Factors Causing Joint Cracking in Perforated Acoustic Panels and Fiber Cement Board Lightweight Walls
Date:2019-04-08 Views:1544
After analysis, the main factors affecting joint cracking of fiber cement boards are categorized as follows:
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Structural Factors:
As a basic decorative material, fiber cement boards must be attached to the main structure whether used for suspended ceilings or partition walls. Sometimes, due to inadequate design, construction, or material selection of the main structure—such as building inclination or cracking caused by uneven foundation settlement—beams, slabs, and walls in the building may warp, deform, or develop through cracks. Since fiber cement boards are directly fixed to the surface with light steel keels, the strong stress generated by cracks in the main structure will cause cracks at the joints of fiber cement boards, which are the weakest points.
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Keel Factors:
Whether for suspended ceilings or partition walls, fiber cement boards must be fixed to light steel keels. The quality of light steel keels directly affects whether the joints of fiber cement boards crack.
National Standard GB/T11981 "Light Steel Keels for Construction" specifies requirements for the appearance quality, dimensional deviation, and mechanical properties of light steel keels. To reduce costs, many projects use light steel keels thinner than the negative deviation specified in the national standard, with mechanical properties failing to meet national requirements. This results in insufficient rigidity of fiber cement board walls, leading to cracking under stress. Similarly, if the thickness and mechanical properties of ceiling keels do not meet national standards, excessive overall deflection often occurs, causing cracks at board joints.
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Joint Material Factors:
Improper selection of joint materials also affects the handling of board joints. If the joint putty used with fiber cement boards is of poor quality, joint cracking will occur quickly.
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Design and Construction Factors:
Construction technology and quality are also important factors determining whether fiber cement board joints crack. Only by strictly controlling construction quality can joint cracking be prevented. After the construction of the light steel keel frame, it should be left to stand for a period of time to achieve internal stress balance before fiber cement board installation.
