Waterproofing below-grade portions of buildings is increasingly important to owners as technological advancements and limited city space have pushed basements deeper into the ground and further into water tables.
There are two types of flood-proofing—dry and wet. The design intent of dry flood-proofing is to allow flood waters to enter and exit the structure freely and allow the waters to rise and fall evenly inside the structure in the same rate and manner they rise and fall on the outside.
When materials like concrete are constrained to prevent volume changes, large internal forces and stresses develop. Therefore, it is important for architects and engineers to work together to avoid inappropriately constraining building materials.
The current design of some wood-framed, non-ventilated roof assemblies in northern climates results in discontinuities in the vapor/air barriers, which allows moisture-laden air to migrate into the truss space and condense.
Below-grade construction with shotcrete is gaining popularity across the country. The trend of using shotcrete instead of conventional cast-in-place (CIP) concrete can be attributed to the lower construction cost and time saved by not having to place and remove formwork.