IMPROVED ROOF TILE

Abstract: A concrete roof tile (10) having a front edge surface (44), that is, that surface of the tile across the width thereof and which surface (44) faces downwardly of a roof in use, said surface (44) being of progressively greater depth as between a relatively thin profiled central portion (46) and thicker profiled side portions (52, 54) thereof wherein, in use, horizontal rows of such tiles are laid in half-bond relationship with adjacent horizontal rows to give a pleasing appearance in which the combined overlapped thicknesses of the tiles in one such row of tiles and the tiles of adjacent rows of tiles thereabove and/or therebelow at overlapped headlap and tail portions are the same or substantially so. In addition to the aesthetic effect of the novel tile (10) in use, the tiles (10) are advantageously up to 15 % lighter than conventional concrete roof tiles.

Description: IMPROVED ROOF TILE This invention is concerned with improvements in or relating to a roof tile and particularly this invention is concerned with improvements in or relating to contoured interlocking roof tiles. By "contoured" where used herein it is meant a roof tile having a profiled upper surface, for example, a double roman, a bold roll or similar tile. Such a tile generally comprises profiled side portions on each side of a profiled central portion with the side portions being provided with upwardly or downwardly facing channels respectively for facilitating, in use, the interlocking of each tile with sideways adjacent tiles on a roof• It is well known that the front edge thickness of most inter¬ locking concrete roof tiles is governed by the minimum thickness required for the interlock at the longitudinal edges of the tiles. The thickness of the interlock portion of the tile is maintained across the tile so that the depth of a front edge surface thereof, i.e. that surface facing downwardly of a roof, in use, is constant or substantially so. Thus, when one tile is laid upon another in use, no gaps are evident between the overlapped head and tail lap portions of the tile whether the tiles are laid in full bond or broken bond relationship across the roof. Such design of roof tile dictates that an unnecessary proportion of the tile weight is evident in the thick front edge portion of the tile which thick front edge portion adds little if any structural value to the tile and has a principal aim of closing any gaps which might otherwise be evident between overlapped tail and headlap portions of tiles laid on a roof. The present invention seeks to mitigate or overcome the short¬ comings of known tiles and conveniently provides a roof tile as hereinbefore defined characterised in that a front edge surface of the tile, that is that surface of the tile across the width thereof and which surface faces downwardly of a roof in use, is of progressively greater depth as between a relatively thin profiled central portion and thicker profiled side portions thereof. Preferably the present invention also provides a tile comprising valley portions located between each of the side portions and said central portion, the front edge surface of the tile in the area of said valley portions being of greater depth than the depth of the front edge surface of the relatively thin central portion whilst being of less depth than the front edge surface of the thicker side portions. Conveniently the depth of the front edge surface in the area of the valleys thereof approximates to one-half the combined depths of the front edge surfaces of the central portion and inter¬ locked side portions of mutually sideways adjacent tiles in use. Preferably the central portion is relatively thin as aforesaid for at least one-third of the length of the tile and more especially the central portion is relatively thin as aforesaid for the full length of the tile. The present invention also conveniently provides a tile wherein the central portion thereof comprises an upper profile generated along the length thereof wherein an apex of said upper profile lies below a corresponding apex of a similar profile generated along one of the two opposed side portions, that is the side portion provided with the downwardly facing channels. Conveniently tiles according to the present invention, as set out above, may comprise a bold roll, a double roman or similar profile of roof tile. The present invention still further provides a roof covered with roof tiles according to any one of the last seven preceding paragraphs wherein, in use, each horizontal row of tiles is laid in half-bond relationship with adjacent horizontal rows of such tiles and wherein the combined overlapped thicknesses of the tiles in one such row of tiles and the tiles of adjacent rows of tiles thereabove and/or therebelow at overlapped headlap and tail portions thereof are the same or substantially so. Conveniently the visual appearance of the roof is one in which a constant thickness is evident at the valley portions of the tiles of each column of tiles on the roof whereas the roll portions thereof have a thick-thin, thick-thin appearance both in sideways adjacent columns of such tiles and in each indivi¬ dual column thereof. There now follows by way of example a detailed description of one embodiment provided by the invention, which description is to be read with reference to the accompanying drawings in which: Figure 1 is an upper perspective view of a roof tile provided by the invention; Figure 2 is an end view of two layers of tiles as seen in the longitudinal plane of the tiles; and, Figure 3 is an upper perspective view of a plurality of tiles in use on a roof. The front edge thicknesses of conventional concrete roofing tiles result from having relatively thick, i.e. deep, sidelock portions the depth of which is maintained across the front edge portion of a tile to prevent gapping as between superimposed tiles on a roof. Prudent reduction of the front edge thicknesses of a tile provides a lighter product with consequent savings of cement, aggregate and pigment utilised for the com¬ position from which the tile is manufactured. The present invention provides an interlocking contoured roof tile 10, i.e. a "bold roll" type of tile, see Figure 1. The tile 10 is generally rectangular in plan and comprises left and right hand profiled side portions 12 and 14 respectively. The portion 12 is provided on an underside 16 thereof, see Figures 1 and 2, with longitudinally extending ribs 18 and 20 and channels 22 and 24 while the portion 14 is provided on an upperside 26 thereof with complementary ribs 28 and 30 and channels 32 and 34. The ribs and channels enable the mutual interlock of like tiles on a roof in use. The tile 10 also comprises a profiled central portion 36 an apex 38 of which lies substantially below a corresponding apex 40 of the portion 12, see especially Figure 2. Between the profiled side portions 12 and 14 and the profiled central portion 36 are respective valley portions 41 and 42, see Figures 1, 2 and 3. The tile 10 further comprises a front edge surface 44 which varies in depth across the width of the tile as between a relatively thin section portion 46 coincident with the central portion 36, deeper sections 48 and 50 coincident with said valley portions 41 and 42 and side face portions 52 and 54 of intermediate depth coincident with said portions 12 and 14 respectively. The depth of the portion 46 reflects the thin section portion 36 which may be relatively thin for all of its length along the tile 10 or for a proportion of such length, say one-third thereof. The depths of the sections 48 and 50 are such that each is one-half the depth of a thin section portion 46 plus the combined depth of interlocked side portions 12 and 14 of a tile, see Figure 2, where it is evident that in use the depth of two superimposed valley portions 40 and 42 is equal, or substan¬ tially so, to the combined depth of a thin section portion 46 and the interlock side portions 12 and 14. The tiles 10 of the present invention may be formed by the well established concrete roof tile processing route wherein tile mortar provided to a hopper is constrained to pass under a shaping roller and slipper to emerge as a ribbon of tile mortar on a series of identical tile pallets with the tile shape and thickness being dictated by gaps provided between the upper surfaces of the pallets and the undersides of the shaped rollers and slippers. The ribbon of mortar so formed is thereafter cut to form discrete tiles on the pallets. In use, the tiles can only be assembled, i.e. laid, on a roof in half-bond relationship, see Figures 2 and 3; however, the effect is startlingly attractive in that while the in-line valley portions of the tiles are of uniform thickness the roll portions of the tiles both up and across the roof have a thick-thin, thick-thin appearance. A considerable saving, up to 15% by weight, results from manufacturing tiles according to this invention while the strength of the tile is evenly distributed over the roof in a most effective way. Modifications may be made within the scope of the present invention. Also it is envisaged that tiles according to the invention may be made from clay or any other suitable composition.

