GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Reusing XPS Insulation – it stinks!

user-5631279 | Posted in General Questions on

In an attempt to be more green as well as save some money we purchased a good amount of used Agtek Foamular XPS 1.5″ insulation from a farmer who pulled it from a series of barns he was tearing down. This came in 4′ x 21′ sheets and was about 15 years old. It is in good physical shape and the plan was to use it under the slab as well as anywhere else we can. Here is the problem: it smells terrible. It was used to line the roof of chicken barns – no ground contact or anything else but it still smells like the inside of a huge chicken coop after several months on the lot. We were hoping the smell would dissipate a bit but it’s just not happening in any measurable way.

Have other people reusing insulation run into this? Is there something we can do to get rid of the smell without damaging the insulation? If it’s used only under the slab and with a good vapor barrier (SteggoWrap was our plan) will we be fine? If we can use it only under the slab, that would be fine by me but the smell is strong enough that I’m really starting to get nervous about putting it anywhere in the project.

Any suggestions or thoughts would be appreciated. Thanks!

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. davidmeiland | | #1

    I would get a big chunk of it, seal it in a plastic trash bag, and put it in your living room. If you notice the smell, proceed with caution, if not, use it as underslab insulation with an impeccably-detailed vapor barrier over (and perhaps under?) it.

  2. GBA Editor
    Martin Holladay | | #2

    This is an example of a low-frequency, high-consequence risk.

    I think that it's unlikely that you will be able to detect the odor if the rigid foam is used under the slab. However, in the event that the odor enters your house, the effect would be devastating. I would say that the risk isn't worth it.

  3. STEPHEN SHEEHY | | #3

    I'm with Martin. Once you place the slab over it, if it still smells you're really in trouble and the fix will cost a lot more than the insulation did.
    Most reclaimed insulation is from commercial roofs and smell isn't an issue.

  4. Dana1 | | #4

    Exposing it to sunlight for several weeks (both sides) may sufficiently break down whatever it is that stinks. Chicken crap is about 50% oxalic acid/ ammonium oxalate by weight- it may respond to an alkaline rinse too, if that's what stinks. Find an extra-stinky panel and experiment on it with dilute sodium hydroxide (in a well ventilated area). This may be easier to deal with than you think.

  5. charlie_sullivan | | #5

    OK, that makes it official. Dana is an expert on everything. If anyone ever tries to say to him, "you don't know crap," well, it turns out he knows more about crap than a chicken farmer.

    For an odor-proof barrier, aluminum foil or aluminized plastic film is better than plastic films. The barrier properties of a thin aluminized layer are used in potato chip bags, for example. Unfortunately, it might be hard to be confident that the aluminized layer would survive long term in a damp environment. The smelly compounds might break down before the aluminum does, in which case you'd be safe, but it's an expensive experiment. So it would be best to have the aluminum layer laminated between two plastic layers, rather than on the surface of one. Materials like that are made in large volume for food packaging, but I'm not sure where to go to buy it.

  6. GBA Editor
    Martin Holladay | | #6

    Sell the XPS on eBay or Craig's List: "Inexpensive rigid foam insulation. Good for barn."

  7. Expert Member
    Dana Dorsett | | #7

    Charlie: If your read Primo Levi's "The Periodic Table" you'll discover that snake crap has an even higher percentage of oxalic acid than chicken crap (assaying in at 90% or higher) making it a more valuable "ore" from which to extract oxalates when you're desperate.

    (OK, so I have a mind like a steel garbage can- I can't help it alright!?! :-) And yes, I got more than just that fragment of "fun facts to file away" out of the book. )

  8. Chaubenee | | #8

    Ok, don't be chicken- find a good use for it by winging it and putting it on the outside walls of your basement. The stuff(ing) that is stinking up the joint will be pounded down by soil organisms under the ground. Any of it that goes above beak level will be cleansed by the sun, wind and rain. Once it is well seasoned I bet it is fine. But if you are really scared (chicken s#+) of leaving any exposed, don't fly by the seat of your pants- try washing it with a mild bleach solution first. Don't beat your breast over it or get all Kentucky fried, because your wallet will take a battering if you let it go to waste. I hope we have egged you on to figuring it out.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |