Tiles and in particular roofing tiles are often made from mouldable compositions comprising powdered slate and slate granules together with a resin, such as a polyester resin, as their principle components. The mouldable composition is generally pressed into a mould body and heated to cure the resin. The moulded tile is then removed from the mould and allowed to cool. It is known to produce such tiles so that they have the appearance of natural slate tiles when in use. In addition it is known to provide roof tiles made by such a process with interlocking regions which are not visible in use. Such interlocking regions are generally defined on the front face near to one side edge of the tile and on the rear face near to the other side edge of the tile, when tiles are laid in a course, i. e. in a row next to one another, the front interlocking region of one tile may thus engage the rear interlocking region of an adjacent tile on one side and on the other side its rear interlocking region may engage the front interlocking region of a second adjacent tile. The interlocking regions are intended to prevent the ingress of the elements, i. e. wind and/or rain between adjacent tiles in same course. Such tiles are also often provided with protrusions or weatherbars adjacent to their top edge and/or occasionally their bottom edge which are intended to prevent the ingress of the elements between adjacent tiles in overlying courses.

Whilst there exist a number of designs of interlocking roofing tiles none has proved entirely satisfactory. In particular the weather seal formed between adjoining interlocking tiles of the prior art has been found to be inadequate. More particularly the weather seal between subsequent courses of tiles, i. e. between the bottom of one tile and the top of the tile or tiles in the preceding course which it overlays has been found to be inadequate.

Unless such tiles are employed in a roofing structure constructed with a pitch of at least 18° it has generally been found that said roof structure will not meet building standards.

Apart from allowing the ingress of the elements between overlaying courses of prior art tiles such tiles may also be prone to lifting due to the effects of the wind. In order to ensure that such tiles remain securely in position during normal weather conditions it is again generally only possible to employ the tiles in a roofing structure having a pitch of at least 18°.

It is an object of the present invention to address the above described problems.

According to a first aspect of the present invention, there is provided a first roofing tile having a first interlocking region adjacent a first side edge of the tile and arranged to engage an adjacent tile in an assembly of said tiles, and a second interlocking region adjacent a second side edge of the tile and arranged to engage an adjacent tile in an assembly of said tiles, wherein a front face of the tile comprises a first protrusion

extending therefrom between the two side edges of the tile and in a region adjacent to a top edge of the tile and wherein a rear face of the tile comprises a substantially planar bridging section in the region of the bottom edge of the tile wherein said first protrusion is arranged to abut against a corresponding planar bridging section of an overlying tile disposed in a row of tiles above a row in which said first tile is disposed and wherein said planar bridging section of said first tile is arranged to abut against a corresponding protrusion of an underlying tile disposed in a row of tiles below a row in which said first tile is disposed.

Preferably, the protrusion acts as a weather bar which may prevent or limit the ingress of wind and rain between overlapping tiles. By abutting against said planar bridging section, a relatively efficient seal may be defined between overlapping tiles to prevent or limit the ingress of water between the tiles.

Preferably, said first tile has a width as measured between said first and second side edges of between 270 and 400mm, more preferably between 300 and 350mm, for example between 320 and 340mm.

Preferably, the tile has a length as measured between said top and bottom edges of between 250 and 350mm, more preferably between 270 and 330mm, for example between 290 and 320mm.

Preferably, the tile has a maximum thickness of between 2 and 15mm, more preferably between 4 and 10mm, for example

between 4 and 7 mm. Preferably, said maximum thickness is measured excluding protrusions described herein.

Preferably the bridging section has a dimension, measured in the same direction as said tile length, of between 20 and 80mm, more preferably of between 40 and 60mm.

Preferably, the bridging section has a dimension, measured in the same direction as said width of the tile, of between 150 and 350mm, more preferably of between 220 and 280mm.

Preferably, the tile further comprises a reinforced section. Preferably, a part of the reinforced section of the tile is thicker than another part of the tile.

Preferably, the reinforced section forms part of the rear face of the tile. Preferably, the reinforced section comprises ridges which may be arranged to meet at a point.

Preferably, the reinforced section comprises between 3 and 6 ridges, more preferably 4 ridges which may be arranged to meet at a point. Preferably, the reinforced section has the form of a pyramid. Preferably, the pyramid is such that it has a pitch of less than 10°, more preferably of less than 5°. Preferably, the ridges define the ridges of the pyramid.

Preferably, the tile is arranged such that the bridging section lies immediately adjacent to the reinforced section. Preferably, the second interlocking region also lies immediately adjacent to the reinforced section and may also lie immediately adjacent to the bridging section.

Suitably, the first protrusion has a height, measured from the front face of the tile, of at least 2 mm, preferably at least 3 mm, more preferably at least 4 mm, especially at least 4.5 mm. The height may be less than 10 mm preferably less than 8 mm, more preferably less than 6 mm.

