Rim board insulation with outside 2 1/2 “ of foam
Been living in my house for about 10 months all the insulation has paid off bills are great house is very very comfortable.
however around the rim board I currently just have bat insulation but I have been considering possibly doing an open cell spray foam since I already have 2 1/2 of exterior foam even though its probably semi vapor permeable I’m guessing around 1 perm or slightly less than that even based on the literature I can find.
id like to use open cell only because it could still breath some but also seal off any potential areas of air infiltration or would I be safe using closed cell then I worry it potentially not allow the rim board area to breath. The area I’m concerned about is roughly 16” wide going around the entire outside of the house. I used floor trusses so it’s just sheeting on the outside covered by a really good water barrier then the 2 1/2” of foam.
lastly One area on the outside rim board only has a 1/2” of foam due to an over site so the concrete would not sit proud of where the concrete stoop was poured so we now have cold concrete up against only 1/2” foam and then they good rain barrier behind that. In this area I’m wondering if it would be ok to use closed cell spray foam since the 1/2” foam is not a great vapor barrier like the 2 1/2” foam is it should still be able to breath somewhat from the outside.
appreciate any thoughts on solutions for these areas
ive had great success sharing thoughts and ideas in this forum look forward to your responses.
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