GB2490375A - Roof structure with tiles covered in a turf finish. - Google Patents

Abstract

The roof structure comprises a tiled surface comprising a number of base tiles 26 interleaved with a number of capping tiles 24. Each base tile defines a channel which extends in a first direction 221 and a second, not parallel to the first, direction 222. The base tiles are connected such that they form a zig-zag, serpentine, S shape or wavelike row, each row being adjacent to similar rows and the adjacent portions being covered by the capping tiles. The tiles are covered in turf 29 and may include an irrigation system using flexible perforated tubes. Preferably the roof tile is made from a recycled car tyre the bottom portion of the channel formed from the sidewall of the tyre and the sides of the channel formed from the treaded base of the tyre and a flange extending from the inner portion of the tyreâ s sidewall.

Description

t V.' INTELLECTUAL ..* PROPERTY OFFICE Application No. GB 1118206.0 RT1VI Date 31 May 2012 The following terms are registered trademarks and should be read as such wherever they occur in this document: Pearlite Intellectual Properly Office is an operating name of the Patent Office www.ipo.gov.uk Tiled roof structure and tile

Background of the Invention

The present invention concerns a roof structures and roof tiles. More particularly, but not exclusively, this invention concerns a roof structure comprising tiles, a roof tile, and a method of manufacturing a roof tile, all having particular, but not exclusive, application within the eco-build market.

Eco-build projects are an aftractive proposition not only because of the low environmental impact but also because of the potential cost savings to be made. One aspect of an ceo-build building which is of importance is the roof It would be desirable for the roof of an ceo-build building to utilise recycled materials, have an attractive appearance, have strength, have good drainage, and be cheap and easy to construct.

It has been proposed to use tiles made from used vehicle tyres to build a roof Such a proposition is attractive in the ceo-build market, as it potentially solves the problem ofhow to effectively dispose of used vehicle tyres in a cost-efficient and environmentally friendly manner whilst also providing a building material for the ceo-build market. US 5,675,954 described such a method of making a roof tile from a used vehicle tyre. A preferred version of the method requires cuffing the tyre into segments by means of radial cuts. Each segment is then trimmed, shaped and heat-treated to remove pieces of unwanted tyre and to straighten out the curvature about the axis of the tyre. The resulting pieces of tyre are therefore in the form of straight lengths of U-shaped channel, referred to in US 5,675,954 as having a colonial type shape. Such tyre tiles may then be assembled to form a tiled surface on a roof, where the straight channels run from high to low (i.e. with the pitch of the roof). Adjacent tiles may be capped with inverted tiles, forming an interleaved array of tiles.

There are however various disadvantages with US 5,675,954. The processing of the tyre that is required to produce the tiles is relatively time and cost intensive. Parts of the tyre need to be removed and presumably disposed of in alternative ways.

Straightening the tyre by means of a heat-treatment process appears particularly time and cost intensive. An alternative embodiment is proposed in US 5,675,954, which omits the straightening process. It is not clear however how this alternative embodiment is supposed to work in practice. It would seem that the tyre sections are supposed to be arranged to form an undulating channel (undulating vertically up and down) along its length. Quite how proper and full drainage would be achieved without pooling ofwater and quite how such tiles would be properly secured to a roof structure is not clear however.

A further prior art document (GB 2 367 077 A) shows interlocking rubber tiles, each being formed from a one-sixth segment of a used vehicle tyre. The segment is cut from the side wall of the tyre, with little or no portion of the treaded part of the tyre being used. The tile has a flat and shallow profile. A tile system using tiles of this type could provide effective roof cover, but may be prone to leaking if there is strong rain, melting snow, or if the length and/or pitch of the roof is such that the volume of water reaching the end of the channel defined by the tiles is too great to be contained in the relatively shallow channel.

The tile system shown in GB 2 367 077 would not be suitable as a base for a turf roof and/or is disadvantageous in for several reasons. Firstly, the weight of the soil would distend the rubber tiles, causing the tile profile to flatten. This would mean that water would escape the confines of the channel causing damage to the roof support structure. A second reason is that for any pitch of roof greater than, say, 15 degrees, such a roof covering has no significant key to hold the soil from sliding off the roof A third Is limitation is that, after time, the roots of the turf could penetrate the joints ofthe tiles and cause further leakage. Finally, turf roofs are often put on roundhouses. The construction of these is typically such that the tiles are arranged in triangular panels, whose channels run at an oblique angle to the pitch of the roof Consequently they are almost sideways on to the roof pitch. This would mean for a tyre tile roof such as that shown in GB 2 367 077 that the water would escape over the sides of the channel defined by the tile, not along it.