Preferably, substantially the entirety of said first protrusion has the same height. Preferably, said first protrusion has a substantially constant cross-section along its extent. Preferably, substantially the entirety of an uppermost edge of the first protrusion extends within a plane which extends substantially parallel to a plane in which said planar bridging section of said first tile is disposed. Said uppermost edge is preferably substantially flat. Preferably, the first protrusion comprises curved regions lying between said uppermost edge and side edges thereof such that said first tile may readily be released from a mould during its manufacture.

Preferably, the first protrusion is elongate. The first protrusion may comprise a section having a slight curvature.

Preferably the first protrusion has a length of between 100 and 140mm, more preferably between 105 and 125mm.

Preferably, the first protrusion has a width of between 1 and 10mm, more preferably between 3 and 5mm.

Preferably, the first protrusion is spaced from the top edge of the tile by between 20 and 50mm, more preferably by at least 25mm. Preferably, the first protrusion is spaced from the top edge of the tile by between 25 and 40mm, more preferably between 28 and 38mm.

An imaginary straight line extending between opposite ends of the first protrusion may extend at an angle of less than 5° relative to the top edge of the tile. Preferably, said imaginary line may extend at an angle of between 1 and 5° to the top edge of the tile, more preferably at an angle of between 1 and 3°.

Preferably, the end of the first protrusion which lies closer to the first interlocking region lies closer to the bottom edge of the tile than does the other end thereof.

Preferably, it lies between 0.1 and 6mm closer to the bottom edge, more preferably between 0.5 and 4mm closer.

Preferably, the tile further comprises a second protrusion extending from its front face between the two side edges thereof and in the region of the top edge of the tile.

Preferably, a part of the second protrusion is not as tall as a part of the first protrusion.

Suitably, the second protrusion has a height, measured from the front face of the tile, of at least 0. lmm, preferably at least 0.2mm, more preferably at least 0. 5mm, especially at least 0.8mm. The height may be less than 5mm, more preferably less than 3mm, more preferably less than 2mm, especially less than 1. 5mm. Preferably,. substantially the entirety of said second protrusion has the same height. Preferably, said second protrusion has a substantially constant cross-section along its extent.

Preferably, substantially the entirety of an uppermost edge of the second protrusion extends within a plane which extends substantially parallel to a plane in which said

planar bridging section of said first tile is disposed.

Said uppermost edge is preferably substantially flat.

Preferably, the second protrusion comprises an elongate protrusion. The second protrusion may comprise a section having a slight curvature.

Preferably the second protrusion has a length of between 40 and 80mm, more preferably between 50 and 65mm.

Preferably, the second protrusion has a width of between 1 and 10mm, more preferably between 3 and 5mm.

Preferably, the second protrusion is spaced from the top edge of the tile by between 20 and 50mm, more preferably by at least 25mm. Preferably, the second protrusion is spaced from the top edge of the tile by between 25 and 40mm, more preferably between 28 and 38mm.

An imaginary straight line extending between opposite ends of the second protrusion may extend substantially parallel to the top edge of the tile.

The second protrusion may define a seat against which a part of an overlying tile in an assembly of tiles can abut. Preferably, the second protrusion defines a seat against which a rear protrusion extending from the rear face of an overlying tile can abut.

Preferably, the tile further comprises a third protrusion extending from its front face between the two side edges thereof and in the region of the top edge of the tile.

Preferably, a part of the third protrusion is the same height as a part of the first protrusion.

Suitably, the third protrusion has a height, measured from the front face of the tile, of at least 2mm, preferably at least 3mm, more preferably at least 4mm, especially at least 4.5mm. The height may be less than l0mm, preferably less than 8mm, more preferably less than 6mm. Preferably, substantially the entirety of said third protrusion has the same height. Preferably said third protrusion has a substantially constant cross-section along its extent.

Preferably, substantially the entirety of an uppermost edge of the third protrusion extends within a plane which extends substantially parallel to a plane in which said planar bridging section of said first tile is disposed.

Said uppermost edge is preferably substantially flat.

Preferably, the third protrusion comprises curved regions lying between said uppermost edge and side edges thereof such that said first tile may readily be released from a mould during its manufacture.

Preferably, the third protrusion comprises an elongate protrusion. The third protrusion may comprise a section having a slight curvature.

Preferably the third protrusion has a length of between 100 and 140mm, more preferably between 115 and 125mm.

Preferably, the third protrusion has a width of between 1 and 10mm, more preferably between 3 and 5mm.

Preferably, the third protrusion is spaced from the top edge of the tile by between 20 and 50mm, more preferably

by at least 25mm. Preferably, the third protrusion is spaced from the top edge of the tile by between 25 and 40mm, more preferably between 28 and 38mm.

An imaginary straight line extending between opposite ends of the third protrusion may extend at an angle of less than 5° relative to the top edge of the tile. Preferably, said imaginary line may extend at an angle of between 1 and 5° to the top edge of the tile more preferably at an angle of between 1 and 3°.

Preferably, the end of the third protrusion which lies closer to the second side edge of the tile lies closer to the bottom edge of the tile than does the other end thereof. Preferably, it lies between 0.1 and 6 mm closer to the bottom edge, more preferably between 0. 5 and 4mm closer.

