Air seal and insulation for existing 100-year-old exterior walls
Wall assembly is (outside to in) … cedar clapboard, tar paper, pine board sheathing, 2×4 wall, lathe and plaster. IR scan confirms no insulation in the wall cavity. The walls will not be opened.
BSC teaches me that control layer priority is water, air, vapor, thermal. Lightbulb for me … air control is more important than thermal (R value).
So what to do with these old walls which have been doing their thing for 100 years? Would blown-in cellulose screw them up? Retain moisture in the wall, exterior paint lifting, rot, etc?
A couple tactics I’m considering.
– Aerobarrier the house, improving the air control layer of these old walls.
– Blown in / dense pack mineral wool. Yes I did mean mineral wool … evidently it can be blown-in (though rarely discussed). Won’t absorb water, lets vapor pass to dry into the interior.
What do you think?
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