The present invention seeks to mitigate the above-mentioned problems.

Alternatively or additionally, the present invention seeks to provide an improved roof tile and/or an improved roof structure.

Summary of the Invention

The present invention provides a roof structure comprising a tiled surface, the tiled surface comprising a multiplicity of base tiles interleaved with a multiplicity of capping tiles, wherein each base tile defines a channel along its length such that there is a first portion of the tile that channels in a first direction, and a second portion of the tile that channels in a second direction, the first direction being non-parallel to the second direction, the base tiles are arranged in alignment with adjacent base tiles, the capping tiles each bridge at least one pair of adjacent base tiles, and the base tiles together form adjacent zigzagging channels that run from high to low on the roof The roof structure of the present invention is of particular application to a roof, particularly a pitched roof, of an eco-build building, that supports a turf layer. In the context of the present invention it may be a sufficient condition for a building to be deemed an eco-build building that the roof is covered with a turf layer.

The particular shape and arrangement of tiles, particularly the zigzagging shape, allows roof structures to be built where the tiles interlock and are less likely to slip relatively to each other, whilst also facilitating good drainage. Preferably all parts of the channel of each tile have a downward slope to facilitate such good drainage.

The channel may be generally arcuate in cross-section. Each base tile preferably has a generally U-shaped channel. The channel may have relatively flat surfaces and/or edges between adjacent surfaces defining the channel. Furthermore, a U-shaped channel may be of particular advantage if the direction of the channel is at a significant angle to the natural direction of water drainage, as the upwardly extending side walls of the channel will act to retain the flow water. The tile may be formed by means of a channel that has side walls that extend upwardly from the bed of the channel. Good drainage is important for a turfed roof The provision of a zig-zagging shape facilitates the keying-in of a turf layer. A greater pitch of roof may thereby be sustained and supported, without slippage of soil or turf A greater pitch of roof may, in certain embodiments, assist in maintaining water tightness, as precipitation may be more likely to run-off the outer surface of the roof The first portion of the tyre may extend in the first direction for a significant length of the tyre. Similarly, the second portion of the tyre may extend in the second direction for a significant length of the tyre. There may for example be a sharp change in direction between the first and second portions. Preferably, however, the tyre gently curves as between the first portion and the second portion, such that for example the direction of the channel gradually moves from the first direction to the second direction with increasing length along the tile. Preferably the angle of the first direction is different from the angle of the second direction by more than 30 degrees. The angle of the first direction may be different from the angle of the second direction by more than 45 degrees. The angle ofthe first direction may be different from the angle of the second direction by 60 degrees or more.

The base tiles preferably all have substantially the same shape. The cap tiles preferably all have substantially the same shape. The cap tiles preferably have substantially the same shape as the base tiles.

The tiles may be made from clay material. The tiles may be made from timber.

The tiles are preferably made from a flexible material. The flexible material may be flexible in the sense that an average man can cause a deflection of over 5cm in the tile with his bare hands. Standard ceramic or concrete tiles would not be so flexible. The flexible material is preferably an elastomeric material, for example a rubber material.

The present invention has particular application when the tiles arc made from used automobile tyres, particularly from large vehicles such as trucks or a buses.

The roof structure is preferably part of an eco-build building. The tyres may be left uncovered. Alternatively, the tiles may be covered with a further layer that hides and/or covers the tiles. The tiles may be covered with soil. The tiles may be covered with a living and growing grass layer. The roof is preferably in the form of a pitched and turfed roof There may be a fleece layer. The fleece layer may be provided within the channel defined by the base tiles. The fleece layer may be in the form ofa non-degradable fleece. The fleece layer may be disposed beneath a layer of soil, for example to reduce the risk of soil interfering with clear drainage. Preferably the fleece layer extends across a plurality of tiles both widthwise and up and down the roof There may be no need for a waterproof membrane in the roof structure.

