Metal roof refers to the sheet metal as roof material, combined structure layer and waterproof layer of roof forms.Many different kinds of sheet metal, zinc plate, aluminium zinc plate, aluminum plate, aluminum magnesium alloy plate, titanium plate, copper plate, stainless steel plate, etc. Average of 0.4一0.4 mm thickness, the surface of the plate coating processing. Because of the different material and coating quality, life can be more than 50 years. The production of plate shape are varied, some for composite panels, the thermal insulation layer composite between two layers of sheet metal, also for veneer, construction, plate processing after the scene in the factory assembly,insulation composite good in the factory, so sheet metal roofing in a variety of forms, from the large public buildings to the workshop, warehouse, house, etc were used.