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Community and Q&A

Rigid Foam Smell

Monte_Main | Posted in General Questions on

I just purchased recycled 40 PSI EPS foam that came off a commercial roof a few months ago. A few hours after stacking it in my garage, I could smell the foam. It reminded me of a sort of adhesive smell.  There does not appear to be any adhesive on the foam.

It had set outside in the recyclers yard for 2 months before I picked it up.

I intend to encapsulate the crawlspace with this, but I’m afraid the smell will persist, even after covered with 1/4″ plywood (fire retarder). Is there something I can paint the foam with before putting down the plywood?  

Is this normal for EPS foam (or any rigid foam) to have a smell?

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  1. Expert Member
    BILL WICHERS | | #1

    I wouldn’t expect reclaimed foam to smell, unless you cut it with a hot wire cutter or maybe break off a chunk, since reclaimed foam is essentially “pre-aged” wherever it was installed previously. It’s possible the smell is coming from whatever they wrapped or taped the stacks of foam sheets with. I suggest you put spacers between the sheets in the stacks (1x2 furring strips would work here, or whatever you have handy that can provide vent space between sheets) so that all the sheets can air out for a while. Hopefully the smell will dissipate after a few days like this. Note that a fan blowing air through those air gaps will speed up the process.


  2. charlie_sullivan | | #2

    It's normal for new foam to have a smell but it should be long gone by the time it's taken off another job. It's possible that it took on that odor from something else in the roof assembly. More far fetched, it's possible that it has a surface layer that's been damaged by UV sitting outside are smelling decomposition products. I'm not sure what to suggest other than Bill's advice to let it sit with air circulation and see what happens.

  3. jamesboris | | #3

    For what it's worth -- any time I make a big stack of 4x8 sheets of polyiso in a workshop or warehouse, the smell is distinctive and obvious... but after I install it, it seems to vanish.

  4. nynick | | #4

    Try isolating one sheet from all the others and smelling it.

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