The roof structure may include separate pipes within the channels defined by the tiles for example to enhance drainage and/or flow of water within the roof structure. For example, the drainage pipes may be in the form of perforated flexible pipes. Perforated pipes may be advantageous as they may provide additionally integral drainage which acts to reduce weight when the turf is saturated by rainwater or melting snow (water fecing into the perforated pipes via the perforations and then draining down via the pipes). Such drainage pipes may also facilitate irrigation of the soil/turf, for example in times of drought. Again, perforated pipes may provide advantage, as irrigation water may feed out of the perforations into the surrounding soil, for example without the need for spraying or the presence of anybody on the roof Also, if the water is foul water from the building's waste water system, such water can be fed to the soil, via such pipes, without any odour escaping. The perforations in the perforated pipes that facilitate the ingress and egress of water may be any suitable shape or size, ranging from very small perforations to larger slot shaped apertures in the pipe.

Said separate pipes may be located at or very near to the sides of the zigzagging channels defined by the tiles. One tile may for example accommodate two continuous lengths of separate pipes, one running down each side and extending to the tiles above and below.

The base tiles may be spaced apart from the capping tiles in a direction normal to the plane of the tiled surface by means of one or more such separate pipes. The pipe is preferably gripped to the sides of the channel by the interlocking nature of the tiles. Each pipe may be held between the base tile and the capping tile so as to be positioned to one side of the centre line of the channel. Two pipes may be so held, one down each side of the centre line of the channel.

There may be a pipe that lies on the outer curvature of a channel, such a pipe for example being held principally within a relatively sharp angle formed between the lowermost side wall of the channel and the bed of the channel, for example (in the ease where the tiles are made from used vehicle tyres), the angled region at which the tyre wall becomes the tread. The roof structure may be so arranged that, on the inner curvature, it is the upper, capping tile which has the sharp angle described above. In both cases, the roof structure may be so arranged that the other tile gripping the pipe has a softer angle, formed by what was the inner rim of the tyre. The action of the two tiles together is enough to hold the pipe in place during construction.

Furthermore, providing a drainage pipe (particularly a perforated pipe that allows ingress and egress of water) near the upper edges of the side walls of channel defined by the tile, may be of particular advantage if the direction of the channel is at a significant angle to the natural direction ofwater drainage. For example, in embodiments of the invention using tiles made from used vehicle tyrcs, where the direction of the channel is at a significant angle to the downward water flow direction, the pipe itself is more exposed by virtue of there being the less substantial rim edge in front of the pipe and the more substantial tread edge behind. Consequently drainage may be more efficient, as the water in the soil at this point is directed by gravity towards the perforated pipe rather than a rubber wall of the tile.

The drainage pipe serves to create depth in the channels, roughly equivalent to the bore ofthe pipe plus the thickness of the tyre rubber, for example by means of holding the base and the capping tiles in a spaced apart configuration. This depth may assist in creating a strong key for the turf There may, alternatively or additionally, be a gap separating adjacent base tiles from each othei That may also assist in creating a strong key for the turf, in the case of a turfed and pitched roof, because it is only the edges of the tiles which interlock, exposing a good variation in depth along the roof structure. It is believed that the greater the gap between base tiles is, the better the key for the turf will be. A larger gap between base tiles also has the advantage of reducing the weight of the tiles on the roof overall, per unit area, because fewer tiles are required. It will be appreciated that if separate pipes are gripped between base tiles and capping tiles, the size of the gap may depend on the diameter of pipe used.

The or each separate pipe may extend the length of the channels defined by several tiles in series. One or more pipes may extend to the top of the roof such that the pipes can receive water, for purposes of irrigation to the roof, when a turf roof, for

example.

One or more pipes may extend to the bottom of the roof such that the pipes can release water for purposes of drainage from the roof The roof structure may include granular material accommodated within the channels of the base tiles to assist with drainage within the roof structure.

The base tiles are preferably held in place and strengthened, at least in part, by a layer of expanded foam underneath the base tiles. The foam may also assist in holding the shape of the tiled surface when loaded. The foam may also assist in holding the shape of the individual tiles when loaded. The foam layer may assist the tiled surface in supporting a turf roof without distending, thus maintaining the integrity of the design.

The foam layer may also provide a significant insulation benefit, especially if provided together with rubber tiles and the soil layer. The roof may not therefore require further insulation after construction. The foam layer may also enhance water tightness.

