1950s brick home: Crawl space wall insulation questions
Hi, I am working on insulating and sealing the crawl space of my 1950s brick home in Zone 4 in central VA. I have pulled out the fiberglass insulation on the floor joists and am getting ready to start work on replacing the vapor barrier and insulating the walls with foam board.
The walls of the crawl are block and brick with uneven areas where extra mortar dried. I was planning on using borafoam http://www.nisuscorp.com/pest-management-professionals/products/bora-foam to insulate the walls and the areas of the crawl space walls between the joists because it insulates and functions as a vapor barrier. The house doesn’t really have rim joists, the joists just sit in the brick and there are 2 x 4’s nailed in at the top. The questions I have are:
1. Is it ok to cut and cobble the foam board into the areas of the crawl space walls between the joists where the rim joists would be in a newer home or will this trap moisture near the ends of those joists and cause they to decay/fail? I have attached pictures showing these areas.
2. Does the crawl space wall need to be nice and flat or is chiseling away extra mortar and obstructions to get it mostly flat provide a good enough surface to attach the foam board insulation to?
3. Should I consider other foam board insulation like formular XPS instead of the borafoam EPS (with 3 mil poly on each side of the board)? I like the borafoam because it includes the poly on the board so I figured I wouldn’t need to run poly up the wall as far if I used it and because it is termite resistant.
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