Concrete roof leaks mainly exist in roof expansion joints, roof parapets, and roof pipes. The specific causes of leaks are as follows:

Conventional design of upright structure roof:

Reinforced concrete roofing panel--insulation layer--cement mortar leveling layer waterproof coating--waterproof coiled material--dry hard cement mortar--floor tile paving (cement mortar caulking)

The reason for the roof expansion joint and the parapet wall leakage is the same, the reasons are as follows:

Expansion joint function: The expansion joint is also called temperature joint. Its main function is to prevent the house from cracking due to climate change. Therefore, the contraction force of this area is much larger than other areas, and it is also a weak area for roof waterproofing.

The original waterproof layer is aging and failed. Under the thermal expansion and contraction of the roof and the pressure in the structural layer, it breaks and peels off from the base surface, and the waterproof effect becomes weak. As a result, rainwater enters the insulation layer through the original waterproof, and then flows into the room through the joint between the parapet wall or the expansion joint and the floor, resulting in water leakage.

The perlite board in the thermal insulation layer has a high water absorption rate. Due to the water absorption and thermal expansion, the pressure in the structural layer is becoming larger and larger, and the original waterproof layer is broken. The leakage is becoming more and more serious.

During the waterproof construction of the parapet facade, the coiled material needs to be wrinkled when the yin and yang corners are treated, and the bonding is not strong, and the water channeling occurs.

Causes of water leakage around roof pipes:

When installing the pipeline, the floor slab was penetrated and the original waterproof layer was destroyed. And there is no waterproofing construction around the pipeline. Due to the different materials of the steel and the floor, the coefficients of thermal expansion and contraction are different, cracks are stretched between the pipeline and the floor. When it rains, water penetrates into the structural layer through the roof , And then into the room through the gap between the pipe and the floor through the damaged portion of the coil, causing water leakage.