Preferably the layer of foam has a depth of about 20mm or more. The roof structure may be so affanged that only with the application of the foam does the structure then have the required structural rigidity and watcrpmof integrity.

The roof structure may comprise a support structure for supporting the tiles.

Preferably, the roof structure may include a timber frame, for example including laterally extending support timbers, for supporting the tiled surface.

The tiles may be mounted on clips which are fixed (e.g. nailed) to laterally extending support timbers. The clip may comprise a bolt which secures one tile at its uppermost end. If an object needs fixing to the tiles, a longer bolt can be used which penetrates both the lower and the overlapping upper tile, so that there is thread available to secure the object as well as the two tiles. Tn this instance the upper tile may have an extra hole drilled at its lower end in addition to a hole at its higher end. An advantage of clips, over screws or nails or other such fixings, is that such a clip allows a builder to draw a snap string line up the roof across the support timbers, and then fit the clips accurately over this line. In that way the tiles can achieve a very precise position on the roof A base tile may be fixed to a laterally extending support by means of a strap affixed to the laterally extending support. A bolt may protrude in an upwards direction from the laterally extending support. The bolt may pass through the tile. The bolt may form part of the strap. The bolt may alternatively (or additionally) be provided separately from the strap. The bolt may secure the tile in place, by means of a nut, and optionally a washer. The bolt may be long enough to allow a separate object to be affixed thereto.

The bolt may be long enough to pass through a base tile and a further, overlapping, base tile. The base tile and further, overlapping, base tile may be provided with holes for such a purpose. Such other separate objects may be bolted to the surface of the roof without risk of penetration to the waterproof layer -a common limitation of other turf roofs, by means ofthe waterproof later being provided underneath the tiles.

The support structure, for supporting the tiles, may comprise a plurality of parallel strips of timber, for example plywood. Parallel strips of plywood may be laid laterally on edge so that a tile, set perpendicular to the strips, may be supported at several points in its length. In this instance the plywood may be too thin to receive a securing screw or the strap described above. The tiles could in such a case (or in any case) be attached to the plywood by flexible clips, or ties with a hook at the bottom. Such a hook may be arranged such that it grips the lower edge of a plywood strip. If expanded foam is used in forming the roof, such foam may expand and thus tend to raise the tile slightly and thus tighten the clip. These clips may be attached to a tile by means of a rivet, or other

suitable means.

More generally, a base tile may be fixed to a laterally extending support by means of a tie. The tie may for example wrap at least partially around a laterally extending support. The tie may pass through a hole in the tile. The tie, for example at one end of the tie, may be secured to the tile by means of a toggle, that for example resists removal of the tie from the hole in the tile. The tie is preferably under tension. The tie is preferably secured, for example an opposite end, to the laterally extending support and/or to the tie itself There may be a hook provided at such an opposite end of the tie to enable the tie to be so secured.

The above mentioned clips or tics may be inserted manually and attached by a toggle, which gives an advantage of allowing the correct length clip or tic to be selected.

This may be of advantage for people who choose to build a roof support structure with logs and sticks, rather than sawn timber -a priority for those who choose to work with natural materials. The tie selected is preferably arranged such that it extends around the stick or log, so that the hook is attached to the tie near the point where it enters the tile.

The roof is preferably pitched at a suitable angle, for example between 15 and 40 degrees. The pitch of the roof may be between 15 and 60 degrees. The pitch is preferably greater than 15 degrees. The pitch may be greater than 30 degrees.

The tile system provided by the present invention advantageously supports a pitched turf roof The tile system provided by the present invention may remain uncovered, as a robust roof covering able to withstand all weathers, including high winds that would otherwise lift tiles. In the case where the tiles support a turf roof, a pitch of greater than 30 degrees may be made possible, by means ofthe zig-zagging of the channels and/or the shape of the tiles providing an effective key to stop the turf from sliding off the roof The present invention also provides a roof tile. The roof tile preferably possesses those features required to make it suitable for use as a base tile ofthc roof structure as claimed or described herein according to any aspect of the present invention.

The roof tile may include a channel defined along its length. The channel may be so shaped that there is a first point along the length of the tile in which the channel is oriented in a first direction and a second point along the length of the tile in which the channel is oriented in a second non-parallel direction.

