Our architect specified 6" drain pipes in silt sleeves, holes down, tucked into the outside corner of the footings, which were 12" below the surface of the slab. The walls were concrete block but waterproofed on the outside with tar, tar paper, and bentonite. 2' of gravel over the drains, clay and earth on top of that backfilled and mechanically compacted every 8 inches, and sloped away from the house. Never had a leak during the time we lived there, and I'm still in touch with the buyer. Only problem he's had is with a leak in the water line that City of Atlanta water Dept. installed (big surprise . . . not!)
I think the preformed concrete walls are better - but block was cheaper and we were young marrieds . . . 850 square feet heated and cooled space, plus a solarium on the south side with a 12' x 12' x 12' concrete cube in the ground for solar mass . . .
How deep are your wells for the geothermal heating?
"How deep are your wells for the geothermal heating?"We don't use wells, we have 500' of coiled tubes buried 10'. We had a week of -26F this winter and everything worked great. Heating, cooling and hot water are averaging a little over a buck a day. We are adding a fireplace this year as a back-up in case we lose electricity during one of those cold snaps.