Abstract: The invention concerns an extruded concrete roof tile of the kind which is designed to be laid in broken bond, is generally rectangular in plan view and has underlying and overlying side lock portions at opposed edges respectively. The upper surface of the tile at the upper end thereof, when on the roof, is recessed to receive the side locks of two similar upper tiles laid in broken bond, and the underlying side lock portion is cut away at the lower end of the tile so that the lower end portion of the tile may lie over the upper surface of the tiles down the roof (in use) to extend beyond the said recessed portions of the lower tiles. The recessed portion is arranged to receive the tile hanging nibs of an identical tile when the two tiles are stacked one upon the other.

Abstract: In the manufacture of roof tiles comprising extruding a continuous shaped ribbon of tile forming material onto a succession of pallets, and cutting the ribbon where pallets adjoin to form individual green state tiles on pallets, there is performed the step of causing a cutting tool to engage with the upper surface of the ribbon only for part of the length of each pallet whereby a recess is formed in the upper surface of each tile. In a particular embodiment the recess is a channel cut in the tile at a location immediately downstream of the extruding step. The recess is also subsequently smoothed by applying a smoothing roll thereto.