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How to seal a crawl space in new constuction?

Larry Ogden | Posted in Green Building Techniques on

My idea is to put down 10-mil poly before pouring the footings and run the poly into the footings.

Will moisture from the concrete walls be a problem? Is there a better way?

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  1. GBA Editor
    Martin Holladay | | #2

    Instead of extending the poly that will cover the crawl space floor under the footings, you may find it easier to use a different capillary break at the footings. Many builders install a capillary break on top of the footings after the footings have cured. Options include:

    1. Dampproofing
    2. Low-permeability paint -- for example, UGL DryLock latex masonry paint
    3. Elastomeric paint
    4. Delta Footing Barrier.

    If you put your floor poly down early in the construction process, it will get dirty and damaged. It's better to put the floor poly down at the end of the job.

    For more information, see Building an Unvented Crawl Space.

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