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Climate Zone 3A – faced vs unfaced insulation in walls and ceilings?

AirstreamJake | Posted in General Questions on

Hello,

I know that this may be a basic question, and excuse me for that.  I am building a new home in far northeast Texas, which I believe puts me in Climate Zone 3a W/H (warm/humid).  Should I be using faced or unfaced batt insulation?

Everything I’ve been able to find seems to indicate unfaced insulation (in the walls, anyway – not sure about ceiling), yet all the big-box stores and lumber companies in my small town sell only faced fiberglass batts.

The house is well sealed on the outside.  The exterior walls, from interior out, consist of 1/2″ OSB, 1″ polyiso rigid foam, Tyvek Drainwrap (tightly wrapped and taped around all corners, and Hardie board and batten siding.  My crawl space is insulated and with vapor barrier under concrete floor – all A/C ductwork will run in this insulated crawl space with a single air duct to provide minimal air conditioning and moisture control in the crawl space (in conjunction with a dehumidifier).

 

 

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Replies

  1. Expert Member
    Dana Dorsett | | #1

    As long as it's an asphalted kraft facer (= not a true vapor barrier) and NOT a shiny aluminized facer (= vapor barrier) it's just fine to use faced batts in a 3A climate.

    Asphalted kraft facers are "smart" vapor retarders- they are fairly vapor tight when humidity inside the stud bay is low, but becomes more vapor open than interior latex paint when it's humid enough in the cavity to support mold, allowing water vapor to pass somewhat freely through the facer until the humidity is low again.

    1. AirstreamJake | | #2

      Thanks, Dana. That is what I needed to know.

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