There is also provided a method of manufacturing a roof tile. The roof tile so manufactured is preferably one that is suitable for use as a roof tile as claimed or described herein according to any aspect of the present invention or suitable for use as a base tile ofthe roof structure as claimed or described herein according to any aspect of the present invention. The method may include a step of dividing an automobile tyrc, preferably a used lyre for example a used car-tyre, into one or more pieces. At least one of those piece may then form the roof tile. Each tyre may be cut into at least four separate pieces by means of at least one cut along a section perpendicular to the central axis of the tyrc and at least one cut parallel to the central axis of the tyre. Each of said four pieces may then be used to make a tile. The tyre from which the tyrc is made may include a circumferentially extending portion (the portion that is or was treaded for contact with a road surface), two side walls extending from the circumferentially extending portion (treaded) portion and a flange (the inner rim of the tyre) extending from at least one of the side walls. There may be no discernable junction between the flange and the side walls. It will be appreciated that the flange extends axially inwardly from the side wall. The tile produced by the method is preferably such that the tile includes a channel along its length defined by a opposing sides, one of which sides being defined by at least a part of said flange, and the other of which sides being defined by at least a part of the treaded (or previously treaded) portion.

There may also be a method of making a roof from one or more tiles of the present invention. Such a method may for example include spraying the roof structure with expanding foam from underneath, for example to assist with holding the constituent parts of the roof in place and/or to assist with making the roof water-tight. The leaking of water out of the channels or perforated pipes may thereby be reduced and/or prevented.

It will of course be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects ofthe present invention. For example, the method of the invention may incorporate any of the features described with reference to the roof structure and/or tile of the invention and vice versa.

Description of the Drawings

Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which: Figures 1 a and lb show plan and sectional views of a tile according to a first embodiment of the invention; Figures 2a to 2c show stages in a method of building a roof according to a second embodiment of the invention; Figures 3a to 3c show stages in a method of building a roof according to a third embodiment of the invention; Fig 4 shows a sectional view of tiles, drainage pipes, foam and fleece according to a fourth embodiment ofthc invention; Figures 5a to Sc show a plan and sectional views of the fixing bracket for the tiles according to a fifth embodiment; Figure Sd shows the bracket fixing a foreign object to the roof of the fifth embodiment; Figures 6a to 6 show a fixing bracket for the tiles according to a sixth embodiment; and Figure 7 shows a tie member according to a seventh embodiment.

Detailed Description

The first embodiment relates to a new shape of ceramic roof tile 2 as shown in plan view in Figure la. A sectional view of the tile, taken about the line A-A is shown in Figure lb. It will be seen that the tile has a non-straight channel 3 defined along its length. The channel has a first section 3a, a second section 3b, and a third section 3b. If one assumes the length of the tile extends in one single general direction L, then the direction of the channel in the first section 3a is at an acute angle of about 45 degrees to the direction L, the second section 3b is approximately parallel to the direction L, and the third section 3c is at an acute angle of about 45 degrees to the direction L in the opposite sense to the first section, such that the angular difference between the directions of the first and third sections is about 90 degrees. The direction of the channel may be defined as the direction of the curve that describes the mid-points (in a transverse direction) of the channel (the locus of the mid-points ofthe channel, which need not necessarily be the same as the locus of the midpoints ofthe tile).

In cross-section (see Figure lb) the tile 2 defines a channel 3 that when viewed from above has a generally concave shape.

Figure 2a shows six tiles 2 of a form shown in Figures la and lb arranged on a sloping roof (the top of Figure 2a being higher vertically on the roof than the bottom of Figure 2a). The pitch of the roof is about 30 degrees. The three upper tiles 2u are arranged such that their lower ends rest on top of the upper ends ofthe three lower tiles 21. A zigzagging channel is thus formed which extends from the upper end of each upper tile 2u to the lower end of each lower tile 21 on which the upper tile rest. The base tiles are arranged in alignment with each other, but do not need to tessellate exactly. There are for example gaps 6 between adjacent tiles 2.

The tiles 2 shown in Figure 2a are in the form of base tiles. Identically shaped tiles are placed, in an inverted orientation (upside down), on top ofthe base tiles 2, thereby forming capping tiles 4. Each capping tile is associated with and bridges a pair of adjacent base tiles.

The capping tiles 4 are similarly positioned such that the upper capper tiles are arranged such that their lower ends rest on top of the upper ends of the lower capping tiles. Figure 2c shows a sectional view taken along line B-B of Figure 2b.