Claims: CLAIMS 1. A roof tile as hereinbefore defined characterised in t a front edge surface of the tile, that is that surface the tile across the width thereof and which surface fa downwardly of a roof in use, is of progressively grea depth as between a relatively thin profiled cent portion and thicker profiled side portions thereof. 2. A tile according to Claim 1 comprising valley porti located between each of the side portions and said cent portion, the front edge surface of the tile in the area said valley portions being of greater depth than the de of the front edge surface of the relatively thin cent portion whilst being of less depth than the front e surface of the thicker side portions. 3. A tile according to Claim 2 wherein the depth of the fr edge surface in the area of the valleys ther approximates to one-half the combined depths of the fr edge surfaces of the central portion and interlocked si portions of mutually sideways adjacent tiles in use. 4. A tile according to any one of Claims 1, 2 or 3 where the central portion is relatively thin as aforesaid for least one-third of the length of the tile. 5. A tile according to Claim 4 wherein the central portion relatively thin as aforesaid for the full length of t tile. 6. A tile according to Claim 5 wherein the central porti thereof comprises an upper profile generated along t length thereof wherein an apex of said upper profile li below a corresponding apex of a similar profile generat along one of the two opposed side portions, that is the side portion provided with the downwardly facing channels. 7. A tile according to Claim 6 which comprises a bold roll, double roman or similar profile tile. 8. A roof covered with roof tiles according to any one of Claims 1 to 7 wherein, in use, each horizontal row of tiles is laid in half-bond relationship with adjacent horizontal rows of such tiles and wherein the combined overlapped thicknesses of the tiles in one such row of tiles and the tiles of adjacent rows of tiles thereabove and/or therebelow at overlapped headlap and tail portions thereof are the same or substantially so. 9. A roof according to Claim 8 wherein the visual appearance of the roof is one in which a constant thickness is evident at the valley portions of the tiles of each column of tiles on the roof whereas the roll portions thereof have a thick-thin, thick-thin appearance both in sideways adjacent columns of such tiles and in each individual column thereof. 10. A tile substantially as herein described with reference to Figures 1 and 2 of the accompanying drawings. 11. A roof substantially as herein described with reference to Figure 3 of the accompanying drawings.

Inventors: LAW FRAZER WILLIAM TIMOTHY, LAW, FRAZER, WILLIAM, TIMOTHY
Applicants: LAW FRAZER WILLIAM TIMOTHY, REDLAND TECHNOLOGY LTD, LAW, FRAZER, WILLIAM, TIMOTHY, REDLAND TECHNOLOGIES LIMITED
Application year: 1993
Main classification: E04D1
IPC codes: E04D1