Cracks are mostly caused by the expansion and contraction of wood. When suspending the ceiling, try to reduce the number of joints, and the joints must be strong. A three-millimeter gap should be left to facilitate the adhesion of plaster. It is best to use quick-adhesive powder. The caulking strength is high, and then the paper tape is glued, and the putty is scraped after drying. Crack treatment: Use a knife to cut the crack into an eight-shaped groove, then embed it with quick-adhesive powder, then apply white latex glue to the caulking tape and then apply putty after it dries.