underground building will always be more expensive than the above ground equivalent. Some of the more interesting close to underground alternatives are still v

underground building will always be more expensive than the above ground equivalent. Some of the more interesting close to underground alternatives are still very costly in labour (earthships, straw bale), and not thoroughly tested in many climates. Engineered below ground construction will always cost a shit-tonne in concrete and waterproofing (source - just built an engineered 3.5 metre downstairs in a 2m cut on the side of a hill).