Use a frost-protected shallow foundation

Tags: Kitchen or bath addition, New construction, Gable or eave end add-on, Slab, Board Insulation, cold, mixed_humid

A frost-protected shallow foundation allows foundations as shallow as 16 in. (0.4 meters) in the most severe American climates.
Insulation, strategically placed around the foundation, raises the frost depth around a building. Since the late 1970s in Scandinavia, more than 1 million homes have used this technique successfully. This type of foundation reduces concrete use and excavation.

Despite its support by building codes and extensive research by the NAHBNational Association of Home Builders, which awards a Model Green Home Certification. Research Center, this foundation system doesn't have a long track record in the U.S. Contractors may be unfamiliar with the system. In addition, it requires a lot of rigid insulation–usually rigid foam.