What about weight? I have a basement, so I'd be building the heater over the basement on a floor suspended by basement rafters. Has anyone done this?
Also, I called a local excavator and tried to explain about cobb and asked about clayish soil. He said what they term as "Berm" soil would probably fill the ticket. My land is rock. I can hardly plant a petunia, so I gotta get it from someone.
