Mike and Greg used chunks of urbanite and old bricks, and then gravel on top of that. After some tamping the base is ready for the sub floor mix! The mix they used for the sub floor was 4 parts sand to 1 parts clay slip, made from the local clay subsoil.
Here's another inspiring earthbag construction for fans of natural homes out there! The Shantikuthi Earthbag Spiral House is called such because its walls were built in a spiral pattern. Its roof also has a spiral garden where visitors can harvest seeds