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You told someone that they could patch open cell foam insulation with

Ken_Sayers | Posted in Green Products and Materials on

You told someone that they could patch open cell foam insulation with spray insulation from the hdw store. The spray “stuff” that I am familiar with is of the closed cell variety. Is it that to which you are referring? Please advise, as I have some holes that need repairing.

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  1. Expert Member
    Dana Dorsett | | #1

    The most commonly found can-foams are also polyurethane. If allowed to expand fully they're not really closed-cell- it's open cell, but that doesn't matter.

    Spraying water to wet the surface enhances both the surface bonding and the total amount of expansion from the can foam. Bonding onto the open cell foam wouldn't be a problem, but it's worth doing it to ensure that the void is maximally filled. The R-value of the can-foam will be slightly higher than the open cell foam, not that it matters a lot.

  2. GBA Editor
    Martin Holladay | | #2

    I agree with Dana: Don't worry too much about the distinction between open-cell spray foam and closed-cell spray foam. If you have some voids that need to be filled, use canned spray foam from the hardware store. It will work fine.

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