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Air Sealing Cathedral Ceiling

Tom Wheeler | Posted in General Questions on

So the other day someone posted about using zip sheathing for the air barrier above their flat ceiling. I can’t find the thread, but could that work in a cathedral ceiling situation?  Would the air barrier be broken by nailing up t&g after?
It just seems like getting a good, lasting seal would be easier with tape than a plastic sheet going up.

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Replies

  1. Expert Member
    Akos | | #1

    Sheet good is always the best. Not sure ZIP is worth it here as 7/16 OSB would work just as well.

    If you are nailing up T&G, the best air barrier would be 3/4" to 1" foil faced polyiso. You would still be able to nail up the boards with 2.5" nails. It is not much more than OSB, super easy to tape and would bump up your assembly R value by a fair bit.

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