Cracks appear in the plaster layer of the wall, generally showing two types of cracking: normal and abnormal. Normal cracking is caused by the shortening of the cement mortar after it dries; abnormal cracking is caused by the quality of the material and the Caused by poor construction techniques.
If only the surface paint film cracks, the dirt on the base surface must be removed before painting the wall. Then you can use fine sandpaper to repair the cracks, then choose paint with the same color as the original wall and repaint it.
Normal cracking cannot be prevented, and abnormal cracking should be avoided. For example, when the hollow area of ??the plaster layer is too large, it must be knocked out and remade. The plaster layer must be leveled first and then painted. The repair price is higher and affects the normal living environment. If it is a small area of ??cracking, there will be no voids. If there are problems such as bulging or peeling, you can cover the wall with vermicelli cloth and then paint it.
Extended information:
Repair steps for plastering hollows and cracks:
1. Use a putty knife to scrape out the width of the gap and scrape it into a figure-eight shape. , wide on the outside and narrow on the inside.
2. Use gypsum block dry powder to fill the gap. The filling depth should not be less than 30-40mm. It does not need to be filled level with the wall, and it should be 1-1.5mm lower than the wall.
3. Apply 108 glue to the gap and then paste glass cloth or cowhide note.
4. Scrape 821 putty 2-3 times and smooth it with the original wall surface. After drying, smooth it with sandpaper.
5. Adjust the wall paint. After the paint is adjusted, paint the sample first. After it dries, compare it with the color of the wall. If the color is close and the color difference is not big, then paint the wall.