Good afternoon! I hope some of y'all know more about insulation than I do.
I have a raised ranch (split level) style home, with a partially finished basement. On the front of the house, a part of the foundation is fully exposed. Inside this corner of the foundation is an unfinished store room. This room faces west, is closed off with a door, has no AC or return vent, and is easily 20* hotter than the rest of the basement, or the whole house even. I believe heat is leeching from this room into the rest of the home.
I'd like to use construction adhesive and glue some foil face rigid insulation directly to the foundation walls, but I'm reading all sorts of stuff about EPS, XPS, faced, unfaced, concrete breathing, moisture levels, vapor barriers, etc. My plan does not involve studding it out or drywall or anything... it's just a small-ish junk room. Do I have to worry about moisture or breathability considering that both sides of the concrete are fully exposed? Foil facing the room or the concrete?
The foundation is sound everywhere with no cracks or water issues. The basement was finished around 15 years ago and there's no evidence of damage OR repairs.
Pics attached. The yellow area is the fully exposed area I'm talking about. House is located in the Heartland; 100+ degree summers, 10 degree winters.
Sorry for the shotgun approach; there's a lot of conflicting info out there... Thanks.