Insulating Cold Room in Finished Basement
My 1950s house is in Calgary, Alberta (dry, cold winter climate similar to Zone 6 – Montana).
The basement is finished and heated; however, on the west side of the house consisting of closet spaces and a stairwell/cold-room, the concrete walls (partly below outside ground level) were left as bare concrete. Consequently that side of the basement feels cold. I’ve done a ton of reading on this forum and am leaning towards the following strategy:
1. Joist area above stairwell landing and main level: Caulk gaps between joist and the subfloor on top. Place 2″ XPS foam in the joist cavities and use polyurethane foam to seal the gap.
2. On the bare concrete walls themselves, place 2″ XPS glued straight to the wall and tape all joints. polyurenthane foam around perimeter and interface between foam and concrete floor.
3. Glue (or affix via Tapcons) drywall over the XPS for fire code compliance.
My concern is that there seems to be a 2×4 ? nailing strip embedded right into the concrete. The wood looks to be in excellent condition and isn’t serving any purpose now, but I wonder whether covering it with XPS would cause it to stay wet and rot. Should I aim to chip/drill it out? cover with sealant? Or just insulate on top of it with no worry?
Also, the corners of the cold room have existing 2x4s holding up the landing above. How do you fine folks suggest I insulate around/over those?
The photo shows the cold room under the stairs. The framing supports the stair landing above it. You can also see the 2×4 nailing strip embedded in concrete. Thanks!
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