-10 -The tiles may be fixed using conventional methods. The angular shape of the tiles 2, 4 assist in keeping the tiles in position. The zigzagging pattern of the tiles may form an attractive alternative to the look of conventionally tiled roofs.

The tiles may be left exposed to the elements and there may be no need for extra roof elements on top of the tiles. In use, rain water falls on top of the capping tiles or directly into the base tiles and then flows into the zigzagging channel, flowing downwards within the channel toward the lower edge of the tiled surface at which location the rain water may drain into a gutter.

The tiles and tiled roof surface of the first embodiment could be used on a conventional roof or the roof of an eco-build house or dwelling. The second embodiment described below concerns a different type of tile primarily for use the roof of an ceo-build house or dwelling and which has the extra benefit of being made from used vehicle tyres, which might otherwise be disposed of in a manner that impacts negatively on the environment.

Is The tiles of the second embodiment are particularly suited for use on a turf roof.

Turf roofs are normally made on a plywood support covered by an impermeable (for example plastic) sheet, which acts to watemroof the roof when finally constructed. In this sheet, jointing is critical, and should the sheet be punctured or otherwise compromised it can be hard to find the source of the leak. A method of constructing a roof from curved tiles made from processed sections of used vehicle tyres will now be described with reference to Figures 3a to 3c.

The roof is pitched at a suitable angle, for example between 15 and 40 degrees (but possibly as high as 60 degrees). Transverse roof battens 25 are installed on top of supports 23 (Joists). Curved base tiles 22 are mounted on the transverse battens 25. Each base tile 22 is nailed at its top end into the batten, with its lower end resting on top of the tile 22 below. As shown in Figure 3a, a trough 26 is thereby created which caries the rainwater down the roof Each tile 22 therefore has a curve along its length such that the tile curves between first and second portions. If one consider the direction of the run of the channel at a point in the first portion as a first direction 221 and the direction of the run of the channel at a point in a second portion downstream ofthe first portion as a second direction 222, it will be observed that the first direction is at an acute angle to the second direction. The tiles of Figure 3a are shaped such that the direction of the channel turns through about 90 degrees with increasing distance along the length of the tile (from one end of the tile to the other).

The curve of the tile means that each tile is generally arcuate in shape when viewed in plan. The cross-section of the channel also curves and the tile is therefore also generally arcuate in cross-section.

Into this trough is poured a granular material 28 (typically Pearlite) -as shown in Figure 3b, an enlarged portion of which being shown in Figure 3c. Capping tiles 24 of an -11 -identical shape to the base tiles 22 are then placed on top of the base tiles 24, such that each capping tile 24 straddles the gap between the adjacent base tiles. Again, each capping tile 24 rests its lower end on top of the capping tile 24 below. A series of internal drains 26 is then created into which all descending rain necessarily leads.

S Once the roof 21 is tiled a fleece 27 is spread over the ensemble to keep the soil 29, which is laid on top ofthe fleece 27, out ofthe drains formed by the channels 26.

The soil spread over the fleece, can then be planted with (typically) sedum or grass, which in time grows to form a turf on the roof Because the fleece fits snugly into the deep undulating (zig-zagging) channels it does not enable any displacement of itself or of the turf There are various potential advantages that arise from the roof and tiles of the second embodiment beyond the good use to which used tyre are being put. The tyre-based roof tiles described above are by their nature very robust. The steel banding inside the dissected car tyre helps to give it strength. Due to their curved shape they are also unlikely to become dislodged, and so present a roofing solution that should last as long as the timber support underneath. They can also be put down as simply as a conventional tile, and require none ofthe expertise needed to put down a plastic liner.

The tiles are readily made from a used vehicle tyre by means of dividing the tyre into eight pieces. The tyre is cut into eight pieces by means of culling along a section perpendicular to the central axis of the tyre to form two half tyres, each being ring-shaped, and then cutting each ring into four pieces (quadrant pieces) by means of four equiangularly spaced cuts parallel to a radius of the ring. As each tile is made from one eighth of a car lyre, it is in the form of a trough that turns at a right angle. The tyres will typically have metal banding inside, in which case the ends of the tyres may require finishing to cover, smooth or otherwise remove any sharp metal ends that might otherwise result. Such finishing could include local heat treatment to remould the cut edges.

