At present, most of the existing buildings in China adopt flat roof structure, and the long-term temperature fluctuation range of the roof is - 30-90 ℃. Therefore, what kind of thermal insulation material is used becomes particularly important. When laying flat roof, the thermal stability of roof material is the main factor. Rigid polyurethane foam can meet the above requirements, and can withstand the high temperature generated by the long dark sunlight on the dark surface of the sealing layer of the roof, and has long aging resistance. Application in wall.