Foundation waterproofing: When and why to use it?
In some construction projects, there is a need to apply waterproofing before the foundation concrete is cast. This approach is commonly needed in high water table environments in urban locations and on any structure where the owners are concerned about water infiltration through the foundation slab or confined walls.
Until the 1990s, there were a range of sheet membranes used for this purpose. However, these solutions were often not ideal for such applications. The problem was the lack of adhesive bond between the membrane and the concrete cast against it. This meant that even if minor damage occurred to the membrane, water could pass between the membrane and the concrete. Once the water found cracks or joints in the concrete it would then enter the building.
In some cases, waterproof concrete was used for these applications. However, there are many variables to ensuring that waterproof concrete performed optimally in these environments, and some architects and engineers had concerns about specifying this for more critical projects.
In the mid 1990s, GCP Applied Technologies introduced a fully bonded solution called the PREPRUFE® waterproofing membrane to address these limitations. Specifically engineered for below slab and behind confined walls, the PREPRUFE® waterproofing membrane bonds to the concrete that is cast against it. Its adhesive layer creates a tight seal between the concrete and the waterproofing membrane so that even if the membrane gets damaged, water is prevented from bypassing the membrane and migrating into the building.
For the first time, construction and waterproofing professionals could use different technologies depending on whether the waterproofing needed to be pre-applied or post-applied (that is, depending on whether the waterproofing needed to be applied before or after the concrete was poured) and still have a strong adhesive bond to the foundation.
For critical applications where there is low tolerance for water leaks, using the PREPRUFE® waterproofing membrane with a tight adhesive bond to the concrete is a safest choice.