How to Handle the Roof of a Prefabricated Panel House

The treatment method for the roof of a prefabricated panel house should be selected based on specific issues. Common problems and corresponding treatment solutions are as follows:

1. Crack Treatment
The main causes of cracks in the roof of a prefabricated panel house are material aging or structural stress changes. It is recommended to use the mesh reinforcement method: First, clean up the loose parts around the cracks to ensure the base layer is dry and dust-free. Then, apply special construction adhesive to the cracks and attach anti-crack mesh (such as fiberglass mesh) flatly to the surface of the cracks. The width of the mesh should extend 10-15 centimeters on both sides of the cracks. Finally, apply elastic waterproof putty in layers, with each layer not exceeding 2 millimeters in thickness. After complete drying, sand it flat. This method can effectively disperse stress and prevent crack expansion, especially suitable for repairing fine cracks (width less than 0.3 millimeters). If the cracks are wider (more than 0.5 millimeters), inject epoxy resin adhesive for structural reinforcement before applying the mesh.

2. Flatness Treatment
Choose different solutions based on the error range:

• Error < 5 millimeters: Directly use gypsum for leveling, with a cost of about 30 yuan per square meter. During construction, strictly control the thickness, with a single application not exceeding 3 millimeters, otherwise, it may cause hollowing and peeling due to differences in shrinkage rates. It is recommended to apply thinly in 2-3 batches, with an interval of 6-8 hours between each batch, and use a straightedge to detect flatness in real-time.
• Error 5-20 millimeters: Use cement mortar for leveling, but pay attention to the mortar mix ratio (recommended 1:3 cement mortar) and curing, otherwise, it may crack easily. It is more recommended to use a light steel keel ceiling, which achieves flatness by adjusting the height of the keels and can also hide pipelines, with a cost of about 80-120 yuan per square meter.
• Error > 20 millimeters: A ceiling treatment must be done. Before construction, use a laser level to measure the error of the entire house, mark the high and low points, and ensure the ceiling is flat by adjusting the height of the main ceiling keels (with an error controlled within ±2 millimeters). If the space height allows, add an insulation cotton layer to improve thermal insulation performance.

3. Leakage Treatment
Since prefabricated panels have a hollow structure, surface treatment alone cannot cure leakage. The correct approach is:

• Locate the leak source: Use a water spray test or infrared thermal imaging camera to locate the leakage points, focusing on checking panel seams, the base of the parapet wall, and the surrounding areas of roof pipes.
• Panel seam treatment: Cut a V-shaped groove along the panel seams (depth 3-5 centimeters), clean it, and then inject polyurethane foam for filling. Apply a 2-millimeter-thick polymer cement waterproof coating on the surface and lay a 300-gram-per-square-meter polyester胎 (polyester felt) waterproof membrane, extending 15 centimeters on both sides of the panel seams.
• Overall waterproofing: If the leakage range is wide, lay SBS modified asphalt waterproof membranes (thickness ≥ 4 millimeters) on the roof, using hot-melt construction to ensure the membrane overlap width is not less than 10 centimeters, and add additional layers at internal and external corners. After construction, conduct a 48-hour closed water test to confirm no leakage before proceeding with the protective layer construction.

Summary of Treatment Points: Crack repair should focus on structural reinforcement, flatness adjustment should control thickness in layers, and leakage treatment must be sealed from the inside. Before construction, be sure to check the roof load-bearing capacity to avoid safety hazards caused by increased weight.