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Foam insulation — venting before covering?

celtec | Posted in General Questions on

in a previses question i asked about timing of batts installions
in flash and batt
respondes were very helpful
but still have concerns manf. web sites say wait 24 hours
depending on condition and amounts of foam
i hade read an artical in JLC a while back about problems with foam
were it was stated if you can smell it its still off gasing
most jobs where were going to install batts after foam contracter has finished
seem to have oders well past 2 or 3 days
as so ive read in manf. spec. that if existing attic is being sprayed
all existing insultion has to be removed as not to trap fumes
are these things a problem of foam or the installon????

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  1. GBA Editor
    Martin Holladay | | #1

    There are several issues here, all revolving around odor issues.

    The worst cases of "lingering odor" problems with spray foam installations have to do with installer error. These are off-ratio mixes. These problems are rare, but they are huge problems when they happen. If an installer makes this type of error, the odor doesn't go away, and everyone ends up talking to a lawyer.

    Ordinary odors due to properly installed spray foam are another matter. These odors generally dissipate in a few days. The problem with these odors is that humans have a range of sensitivity to odors. There are a few people who are extremely sensitive to odors, and this type of person probably shouldn't be specifying spray foam. Sensitive people can detect odors that I can't detect.

    I don't know what type of person you are. Maybe you are very sensitive to odors; if so, choose your insulation materials with that fact in mind.

    Maybe you are very, very worried about chemical off-gassing. If so, choose your insulation materials with that fact in mind.

    If you are just an ordinary guy who doesn't worry too much, and doesn't have an unusual nose, I wouldn't worry.

    That said, if you have some worries, there is nothing wrong with waiting 5 or 6 days after the spray foam is installed before completing your flash-and-batt job.

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