Re: Gun vaults?
The one built was in a new house, in master bathroom. It was in the plans so rebar was placed before slab was poured. Then we welded rebar to that to about 5 foot off the floor. Laid concrete blocks up to there then welded more rebar. Then more blocks. When we got to the ceiling we used a couple layers of really tight fitting plywood, and pillars, and braces, and silicones the edges for the ceiling. Welded rebar in place for the ceiling then poured concrete on top of it. Slapped a steel door on it and boom, a safe room.