I have a small ?30' x 12'? addition. on a cement slab. I think the slab is 4 inches and was reinforced with some steel. Could this cement foundation be the roof for a root cellar?
Other than the edges of this foundation, it does not have to hold up anything but foot traffic. The building on top is a very minimal, one story board and baton single room, build up against an existing structure on one of its long sides.