Because of leakage and bad heat-insulating performance of the flat roof in the old house and in order to enrich the elevation effects ,the paper puts forward the reconstructing method of changing flat roof into pitched roof and expounds upon it.

Resource study status of old building demolition waste was summarized,resource methods for waste wood,waste concrete,waste tiles,waste roofing material and demolition waste powder were introduced,application of the old building demolition waste as pile filler to mollisol foundation strengthening was also generalized.