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Community and Q&A

What do we do with the ridge vent?

buzziam | Posted in General Questions on

Hello – I’m a n00b to this stuff and my search-fu seems to be failing in regard to what we should do to the ridge vent if we want to enclose the attic to be within the conditioned space of our 1976 home. 

We live in Hot-Humid IECC climate zone 2 moisture regime A and are strongly considering 2-inches of closed cell followed by open cell against the roof sheathing. This a single story gable roof home and there is a ridge vent as well as soffit vents.

So the question is:
Do we just leave the ridge vent as is such that the closed foam, once applied, is exposed to the weather that could possibly get up and in through the ridge vent?

Many thanks in advance for your time and patience in answering my question.

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  1. Expert Member
    BILL WICHERS | | #1

    If you apply spray foam under a ridge vent, it will probably expand out through the vent and make your roof look messy. What I would do is seal up the ridge vent using either house wrap (preferred), or stuffing some fiberglass in it as a backer for the spray foam to be sprayed against. Which will work best depends on the type of ridge vent you have and how accessible the underside of the ridge vent is from inside your attic. The ideal scenario is to put strips of house wrap under the ridge vent stapled to the sheathing on either side. Try to keep the housewrap tight to the sheathing and following the roofline as much as possible so that you don't have a think spot of spray foam along the ridge when you're done.

    You don't need a heavy barrier like plywood since the spray foam itself will support everything after it cures. All you need is to have something to keep the spray foam out of the ridge vent during application.


    1. buzziam | | #2

      Many thanks @Zephyr7 - your suggestion helps quite a bit.
      Also apologies for my late response.

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