectangular section at its bottom face adjacent to the lower edge of the tile. Preferably the first layer has a projecting portion of generally rectangular section at its bottom face adjacent to the upper edge of the tile. Preferably the shape and size of said recess and projecting portion are adapted such that when tiles in an upper row lap with tiles in a lower row the bottom surface of the first layer of the tiles in the upper row rests upon the top surface of the projecting portion of the tiles in the lower row. Preferably also the portion of the first layer above the recess of the tiles in the upper row rests upon the top surface of the tiles in the lower row.

Preferably the second layer projects beyond the first layer at a first lateral edge of the tile. Preferably the tile is provided with a recess in its upper surface at the second lateral edge of the tile. Preferably said recess is adapted to accommodate the lateral projection of the second layer of a laterally adjacent tile. Preferably the lateral edges of the first layer are provided with mutually interfitting step formations.

The tile may comprise a third layer of metallic sheet below the first insulation layer, preferably of steel, most preferably of plastisol (TM) or similar plastic coated steel.

The tile may comprise an adhesive layer between the first insulation layer and the or each metallic sheet layer.

The tile may comprise a bonded particulate layer above the second layer. Said bonded particulate layer may comprise resin and a granular material such as sand, grit, chippings, gravel etc.

The invention will now be described with reference to the accompanying drawings in which: Fig. 1 shows a front view on a tile according to the invention; Fig. 2 shows a side view of the tile of Fig. 1; Fig. 3 shows a sectional view through a lateral joint between two tiles according to the invention; Fig. 4 shows a sectional view of a lapped end to end connection between two tiles according to the invention; Fig. 5 shows a lateral section through the upper steel layer of the tile according to the invention; Fig. 6 shows a lateral sectional view through the insulating layer of a tile according to the invention; Fig. 7 shows a lateral sectional view through the optional lower steel layer of a fully bonded tile according to the invention; Fig. 8 is a partial view on a roof comprising a plurality of tiles according to the invention; and Fig. 9 is a perspective view of a tile according to the invention adapted to be placed on a hip of a roof.

Figs 1 to 7 show the construction of a tile according to the invention. The tile is formed from an insulation board 1 onto which is bonded a sheet of coated steel 2. A layer of resin bonded grit 3 is shown bonded to the upper surface of the coated steel sheet 2. The layer of resin bonded grit may be omitted if required.

A bottom layer of steel 4 may optionally be fastened to the underside of the insulation board 1.

The insulation board 1 is shaped so as to permit easy lapping and fitting of adjacent tiles. One side of the insulating board is provided with a projecting portion 10, which is typically 25 mm square in section, while the other side of the insulating board is provided with a rebate 11, which is also typically 25 mm square in section. The first lateral side of the steel sheet 2 forms a channel 12, which typically may have a depth of 2 mm. This channel 12 accommodates the projecting portion 13 of the steel sheet 2 of an adjacent tile.

As can be seen in Fig. 3, when two tiles are placed laterally side by side the projecting portion 13 of the steel plate 2 of one tile laps with the steel plate 2 of the other tile in the area of the channel 12. At the same time the insulating boards 1 interlock to form a continuous insulation path at the joint. Mastic material 14 may be applied on top of the projecting portion 10 of the insulating board and on the channel 12 to form a positive seal with the lapping tile.

At the upper edge of the tile the steel sheet 2 is bent back to form a u-shape 20, a return flange 21 and a small angled flange 22. Typically the angled flange forms an angle of about 300 with the plane of the steel sheet 2. The angled flange 22 may be omitted so that the return flange 21 is straight and extends either parallel to the upper edge of the tile or at a slight angle towards the upper edge of the tile. The insulation board 1 has a projecting portion 24, which is typically 25 mm by 25 mm in section.

At the lower edge of the tile the insulating board is formed with a large rectangular rebate 25 on its underside. The rebate preferably has an angled upper surface 35, an angled side surface 36 and a radiused corner 37.

The lower edge of the steel sheet 2 is bent around the insulating board in the area of the rebate 25 to form a perpendicular flange 26, a return flange 27 which is generally parallel with the steel sheet 2 and an angled flange 28. The return flange 27 is spaced from the portion 29 of the insulation board above the rebate 25, forming a void 30. As can be seen in Fig. 4 the upper return flange 21 of the lower tile may be inserted into the void 30 of the upper tile by placing the upper tile to the right of the joint as shown in Fig. 4 and moving the upper tile towards the left. The upper return flange 21 and the lower return flange 27 are resilient so that they deform as the two angled portions 22 and 28 move past each other. The resilient nature of the return flanges 21 and 27 serve to hold the tiles together.

