Rim board air sealing
I have posted on this previously and and having trouble with my original plan. I have essentially a double rim board between my 1st and second floor.
I framed over the existing ceiling joist to level and install new I joists for 2nd story. In my haste to finish framing and dry in my home I simply insulated with R-23 roxul.
I planned on cutting up the subflooring to access and use a cut-and-cobble foam board to air seal. After thinking of access I simply don’t think I can access the entire rim. So I would have say 15% not air sealed.
What would be the concern with not air sealing this location? I have plaster ceiling below and plywood sub with 3/4″ tongue and grove with tile in bath and laundry.
So could I reasonably air seal the ceiling on the 1st floor and the floor above it? My house typically has low humidity in the winter time, I believe in part because of cold air infiltration. Could this be left alone with minimal risk?
The space between ceiling and floor above is approximately 24″. Exterior is plywood with Tyvek then vinyl siding and a 1×6 PVC rim board to transition from brick to vinyl. I’m in zone 5.
My furnace will be a minisplit on the 2nd floor and a condensing furnace in the basement that I may swap for another minisplit down the road. I do not use a humidifier in the winter. As of today my relative humidity is 30% and it is currently 35 degrees this morning and has been somewhat wet outside this past week. When temps drop to single digits my RH is closer to 15-20%.
I live in zone 5.
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