I am looking at building a FEMA spec’d safe room in my basement. Two of the walls would be poured concrete the other two I am debating. I am thinking about putting in a wood constructed ceiling. Once I put all the layers in if I put it tight to the floor joists I will have 86” of headroom. The problem is without attaching to the floor joist how do I build the ceiling. I think I would have to build the ceiling then lift it. Then install the walls underneath. The room is going to be 12’x12’ so the ceiling would be heavy. I don’t know how I would install a poured ceiling either. Thanks in advance for the suggestions.