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Community and Q&A

Vented vs. non-vented roof

Dwight Foreman | Posted in GBA Pro Help on

I live in zone 2A north of Lake pontchartrain. I am building a gable house with living area upstairs. The roof is galvalume with a metal ridgevent. The ceiling in the upstairs living area is cathedral then it goes flat. Should I go to the trouble of providing air space under the roof sheathing or close off the ridge vent with closed cell foam and foam the underside of the sheathing?

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Replies

  1. GBA Editor
    Martin Holladay | | #1

    Dwight,
    Whether or not to include ventilation under the roof sheathing depends on many factors, including the type of insulation you intend to use to insulate the sloped sections of your ceiling. If you choose to use closed-cell spray foam, no ventilation is necessary -- although some builders prefer to provide ventilation channels to facilitate future roof sheathing repairs.

  2. Dwight Foreman | | #2

    Thanks alot Martin, I do intend to use closed-cell foam.Should i insulate the roof to R-38? Do you reccomend removing the ridge vents or just let foam seal them?Zone 2A

  3. Aj Builder, Upstate NY Zone 6a | | #3

    Dwight, if your spray foam company has done hundreds of homes like yours with success, then they should guide your install best not someone hear posting from the northeast.

    The key to your needs is hiring the best contractor with the most solid track record and make sure you get his best crew and they work during good weather.

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