I was thinking of doing the same thing 11 or so years ago when I built this house Mercy. Was thinking of having the foundation crew pour that hydraulic stuff 30 inches wide with the sealer outside and fireproof ins. on the inside. By the time we factored in capping it, the room offset (sure wasn't gonna have the whole foundation like that) and then the door cost, it was insanely expensive. Wife said nope...uhuh...My wallet agreed!