Preferably, the first protrusion lies closer to the first interlocking region than does the second protrusion.

Preferably, the second protrusion lies closer to the first interlocking region than does the third protrusion.

The first and second protrusions may adjoin one another such that they form a protrusion having sections of varying heights. The second and third protrusions may adjoin one another such that they form a protrusion having sections of varying heights. Preferably, the first, second and third protrusions are integral with one another such that they form a first combined protrusion having sections of two distinct heights.

Preferably, the first protrusion extends from the first interlocking region. Preferably, the third protrusion extends from the second side edge of the tile.

Preferably, the first combined protrusion extends from the first interlocking region to the second side edge of the tile. Preferably, the first combined protrusion is an elongate protrusion.

Preferably, the first tile further comprises regions through which retaining means may be passed to secure the tile to a roof structure (hereinafter"fixing points").

Preferably, one or more of said fixing points comprise a portion which is thinner and may be weaker than other parts of the tile such that retaining means may be caused relatively easily to pierce said portion and extend therethrough. Preferably, one or more of said fixing points include a reinforced section defining a cavity in which said thinner/weaker portion may be defined.

Preferably, the tile comprises a first fixing point in the region of the top edge of the tile. Preferably, the first fixing point lies substantially the same distance from the two side edges of the tile.

Preferably, the first fixing point comprises a protrusion extending from the front face of the tile. Preferably, the uppermost edge of the protrusion is substantially flat.

Preferably, the first fixing point comprises a substantially flat section defining a seat against which a part of an overlying tile in an assembly of tiles can abut. Preferably, the first fixing point comprises a substantially flat section defining a seat against which a

rear protrusion extending from the rear face of an overlying tile can abut.

Preferably, the tile comprises a second fixing point in the first interlocking region of the tile in the region of the bottom edge of the tile.

Preferably, the tile comprises a third fixing point in the region of the top edge of the tile and arranged to lie between the first side edge of the tile and the first fixing point.

Preferably, the tile comprises a fourth fixing point in the region of the top edge of the tile and arranged to lie between the second side edge of the tile and the first fixing point.

Preferably, the tile further comprises a fourth protrusion extending from its front face between the two side edges and in the top region thereof.

Suitably, the fourth protrusion has a height, measured from the front face of the tile, of at least 2mm, preferably at least 3mm, more preferably at least 4mm, especially at least 4.5mm. The height may be less than lOmm, preferably less than 8mm, more preferably less than 6mm. Preferably, substantially the entirety of said fourth protrusion has the same height. Preferably, substantially the entirety of an uppermost edge of the fourth protrusion extends within a plane in which said planar bridging section of said first tile is disposed. Said uppermost edge is preferably substantially flat. Preferably, the fourth protrusion comprises curved regions lying between

said uppermost edge and side edges thereof such that said first tile may readily be released from a mould during its manufacture.

Preferably, the fourth protrusion has a length of between 100 and 150mm, more preferably between 110 and 140mm.

Preferably, the fourth protrusion has substantially the same height as the first protrusion.

Preferably, the fourth protrusion comprises an elongate protrusion which may be substantially straight.

Preferably, the elongate protrusion has a width of between 1 and 10mm, more preferably between 3 and 7mm. Preferably the fourth protrusion comprises a section extending from a side of the elongate protrusion and which is arranged to define a fixing point by which the tile can be secured to a building structure. Preferably, the fourth protrusion comprises a substantially"L"shaped section extending from the end of the elongate protrusion in the region of the first interlocking region. Preferably, the"L"shaped section is arranged such that one arm of the"L"lies adjacent to a side edge of the first interlocking region and the other arm of the"L"lies adjacent to the top edge of the tile and a part of the top edge of the first interlocking region.

Preferably, an imaginary straight line extending between opposite ends of the fourth protrusion, excluding the"L" shaped section, extends at an angle of less than 5° to the top edge of the tile. Said imaginary line may lie at an angle of between 1 and 5° to the top edge of the tile, more preferably at an angle of between 1 and 3°.

Alternatively, said imaginary straight line may lie substantially parallel to the top edge of the tile.

The fourth protrusion may extend substantially parallel to the first protrusion.

Preferably, the fourth protrusion lies closer to the top edge of the tile than does the first protrusion.

Preferably, a substantially straight elongate section of the fourth protrusion is spaced from the first protrusion by between 10 and 30mm, more preferably by between 13 and 20mm.

Preferably, the tile further comprises a fifth protrusion extending from its front face between the two side edges and in the top region thereof.

Suitably, the fifth protrusion has a height, measured from the front face of the tile, of at least O. lmm, preferably at least 0.2mm, more preferably at least 0.5mm, especially at least 0.8mm. The height may be less than 5mm, more preferably less than 3mm, more preferably less than 2mm, especially less than 1. 5mm. Preferably, substantially the entirety of said second protrusion has the same height.

Preferably, substantially the entirety of an uppermost edge of the fifth protrusion extends within a plane which extends substantially parallel to a plane in which said planar bridging section of said first tile is disposed.

