There are about 15 provinces, municipalities and autonomous regions with an annual rainfall of more than 1,000 mm. On rainy days, the roof is always wet, and the drainage is not smooth, and there may even be water accumulation, which will not dry up for several months, soaking the waterproof layer. Paints with poor water resistance are prone to re-emulsification or hydration reduction reactions; adhesives that are not resistant to blisters seriously reduce the bonding strength, causing the polymer membranes in the bonded joints to crack, especially the gutters for internal drainage, which will leak due to long-term soaking in water. For this reason, waterproof materials with higher water resistance should be selected, such as modified asphalt membranes with glass fiber or polyester tires, or polymer membranes bonded with water-resistant adhesives.

As for the arid and rainless northwest region, evaporation is much greater than rainfall, and often no water is seen on the eaves after rain. These regions obviously have lower requirements for waterproofing. A secondary building with a defense layer can also meet the waterproofing requirements. If a good protective layer is built, there is no problem in reaching the durability.

In cold and snowy areas, some waterproof materials cannot withstand the cycle of low temperature expansion and contraction, and will age and break in a short time. Four or five months a year are covered with white snow, and the snow water soaks the waterproof layer for a long time. At the same time, the snow melts and freezes. Adhesives with poor frost resistance and poor water resistance will become vulnerable in such a harsh world.

In addition to the influence of the region on the selection of materials, the seasonal selection of waterproof construction cannot be ignored. In the cold winter, water-soluble coatings cannot be used, and the adhesive will reduce its bonding performance at 5°C, and it cannot be constructed at sub-zero temperatures. The design was in summer, and the construction was in the coldest days of winter. The adhesive froze and lost its adhesion when it met the concrete. The self-adhesive waterproofing membrane could not stick to the seams, resulting in construction failure, delays in construction period, and waste of materials and labor. In the Northeast, some projects used waterproof materials with low low-temperature indicators in the summer, but in the severe winter, these completed waterproof layers could not withstand the ravages of frost expansion and contraction, and were prematurely abandoned. When designing, attention should be paid to understanding the adaptability of the selected materials.

02 Construction process quality monitoring

For the construction of waterproof base and waterproof layer at all levels, formulate the acceptance system before each waterproof construction, strictly organize the acceptance according to the acceptance procedure of concealed works, and do on-site supervision in key processes and key parts. Strictly check whether all technical data meet the standard requirements, attach importance to the collection of construction technical data, and do a good job of construction logs, on-site supervision records and concealed project acceptance records. If the technical data is incomplete and the construction quality does not meet the standard requirements, the next process shall not be carried out. At the same time, the method of leading by example is promoted, that is, after the model is approved by Party A, supervision, owner, and design, the scope of construction will be expanded to further improve the construction organization design plan and achieve effective control.