坡度是屋面排水、防水的首要基础，同时要依据屋面设计的落水口分布位置，划分排水区域。一般以房屋面横向宽度分中为屋脊中心线，阳台反向落水口反坡，纵向以两落水口之间划分区域分岭。排水坡度在2％一3％ ,这样可减少屋面积水弊病。
Slope is the primary basis of roof drainage and waterproofing, and the drainage area should be divided according to the distribution of roof water outlets. Generally, the center line of the roof is divided by the transverse width of the roof, the balcony is divided by the opposite water outlet and the opposite slope, and the area is divided by the two water outlets in the longitudinal direction. The drainage gradient is 2% - 3%, which can reduce the water problem of the house are