Dismantle the surface layer and re-coat it with a waterproof layer inside. It is recommended to use K 1 1, polyurethane and JS polymer cement-based waterproof coatings, and brush them for 3~4 times, each time with a thickness of 2 ~ 3 mm. Each time, you should wait until the previous one dries to form a film before brushing the next one. After the waterproof coating is painted, you should wait until it is completely dry before doing other surface materials construction.