E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
E04C2/30—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure
E04C2/32—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure formed of corrugated or otherwise indented sheet-like material; composed of such layers with or without layers of flat sheet-like material