I am in the process of adding two rooms and a bathroom in my basement located in the Southeast. The walls are below-ground poured concrete on two sides, regular exterior brick wall on one side, and the garage interior on one side. I have never had a moisture problem.
I have met local code by installing poly on the poured concrete walls and putting in framing that does not touch the concrete walls. First question - how should I insulate and with what - faced or batt fiberglass, or some sort of foam on the poured concrete walls. I will use faced R-13 on non-concrete walls.
Second question - I have installed a FEMA spec basement bathroom for tornado protection. The bathroom has a vent, but is otherwise going to be impermeable (two 3/4 inch plywood sheets with 14 gage steel plate sandwiched between the two sheets, on the two outside walls and the ceiling). This plywood/steel plate sandwich in on the outside of the double code framing. The other two side walls are against the poured concrete. I do not expect to use any insulation on the two walls facing the exterior, but do expect I need insulation against the two walls against the poured concrete. Do I use fiberglass or spray foam? Also - behind the tub- should I use foam there or stuff fiberglass and hope it never gets wet? I am also considering using concrete board instead of sheetrock for the drywall in the bathroom.
I'm in the northeast, and things might be different down south, but the trend here now is to use vapor permeable insulation below ground, to allow the wall unit to dry, either inside to outside or vice versa. The trend is also against using poly or any vapor retarder below ground, though if you are required to follow code, you might be stuck. The recs on buildingscience.com seem to be catching on, as far as I can tell. The recs vary by geography. You might take a look if you haven't already.