Q. We‘ll be building a house on a frost-protected shallow foundation. Are the requirements for sizing the portion of the slab that forms the thickened footing around the perimeter of the slab the same as the requirements for a typical monolithic floating slab?

A.Jay Crandell, a licensed professional engineer and director of the structures and materials division at the NAHB Research Center, responds: Yes, the footing should be sized just as required in the building code for any footing. The key to a frost-protected shallow foundation is simply to place the right type and amount of insulation in the appropriate locations to prevent frost heave from being a problem.

For more information, consult the Design Guide for Frost-Protected Shallow Foundations, which is available from the NAHB Research Center for $30 (800/638-8556; www.nahbrc.org).