The invention concerns a roofing element (E) of the type of the one consisting of a material board (100) maintained inside a frame (200), characterized in that it consists of a single-walled solid material board and of at least one tensioning means (300) linked to the frame (200) tending to space apart certain parts constituting the frame (200) so as to stress said board (100), the frame consisting of two transverse profiled sections (210 and 220) fixed to two opposite sides of the board (100), the tensioning means (300) tending to space apart said profiled sections (210 and 220), the edges of the board (100) subjected to a tensile stress and slid into the profiled sections being provided with at least one projection (110) facilitating the transmission of said stress, the profiled section being itself preformed to retain said projection in the direction of the tensile stress. The invention is applicable to swimming pool low shelter, veranda and the like.