To improve the efficiency of the execution of works by joining seam sections at both ends in the cross direction of a metallic molded plate, the seam sections of the adjacent metallic molded plate and a clip engaged with a fixture in a seam clamping type and connecting an intermediate fitting rib section to the intermediate fixture of a foundation member in a fitting rib type.

The metal molded plate 4, in which a thin metal plate such as a steel strip is bent along folding clearance extended in the longitudinal direction, is formed, and seam sections 4c are formed at both ends in the axial direction of the metal molded plate 4. The seam sections 4c of the adjacent metal molded plates 4 are superposed to clips 2b in three sheets by the top sections of fixtures 2, and seam-clamped by a seam clamping machine and fixed onto a foundation member 1 while the metal molded plates 4 are connected mutually. An intermediate fixture 3 is mounted at the intermediate place of the fixtures 2 set up to the foundation member 1, and the intermediate fitting rib section 4e of the intermediate section of the metallic molded plate 4 is engaged with the wing section of the intermediate fixture 3 by a spring back when the intermediate fitting rib section 4e is pushed from an upper section. Accordingly, excellent weather resistance and wind-resistant strength can be obtained.