Said uppermost edge is preferably substantially flat.

Preferably, the fifth protrusion has a length of between 40 and 80mm, more preferably between 50 and 60mm.

Preferably, the fifth protrusion has. substantially the same height as the second protrusion. Preferably, the fifth protrusion has substantially the same length as the second protrusion. Alternatively, the fifth protrusion may be slightly shorter in length than the second protrusion.

Preferably, the fifth protrusion comprises an elongate protrusion which may be substantially straight. Preferably the elongate protrusion has a width of between 1 and 10mm, more preferably between 3 and 7mm. Preferably, the fifth protrusion comprises a section extending from a side of the elongate protrusion and which is arranged to define a fixing point by which the tile can be secured to a building structure.

An imaginary straight line extending between opposite ends of. the fifth protrusion may extend substantially parallel to the top edge of the tile.

Preferably, the fifth protrusion lies closer to the top edge of the tile than does the first protrusion.

Preferably, the fifth protrusion may extend substantially parallel to the second protrusion.

Preferably, a substantially straight elongate section of the fifth protrusion is spaced from the second protrusion by between 10 and 30mm, more preferably by between 13 and 20mm.

Preferably, the tile further comprises a sixth protrusion extending from its front face between the two side edges and in the top region thereof.

Suitably, the sixth protrusion has a height, measured from the front face of the tile, of at least 2mm, preferably at least 3mm, more preferably at least 4mm, especially at least 4. 5mm. The height may be less than 10mm, preferably less than 8mm, more preferably less than 6mm. Preferably, substantially the entirety of said sixth protrusion has the same height. Preferably, substantially the entirety of an uppermost edge of the sixth protrusion extends within a plane which extends substantially parallel to a plane in which said planar bridging section of said first tile is disposed. Said uppermost edge is preferably substantially flat. Preferably, the sixth protrusion comprises curved regions lying between said uppermost edge and side edges thereof such that said first tile may readily be released from a mould during its manufacture.

Preferably, the sixth protrusion has a length of between 100 and 140mm, more preferably between 115 and 125 mm.

Preferably, the sixth protrusion has substantially the same height as the third protrusion. Preferably, the sixth protrusion has substantially the same length as the third protrusion.

Preferably the sixth protrusion comprises an elongate protrusion which may be substantially straight. Preferably the elongate protrusion has a width of between 1 and 10mm, more preferably between 3 and 7mm. Preferably, the sixth protrusion comprises a section extending from a side of

the elongate protrusion and which is arranged to define a fixing point by which the tile can be secured to a building structure. Preferably, the sixth protrusion comprises an extension section extending from a side of the elongate protrusion and which is arranged to lie between the elongate section and the top edge of the tile in the region of the second side edge of the tile. The extension section of said first tile may be arranged to lie adjacent to the"L"shaped section of the fourth protrusion of an adjacent tile in an assembly of said tiles. The"L"shaped and extension sections may thus cooperate to limit the ingress of water past the top edges of the interlocking regions of adjacent tiles.

Preferably, an end part of the elongate protrusion is arranged to lie closer to the second side edge of said first tile than is the extension section. Preferably, the top right hand corner of the tile includes a cutaway section bordered by the extension section and end part of the elongate protrusion. Preferably, the cutaway section of said first tile is arranged to accommodate the"L" shaped section of the fourth protrusion of an adjacent tile in an assembly of said tiles.

Preferably, an imaginary straight line extending between the opposite edges of the sixth protrusion extends at an angle of less than 5° to the top edge of the tile. Said line may lie at an angle of between 1 and 5° to the top edge of the tile, more preferably at an angle of between 1 and 3°. Alternatively, said imaginary straight line may lie substantially parallel to the top edge of the tile.

The sixth protrusion may extend substantially parallel to the third protrusion.

Preferably, the sixth protrusion lies closer to the top edge of the tile than does the third protrusion.

Preferably, a substantially straight elongate section of the sixth protrusion is spaced from the third protrusion by between 10 and 30mm, more preferably by between 13 and 20mm.

Preferably, the fourth and sixth protrusions have substantially the same height. Preferably, the fifth protrusion is not as tall as the fourth protrusion.

Preferably, the fourth protrusion lies closer to the first interlocking region than does the fifth protrusion.

Preferably, the fifth protrusion lies closer to the first interlocking region than does the sixth protrusion.

Preferably, the fourth protrusion extends from the first interlocking region. Preferably, the sixth protrusion extends from the second side edge of the tile.

The fourth and fifth protrusions may be integral and form an extended protrusion. The fifth and sixth protrusions may be integral and form an extended protrusion.

Preferably, the fourth, fifth and sixth protrusions are integral and form a second combined protrusion.

Preferably, the second combined protrusion extends from the first interlocking region to the second side edge of the tile.

Preferably, the first combined protrusion is spaced from the second combined protrusion by between 10 and 30mm for at least 70% of its length. Preferably, the first combined protrusion is spaced from the second combined protrusion by between 13 and 20mm for at least 70% of its length.

