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Do I need a vapor barrier on my block foundation wall?

mapnerd | Posted in General Questions on

Our current house in Omaha NE was built in the early 1970’s. I have noticed a problem with one of my foundation walls. The drywall is kind of soft and it looks like I might have a moisture issue in the corner. The wall is concrete block with 2×4 studs against the concrete and batt insulation only starting at the exterior grade and above (about 3/4 of the way up the basement wall). I don’t know if any type of waterproofing would have been used on the exterior walls back then – nothing is visible from the outside.

Assuming I need to pull off the drywall and replace it, what would you recommend for adding insulation and do I need to be concerned about vapor? I do plan to inspect and correct any soil grading issues on the exterior of the house at this corner.

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  1. GBA Editor
    Martin Holladay | | #1

    Q. "Assuming I need to pull off the drywall and replace it, what would you recommend for adding insulation?"

    A. Either EPS, polyisocyanurate, or closed-cell spray polyurethane foam.

    Q. "Do I need to be concerned about vapor?"

    A. No, but you need to be concerned about air tightness.

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