Hi,

I’ve found a lot of different advise about insulating CMU basement walls and Stucco over CMU on slab but I’m not finding anything about what would be best for a house similar to mine. I’m in Zone 5a for climate. The house is a 1300 sq. ft. single story ranch with a concrete basement foundation. It was built between the late-1950s to early-1960s.

The exterior above grade wall is constructed as follows from the exterior to interior:
  –  4 inch brick veneer,
  –  .5 to 1 inch air gap,
  –  8 inch CMU
  –  1×3 furring strips (vertically installed)
  –  .5 in thick cement board 
  –  .5 to 1 inch plaster

We are working slowly through remodeling / rebuilding the interior of the house. We’ve just recently finished the basement after having an interior and exterior French drain system retrofitted to the foundation. We used the DMX dimpled mat with a T & G OSB subfloor assembly then used 2in XPS on the basement walls with 2×4 framing. 

I don’t feel comfortable with using the same wall system from the basement on the main floor, mainly from the additional space that using the XPS would take up and the environmental impact (I only learned about how bad it is after 50% of our basement was completed).

Would using foilfaced Poly ISO against the CMU work as a good moisture / vapor barrier / retarder? Something like what’s described here  https://www.greenbuildingadvisor.com/question/interior-insulation-for-a-1950s-cmu-house#comment-162544