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Community and Q&A

Vapor Control Layer in Climate Zone 6?

bauchin | Posted in General Questions on

I am building a new home in northern Vermont (climate zone 6) and have the following wall section from outside to inside:
LP Smartside Board & Batten siding
3/4″ PT vertical furring strips
Rainscreen drainage matt
2″ Rockwool rigid insulation
Henry Blueskin VP 100 self adhering rain barrier
1/2″ CDX plywood sheathing
2×6 studs at 24″ O.C.
5 1/2″ Rockwool Batt Insulation
1/2″ drywall (air barrier)

My question is do I need a vapor control layer between the wood studs and interior drywall?  If so, what product do you recommend?

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  1. Expert Member
    Akos | | #1

    2" or rockwool is not enough for condensation control in your climate, so you do need a vapor retarder.

    This can be faced batts, one of the smart vapor retarders, vapor barrier paint or 6mil poly. They are all code compliant and work.

  2. climbing_carpenter | | #2

    I'd consider a 2x8 wall with advance framing techniques over your proposed assembly. It'll be much less expensive and avoid the issue you're creating with inadequate exterior insulation. Thick exterior insulation is crushingly time consuming. In my book, a double stud wall is preferable.

    The Bonfiglioli Wall is another option and has become, as a builder, my price-point standard.

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