Underground structures are constantly moving. As they move, they develop strains due to earth loads, stress redistribution and tectonic and seismic influences, which may cause cracks to develop in the structure. If not waterproofed, the cracks can allow water to migrate into the structure and possibly damage utilities, interior finishes and even the structure itself.
A waterproofing system must be able to handle the strains and bridge the cracks in order to keep the structure dry. Fortunately, flexible membranes can fulfil these requirements and also have the advantage that the seams can be pressure tested during installation to ensure the integrity of the membrane.