Cracks on the Roof of a Prefabricated Panel House

Cracks appearing on the roof of a prefabricated panel house require determining the cause and taking appropriate measures based on the specific situation.

Causes of Cracks

• Jointing Process Issues: When using the 3D steel bar truss floor panel prefabricated construction process, cracks often occur at the joints of the prefabricated bottom formwork panels. This is due to possible improper operation and loose connections during the jointing process, leading to stress concentration at the joints during subsequent use due to factors such as building settlement and temperature changes, resulting in cracks.
• Building Load Factors: According to the "Technical Guidelines for Structural Safety Inspection of Self-built Houses", load-induced cracks are one of the important causes of roof cracks. For example, horizontal cracks that appear when the roof sags, even if they are only 0.8 millimeters wide, require attention. Such cracks indicate abnormalities in the building's structural load-bearing capacity, which may affect the overall stability of the house.

Assessment of the Danger Level of Cracks

• Crack Width: Cracks in prefabricated panels exceeding 1 millimeter require vigilance. Generally, the wider the crack, the greater the potential impact on the building's structural safety. However, crack width is not the only criterion for assessment; other factors must also be considered comprehensively.
• Crack Location: If a crack extends from the roof all the way to two-thirds of the wall height or is exactly on a load-bearing beam, the danger factor doubles. These locations are key load-bearing parts of the building's structure, and the appearance of cracks may indicate a decrease in structural load-bearing capacity, posing significant safety hazards.
• Crack Changes: If a crack continues to lengthen and widen, even if it has not reached 1 millimeter, a professional organization should be consulted. Continuously changing cracks indicate that the building's structure may be undergoing dynamic changes, potentially posing hidden dangers that require timely inspection and assessment.

Repair Methods

• Fine Cracks: Cracks as thin as a hair can be directly sealed with glue. Such cracks have a relatively small impact on the building's structural safety, and simple glue sealing can prevent moisture, dust, etc., from entering and avoid further expansion of the cracks.
• Medium Cracks: Medium cracks require the injection of special glue, which takes 72 hours to dry. Special glue has good adhesion and filling properties, effectively repairing cracks and enhancing the overall integrity of the structure. After injecting the special glue, sufficient time must be allowed for it to dry thoroughly to ensure the repair effect.