Indoor Waterproofing for Prefabricated Slab Houses

Indoor waterproofing for prefabricated slab houses requires systematic measures tailored to their structural characteristics. The key points are as follows:

1. Slab Joint Treatment: Blocking the Core Water Infiltration Path

Prefabricated slabs are composed of multiple concrete panels joined together, with slab joints being the primary path for water infiltration. Rigid filling materials such as epoxy resin or polymer mortar should be used to reinforce the slab joints, preventing the waterproof layer from cracking due to temperature variations or building settlement. For example, in the renovation of old residential areas in Chengdu, a double-layer waterproofing process on walls and floors ensures the sealing of slab joints, eliminating horizontal water vapor spread.

2. Base Layer Repair: Eliminating Hidden Water Migration Risks

The surface of prefabricated slabs often exhibits unevenness, sanding, and peeling due to aging, leading to water migration beneath the waterproof layer. Fine repair of the base layer is necessary before construction, removing loose layers and filling sand holes to ensure a flat surface and straight edges. For instance, the Shanghai Zhonghuan Jiayuan project provided a stable attachment surface for the subsequent waterproof layer through base layer cleaning and obstacle removal.

3. Comprehensive Waterproofing: Covering the Entire Structure

Local repairs cannot根治 hidden water migration issues. National standard thickened membranes such as SBS modified bitumen membranes should be used for comprehensive铺设 (laying), forming a continuous waterproof barrier. For example, the Shanghai project effectively addressed顽疾 (persistent issues) such as roof leakage and interior wall mold through a combined solution of slab joint reinforcement and comprehensive membrane laying.

4. Reinforcement of Key Areas: Targeted Protection

• Gutters: Specialized waterproofing processes exposed to the elements, such as weather-resistant waterproof coatings, should be adopted to reinforce the thickness of the protective layer and resist ultraviolet and rain erosion.
• Bathrooms: A secondary drainage system must be installed to prevent water accumulation in the backfill layer. In humid regions like Chengdu, the waterproof height in shower areas should be extended to at least 1.8 meters, with a reserved inspection port for the backfill layer waterproofing.

5. Material and Process Selection: Ensuring Long-Term Effectiveness

• Materials: Avoid using ordinary thin waterproof coatings or non-standard membranes. Prioritize national standard genuine materials with strong tensile and deformation resistance, such as polyurethane waterproof coatings and polymer waterproof membranes.
• Processes: Follow standardized procedures, such as the four-step method used in the Shanghai project: base layer cleaning → slab joint reinforcement → membrane laying → gutter reinforcement, ensuring tight connections between each step.

6. Warranty and Maintenance: Establishing a Long-Term Mechanism

A written warranty (recommended for more than 5 years) should be provided upon completion, along with regular inspections and maintenance. For example, the Shanghai project achieved a permanent solution to recurrent leakage issues and extended the service life of the houses through a systematic renovation plan combined with regular inspections.

Summary: Effective waterproofing for prefabricated slab houses requires a comprehensive approach covering slab joints, base layers, comprehensive waterproofing, key area reinforcement, material and process selection, and warranty and maintenance to achieve long-term waterproofing goals.