Ministry of Housing and Urban-Rural Development Mandates

Recently, the Ministry of Housing and Urban-Rural Development released the full text of the mandatory engineering construction standard “Residential Project Specifications (Draft for Comment),” which introduces new requirements for building waterproofing. This overturns the current “five-year waterproofing warranty period” regulation, replacing it with significantly higher standards!

Clause 2.2.1 stipulates that the design service life for residential buildings must meet the following standards: structural components shall not be less than 50 years; roof and bathroom waterproofing shall not be less than 20 years; basement waterproofing shall not be less than the structural design service life (i.e., not less than 50 years).

Regardless of when formal regulations are issued, it is certain that the current “five-year waterproofing warranty period” provision will become a thing of the past!

Building waterproofing projects are divided into three major areas: basements, roofs, and interiors. Basement waterproofing is the most challenging aspect of building waterproofing and a high-risk area for quality issues. Moreover, once leakage occurs, subsequent repairs become even more difficult! Based on the requirements of the “Residential Project Standards (Draft for Comment),” the goal is to achieve “structures that stand firm and basements that remain leak-free”!

How can basement waterproofing achieve the same lifespan as the structure?

At this point, we must address a common misconception among many construction participants: the belief that the primary responsibility for basement waterproofing quality lies solely with the waterproofing layer applicators.

This notion is flawed. Basement waterproofing must be “rigid-based” while “combining rigidity and flexibility”: Rigid waterproofing refers to waterproof concrete (i.e., structural self-waterproofing) and mortar layer waterproofing; flexible waterproofing refers to coating waterproofing layers and membrane waterproofing layers.

How should we interpret “rigid as the foundation” and “combining rigidity with flexibility”?

Achieving basement waterproofing that lasts as long as the structure itself is difficult to accomplish solely with flexible waterproofing layers. Flexible waterproofing suffers from material aging issues, making it hard to match the lifespan of concrete structures. Therefore, the fundamental solution for basement waterproofing remains structural self-waterproofing (i.e., rigid waterproofing). However, rigid waterproofing has a critical flaw: it is prone to cracking, forming micro-cracks that can lead to leaks. This necessitates the use of flexible waterproofing as a secondary defense to compensate for the shortcomings of rigid waterproofing.

It is evident that flexible waterproofing materials should be applied on top of rigid waterproofing. Yet, at present, construction participants often prioritize flexible waterproofing while neglecting rigid waterproofing. This imbalance is the root cause of countless basement leakage issues in buildings.