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Community and Q&A

Is this wall system adequate for Zone 6a — maritime climate?

GBA Editor | Posted in Energy Efficiency and Durability on

I would like to build a garage with 2″x6″x 10′ studs. From exterior to interior: 3/8″ ply siding, 3/8″ gap, Tyvek wrap, 1″ EPS board, 2″x6″ studs, 4″ EPS fitted between studs, 6-mil vapor barrier (called for by code), then drywall.

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  1. GBA Editor
    Martin Holladay | | #1

    As far as I know, there is no code anywhere in the country that requires an interior 6-mil poly vapor barrier.

    Rather, the code requires a vapor retarder. Kraft facing or vapor-retarder paint can satisfy this requirement.

  2. James | | #2

    Martin,I should have stated I am in Canada.According to the building inspectors in Halifax,N.S.
    ,section 9:25:42 of code says 6mil.poly vapor barrier is standard. The question is "is this going to cause moisture issues."

  3. Riversong | | #3

    The question is "is this going to cause moisture issues."


  4. James | | #4

    Thank you for response.I will have to find another solution.

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