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Community and Q&A

Roxul stone wool batts

jackofalltrades777 | Posted in Green Products and Materials on

Looking to use Roxul stone wool batts in the ceiling area. Anyone here know about any air quality testing with these batts? Even though it will be behind 1/2″ drywall, are there any issues with the fine particles from the batts or any off-gassing?

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  1. GBA Editor
    Martin Holladay | | #1

    Personally, I wouldn't worry, since the insulation will be behind the drywall. It's always a good idea to pay attention to air sealing when installing drywall.

    Some builders and homeowners are concerned about the formaldehyde content of Roxul insulation. Whether this is a matter of concern depends on your level of sensitivity to the idea that there might be formaldehyde behind your drywall. Here are some recent comments and reports on the issue from GBA:

    Shannon Cowan and Patrick Walshe: "Recently, some green builders have expressed concerns over reports that Roxul mineral wool products may contain formaldehyde. When we sent an inquiry to Roxul about the formaldehyde question, a company spokesperson responded, "Although a formaldehyde-based organic binder is used during manufacturing, a high-temperature curing phase virtually eliminates volatile compounds. The result is no measurable free-form formaldehyde in the final product and no volatile organic compounds that can off-gas.""

    Mike Eliason: "Per Roxul's MSDS, panels do contain cured urea extended phenolic formaldehyde binder (1-6%)."

    Gregory La Vardera: "I've asked Roxul directly about the formaldehyde content. I was told it was very small and disperses before the product reaches consumers. There would be no significant off-gassing of the binder in place. I'd like to see info otherwise to be sure."

    Keith H.: "I can smell a distinct catty odor [when I open a bundle of Roxul insulation]. ... Ask my helper to smell it. Helper describes it as 'doggy'. To me, it seems to be coming from the batt. I could only detect it within a few feet, such as by holding the batt or sniffing it directly. ... Now I'm concerned. I got this stuff because it was GreenGuard rated and the formaldehyde binder is supposed to be cooked off during production. I'm not sure what I smelled but I doubt I want to breathe it. I see elsewhere on this site that people suggest a catty odor being from ammonium sulfate potentially."

    Alex Wilson: "Manufacturers [of mineral wool insulation] use a phenol formaldehyde or a urea-extended phenol formaldehyde binder. Formaldehyde is a known human carcinogen, and if a lot of it escapes into the indoor air, that would clearly be a health concern. Fortunately, the processing drives off nearly all of the free formaldehyde in the material, so formaldehyde emissions from mineral wool have extremely low formaldehyde levels — in some cases as low as background formaldehyde levels. Nonetheless, there is a perception problem with formaldehyde binders — if not a real problem — and manufacturers are working on alternatives — as has occurred with fiberglass insulation."

  2. Kamboji | | #2

    We recently installed batts of Roxul and then drywall. The roxul has a sweet-ish odor, but cannot be detected once drywalled in (and we're pretty sensitive to this kind of thing).

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