Gypsum board ceiling is easy to crack

Based on years of design and construction experience, some effective measures have been taken to solve the problem of ceiling cracking quality.

The main reason for the cracking of gypsum board ceiling: the stable volume of gypsum board

Because industrial gypsum is formed by heating dihydrate gypsum and discharging crystal water. The gypsum board is shaped and shaped, and water is added to the burned and ground hemihydrate gypsum to re-form the important characteristics of the dihydrate gypsum structure. It separates the needle-like body from the gypsum slurry. During the drying process, micropores are formed, which makes the gypsum have a "breathing" characteristic, that is, when the humidity of the air changes, it can absorb moisture and can be quickly re-emitted. .

The linear expansion and contraction of the gypsum board in the air-dry state is negligible. Even if the air humidity reaches 90%, the maximum lateral expansion of the gypsum board is only 0.015% in 24 hours. Therefore, the slight amount of expansion and contraction does not cause the board. The main reason for surface deformation and joint cracking.

Gypsum board ceiling cracking is affected by the strength of gypsum board

The structure of the gypsum board is a plate which is firmly bonded together with the gypsum core and the facing paper. The facing paper bears the tensile force and the reinforcing effect, and the protective paper layer has a great influence on the quality of the plate, the paper surface Unpaved sheets are not usable. The longitudinal and transverse fibers of the face paper have different strength and elasticity, the longitudinal direction is larger than the transverse direction, and the longitudinal bending resistance and deformation resistance are also stronger.

The gypsum board has strong moisture resistance, and the paper surface layer can extend the time the plate absorbs water, but does not prevent water absorption. During installation and construction, the strength of the gypsum board will decrease for a longer period of time or continuous wetness. Therefore, wet boards must never be installed. High temperatures have a certain effect on the strength of the plasterboard. When the ambient temperature of the gypsum reaches 42°, the solidified gypsum will start to change the crystal structure and the strength is impaired, so the gypsum board cannot be directly connected to the heater or the like.

Gypsum board ceiling cracking is also affected by the design and construction of the suspended steel keel skeleton structure

The rational design of the dragon skeleton, the use of qualified materials and parts, and strict control of construction quality are important guarantees to ensure that the ceiling of the QST system is not deformed or cracked. Any mistake or negligence in any of these links can lead to deformation and cracking. For example, the fixing between the gypsum board and the keel, if not in order or fixed, makes the plate generate internal force, and the joint is sheared, causing deformation and crack; the rigidity and straightness of the light steel keel are insufficient, and the spacing is not correct. Deformation cracking will occur.

The caulking process when the ceiling is installed is the direct factor for the success of the seam treatment.

The light steel keel gypsum board ceiling is in various stress states. Therefore, the longitudinal and transverse joints of the gypsum board are affected by various stresses. This requires proper spacing between the plates. The caulking material itself has sufficient strength and viscosity. The joint force must also have a reasonable joint construction process and high operational skills to offset the tensile stress and avoid cracks. At present, there is no clear regulation on the design of caulking materials. Most of the construction units use caulking putty arbitrarily, and the strength cannot meet the requirements; some construction units use high-grade rubber materials, but the price is expensive; some construction units use double-layer perforated paper tape. Strengthen, or strengthen with a mesh cloth to achieve good results. Therefore, how to grasp the caulking process is very important.

Gypsum board ceiling installation is not in accordance with the process and uncivilized construction

Commonly, when the caulking process is completed, even after the wallpaper coating is finished, the installation work of water, electricity and wind on the ceiling of the wall has not been completed, and the installer steps on the dragon skeleton or skids the fixed plate, which will cause The seam is cracked and even the surface of the board is deformed. Some ceiling designs are not on the subject. Some operators also step on the secondary keel to make the deformation of the skeleton deformed. This situation is especially common in the progress of the project, and management must be strengthened to overcome it.

The above factors are the main reasons leading to the cracking of the gypsum board ceiling.

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Label: Why the gypsum board ceiling is easy to crack

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