Powerful Cement Prefabricated House Waterproofing

Waterproofing for powerful cement prefabricated houses requires a comprehensive approach encompassing design, material selection, and construction to ensure that the waterproofing performance of all key parts meets the standards.

I. Specialized Design for Waterproofing Projects

1. Define Waterproofing Objectives and Areas: The waterproofing grade of the project is Level II, with a designed service life of 15 years, covering the roof, exterior walls, floors, and joints (such as roof seams, wall panel joints, door and window openings, pipe penetrations, and the damp-proof layer at the bottom of exterior walls).
2. Environmental Adaptability: Suitable for temperate climate regions with an annual rainfall of 800-1200mm, it requires verification of no leakage through a 24-hour closed water test, and the waterproofing layer should remain intact within the designed service life.
3. Environmental Protection Requirements: Select waterproofing materials with low VOC and high solid content to reduce the impact on the environment and human health.

II. Material Selection and Technical Parameters

1. Base Layer Treatment: Use polymer cement-based waterproofing coating JS-II type (solid content ≥ 65%, tensile strength ≥ 1.8MPa, elongation at break ≥ 80%) for the base layer treatment of roofs, exterior walls, and floors.
2. Large-Area Installation: Self-adhesive polymer-modified bitumen waterproofing membrane (1.5mm thick, tensile force ≥ 400N/50mm, elongation rate ≥ 30%) for the waterproofing layer of roofs and exterior walls.
3. Sealing Materials: Polyurethane sealant (Shore hardness 35-45A, tensile strength ≥ 1.2MPa, elongation at break ≥ 400%) for wall panel joints and door and window frame sealing; cement-based capillary crystalline waterproofing coating Type D (impermeability pressure ≥ 0.8MPa, penetration depth ≥ 40mm) for prefabricated component joints and pipe roots.
4. Auxiliary Materials: Polyethylene polypropylene composite waterproofing membrane (0.7mm thick, breaking strength ≥ 150N/50mm) for the floor damp-proof layer; 100g/㎡ polyester non-woven fabric for joint reinforcement; 20×1.5mm stainless steel batten for fixing membrane ends; and hydrophilic expansion waterstop strip (expansion ratio ≥ 300%) for vertical seams of prefabricated wall panels.

III. Construction Techniques and Key Points

1. Roof Waterproofing: After cleaning the surface dust, level it with 1:3 cement mortar (mixed with 5% waterproofing agent); apply JS-II type coating at joints and lay non-woven fabric reinforcement layer; lay the membrane from low to high, with hot-melt welding for overlapping seams; fix the ends with metal battens and seal them; finally, lay an isolation layer and a 40mm thick C20 fine stone concrete protective layer.
2. Wall Waterproofing: Ensure that wall panel joints are sealed, with seams filled with sealant; apply waterproofing coating on the exterior wall surface to enhance impermeability.
3. Door and Window Waterproofing: Select door and window products with tightly installed sealing strips, treat connections with sealing materials, and regularly inspect and replace damaged strips.
4. Foundation Waterproofing: Apply damp-proof coating on the foundation surface and set up drainage facilities (such as drainage channels and outlets) around it to prevent water erosion from accumulated water.