You do know the most popular cheap route to a shelter is to bury a school bus? I know several folks up here in Maine who have them buried at camp and around there home for everything from tater storage to a full on shelter. While I agree on your facts and stress I also do not know anybody putting them under a wetland where that would be a issue but I would not wanna be in that one. There is a very well known survivalist guy in Canada who has a few dozen school buses buried at his place for 30 some years not without any problems. His have no added support just stripped school buses buried in a field.