How should I insulate my concrete ceiling in a safe room under a concrete porch?

Question

We have a safe room roughly 25' long x 7' wide x 10' tall. It has concrete walls with a metal ceiling and concrete covered porch above it. The room gets very cold in the winter, I suspect mostly due to the uninsulated ceiling. Right now we have an open door to your conditioned basement from the safe room. How would you recommend insulating the ceiling?

I have considered:

1. Foam board attached to metal. I wondered if I could glue this up or would have to attach some other way?

2. Spray foam ceiling. I am guessing that would cost much more than the foam board and wouldn't be something I could do myself.

3. Putting a door in the opening to the safe room to slow the cold air. This would help but the room still shares uninsulated concrete walls with the rest of the basement.

With any option I have to deal with minor water leaks when water blows onto the porch and leaks through the concrete.

Thank you for any ideas and suggestions!

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Answer 1

Given it's 10 feet tall a dropped ceiling and insulation batts would be the "most obvious" approach (to me) if you deal with the leaks from above by sealing them above. Come down to 8 feet with a grid and place batts on top of the panels.

If you let it leak, then you need to come up with a way to redirect the leaking before you hit the insulation, or use insulation that doesn't care (and costs more.) Something like a set of sloped 2x4 "rafters" to support a piece of plastic attached at the high side and directed into a gutter on the low side, then hang ceiling below them and insulate between.

If the concrete walls to the porch floor are partially above-grade and uninsulated inside or out, then they are also contributing to the cold, since concrete is a terrible insulator, at roughly R1 for 15 inch thickness. Concrete below grade transitions to seeing less extreme temperatures on the outside, but still generally below "comfortable" for people for much time.