Mikal Jakubal's Strawbale Vault
The entire foundation is sloped approximately 3/8" per foot and drains to daylight at the SE corner.
4"-12" of drain rock was placed in the trenches, and then wire-mesh gabions (18" deep, 3' wide) were placed on the drain rock. Gabions are literally cages of rocks, typically used in erosion control. Want to see a close-up of a gabion?
"U"-shaped 5/8" rebar anchors for the exoskeleton are being placed into the still-empty steel-mesh gabions. To evenly distribute any upward loads on the anchors (in the inevitable earthquake), scrap steel pipe was laid in the bottom of the gabions, on top of the "U"s, before the gabions were filled with rock. This is very similar to a technique outlined in issue #25 of The Last Straw, except the U-shaped rebar was cast into a concrete stemwall.
Completed gabion foundation system. The 2' wide three-string rice straw bales fit down between the rebar posts of the "U"s. (Though the posts were a little out of line, they were bent into place once the bales were set in.) In the background, 20' pieces of #3 rebar are being welded to the anchors. (The interior of the vault is to the right in the photo.)