Design Guide for Frost-Protected Shallow Foundations

A frost protected shallow foundation (FPSF) is a practical alternative to deeper, more-costly foundations in cold regions with seasonal ground freezing and the potential for frost heave. Figure 1 shows an FPSF and a conventional foundation. An FPSF incorporates strategically placed insulation to raise the frost depth around a building, thereby allowing foundation depths as shallow as 16 inches, even in the most severe climates. The most extensive use has been in the Nordic countries, where over one million FPSF homes have been constructed successfully over the last 40 years. The FPSF is considered standard practice for residential buildings in Scandinavia. The objective of this design guide is to assist U.S. builders, designers, code officials, and others in employing the technology.