There is a crack in the roof, which leaks to the ceiling. I don't know what to do with it.

1. For cracks on the surface of general concrete floor slab, the cracks can be cleaned first, and then sealed with epoxy grouting or surface painting after drying. If cracks are found before final setting during construction, they can be treated with plastering.

2. For other general crack treatment, clean the board joints, sew 1: 2 or 1: 1 cement mortar socks, flatten them and maintain them.

3. When the crack is large, a splayed groove should be chiseled along the crack. After cleaning, level with 1: 2 cement mortar, or caulk with epoxy mortar.

4. When the crack area of the floor is large, static load test should be carried out on the floor to check its structural safety. If necessary, a layer of steel wire mesh can be added to the floor to improve the integrity of the floor.

5. Long and well-connected dangerous structural cracks with crack width greater than 0.3mm can be reinforced with structural adhesive flat steel, and joints between plates are filled with high-pressure joint sealant.