屋脊roofridge 坡度slope 坡跨比 pitch 分水线 water-shed 二毡三油 2 layersof felt & 3 coats of bitumastic 附加油毡一层 extraply of felt 檐口eave 挑檐overhanging eave 檐沟eavegutter 平屋面 flatroof 坡屋面 pitchedroof 雨水管downspout, rain water pipe)(R.W.P) 汇水面积catchment area 泛水flashi...