Abstract: This invention relates to a fixing element (1) for fixing insulating strips (5) and optionally, additional sealing strips (6) on a solid substructure (7). A screw (4) and a large-surface washer (2) with a tubular extension (3) are used. A rib (15) that projects radially inward into the displacement area is provided in a partial section of the tubular extension (3), which accommodates a screw bead (11) in such a way that it is axially displaceable. After passing the rib (15) in the direction of the free end of the tubular extension (3), the screw head (11) can rest on the rib in the direction opposite to the screwing-in direction.