... , waterproofing, Thickness is 50mm,75mm,100mm,150mm roof of the sandwich panel: Polystyrene foam plastic sandwich board uses colored steel ... material. The board is mainly used for public buildings,roof and walls of industrial workshop,clean workshop,combined refrigerated warehouse, ... and am very pelased to show you . so please aks me at any time .Bestregards &Sincerelyada roof of the sandwich panel