One of the most commonly asked questions to the structural department involved the required distance between the top of a foundation wall and the adjacent exterior grade. The 2009 International Residential Code requires a minimum of 6 inches of separation where brick veneer is not present. The idea here is to provide a buffer zone to help prevent moisture wicking into the timber framing typically framed above residential foundations. Where brick veneer is present this requirement drops down to 4 inches.
The code text reads:
R404.1.6 Height above finished grade. Concrete and masonry foundation walls shall extend above the finished grade adjacent to the foundation at all points a minimum of 4 inches (102 mm) where masonry veneer is used and a minimum of 6 inches (152 mm) elsewhere.