This is a fascinating thread. I have wanted to build a small shop with an underground room for years. I thought it would be just like a small basement however in my part of Texas everything is build slab on grade and couldn't find a contractor to do what I wanted to do. I too thought about a 20' shipping container but was told that was a bad idea for several reasons. I even thought about trying to use a large pre-formed septic tank and building on top of that.
The ICF forms are interesting and something I hadn't thought about. I don't know how many non- commercial contractors around here have experience with that method.
The ICF forms are interesting and something I hadn't thought about. I don't know how many non- commercial contractors around here have experience with that method.