Abstract: A roof system with rows of superimposed tiles (1) comprising rafters (4) and parallel horizontal shingles (2) fixed to the rafters, each shingle (2) consisting of a shaped section having an upper planar support surface (2c) partly present on a catching wing (2b) projecting upwards, in the direction of the slope of the roof, whereon is engaged, further down, at least a hook (1a), open downwards, formed on the low marginal part of the bottom surface (1b) of each tile of an upper row. The invention is characterized in that it comprises a rail (3) fixed, in the direction of the slope, on the upper surface of each rafter (4), said rail (3) being provided, on its top surface, with elements (3a, 3b) maintaining in place each shingle (2).