I Could Really Use Some Help With A Spray Foam Question
I’m hoping to get advice on filling framing cavities with either open cell or closed cell spray foam. I have 4 framing corner cavities measuring 3 1/2 x 1 1/2 in x 9 ft and 4 rafter cavities measuring 3 1/2 x 9 in x 21 ft with nothing in them but air. The structure in undergoing a major renovation so all sheetrock and interior paneling is removed The current plan is to drill 1 in holes every 16 in or so and fill with closed cell spray foam. I have several concerns; The foam applying too much pressure to the members and moving them, the foam not curing properly because it can’t cool rapidly, and leaving portions of the cavities unfilled because of air pockets.
Is there a better option?
Many Thanks,
Steve
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Replies
Yes, take the drywall off and install the foam properly. Don't mess around. Closed cell foam is the safest option in most climates although not the most environmental option.
If you have proper cladding/wrb/sheathing/flashing, in walls you can also dense pack with cellulose. I've had no issues filling smaller cavities with that through a access holes.
I expect that open cell foam has far less risk of creating excessive pressure. With the right perm ratio it is safe.
You could drill lots of holes and buy the consumer grade "low expansion" foam. Spray it in every other hole and make sure it comes out the holes you aren't spraying it in to be sure you filled it all.
But I like the cellulose idea better.