I'm looking into doing some finishing work on my basement, which is entirely unfinished at this time with the exception of some shelving. House is circa 2008 built in Western NY (Zone 5). Foundation walls are solid concrete pour. The foundation exterior has a dimpled DMX material wrap. On the interior, there is an insulation blanket covering the wall with a white vinyl(?) sheeting holding it in place (alongside what appears to be ramsets in the concrete). The blanket covers from the top of the concrete wall, ending 2 or 3 feet above the slab, leaving that lower section entirely exposed concrete.
The basement has, in the two years we've been here so far, not had a water event, and is dry. There is no damp smell or feel to the air. Visual inspection of all the lumber shows no rot or mold. There is also a sump pump installed which I hear turn on during the odd time of heavy rain or rapid snow melt. I have never witnessed or seen evidence of water penetration into the basement.
All that to say - I have some questions about exterior walls when framing rooms.
- Should the studs be 2 x 4 or 2 x 6?
- Does existing insulation (the blanket) count towards code requirements on top of whatever I may put in the walls?
- Is XPS foamboard sufficient for the exposed concrete wall not covered by the fiberglass blanket (I was looking at 2" board at R10)?
- What should I be doing about moisture control for the external walls? Do I need to use faced insulation or unfaced? If the XPS foamboard and blanket wrap was sealed for a continuous barrier, would that class as a vapor barrier, and wouldn't need to be worried about when framing?
- Does the foundation wrap factor into the moisture equation?
- Would you recommend fiberglass or mineral wool for the insulation material?
Are there any other considerations I am missing? Thank you for your help in advance.
