Why does PU waterproofing often fail? Is this type of waterproofing suitable for roof waterproofing?

What is PU? The English chemical name of PU is polyurethane, and the Chinese chemical name is polyurethane. Generally, domestic PU waterproof materials are mostly green and are often used for roof waterproofing. Chemically speaking, this material itself is still a good waterproof material, and there are still many companies abroad that produce this kind of waterproof material. So why do domestic PU waterproofing often fail? The reasons are nothing more than the following: 1. The bottom layer is not clean-because before applying waterproofing, the plain floor must be clean, and try not to have too much dust and loose materials, otherwise there will be poor adhesion. Excellent condition. 2. There is moisture in the bottom layer - because PU is an oily waterproof material, you must confirm whether the ground is dry before application. Otherwise, after the waterproofing is completed, the moisture will be wrapped inside and converted into powerful steam through sunlight, which will Causes the PU waterproof layer to peel off. 3. The PU waterproof layer is too thin - the PU waterproof layer must be applied to a certain thickness to have a waterproof effect, because the PU material itself still has low water absorption properties. If the thickness is insufficient, after days of heavy rain, the rainwater will not penetrate After passing through the PU waterproof layer to the bottom, water vapor will still be generated at the bottom through sunshine in good weather, causing the waterproof layer to peel off. In addition, because Taiwan is in an earthquake zone, it is recommended that in addition to having a certain thickness of PU, it is best to stick reinforcing mesh at all corners to prevent leakage caused by PU breakage. 4. Inferior materials - Due to the price competition of waterproof materials in the market, many domestic PU material manufacturers have cut corners on waterproof materials and even divided their products into grades. These will reduce the physical properties of the waterproof materials themselves and lead to waterproofing failure. 5. Insufficient construction experience - waterproofing is best done by some professional waterproofing construction companies, instead of just going to the hardware and building materials store to buy a waterproof material for general paint, water and electricity. The cause of leakage must be carefully determined before waterproofing. And then solve it. Therefore, as long as you pay proper attention to the above details, although PU waterproofing is not long-term waterproof, it still has a certain waterproof life.