Figure 4 shows a fourth embodiment, in which the interlocking base (401) and capping tiles (402) are separated by a continuous length of perforated flexible pipe (403) which travels the length of the tile assembly from top to bottom. Each channel will have two such pipes, one at each edge ofthe base tile assembly. The pipe will allow drainage water to exit at the bottom of the roof It will allow irrigation water to be poured into it at the top of the roof The pipe is made of plastic and is of the sort typically known as "Land Drain" pipe or "French Drain" pipe. During construction it may be possible to achieve the desired position of this pipe by virtue of the gripping action of the interlocking tiles. It may be necessary to hold it in place with wire clips.

The undulating shape (the zig-zagging) of the channel formed by the series of tiles (running from top to bottom) is highly significant, and by using tyres cut only in four or even three segments per side, the undulation produces an angle of 90 degrees or sharper -12 -at each twist. If the roof were flat, all the weight of the soil would be taken by the base tile that creates the channel. The more the roof is pitched, however, the greater the weight of the soil falling against the side walls of the channel at the point where the curve of the tyre passes across the downward flow direction of the roof material, were a straight line to be drawn to indicate the pull of gravity down the roof This explains why the key created by the channels is so important to the design. The use of the pipe and foam is therefore integral to the success of the roof, because it creates the required depth in the channels.

Figure 4 shows how the structure is unified. When the fixture of the tiles and pipes is complete the assembly should be sprayed from underneath with expanding foam (411), such that the foam secures all the elements in a semi-rigid unified structure. It will serve to protect the assembly against any egress of water at tile joints or where the perforated pipe separates the base from the capping tiles.

If the roof assembly is intended to support a turf covering, then a fleece (409) should be added. The fleece should be loosely placed over the zigzagging channels such that there is plenty of fleece material available to fill any crevices formed in the channel wall by the pipes and tiles. In this way the drainage system is secured from any root penetration or blockage by soil, and the form of the channel is preserved in order to create the key that holds the soil from sliding. The channel has a depth of about one quarter of the width of the channel and is therefore relatively deep for its size.

Figure Sa shows in accordance with a fifth embodiment how the tiles can be fixed to the timber support. The base tiles (501) can be fixed to the lateral joists (504) by means of a bolt (505), nut and washer, which is held by a metal U-shaped strap (506).

The strap can be secured to the joist by one or more nails or screws (507), as shown in Figure Sb. The base tile (501) can be bolted to the fixing bracket (506) by means of a hole drilled centrally near one end, but this bolt connection can be covered by the base tile (501) above it, which overlaps the joint between the two tiles, as shown in Figure Sc.

If a separate object (508) such as a solar panel needs to be fixed to the roof the bolt (505) can penetrate both base tiles (501) of the overlapping joint, as shown in Figure Sd and secure the foreign object as well. It is possible to repeat this process with the capping tiles (502) if desired, by means of a longer bolt.

Figure 6A, 6B and 6C show, in accordance with a sixth embodiment, how the tiles can be fixed when the support structure for the tile is in the form ofplywood strips (603) standing on edge. In this instance the tile (601) is held onto the plywood by a clip or tie (602). The clip is a strip of tough but pliable material, typically nylon and about 1 centimetre wide and 4mm thick, which is secured to the tile, typically by a rivet (604).

The top of the strip forms a right angle section (607) when the clip is in position holding the plywood. The right angle section is typically about 2 centimetres in length, containing a hole (605) through which the rivet passes, securing it to the tile. It is -13 -possible that for stacking purposes the right angle can be temporarily flaftened. It is possible that the top section of the clip containing the hole is of a different material to the rest of the clip. The top section may be of metal. The tile also has a hole positioned centrally between 5 and 12 centimetres from its end to receive the rivet.

The length of the strip from the point of the right angle (607) to the interior of the hook (606) is the same as the depth of the plywood structure (603) to which the tile is being aftached. At its end the strip forms a hook (606), so that it can be made to grip the underneath of the plywood. The hook may be integral to the strip, or it may be securely aftached to it. It may be of a different material.

The clip may be affixed to either face of the tile, so that it can be used for fixing both channel tiles and capping tiles. For the capping tiles it will be longer than for the channel tiles, and attached to the concave face. On the channel tiles it is affixed to the convex face.

