This invention relates to roof tiles and in particular to roof tiles formed from thin sheet material.

A problem associated with ceramic and slate roof tiles is their inherent lack of flexural strength and brittleness, particularly in the case of roofing slate, so that rooves made from slates or tiles can be easily damaged by per¬ sons walking over the roof.

A further problem associated with large slates and roof tiles in that due to their weight should they come loose from the roof and fall to the ground, they are extremely dangerous and could cause injury or death if a falling tile should strike a person or animal.

In the past fabricated roof tiles have been formed from heavily filled plastic materials, such as P.V.C., col¬ oured to appear like slates. However, these tiles are again brittle and will easily snap into pieces if subject to flexural loads foe example by persons walking on them during maintenance. Flat thin sheet metal roof tiles could be used but such tiles whilst not being brittle will tend to bend and distort when walked upon.

The present invention provides a roof tile which over¬ comes the above problems.

Accordingly there is provided a sheet metal roof tile which in. use co-operates with other such roof tiles for laying in rows upon a roof such that tiles in one row overlap the upper portions of tiles in a lower row, and are themselves overlapped by the pans of tiles in an up¬ per row, characterised in that the sheet metal tile is formed with at least one offset strengthening portion raised out of the plane of the tile and which in use acts as support to a pan of an overlapping portion of an¬ other tile.

The invention also comprises a roof covering comprising a plurality of roof tiles of the above type arranged side-by-side in a single row , the tiles being formed as a single sheet metal pressing and being connected at their lateral edges.

The invention will be described by way of example and with reference to the accompanying drawing in which:

Fig.- 1 is a plan view of a tile according to the invention as showing an overlapping tile in dotted outline, Fig. 2 is a section on the line II-II of Fig 1, Fig. 3 is a section on the line III-III of Fig 1, Fig. 4 is a sketch showing the overlapping arrangement between two rows of tile, and Fig. 5 is a roof covering comprising two side-by-side tiles in a single sheet metal pressing.

With reference to Figs 1 to 3 there is illustrated a roof tile formed from a sheet metal pressing, preferably from sheet steel having a thickness of between 0.5 - 0.9mm, or sheet aluminium.

The tile 10 shown is a rectangular tile having a length of 20 7/8" and a width of 10 5/8" (530mm x 270mm) how¬ ever, other sizes and shapes could be selected.

The tile 10 has a substantially flat body portion 12 which has a turned down peripheral flange 11 around its outer edges.

The flange 11 comprises an inclined bottom flange 11a along the bottom edge of the tile 10 (that is the bottom edge in use when secured on a roof), substantially verti¬ cal side flanges lib, lie, and a top edge flange lid. The peripheral flange 11 is about 6mm in depth and serves two purposes, it strengthens the outer edge margins of the tile 10 and it also gives an appearance of "body" or thickness to the roof tile when viewed from the ground.

The tile 10 has an upper portion 12A which is reinforced by offset portions swaged out of the metal sheet, and a lower portion 12B of the tile which forms a substantially flat pan of the tile.

The upper surface 13 of the lower half of the tile is painted to look like slate, for example, with a layer of

powder coated paint 13 which can be formed with an arti¬ ficial grain effect to enhance its slate like appearance. Alternatively it can be coloured to look like other tra¬ ditional roof covering materials such as concrete or clay tiles .

The upper portion 12A of the tile 10 has raised bosses 14 formed as a pair of spaced apart offset portions 14 raised above the general plane of the pan 12B of the tile. The two offset portions 14 each extend laterally inwardly from a respective side edge for a distance D which is about 30% of the width of the tile, and extend longitudinally downwards from the top edge 11D for a dis¬ tance 'L' which is about 40% of the length of the tile 10. The offset portions 14 have a flat upper surface 18 and are raised out of the body 12 or plane of the tile by a distance R of about 7mm so that the height of the off¬ set (7mm) is slightly greater than the overall thickness (6mm) of the pan 12B of the tile 10 which is set by the depth of the peripheral flange.

Each raised offset portion 14 is formed with a depression 15 having a flat base 16 which is offset below the plane of the body of the tile so that the bases 16 are ap¬ proximately in alignment with the ends αf the turned over bottom edge flange 11a, and the lower portions of the side flanges lib and lie. The dimension of the depres¬ sions 15 and their bases 16 are sufficient to allow ac¬ cess by a hammer head. The offset portions 14 and depres

sions 15 also help strengthen the tile together with the flanges 11.

The top edge flange lid extends away from the body por¬ tion 12A of the tile between the two offset portions and is formed with a horizontal edge portion lie providing a back rest in use against a roof batten 23.

With reference now, also to Fig 4, the tiles 10 are laid on a roof in rows 20, 21, secured to roof battens 23 or other wooden supports so that lower portion or pan 12B of each tile in the upper row 21 overlaps with the upper portions 12A of the tiles in the lower row 20. As can be seen, the tiles are fixed in position to a roof batten 23 (see Fig 2) by nails passing through holes 24 in the base 16 of each depression 15, with the undersides of the bases 16 resting against a batten. When tiles 10 are laid in the conventional manner the substantially flat pans 12B of each tile in the upper row 21 extend over and rest on a raised offset portion 14 on each of a pair of adjacent tiles in the lower row 20 with the turned over side edge flanges lib, lie being accommodated by the flat portion of the tile between the offset portions 14.

The upper flat surface 18 of each offset portions 14 on the lower row tiles 20 provides support for the underside of the pan of one of the tiles in the upper row 21 of tiles, so that each tile 10 in use supports the tile above. Further the formed offsets 14, depressions 15 and

flanges 11 provide a reinforced structure formed out of the steel sheet in a single stamping operation.

In use it may be necessary to provide a hole 25 at a cen¬ tral location in the lower half of each tile to provide a means for holding each lower half down against a batten using copper disc nails to prevent lifting by high winds.

A roof formed from the above tiles is a very strong, tough, light weight, structure, that can be walked on without danger of breaking or bending the tile, has an appearance that is that of slate, and cannot be dangerous to persons or animals below.

Fig 5 illustrates a roof covering 110 formed from two tiles, 10 formed integrally from a single metal sheet. The tiles as illustrated are formed as pairs 600mm X 300 mm tiles to give a roof covering of approximately 600 X 600 mm . The covering has identical features to the tile de¬ scribed above.

The covering comprises a single row of side-by-side roof tiles connected through their lateral edges. Any number of tiles can be formed in a single row- dependant upon the size of the tile. For large tiles e.g. 600mm x 3ϋOmm the number is unlikely to exceed two , but for smaller tiles e.g. 500mm x 250mm there could be upto four tiles per row, and for 300mm x 150mm there could be upto six tiles per row.

However in each roof covering the raised portions in the upper portions of each tile will support a pan of an overlapping above tile .