Question about cut and cobble rim joist insulation
I’m planning on insulating around the rim joist of my 1901 home using the cut and cobble method with rigid foam insulation sealed shut with spray foam. I know that normally you fit the pieces right up against the sheathing and between the joists. However, mine are a bit different than all of the diagrams and photos I’ve seen. My studs seem to go all the way down through the sub-floor to the rim joist. So between most (but not all) of my floor joist, there’s one stud, either against the floor joist or in some cases right in the middle of the two.
My question is, should I still cut the foam panels for the whole width between the joists? In most cases, this would leave an air cavity between the panel and the sheathing the depth of the studs. This would be easier to install, but would the air cavity lead to moisture or other issues? Or, should I cut the foam to fit around the studs so it goes flush with the sheathing? In this case, I worry about the studs acting as a thermal bridge and diminishing the effectiveness of the insulation job.
In case my description wasn’t clear, I’m posting some photos of what I’m talking about.
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