Waterproofing Construction for Prefabricated Houses

Waterproofing construction for prefabricated houses needs to target the characteristics of the assembled structure, achieving long-term water leakage prevention through standardized processes, material specifications, and new technologies. The key points are as follows:

I. Structural Characteristics and Leakage Risks

The roof of a prefabricated panel house is assembled from multiple concrete panels. The panel joints are natural channels for water infiltration and are prone to cracking due to long-term exposure to temperature differences and settlement. The base layer is prone to issues such as unevenness and sanding, causing rainwater to flow beneath the waterproof layer and resulting in hidden leakage. The gutter area, due to water accumulation and ultraviolet exposure, requires a specialized waterproofing process with strong weather resistance; otherwise, material aging can lead to leakage.

II. Standardized Construction Process

1. Base Layer Treatment: Completely remove the old waterproof layer to ensure the base layer is free of oil, dust, debris, and standing water. Repair honeycomb cracks, sanding, and other defects to ensure the base layer is flat and solid, preventing waterproof layer failure due to base layer defects.
2. Panel Joint Reinforcement: Use rigid filling materials (such as high-strength mortar) to reinforce panel joints, preventing waterproof layer cracking due to dynamic displacement. The filling must be dense and free of voids to accommodate minor building deformations.
3. Full-Area Waterproofing: Use national standard thickened membranes (such as genuine Oriental Yuhong products) for overall laying, covering all assembled joints. The membrane overlap width must comply with specifications (usually ≥100mm) to ensure the continuity of the waterproof layer.
4. Detail Node Reinforcement: Strengthen areas with cracks or voids using materials like waterproof plugging compound. For gutter areas, use an exposed specialized waterproofing process (such as weather-resistant coating + reinforcement layer) to enhance local water resistance.

III. Material and Process Specifications

1. Number of Waterproof Layers: Follow the "General Code for Waterproofing of Building and Municipal Engineering" GB 55030—2022. For flat roofs, Class I waterproofing requires no less than 3 layers, and Class II waterproofing requires no less than 2 layers, with at least one layer being a membrane waterproof layer.
2. Construction Environment: Avoid working in rain, snow, or winds exceeding Force 5 to prevent rainwater erosion or wind damage to the uncured waterproof layer.
3. Material Re-inspection: All waterproof materials must pass re-inspection before use to ensure their performance meets design requirements (such as tensile strength and aging resistance).

IV. Warranty and Maintenance

It is recommended to provide a written warranty of more than 5 years after project completion. Long-term leakage issues can be effectively resolved through standardized and meticulous construction (such as using genuine main materials throughout and precise repairs). Regularly inspect the roof condition and promptly repair local damage to extend the lifespan of the waterproof layer.

V. New Technology Trends

The "Non-fire Rapid Waterproofing Construction Technology for Roofs" that emerged in 2025 adopts a cold construction method, using polymer materials for direct粘贴 (pasting) or spraying, avoiding the risks of hot-melt operations and adapting to building deformations. It is particularly suitable for renovation scenarios of prefabricated panel roofs.