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Community and Q&A

Air Gap Beneath Roof Sheathing

breakingcustom | Posted in General Questions on

I am building a tiny house and have an unvented gable roof with 5/8″ ZIP sheathing above 2×6 rafters. I am planning to use Rockwool Comfort Batt insulation, but haven’t found a definitive answer on whether or not I need to leave an air gap underneath the roof assembly. If an air gap is needed, I will need to fur out the rafters 1/2″ to 3/4″. I am in climate zone 2/3 so not worried about a heavy snow load or typical northern climate issues.


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  1. breakingcustom | | #1

    Just following up on this... another question: Would it be better to use Rigid Foam Insulation board to fill the rafter cavity or stick with Rockwool?

  2. GBA Editor
    Kiley Jacques | | #2

    I'm replying to your question to give it a bump and to suggest that you read this Q&A thread.

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