We Don’t Like Our Underground House
If it touches the ground, it gets moist. So it has to be solid rock or steel. Maybe some plastic might work.A cellar can be built if you surround it with gravel and install drainage pipes everywhere - and protect the outer wall with plastic or tar - and even then it doesn't last very long and problems with moisture are frequent so you have to dig and expose it again every now and then.The best houses sit high on solid granite foundation pieces and are ventilated from below. They have steeply sloping roofs and long eaves. They have the minimal amount of holes in the floor or roof (preferably no cellar or skylights). They are built on a knoll so no water flows towards the building from any direction. Rain water from the roof is directed away with gutters and ditches. All building materials are breathing and can be dried if they get wet (no plastic or glass wool).