What are the lap length and acceptance criteria of secondary roof waterproofing and waterproofing membrane?

Lap should not be less than 10CM, and the coil should be tightly closed. Additional layers must be laid around all foundations and parapets, and the coiled material shall not be less than 250 mm above any foundation or pipeline (construction finished surface). All waterproof roofs must be tested for waterproofing.

Closed water experiment is also called water storage experiment. To hold water, the water should have enough volume. In the water storage test, the water storage depth should be not less than 20mm, the water storage height is generally 30- 100mm, and the water storage time is 24 hours, with no obvious drop of water surface. This kind of test is usually carried out on the roof, bathroom or room with waterproof requirements. Check the downstairs every 1 hour in the early stage of water storage test and every 2-3 hours in the later stage. If water leakage is found, the water storage test should be stopped immediately and the waterproof layer should be improved again. The water storage test shall be carried out after the treatment is qualified.