Steel quonset structures or ‘culvert homes’ are usually not rated for underground residential use. From what I’ve heard, most quonset hut manufacturers will not sell to anyone who intends to bury the structure. Covering a building with earth adds enormous weight on the structure and manufacturers don’t want any liability issues in case of collapse. This is unfortunate because quonset structures are well suited for underground homes, rootcellars and storm shelters. For one, they’re quick and easy to build. The main step involved is bolting the arched sections together with cordless drills.