Building a foundation in a cold climate can be a challenge, especially if you are on a tight budget. All foundations must be protected from frost heave, which occurs when soil underneath the foundation freezes and expands. In colder climates, such as extreme northern areas of the U.S., soil can freeze more than seven feet deep.
A basement foundation is the most common choice in cold climates. Because foundation walls often need to be five, six or even seven feet deep to prevent frost heave, it might be cost-effective to make them eight feet deep, pour a concrete floor and use the area as living space. Basement foundations are expensive, though, and they are susceptible to serious moisture problems.
A pillar foundation involves less concrete, and perhaps less labor, than a basement. This might add up to considerable cost savings in cold areas, because only the pillars need to extend below the frost line, instead of the entire foundation perimeter. Special care is required, however, to insulate the floor and to protect water pipes from freezing.
Frost-Protected Shallow Foundation
Perhaps the most cost-effective option for cold climates is the frost-protected shallow foundation (FPSF), which uses strategically placed rigid insulation to prevent soil below the foundation from freezing. The National Oceanic and Atmospheric Administration reports that a FPSF can be as shallow as 16 inches, even in the coldest areas.
References and ResourcesNOAA Manual NOS NGS 1: Extreme Depth of Frost Penetration
National Oceanic and Atmospheric Administration: FPSF