Foundation:

The slab is 6 inches thick, with 14 inch depth for the first two feet in around the perimeter, and across the area where supporting walls are positioned. The entire slab is heavily strengthened with rebar.

The slab is insulated beneath with a bubble-foil reflective insulation. It is also insulated around the perimeter using rigid foam. This was applied vertically to the edges of the pad and sloping outward four feet to form an apron around the house a foot below ground level.

In addition to the heating pipe, the pad also has embedded plumbing and some wiring.