Cracking in the Roof of Prefabricated Panel Houses

Cracking in the roof of prefabricated panel houses may be caused by structural deformation, differences in material properties, defects in construction techniques, and other reasons. The treatment should be determined based on the condition of the cracks.

Causes of Cracking

1. Structural Deformation: Foundation settlement, temperature changes, and material shrinkage can easily cause deformation in laminated panels. In hot and humid climates, long-term exposure to temperature fluctuations can lead to stress concentration at the joints of laminated panels, which are structural weak points. When the stress exceeds the tensile limit of the plaster and decorative coatings, cracks will appear.
2. Differences in Material Properties: The elastic modulus and coefficient of linear expansion differ among prefabricated laminated panels, plaster layers, and decorative coatings. Under the influence of environmental factors, relative deformation between different materials can accumulate stress at the joints, leading to cracking in the plaster and decorative coatings. For example, during hot summer periods, the different degrees of expansion between laminated panels and decorative coatings can cause cracks at the joints.
3. Defects in Construction Techniques: Improper joint treatment, such as insufficient roughening or cleaning of concrete surfaces, or unreliable steel bar connections, can weaken the integrity of the joints. Improper application of decorative coatings, such as non-compliance with temperature and humidity requirements during construction, uneven coating thickness, or poor adhesion to the plaster layer; incorrect material ratios or construction and curing issues, such as not adding paper fibers during construction or inadequate curing, can all lead to cracking.

Treatment Methods

1. Small Crack Width and No Impact on Aesthetics: No special treatment may be necessary.
2. Wider Cracks or Impact on Aesthetics: Surface repair can be performed. For hairline cracks, they can be directly sealed with glue; for medium-sized cracks, a special adhesive should be injected, which takes 72 hours to dry.
3. Crack Width exceeding 0.3 millimeters, especially exceeding 1.5 millimeters or fully penetrating: This may affect the load-bearing capacity of the house, indicating structural issues with the prefabricated panels. Immediate contact with a professional agency for house safety inspection is required, and corresponding reinforcement measures, such as grouting or carbon fiber reinforcement, should be taken based on the inspection results.
4. Cracks Accompanied by Foundation Issues: If foundation settlement, wall tilting, or other similar conditions occur simultaneously, it indicates serious structural safety hazards in the house. Immediate inspection by professionals is required, and corresponding remedial measures should be taken based on the inspection results to ensure居住安全 (living safety).