... Floor beam: C style steel, 200*40*2.0mm4) Floor: light magnesium board (our patent)5) Stair: metal6) Roof truss: angle steel7 ... of foam, polyurethane, and mineral wool, and the top board, back board are steel plate.2 FeaturesIt gathers Insulation, heat insulation, ... of foam, polyurethane, and mineral wool, and the top board, back board are steel plate.2 FeaturesIt gathers Insulation, heat insulation, ...