I had a cabin built recently with superior walls XI in WV. 24x26, 10 feet high. Cost for the walls was ~11k. The walls were built into the hill. The back is completely covered with dirt, the side walls maybe 40%. I did ask the construction guys to seal them, but they used same thing they would use to seal the floors. They did feel it was necessary. The basement did feel damp (I don't have heating there and there was a LOT of snow lately). I bought a dehumidifier and it wouldn't kick in until I lowered it to 35/40%. I figured the dampness 'smell' came from some old furniture I have sitting there. The dirt here is mostly clay, but you hit shale pretty quickly as it's a hill. I do not anticipate any drainage problems around the house.