I'm a bit of a newcomer to DIY, but I've recently taken the plunge into a project and I could use some advice. I purchased a small starter home 2 years ago. The house is a 1 story bungalow with a finished basement. The concrete foundation is partially above ground (driveway is the same elevation as the basement floor, other 3 sides of the home are back filled. There is no exterior insulation around the foundation. The foundation is only about 4' high throughout the basement. We use the basement as a common area daily.
We noticed this summer that we were having some moisture issues (floor condensation on tiling) associated with some unseasonably hot days. In addition, our heating costs were high last winter, which was unseasonably cold. This prompted me to tear apart the basement walls to get a look at the foundation insulation.
To summarize what i found:
- Insulation is generic (white) Styrofoam, roughly 2" thick. No fiberglass.
- Insulation is just placed against the wall, behind the 2x3 framing, no adhesive, no anchors, no tape, no expanding foam around the edges (not airtight).
- Behind the wood stove there is: Brick firewall | Air gap | Concrete. This is the part of the house where the foundation is above ground.
My issues/questions:
- Is the Styrofoam OK to leave in, provide I can make it airtight? Is it worth replacing with purpose made foam insulation? Spray foam insulation?
- Can I insulate behind the firewall? We use the stove during the winter, but it doesn't burn 24h a day (usually gets lit at 5pm and burns into the night. I feel this is a major source of heat loss when the stove is not lit.
- I plan to add fiberglass insulation against the foam and replace the existing wood paneling with drywall. Is it worth re-framing the half wall with 2x4s for the added thickness? or will 3" make enough of a difference? Obviously re-framing will create a lot of additional work/cost, but we can burn/re-purpose the old framing, so it's not so bad.
My current thinking (cheapest route) is to attempt to seal up the Styrofoam and add 3" of fiberglass insulation. However, while I've got the walls apart, maybe some additional cost will save $$$ in the long run. What would you do?