Preferably, the entirety of the first combined protrusion is spaced from the second combined protrusion by at least O. lmm, more preferably at least 0.5mm.

Preferably, the second combined protrusion lies substantially parallel to the top edge of the tile.

Alternatively, or in. addition, the second combined protrusion may be substantially parallel to the first combined protrusion.

Preferably, the second and/or third and/or fourth and/or fifth and/or sixth protrusions are arranged to prevent or limit the ingress of water between overlapping tiles in an assembly of said tiles.

Preferably, the bridging section and third protrusion are arranged such that the bridging section of said first tile can abut the third protrusion of an adjacent underlying tile.

Preferably, the bridging section and fourth protrusion are arranged such that the bridging section of said first tile can abut the fourth protrusion of an adjacent underlying tile.

Preferably, the bridging section and sixth protrusion are arranged such that the bridging section of said first tile can abut the sixth protrusion of an adjacent underlying tile.

Preferably, the tile comprises a region which is arranged to be visible when the tile forms part of an assembly of said tiles (hereinafter the"visible region").

Preferably, the regions of the front face of the tile which are not arranged to be visible are"hidden"from view by overlying tiles in an assembly of said tiles.

Preferably, the visible region has a width of between 250 and 350mm, more preferably between 260 and 320, for example between 290 and 310mm. Preferably, the visible region has a length of between 200 and 300mm, more preferably between 230 and 280mm, for example between 250 and 270mm.

Preferably, the visible region comprises a surface resembling that of a natural roofing material.

Preferably, the visible region has the appearance of natural slate. The visible region may thus have a riven matt appearance. Alternatively, the visible region may have the appearance of wood, for example natural shingle.

Preferably, the first interlocking region is arranged to extend between the top and bottom edge of the tile on the front face thereof.

Preferably, the first interlocking region defines a channel. Preferably, the first interlocking region defines an elongate channel. Preferably, the first

interlocking region comprises a protrusion. Preferably, the protrusion extends within the channel. Preferably the protrusion is arranged to extend between the top and bottom edges of the tile. Preferably, the protrusion is arranged to extend from the top edge of the tile towards the bottom edge thereof. Preferably, the protrusion is arranged such that it divides the section of the channel in the region of the top edge of the tile into two sections.

Preferably, the channel is defined between the first side edge of the tile and an edge of a visible region of the front face of the tile. Preferably, the channel is defined on the side adjacent to the first side edge of the tile by a protrusion extending from the edge of the channel base.

Preferably, the protrusion comprises a wall extending between the top and bottom edges of the tile.

Preferably, the first interlocking region has a width of between 20 and 40mm, more preferably between 25 and 35mm.

Preferably, the channel has a depth of between 2 and 10mm, more preferably between 2 and 6mm.

Preferably, the second interlocking region is arranged to extend between the top and bottom edges of the tile on the rear face thereof.

Preferably, the second interlocking region defines a channel, for example, an elongate channel.

Preferably, the channel is defined between the second side edge of the tile and a protrusion inwards thereof.

Preferably, the protrusion extends between the top and

bottom edges of the tile. Preferably, the channel is defined on the side adjacent to the second side edge of the tile by a protrusion extending from the edge of the channel base. Preferably, the protrusion comprises a wall extending between the top and bottom edges of the tile.

Preferably, the second interlocking region has a width of between 20 and 50mm, more preferably between 25 and 40mm. Preferably, the channel has a depth of between 2 and lOmm, more preferably between 2 and 6mm.

Preferably, the interlocking regions are arranged to cooperate such that they can limit or minimise the ingress of water between adjacent tiles in an assembly of said tiles.

Preferably, the bottom edge, of the tile comprises a lip.

Preferably, the lip extends from the rear face of the tile between the two side edges and adjacent the bottom edge thereof. Preferably, the lip comprises a groove which may be arranged to extend between the two side edges of the tile. Preferably, the lip is arranged to abut the front face of an adjacent tile with which it overlaps in an assembly of said tiles. Preferably, the bottom left hand corner of the tile includes a cutaway section such that the first interlocking region does not extend as far as the bottom edge of the tile. The cutaway section of said first tile may thus be arranged to accommodate the lip of an adjacent tile in an assembly of said tiles.

Preferably, the tile further comprises a rear protrusion (hereinafter 88rear formation") extending from the rear face thereof in the region of the first side edge of the

tile. Preferably, the rear formation extends between the top and bottom edges of the tile.

Preferably, a part of the rear formation in the region of the bottom of the tile (hereinafter the"lower region") is arranged to abut a protrusion extending from the front face of an adjacent second tile when the first tile forms part of an assembly of such tiles. Preferably, said lower region of the rear formation is arranged to abut the second protrusion of an adjacent second tile when the first tile forms part of an assembly of such tiles.

Preferably, a part of the lower region of the rear formation is arranged to abut the fourth protrusion of the adjacent second tile. A part of the lower region of the rear formation may also be arranged to abut the first fixing point of the adjacent second tile. Preferably, the rear formation is arranged such that when it abuts the second and/or fourth protrusion of an adjacent second'tile the bridging section of the first tile abuts the third and/or sixth protrusion of the second tile. Preferably, the bridging section also abuts the first and/or fourth protrusions of a third tile lying adjacent to the second tile.

