Abstract: A metal roof construction of the type wherein elongated metal panels are joined together at upstanding vertical side walls by a crimped batten strip. Shallow step strengthening ribs are positioned closely adjacent to the side walls to strengthen the side walls and prevent buckling and to promote flexure of the panel central portions at the step strengthening ribs under high upward stresses on the panels. The panels are secured to underlying roof support means through a special clip having a radius of curvature between an upstanding body portion, positioned between side walls of adjacent panels, and a lower flange portion, positioned beneath a panel. The radius of curvature is sufficient to accommodate the head of a threaded fastener between the clipped lower flange and an overlying panel. Radius bends are also provided between the clipped body portion and top flanges which overlie inwardly directed flanges on the panel side walls.