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In order to get R-15 in Zone 5 on a 60-year crawlspace concrete wall, can I run R-10 outside and R-6 inside?

Charles Nelson | Posted in Building Code Questions on

Need help. The code says “continuous,” but ICF walls are not.

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Replies

  1. User avater GBA Editor
    Martin Holladay | | #1

    Charles,
    R-10 outside and R-6 inside is fine with me. But you should talk to your local code inspector (if in fact a code inspector is involved with this project) -- because it's the local code enforcement authority that you have to convince, not me.

  2. User avater
    Dana Dorsett | | #2

    I'm not sure how ICF walls are not considered continuous- please explain!

    Note: In zone 5 when more than half the insulation is on the exterior of a mass wall even R13 would meet code for above-grade walls. You might run that by the inspector as well.

  3. User avater
    Michael Maines | | #3

    Charles, the intent of "continuous" in the code means no interruptions by studs or similar. Although the concrete obviously splits your two layers of insulation, each layer is continuous. At least that's my common-sense interpretation. Like Martin says, it's your AHJ who makes the call.

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