The angled flange 28 may be omitted so that the lower return flange 27 extends parallel to the steel sheet 2 and ends at a point spaced apart from the underside of the projecting portion 29 of the insulation board. If the angled flange 28 is omitted, the return flange 21 at the upper edge of the tile is readily inserted between the lower return flange 27 at the lower edge of the tile and the projecting portion 29, whether or not the upper return flange 21 has an angled flange 22 at its end.

The lower tile may be fastened to a batten 40 by a screw fixing 41 or similar which is passed through the upper return flange 21 and the steel sheet 2 adjacent to the u-shaped potion 20. The upper return flange 21 and the steel sheet 2 may have holes 42 preformed therein.

The lower steel sheet layer 4, when fitted, is bent at the lower edge of the tile to form an angled flange 44 which fits around the angled surface 36 of the rebate 25 in the insulating board 2. At the upper edge of the tile it is bent through two right angles to form a parallel flange 45 which fits around the projecting portion 24 of the insulating board 2. Laterally the lower steel sheet layer 4 ends flush with the bottom surface of the insulating board 2.

Fig. 8 shows a number of tiles 50 arranged on a pitched roof. At each horizontal lapped joint it is only the perpendicular flange 26 which is visible, giving the tiles the aesthetic effect of a roof comprising thin tiles. Rivets 51 may be fitted on site as the tiles are laid, to provide secure laps at the lateral joints.

The heads of the pop rivets 51 may have the same finish as the tiles 50 (e.g. plastisol (TM) coating or resin bonded grit) so that the aesthetic appearance of the roof is not adversely affected.

Tiles according to the invention may be formed in shapes other than planar shapes. Fig. 9 shows a tile according to the invention made to fit on a roof hip.

The hip tile 60 comprises two planar portions 61 and 62 connected by a flange 63 on planar portion 62 which is fastened by rivets 64 to planar portion 61.

In contrast to prior art tiles the tile of the invention cannot be broken as it is made from a plastic colour-coated metal sheet formed to the same shape of the tile which is then bonded by a resin or suitable glue to a pre-shaped insulation board.

When fitting this new tile system the competitive advantages are extensive. The tile of the invention is much lighter than conventional concrete or conglomerate tiles. One tile covers approximately the same area as four standard conventional tiles at present. The weight of the tile of the invention is about the same as that of one conventional tile. Therefore there is 75% less dead load per square metre on the roof from the tiles alone.

When laying a conventional roof with conglomerate tiles there is a build up required which normally comprises sarking board, felt layer, battens and counter battens, then the tile. When laying the tile system of the invention all that is needed is counter battens, then the tiles may be laid directly on the counter battens.

At verges and parapet walls the closure flashings may be formed directly from the tiles being laid. At hip ends the corner may be formed from the tile being laid.

At internal valley slopes a bonded internal flashing may be used.

At the eave of the roof, the new tile may be formed to a predetermined length so as to finish inside the gutter. At the roof ridge a bonded ridge tile may be fabricated, similar to two standard planar tiles.

If insulation is also provided in walls, gables, soffit and roof butt, when covering a roof with tiles according to the invention a sealed envelope is effectively created (the warm roof concept).

Traditionally when designing a pitched roof the insulation can be placed either at ceiling level (giving a "cold roof") or above the rafters (giving a "hot roof"). The latter option, with insulation at rafter level, offers the following advantages over insulation at ceiling level:a) the roof structure is kept at a similar temperature as the rest of the building so eliminating the risk of condensation on structural roof members; b) thermal stress will be avoided; c) as all insulation is at the roofline, there is no need to ventilate the roof space; d) there is no need for a vapour check at ceiling level; e) pipes, tanks and other services in the loft space are protected from freezing; f) easier conversion of unused roof space to a living area at a later date.

The strength of the tile according to the invention is excellent. It can accommodate point loads as well as distributed loads so that a person can walk on the tile with confidence to gain access to the roof.

Unlike conglomerate concrete or slate tiles which are nailed on to the roof, the tile and tile batten may be fixed to the rafters with screws. Each tile is fixed at four different points and as the installer progresses up the roof, all the fixings are hidden.

The only fixings visible are two optional flat head pop rivets at each lateral lap. The rivets are pre-painted the same colour as the tile and are hardly noticeable.

The security of the roof is greatly enhanced with the new tile. Once the roof is fixed and finished, it is be very difficult to remove any tile on the roof. When fixing to the roof, the new tile is lap-locked and broke-bonded and bedded in sealant which will give a very long-lasting, trouble-free roof.

If cutting any holes on the roof for soil vent pipes or central heating flues, this may be done very neatly with core cutters and Dektite (TM) pipe flashings. No lead flashings are necessary.

The roofing system incorporating tiles according to the invention is suitable for private and industrial roofs.

