The special, self-tapping screws for concrete are used both for the reconstruction of roofs with ribbed plates and for new roofs. The resistance of the Ø6.3 self-tapping screw against pulling out is at least 2000N, which is more than enough to ensure reliable fixing of a new roof pie. Due to preliminary preparation of the hole with a Ø5.5 mm bore, chipping from the bottom side of the ribbed plate is significantly reduced, and the work can be performed faster. And you produce a lasting roof. For the ease of installation, the screws come with bits for electric screwdrivers and a drill for concrete.