How to Waterproof Prefabricated Slab Houses

The following methods can be used for waterproofing prefabricated slab houses:

Firstly, reinforce the gaps between the prefabricated slabs. Since there are gaps between the slabs in prefabricated slab houses, if waterproofing is done directly, the waterproof layer is prone to cracking later due to structural settlement or temperature changes. Therefore, it is necessary to first pour a layer of concrete 5 to 8 centimeters thick on the surface of the prefabricated slabs and lay steel wire mesh in the concrete. The steel wire mesh can enhance the crack resistance of the concrete, prevent cracks from appearing over time, and at the same time protect the prefabricated slabs to avoid the failure of the waterproof layer due to the peeling of the base layer. When pouring the concrete, ensure that the surface is flat to provide a stable base for the subsequent construction of the waterproof layer.

Secondly, use the 'three-scraping and two-pasting' process for the construction of the waterproof layer.

• Material selection: For large-area waterproofing, it is recommended to use asphalt, which has strong weather resistance and low cost. For small-area or local repairs, JS waterproof coating (polymer cement-based waterproof coating) or leak stopper can be selected. These materials are flexible in construction and have good adhesion.
• Construction steps:
  1. First scraping: Uniformly scrape the first layer of waterproof material (such as asphalt or JS coating) on the base layer (concrete layer), ensuring that all gaps and weak points are covered, with a thickness controlled at 1 to 2 millimeters.
  2. First pasting: After the first layer of waterproof material dries, lay felt (or fiberglass cloth) as a reinforcing layer. The felt should be flat and well-fitted, with the overlapping part of the edges being no less than 10 centimeters, and fixed with waterproof material.
  3. Second scraping: Scrape the second layer of waterproof material on the felt to fill the possible gaps in the first layer and enhance the continuity of the waterproof layer.
  4. Second pasting: Repeat the steps of the first pasting and lay the second layer of felt to further strengthen the waterproof effect.
  5. Third scraping: Finally, scrape the third layer of waterproof material to form a complete waterproof barrier. The total thickness should meet the design requirements (usually not less than 3 millimeters).

Precautions:

• Thoroughly clean the base layer before construction to ensure that there is no dust, oil, or loose material.
• The waterproof material should be mixed according to the proportions specified in the instructions to avoid performance degradation due to incorrect mixing ratios.
• The construction environment temperature should be above 5℃ to avoid material embrittlement at low temperatures or accelerated drying at high temperatures affecting adhesion.
• After the waterproof layer is completed, a closed-water test (water storage for more than 24 hours) should be carried out to confirm that there is no leakage before proceeding with subsequent decoration.

By following the above steps, the waterproofing problems of prefabricated slab houses can be effectively solved, and the service life of the building can be extended.