Preferably, the lower region of the rear formation is arranged to fit in a gap formed between the ends of the first and third protrusions. Preferably, the lower region of the rear formation is arranged to fit in said gap such that it is seated on the second protrusion. Preferably, the lower region of the rear formation is arranged in said gap such that it is spaced from the end of the first protrusion by less than 15mm, more preferably by less than 10mm, still more preferably by less than 5mm, for example

by less than 4mm. Preferably, the rear formation is arranged to be spaced from the third protrusion by less than 10mm more preferably by less than 5mm for example by less than 4mm. The rear formation may be arranged to abut the end of the first and/or third protrusion.

Preferably, the lower region of the rear formation is arranged to fit in a gap formed between the ends of the fourth and sixth protrusions. Preferably, the lower region of the rear formation is arranged to fit in said gap such that it is seated on the fifth protrusion. Preferably, the lower region of the rear formation is arranged to fit in said gap such that it is spaced from the end of the fourth and/or sixth protrusion by less than 10mm, more preferably by less than 5mm, for example by less than 4mm. The rear formation may be arranged to abut the end of the fourth and/or sixth protrusion.

Preferably, a region of the rear formation in the region of the top of the tile is arranged to abut a support member of a roof structure. The support member may comprise a baton.

Preferably, the height of the rear formation measured relative to the bridging section is between 1 and 10mm, more preferably between 2 and 6mm. The height of the rear formation measured relative to the bridging section may be substantially equal to the difference in height between the first and second protrusions.

Preferably, the width of the rear formation, measured in substantially the same direction as the tile width, in the region arranged to abut the second and/or fourth

protrusion is between 30 and 70mm, more preferably between 45 and 55mm. Preferably, the width of the rear formation in the region arranged to abut the second protrusion is slightly less than the length of the second protrusion, more preferably between 0.1 and 15mm narrower for example between 1 and 10mm narrower. Preferably the width of the rear formation in the region arranged to abut the fourth protrusion is slightly less than the length of the fourth protrusion, more preferably between 0.1 and 15mm narrower, for example between 1 and 10mm narrower.

Preferably, the tile further comprises one or more protrusions in the region of the top of the tile.

Preferably, the or each protrusion comprises portions of two distinct heights. Preferably, a first part of the or each protrusion is substantially the same height as the rear formation. Preferably, a second part of the or each protrusion is substantially taller than the rear formation. Preferably, the second part is arranged to lie closer to the top edge of the tile than is the first part.

Preferably, the second part is arranged to lie adjacent to the top edge of the tile. Preferably, the tile comprises three such protrusions. Preferably, the or each protrusion is arranged to hook over a roofing baton of a roof structure to support the tile in position.

According to the present invention in a second aspect, there is provided an assembly of two or more tiles as described in any statement herein.

Preferably, the assembly is arranged such that a part of each tile overlaps with a part of at least one other tile.

Preferably, the assembly is arranged such that the interlocking regions of each tile cannot be seen.

Preferably, the assembly is arranged such that the or each protrusion extending from the front face of each tile can not be seen. Preferably, the assembly is arranged such that it has the appearance of an assembly of natural slate tiles.

Preferably, the assembly is arranged such that a protrusion extending from the front face of at least one tile abuts the bridging section of the rear face of at least one other tile. Preferably, the first interlocking region of at least one tile engages with the second interlocking region of at least one other tile.

Preferably, the assembly is arranged such that the second fixing point of at least one tile overlies the first fixing point of at least one other tile.

Preferably, the assembly is arranged such that retaining means can be inserted through the second fixing point of at least one tile and the first fixing point of at least one other tile. Preferably, said assembly may thus be secured to a roof structure.

According to the present invention in a third aspect, there is further provided a roofing structure comprising a plurality of tiles as described by any statement herein.

Preferably, the roofing structure comprises an assembly of tiles as described by any statement herein.

Preferably, the roofing structure comprises at least one roofing baton upon which the tiles are arranged to be supported. Preferably, the roofing structure comprises a plurality of roofing batons arranged to extend substantially parallel to one another and to extend horizontally across the plane of the roof structure.

Preferably, each tile is arranged to be supported upon a roofing baton by protrusions extending from the rear face of the tile. Preferably, each tile is secured to the roofing baton by retaining means. Preferably, the tiles are arranged such that one retaining means may secure one part of a first tile and another part of a second overlapping tile to a roofing baton. Preferably, the retaining means passes through the second fixing point of a first tile and the first fixing point of a second tile with which the first tile overlaps. Preferably, those tiles arranged to lie at the top of the roofing structure may be secured to the roofing structure by additional retaining means. Preferably, the roofing structure further comprises ridge tiles arranged to overlay the upper course of tiles of the present invention.

According to the present invention in a fourth aspect, there is provided a method of producing tiles as described by any statement herein.

