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Community and Q&A

Low-VOC expansion foam?

zkaufman | Posted in Green Products and Materials on

I’m having trouble finding any low-VOC low-expansion-foam products. For windows and other openings, tape is the preferred option, but when there are larger cracks or spaces that need to be air-sealed (e.g., in a rehab), it would be good to have a foam-sealant option to recommend.
Alternative suggestions are also welcome.

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  1. GBA Editor
    Peter Yost | | #1

    You are right that around windows (between the window unit and the rough opening), you can use an air-permeable cavity insulation material b confining it with an air-impermeable tape.

    In general, VOC's are not the health concern with spray foams; it's the isocyanate content that represents the indoor air/health risk and isocyanates are present in all spray foams.

    I am not sure exactly what insulation characteristics you are including in foam-sealant option for larger cracks/spaces--can you elaborate on this one?


    1. zkaufman | | #2

      Thanks, Peter. I was unaware that isocyanates were different from VOC's. Does this mean that after a certain curing time, low-expansion spray foam should be safe for IAQ?

      I ask this more as a general question because it would be helpful to know how much to steer clear of spray foam, even for filling fenestration installations and duct/pipe penetrations that already exist in the envelope.

  2. Expert Member
    Dana Dorsett | | #3

    Low-expansion always-flexible latex foams (eg DEPtex Plus) are comparable to interior latex paints in terms of volatile organics after a couple of days. Most of the volatile organics are low-persistence and go away pretty fast.

    The 1-Docosanol is probably the highest persistence on the list, but isn't very toxic to humans- often used in cosmetic creams and anti-viral treatments for cold sores/herpes.

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