Insulating a Long Rim Joist With No Sill
We purchased a 1915 1622sqft not including basement outside of Boston (Zone 5). I am starting with blower door directed air sealing. As is common in old homes, the rim joist sits directly on the foundation without a capillary break. I’ve read Martin’s rim joist article and many other q&a’s but can’t get a clear answer. Currently the basement is unconditioned except one room which had the ceiling covered. The sill is above grade although there is a large deck on one side of the house and a sunroom which is not over the foundation as well. There seems to be attempts at previous airsealing with can foam as well as pink batts which I removed.
Questions: I’m assuming airsealing will be done with caulk/acoustic sealant.
Should I take a risk, air seal and insulate at the same time with closed cell spray foam (one with a lower GWP) without a capillary break?
My plan is to finish at least part of the basement in the future and I would also like to insulate the entire basement.
How else would I insulate a long rim joist without a sill and no cap break?(See pic) Should I remove the pictures finished ceiling to get to the rim joist?
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