Preferably, the method comprises employing a mould having first and second mould bodies arranged to define first and second moulding surfaces respectively. Preferably, the mould bodies are arranged to cooperate and define the form of a tile as described by any statement herein.

Preferably, a mouldable composition is laid into one of said mould bodies and pressed between the two mould bodies such that it takes the form of a tile of the present invention. Preferably, the mouldable composition comprises slate and a polyester resin. Preferably, the mouldable composition is heated during the moulding process to cure the resin and the tile so formed is allowed to cool after de-moulding.

According to the present invention in a fifth aspect, there is provided a mould suitable for employment in the production of a tile as described by any statement herein.

Any feature of any aspect of any invention or embodiment described herein may be combined with any feature of any aspect of any other invention or embodiment described herein.

A specific embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a front plan view of a tile; Figure 2 is a rear plan view of the tile of Figure 1; Figure 3 is a cross-section along line A-A of Figure 1 ; Figure 4 is a cross-section along line B-B of Figure 1 ; Figure 5 is a cross-section along line C-C of Figure 1; Figure 6 is a cross-section along line D-D of Figure 1 ;

Figure 7 is a cross-section along line E-E of Figure 1; and Figure 8 is a front plan view of an assembly of tiles.

Referring to Figures 1 and 2 the tile 1 comprises a front face 10 and a rear face 20 together with a first side edge 30, a second side edge 40, a top edge 50 and a bottom edge 60. The front face 10 comprises a first interlocking region 70 arranged to cooperate with a second interlocking region 80 of an adjacent tile in an assembly 2 of tiles.

The second interlocking region 80 forms part of the rear face 20 of the tile.

The tile further comprises a reinforced section 90 formed on the rear side of the tile and a substantially smooth planar bridging section 100 arranged to overlap an adjacent tile 1 in a preceding course of tiles when the tile 1 forms part of an assembly 2 of tiles (Figure 8).

Said bridging section is substantially rectangular.

The tile 1 also includes a first protrusion 111 extending from the front face 10 between the side edges 30,40 thereof together with a second protrusion 112 and a third protrusion 113. The first, second and third protrusions ill, 112, 113 are aligned and form a first combined protrusion 110. The second protrusion 112 is interposed between the first and second protrusions 111, 113 and is shorter in height than the first and third protrusions 111, 113 which are the same height as one another.

The tile further comprises a fourth protrusion 121 extending from the front face 10 between the side edges 30,40 thereof together with a fifth protrusion 122 and a sixth protrusion 123. The fourth, fifth and sixth protrusions 121,122, 123 are aligned and form a second combined protrusion 120. The fifth protrusion 122 is interposed between the fourth and sixth protrusions 121, 123 and is shorter in height than the fourth and sixth protrusions 121,123 which are the same height as one another. The first, third, fourth and sixth protrusions 111, 113, 121,123 are the same height as one another and the shorter second and fifth protrusions 112,122 are also the same height as one another.

The bridging section 100 of the tile 1 is arranged such that it can abut the first, and fourth protrusions 111, 121 extending from the front face 10 of a second tile adjacent thereto and the third and sixth protrusions 113, 123 extending from the front face 10 of a third tile adjacent thereto. The bridging section 100 and protrusions 111,113, 121, 123 may thus cooperate to prevent or limit the ingress of water between subsequent courses of tiles.

The second combined protrusion 120 also defines fixing points 124, 125, 126 arranged to receive retaining means by which the tile may be secured to a support member of a roofing structure. Normally the tile will only be secured by a first central fixing point 125 and a further second fixing point 71 which includes a cavity and is situated in the first interlocking region 70. The additional, third and fourth fixing points 124, 126 include cavities and are used to secure the tile to a support member if it forms

part of the top course of tiles in a roofing structure comprising said tiles. The second combined protrusion 120 further comprises an"L"shaped section 127 at one end thereof, arranged to border part of the first interlocking region 70, and an extension section 128 in the region of the other end thereof, arranged to lie adjacent to the"L" shaped section 127 of an adjacent tile in an assembly of said tiles.

The first interlocking region 70 includes an elongate channel 72 having a base 75 which is bordered on one side by a wall 73, extending perpendicularly to the plane of the tile 1 adjacent the first side edge 30 thereof, and an edge 11 of a part 12 of the front face 10 of the tile which is arranged to be visible when the tile 1 forms part of a roofing structure. The wall 73 also comprises a fixing point 71 arranged to receive retaining means (not shown) by which the tile may be secured in position. The first interlocking region 70 further comprises a protrusion 74 extending from the base 75 of the channel 72 and from the top edge 50 of the tile 1 towards the bottom edge 60 thereof.

