The stem-wall foundation was 18" wide in order to set bales on it. The rebar in the photo at right was stuck in the wet cement for impaling the first course of strawbales. This shallow, frost-protected foundation was also only 18" deep in order to minimize the use of resource-intensive concrete. It is protected by a barrier of rigid foam insulation. Frost must travel 12" down and 48" laterally before it gets to the foundation. A french drain--designed to carry water away from the foundation--is shown at left.