Premanufactured roof plate element

A roof plate assembly for placement on a building as a prefabricated part of a roof of the building comprising:

• hollow longitudinally extending girders disposed at sides of the roof plate assembly and at a position between the sides of the roof plate assembly, each girder including hollow upper and hollow lower longitudinally extending metallic sections which are stacked together with the upper section being above and joined to the lower section, the upper section including a U-shaped portion including a longitudinally extending opening facing upward toward a top of the assembly and the lower section including a U-shaped portion including a longitudinally extending opening facing downward toward a bottom of the assembly, metallic corrugations extending along the longitudinally extending openings, the corrugations of the upper section comprising an upper part of the assembly facing a top surface of the roof when the assembly is placed on a building and the lower section comprising a lower part of the assembly when the assembly is placed on the building;
• each U-shaped portion including two spaced apart sides extending away from the corrugations, a lateral edge extending outward from each of the sides of the U-shaped portions of the hollow upper and lower metallic longitudinally extending sections, the lateral the hollow upper and lower metallic longitudinally extending sections, the lateral edge of the hollow upper metallic longitudinally extending section being connected to the lateral edge of the hollow lower metallic longitudinally extending section of each girder to join the U-shaped sections together, and upper and lower metallic sheets are respectively disposed above the upper girders and below the lower girders which extend transversely to the metallic corrugations and are coupled to the girders to fix the metallic sheets to the upper and lower girders to form the assembly.