Frost-Protected Shallow Foundations (FPSF)
A resource efficient design for foundations in all U.S. climates
Frost-Protected Shallow Foundations (FPSF) provide protection against frost damage without the need for excavating below the frost line. An FPSF has insulation placed strategically around the outside of a foundation to direct heat loss from the building toward the foundation, and also to use the earth's natural geothermal energy.
Traditionally, foundations are protected from frost-heaving damage by placing the footing below the frost line. Because FPSFs are protected from freezing by thermal insulation, bottoms of footings can be just twelve to sixteen inches below grade. This reduces excavation costs, making this an economical alternative for protecting foundations against frost damage.
Insulation around the perimeter of the foundation reduces the amount of heat loss from the warm interior to the cold exterior in the winter, which would normally pass through the slab or floor, and out through the foundation. Heating energy costs are thus reduced.
Courtesy of PATH