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We live in an 1895-converted carriage house with an cold damp basement

Sandra Thomas | Posted in Green Products and Materials on

We live in an 1895-converted carriage house with an cold damp basement made of field stone. We removed mold in the fall and now have the experience of a basement with an average temp of 36 degrees this past winter. SPF was suggested.

We understand EPA is in the midst of looking at long-term outgassing (suggested in a 2011 GBA article), but does not have any answer yet. There was a comment that some chemicals currently used MIGHT be banned in the future….but what facts can a homewowner use to determine whether or not SPF is safe long-term at this time?

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  1. GBA Editor
    Martin Holladay | | #1

    The only insulation material that is suitable for insulating the interior of a field-stone foundation wall is closed-cell spray polyurethane foam.

    Almost all spray foam installation jobs go smoothly and result in happy customers. A few of these jobs -- very few -- result in problems, generally due to installer error (bad chemical ratios, applying at too cold a temperature, etc.). The most common problem is lingering odors.

    I advise you to choose your contractor carefully; ask about the contractor's training and certifications, and check references. You should not be in the house on the day that the work is being performed -- I would stay away for at least 24 hours. The contractor should operate fans to ventilate the job site.

    Under these conditions, I wouldn't worry.

  2. Charlie Sullivan | | #2

    Martin's answer is the established wisdom. I wonder whether there are alternatives. For example, could you coat the wall with concrete to make it flat, and then install EPS insulation in contact with that flat surface, just as you'd insulate an ordinary concrete-wall basement?

    Disadvantages of spray foam include high global warming impact from the gasses used to blow the bubbles ("blowing agents") and high cost, as well as the possible lingering odor problem.

  3. Expert Member
    Dana Dorsett | | #3

    The short answer is yes, you can use the stone foundation as the exterior pouring form of a thinner concrete veneer to make it flat and even use sheet EPS in the interior side concrete form prior to the pour, to make it an air-tight bond between the EPS & concrete. But from a cost point of view that wouldn't necessarily make sense.

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