Waterproof paint selection follows four principles:

(1) According to the factors such as the local maximum temperature, minimum temperature, roof slope, and service conditions, heat-resistant and low-temperature flexible waterproof coatings should be selected. In high temperature areas, waterproof coatings with high heat resistance should be selected to prevent run-off; in cold regions, low-temperature flexible waterproof coatings should be selected to avoid cold brittleness.

(2) According to the degree of ground deformation, structure, local temperature difference, daily temperature difference and vibration factors, waterproof coatings with suitable tensile properties should be selected. For building roofs with large structural deformations, waterproof coatings with high elongation should be selected to accommodate deformation.

(3) According to the degree of exposure of the roofing waterproof coating, waterproof coatings suitable for UV resistance and thermal aging retention should be selected. For exposed roofs, waterproof UV-resistant coatings should be used to increase the service life.

(4) When the roof drainage gradient is greater than 25%, it is not appropriate to use a waterproof coating that takes too long to dry.