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Community and Q&A

Should I spray foam exterior gaps in OSB sheathing or am I wasting time?

Josh_Man | Posted in General Questions on

Hey community –

I am sure this question has been posed before, but I am curious if it makes any sense to fill the gaps (some up to a half in a few spots) with some type of spray foam prior to taping over them? 

I will note that all of the gaps that are large gaps have blocking behind them or studs, so none of it is simply a gaping seam.

It feels odd just taping over such a big gap, but would like opinions if I am simply wasting time, energy, and material worrying about them and I should simply tape the seams (maybe with 4 inch on the wider gaps with a Zip flashing) and move on with my life.

Thanks for the help!

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  1. Expert Member
    Akos | | #1

    Taping is the important part. The canned foam there won't do anything, sheathing tends to move so it will separate over time anyways, there is no real additional air sealing benefit. Spend your extra time rolling the tape properly.

    1. Josh_Man | | #2

      Awesome - appreciate the advice - I tried to caulk some of it and it was a TON of caulk and felt zero benefit..

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