Dirt Mound

I sent Joe a note about dome construction the other day. He's working on the quick, portable type, and it looks as if he's coming close to a viable solution. My idea was borrowed from an architect friend of mine who specializes in earth-sheltered construction, and it's a down and dirty way of erecting a thin-shell reinforced concrete dome without a conventional framework. It's similar to the inflatable balloon method being used today, except you substitute good old dirt for the framework. Here's how it works:

• Dig a circular trench and pour a "ring beam" as a foundation.
• Mound dirt up in the center to form a "mold" in a dome shape. (Have a hill? Use it!)
• Cover the dirt with construction plastic.
• Use 2X6 lumber to define openings, etc.
• Place wire mesh and/or reinforcing bars bent to the shape of the dome.
• Cover with concrete.
• When cured, dig out the dirt! (labor intensive, but cheap!)

The plastic keeps the dirt from sticking to the concrete (that would be messy). You'd need low slump concrete to keep it from running all over the place, but it should be trowlable. Alternately, a swimming pool contractor could spray gunite or shotcrete onto your frame. The concrete thickness can taper from, say 6" at the base to 4" at the apex, it doesn't need to be all the same thickness. This, of course, only applies to those of you who are able to build any kind of permanent structure. I don't know how local code people would react to this either, it would obviously be on a region by region basis. Anyway, for what it's worth!

Offered by Ron.