The second interlocking region 80 includes an elongate channel 81 which is formed between a protrusion 82, extending from the rear face of the tile between the top and bottom edges thereof, and a wall 83 extending perpendicularly to the plane of the tile 1 adjacent the second side edge 40 thereof. The channel 81 further comprises an indentation 84 arranged to accommodate a part of the retaining means (not shown), by which a tile 1 with which it overlaps is secured in position, if said part of the retaining means projects beyond the level of the top

of the wall 73 defining fixing point 71. When the first and second interlocking regions 70,80 of respective adjacent tiles are engaged the wall 83 sits in the channel 72 between the protrusion 74 and the edge 11 of the visible area 12; the protrusion 74 and the wall 73 of the first interlocking region 70 sit within the channel 81 of the second interlocking region. Thus the first and second interlocking regions cooperate to restrict the ingress of water between adjacent tiles.

As best illustrated by figures 2,3 and 4 the rear side 20 of the tile 1 comprises a reinforced section 90 having a pyramidal form. The reinforced section 90 includes ridges 91,92, 93,94 which form the edges of the pyramid, centred at the convergence point 95 thereof. The pyramid is squat, having a pitch of less than 5° but this is sufficient to provide significant strength.

The bottom edge 60 of the tile includes a lip 61, having a groove 62 extending along the length thereof, which is arranged to abut against front faces 10 of adjacent tiles in a preceding course (see Figure 8). The lip 61 abuts the adjacent tile below the first combined protrusion 110.

Thus the lip 61 of the tile 1 contacts the front face 10 of the adjacent tile 1 and the protrusions 110,120 of the adjacent tile 1 abut against the bridging section 100 of the rear face 20 of the tile 1. The ingress of water therebetween may thus be limited or prevented.

The tile 1 includes a rear formation 130 adjacent to the first side 30 thereof. A lower part of the formation is arranged to abut against the second and fifth protrusions 112,122 when said tile 1 is arranged in an assembly. The

rear formation is arranged to fit. in the gap formed between the ends of the first and third protrusions 111, 113 and the gap formed between the ends of the fourth and sixth protrusions 121, 123.. The rear formation is arranged to fit relatively snugly in the gap between the first and third protrusions 111,113 and the gap between the fourth and sixth protrusions 121,123, and may thus restrict the ingress of water between adjacent tiles. The part of the rear formation 130 adjacent to the top edge 50 of the tile 1 is arranged to abut against a baton 200 of a roofing structure. The rear formation 130 also defines a cavity 131 corresponding to the fixing point 71.

The tile 1 further includes lugs 150,160, 170 adjacent the top edge 50 thereof. The lugs 150,160, 170 each comprise two portions 151,152, 161,162, 171,172 having two distinct heights. The shorter portions 151,161, 171 are arranged to have the same height as the rear formation 130. The taller portions 152,162, 172 are arranged to lie immediately adjacent the top edge 60 of the tile 1.

The lugs 150,160, 170 are arranged such that the shorter portions 151,161, 171 may rest against a first face of a baton 200 of a roof structure and the taller portions 152, 162,172 may abut against a second face of the baton 200.

Thus the lugs may"hook"over a baton 200. The lug 160 also defines a. cavity 163 corresponding to the fixing point 125.

The arrangement of an assembly of tiles is best illustrated by figure 8 which also shows batons 200 of a roofing structure in broken lines.

The assembly is produced by"hooking"a tile la over a baton 200a of a roofing structure such that it is held in position by lugs 150,160, 170. A second tile lb is then positioned adjacent to the first side edge 30 of the first tile la by"hooking"it over the baton 200a such that the second interlocking region 80 of the second tile 2b engages the first interlocking region 70 of the first tile la. This process can be repeated by positioning a third tile lc and so on until a course of tiles has been laid.

The next course of tiles can be started by positioning a fourth tile Id such that it"hooks"over a second baton 200b such that its bridging section 100 overlaps the first and second tiles la, lb. The bridging section 100 abuts the third and sixth protrusions 113, 123 of the second tile lb and the first and fourth protrusions 111,121 of the first tile la. The rear formation 130 of the fourth tile ld abuts the second and fourth protrusions 112, 122 of the second tile lb. The rear formation of the fourth tile Id thus closes the gap between the ends of the first and third protrusions 111, 113 and fourth and sixth protrusions 121,123 of the second tile lb.

The second fixing point 71 of the fourth tile ld is arranged to overlap the first fixing point 125 of the second tile 1b and a nail can be hammered through the fixing points 71, 125 and into the underlying baton to secure the tiles to the roof structure. This process can be repeated until the second course of tiles is complete and then a third course may be laid in the same manner and so on. The final course may also be secured in place through third and fourth fixing points 124,126 as well as through the first and second fixing points 125,71.

The interlocking tiles of the present invention may allow for the easy construction of a roofing structure having a good resistance to the ingress of water. In particular an assembly of tiles in accordance with the present invention may have particularly good resistance to the ingress of water between overlying courses of tiles.

'Furthermore an assembly of interlocking tiles in accordance with the present invention may still have satisfactory resistance to the ingress of water when employed in a roof structure having a pitch of less than 18°, for example less than 16° or less than 14°.

Interlocking tiles of the present invention may be employed in roof structures having a pitch of as little as 12°. Thus the tiles of the present invention may create new possibilities for building design and construction.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be

replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s).. The invention extend to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.