Prefabricated House Roof Waterproofing

Prefabricated house roof waterproofing should focus on 'base layer repair + panel joint reinforcement + full-area membrane waterproofing' as the core, combined with deformation-resistant materials and standardized construction, avoiding local repairs, and prioritizing professional teams that offer long-term warranties.

I. Standardized Construction Process

1. Base Layer Treatment: The base layer of prefabricated panel roofs often suffers from issues such as loose leveling layers, unevenness, and sanding or peeling. These problems must be thoroughly removed and repaired to ensure a flat and solid base layer, providing a stable foundation for subsequent waterproofing layers.
2. Panel Joint Reinforcement: Panel joints are the primary channels for water infiltration and are prone to cracking due to temperature variations and settlement. Reinforcement with rigid filling materials (such as cement-based sealants) is necessary to prevent dynamic deformation from tearing the waterproofing layer.
3. Full-Area Waterproofing Layer Installation: Use national standard thickened membranes (such as genuine Oriental Yuhong products) to cover the entire area, forming a continuous waterproofing barrier. Local repairs can lead to water flow beneath the waterproofing layer and should be avoided.
4. Gutter Reinforcement: For areas prone to water accumulation, use specialized exposed waterproofing techniques (such as high weather-resistant coatings) to enhance UV and aging resistance, extending service life.

II. Material and Process Selection

1. Membrane Waterproofing Requirements: According to the 'General Code for Waterproofing of Building and Municipal Engineering', Class I flat roof waterproofing requires no less than 3 waterproofing layers, Class II requires no less than 2, and at least 1 must be a membrane waterproofing layer. For prefabricated panel roofs, it is recommended to use polymer-modified bitumen membranes, which offer excellent tensile and aging resistance and can adapt to thermal expansion and contraction.
2. Cold Construction Process: The fire-free rapid waterproofing construction technology (cold construction method) promoted in 2025 eliminates the need for open flames. It achieves quick installation through specialized adhesives or self-adhesive membranes, improving construction efficiency and safety, especially suitable for prefabricated panel roof renovations.

III. Common Issues and Avoidance

1. Water Channeling Risk: Treating only local panel joints or surface layers can lead to lateral water flow beneath the waterproofing layer, necessitating full-area waterproofing. It is recommended to adopt a composite waterproofing system of 'membrane + coating' to enhance sealing.
2. Construction Environment Limitations: Construction is strictly prohibited in rainy, snowy, or windy conditions above Force 5. The ambient temperature must meet material requirements (e.g., bitumen membrane construction temperature should ideally be above 5°C).
3. Warranty and Maintenance: Choose a reputable team offering a long-term warranty of 5 years or more to avoid repeated leaks due to construction defects or material aging.

IV. Alternative Solutions for Reference

1. Color Steel Roofing: Metal panels are installed in large sections with anti-rust coatings, providing 20 years of waterproofing but at a higher cost (60-80 yuan/㎡), suitable for scenarios requiring high durability.
2. Plastic Film Covering: Extremely low cost (2 yuan/㎡) but with a short service life (2-3 years), suitable only for temporary emergency or low-budget projects.