Abstract: Building sheets consisting of cement, inert materials and additives, and reinforced with plastics mesh and alkali-resistant glass fibers of short and/or continuous type, including a number of superposed elementary layers consisting of a mixture of cement, inert materials and additives and each comprising as reinforcement material a plastics mesh or glass fibers. The apparatus for preparing the building sheets includes a frame, a conveyor belt, support rollers and a slide surface for the conveyor belt, an inversion roller and a drive roller, a possible feeder for a continuous support web, a series of plastics mesh feeders, a series of feeders for glass fiber originating from bobbins, a series of cement mix metering pumps, a series of cement mix distributors and a series of smoothing devices.