FPSFs are a code-permitted way to design and build a foundations that are only 12 inches below grade. FPSFs are more cost-effective than conventional frost-depth foundations, and can be used on challenging lots or where regular basement foundations aren't practical and for walk-out basements.

They can also be used in combination with regular foundations aren't practical or for walkout basements. Examine the thermal principles and learn how to design and install a FPSF.