Why does gypsum board leave cracks?
1. Stabilize the volume
Gypsum board is processed and shaped, and gypsum hemihydrate is burned and ground with water, which is an important feature of gypsum dihydrate structure. It separates needle-like felt crystals from gypsum slurry and forms micropores during drying, which makes gypsum have the characteristics of "breathing", that is, it can absorb water when the air humidity changes and can quickly re-emit it.
Second, the caulking process
The ceiling of light steel keel gypsum board is in various stress states, and the longitudinal and transverse joints of gypsum board are correspondingly affected by various stresses, which requires that joints should be properly left between boards, and the caulking material itself should have sufficient strength and cohesive force, and reasonable joint construction technology and high operating skills are needed to balance tensile stress and avoid cracks. At present, the design of caulking materials is not clearly defined, and most construction units choose caulking putty at will, so its strength can not meet the requirements.
Third, improper construction.
It is common that after the joint filling process is completed, even after the wallpaper paint is pasted, the installation of water, electricity and air on the ceiling in the wall is not completed, and the installer will step on the dragon skeleton or slide the fixed plate, causing cracks in the joints and even deformation of the board surface. Some suspended ceilings are not designed for people, and some operators still step on the secondary keel, resulting in deformation and deflection of the skeleton. This situation is particularly common in projects that are in a hurry, and management must be strengthened.