Masonry Magazine July 2011 Page. 16
Moisture Management of Below-Grade Construction BY JOHN KOESTER
Basements
Building on a strong foundation has been a well-recognized principle of construction for thousands of years, but we still continue to violate the concept. One of the most violated areas of below-grade construction is the failure to include moisture management.
Joseph Cubby says, "Learn the past. Decide the present. Build the future." With apologies to Cubby, let us examine common below-grade construction moisture management errors from the past that are still in practice, and then make some decisions today on how to correct them so that we can build stronger foundations for tomorrow's residential and commercial properties.
Most residential and commercial structures feature below-grade construction that is usually 10- or 12-inch CMU or eight- or 12-inch poured concrete; a much smaller percentage involve ICF and wood walls.
The footings (or caissons) that support these walls can vary in depth and width depending on a variety of soil conditions. The basements may be fully below-grade or partially exposed (a berm) and there may be walkouts, many configurations are possible. However, they all have one thing in common unique moisture management requirements. (See Image #1.)
Image 1.