One of the site details I like about my proposed underground house, is that there is only a few inches of soil to bedrock. This is a good and bad thing.

My plan was to excaavate all the soil right down to bare bedrock, then haul in screened rock to get the concrete slab level. This will do several things. The first is allow the heat from that bedrock to help heat the home; a constant 57 degrees here in Maine. It wil also allow me to build 100% on rock. With the roof having a lot of weight, I like the idea of the building pushing down on the concrete slab, the rock under it, and then the bedrock. As the saying goes, "it is a wise man who builds his house upon a rock." But the biggest thing is, that screened rock under the slab will let any water that migrates there, drain away. That should eleminate any water issues.

Really the only bad part is, with so thin soil, I will have little soil to place on top of the house. But that is not really a big deal. I had intended to just bring in sand anyway. I got a gravel pit 1/2 mile away, so I can just haul some of that up, and cover my house with that. It will cost money to move, but would be a nominal cost really. Moving earth is kind of easy.