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Open-cell spray foam for field stone basement wall?

Behardy | Posted in General Questions on

I am finishing a basement in a old home (1850s) in NE PA. Can open cell spray foam be applied to an interior field stone basement foundation wall if the wall has had a vapor barrier such and Grace ice and water shield attached to it? I ask because open cell for one is much cheaper than closed cell and does not have the off gassing and harmful blowing agents that closed cell does. Closed cell however is vapor permeable. I must put in the grace shield due to the small amount of moisture that does weep from two of the foundation walls. The shield moves the water to a french drain below grade that leads to daylight.

Is the spray foam a necessity or can I just put the grace shield on the foundation and then frame up my walls and insulate them? Or will I have problems with moisture condensation which could lead to mold between the new wall and the foundation wall? Any insight would be appreciated. Thank you.

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  1. Expert Member
    Dana Dorsett | | #1

    With vapor-impermeable membrane on the exterior side of the foam, on the above grade section open cell foam would load up with moisture on the cool side losing performance, may even experience (permanent) frost damage.

    Open cell foam can outgas polyols if the mixture isn't correct during installation, just like closed cell foam, but it doesn't outgas HFCs.

    There are water blown closed cell foams- see if Aloha Energy (a regional player in NY) has an installer in your area.

    Alternatively, Icycene MD-R-200 and MD-R-210 are both water blown mid density foams that run ~R5/inch, and are sufficiently low permeance to apply directly to the foundation without the moisture loading risk.

  2. GBA Editor
    Martin Holladay | | #2

    Dana Dorsett has given you good advice. You want to use closed-cell spray foam, not open-cell spray foam.

    For more information, see these two articles:

    Next Generation Spray Foams Trickle into the Market

    How to Insulate a Basement Wall

    -- Martin Holladay

  3. Behardy | | #3

    Thanks for the information I will look into the closed cell formulations mentioned. Thanks again.

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