Figure 7 shows an alternative means, in accordance with a seventh embodiment, of aftachment for fixing the clip or tie (702) to the tile. The tie might typically be of woven nylon, with varying lengths supplied. At one end it is secured to a hook (706). At the other end it has a loop (709) through which is passed a toggle (708), a cylindrical section of solid material designed to prevent the tie from being drawn back through the tile. The loop ofthe tie is first inserted through the hole in the tile from one side, so that the toggle can be passed through the loop on the other side, thus providing a firm fixing when pressure is introduced to draw the tie back down the hole. The hook (706) can either be placed to grip the lower edge ofthe plywood strip, or it can be passed around the support structure and made to grip the tie at a point on the tie just before it passes through the hole in the tile, thus making the tic wrap entirely around the support. The tie could altematively be made from one single piece of wire, twisted at one end to make the loop and at the other to make the hook.

Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein. By way of example only, certain possible variations will now be described.

The tyre-based tiles of the second embodiment need not be covered. Different shapes of tiles could be provided. Other materials could be used.

In the first embodiment, the tile could curve to a lesser extent. With reference to Figure 1 a, if one assumes the length ofthe tile extends in one single general direction L, then the direction of the channel in the first section 3a could be at an acute angle of about degrees to the direction L, and the third section 3c could be at an acute angle of about degrees to the direction L in the opposite sense to the first section, such that the angular difference between the directions of the first and third sections is about 60 degrees.

-14 -Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.

Claims (17)

1. -15 -Claims 1. A roof structure forming part of part ofan ceo-build building, wherein the roof structure comprises a tiled surface, the tiled surface comprising a multiplicity of base tiles interleaved with a multiplicity of capping tiles, and wherein each base tile defines a channel along its length such that there is a first portion of the tile that channels in a first direction, and a second portion of the tile that channels in a second direction, the first direction being non-parallel to the second direction, the base tiles arc arranged in alignment with adjacent base tiles, the capping tiles each bridge at least one pair of adjacent base tiles, the base tiles together form adjacent zigzagging channels that run from high to low on the roof, and Is the tiles are covered with a turf finish.
2. 2. A roof structure according to claim 1, wherein each base tile is formed by means of a channel that is generally U-shaped in cross-section.
3. 3. A roof structure according to any preceding claim, wherein each base tile has a cross-section having a height that is greater than 20% ofthe width of the tile.
4. 4. A roof structure according to any preceding claim, wherein the angle of the first direction differs from the angle of the second direction by 60 degrees or more.
5. 5. A roof structure according to any preceding claim, wherein each base tile curves between the first and second portions thus causing the first direction to be non-parallel to the second direction.
6. 6. A roof structure according to any preceding claim, wherein the roof structure has a pitch of about 30 degrees or more.
7. 7. A roof structure according to any preceding claim, wherein a gap separates adjacent base tiles from each other
8. 8. A roof structure according to any preceding claim, wherein separate pipes are accommodated within the channels defined by the tiles.
9. 9. A roof structure according to any claim 8, wherein the separate pipes are -16 -in the form of perforated flexible pipes.
10. 10. A roof structure according to any preceding claim, wherein the tiles are made from used automobile tyres.
11. ii. A roof structure according to any preceding claim, wherein the roof structure includes a granular material accommodated within the channels of the base tiles.
12. 12. A roof structure according to any preceding claim, wherein the roof structure includes a layer ofexpanded foam which assists in retaining the tiles in position relative to each other
13. 13. A roof tile for use as a base tile of the roof structure according to any preceding claim.
14. 14. A method of manufacturing a roof tile according to claim 13, wherein the method includes a step of dividing a used automobile tyre into one or more pieces, at least one of which forming the roof tile, the tyre included a circumferentially extending treaded (or previously treaded) portion, two side walls extending from the treaded portion and a flange extending from at least one of the side walls, and wherein the method is performed such that the tile includes a channel along its length defined by a opposing sides, one of which sides being defined by at least a part of said flange, and the other of which sides being defined by at least a part ofthe treaded (or previously treaded) portion.
15. 15. A method of building a roof substantially as herein described with reference to any of the accompanying drawings.
16. 16. A roof substantially as herein described with reference to any of the accompanying drawings.
17. 17. A roof tile substantially as herein described with reference to any of the accompanying drawings.