The new national standard for waterproofing, GB55030-2022, can be said to be the strictest mandatory standard for building waterproofing. It redefines waterproofing levels from two dimensions: engineering waterproofing categories and usage environment categories It puts forward clear regulations on material quality, design service life, construction technology, project acceptance, and operation and maintenance, and the requirements are also upgraded. In particular, it makes clear regulations on the waterproofing of building exterior walls.

In the past, exterior wall waterproofing rarely involved a complete waterproof layer. However, the new standard clearly stipulates that for exterior walls of frame-filled or masonry structures with a waterproofing level of one, two or more waterproof layers should be set. One is waterproof mortar, and the other is waterproof coating or other materials. Specific technical requirements are also put forward for waterproof mortar, including a water absorption rate of less than 4%. Currently, only JC/T 984-2011 polymer cement waterproof mortar type II meets this requirement. In addition to the absorption rate requirement, type II mortar also has clear regulations on shrinkage rate and other indicators, see Table 1:

Table 1 Physical and Mechanical Properties of Polymer Cement Waterproof Mortar Required by JC/T 984-2011