If the tile is used on a factory roof, a second steel layer may be added to the tile on the underside. This second steel layer may be formed from a white liner panel and bonded to the under side of the tile insulation.

The tile of the invention is very versatile, and can be coated with different coloured grit to give a selection of textured finishes. Different lines, ridges and surface decoration may be pressed into the tile.

The lightness and toughness of the tile according to the invention means that there would be very little waste and no breakage with the new tile.

The size and shape of the return flanges may be adapted to suit the type and thickness of the metal sheet layer. It has been found that a 0.7mm thick steel sheet with a 200 micron plastisol (TM) coating is particularly suitable, such as Dobel (TM) 200XT sheet.

The steel may be galvanised for additional protection.

The insulation board may be a closed cell rigid polystyrene board. It has been found that a 50mm thick board provides a good level of insulation without being too thick to handle. However board thicknesses of between 35mm or less and lOOrnm may be used where conditions dictate.

These and other modifications and improvements can be incorporated without departing from the scope of the invention.

Claims

CLAIMS:

1. A roofing tile comprising a first lower layer of insulating material and a second upper layer of metallic sheet bonded to the first layer, the tile having an upper edge, a lower edge and two lateral edges and being adapted to be laid on a pitched roof such that the upper edge is above the lower edge.

2. A roofing tile as claimed in Claim 1, wherein said second layer is steel sheet.

3. A roofing tile as claimed in Claim 1 or Claim 2 wherein the first layer is of foam plastic material.

4. A roofing tile as claimed in any of Claims 1 to 3, wherein said second layer extends at said lower edge of said tile in a substantially U-shaped flange which comprises a generally planar resilient first return flange extending beneath said first layer.

5. A roofing tile as claimed in Claim 4, wherein said first return flange is spaced apart from said first layer.

6. A roofing tile as claimed in Claim 4 or Claim 5, wherein said first return flange is provided at its free end with a first lip portion which extends at an angle towards the top of said tile.

7. A roofing tile as claimed in Claim 6, wherein said first lip portion extends to the lower surface of said first layer.

8. A roofing tile as claimed in any preceding claim, wherein said second layer extends at said upper edge of said tile in a substantially U-shaped flange which comprises a generally planar resilient second return flange extending above said second layer.

9. A roofing tile as claimed in Claim 8, wherein said second return flange is spaced apart from said second layer.

10. A roofing tile as claimed in Claim 8 or Claim 9, wherein said second return flange is provided at its free end with a second lip portion which extends at an angle away from said second layer.

11. A roofing tile as claimed in Claim 10 when dependent on Claim 6 or Claim 7, wherein said first and second lip portions are adapted such that said first lip portion of a first tile engages with said second lip portion of a second tile when said first tile is laid in lapping arrangement on said second tile.

12. A roofing tile as claimed in Claim 11, wherein said second return flange of said second tile is adapted to be inserted between said first return flange and said first layer of said first tile.

13. A roofing tile as claimed any of Claims 8 to 12, wherein said second return flange is provided with one or more fixing holes adjacent to the bend of the U-shaped flange.

14. A roofing tile as claimed in any preceding claim, wherein said first layer has a recess of generally rectangular section at its bottom face adjacent to said lower edge of said tile.

15. A roofing tile as claimed in Claim 14, wherein said first layer has a projecting portion of generally rectangular section at its bottom face adjacent to said upper edge of said tile.

16. A roofing tile as claimed in Claim 15, wherein the shape and size of said recess and projecting portion are adapted such that when tiles in an upper row lap with tiles in a lower row the bottom surface of said first layer of the tiles in said upper row rests upon the top surface of said projecting portion of the tiles in said lower row.

17. A roofing tile as claimed in Claim 16, wherein the portion of said first layer above the recess of the tiles in said upper row rests upon the top surface of the tiles in said lower row.

18. A roofing tile as claimed in any preceding claim, wherein said second layer projects beyond said first layer at a first lateral edge of said tile.

19. A roofing tile as claimed in Claim 18, wherein said tile is provided with a recess in its upper surface at a second lateral edge of said tile.

20. A roofing tile as claimed in Claim 19, wherein said recess is adapted to accommodate the lateral projection of the second layer of a laterally adjacent tile.

21. A roofing tile as claimed in any of Claims 18 to 20, wherein the lateral edges of said first layer are provided with mutually interfitting step formations.

22. A roofing tile as claimed in any preceding claim, further comprising a third layer of steel sheet below the first insulation layer.

23. A roofing tile as claimed in any preceding claim, further comprising an adhesive layer between the first insulation layer and the or each metallic sheet layer.

24. A roofing tile as claimed in any preceding claim, further comprising a bonded particulate layer above said second layer.

25. A roofing tile as hereinbefore described with reference to the accompanying drawings.