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Community and Q&A

Fireproof Paint Smell with Sealed Spray Foam Roof

BluePixel | Posted in General Questions on

Hello,  I apologize if this issue has been already answered but couldn’t find anything on my end when searching.

I am located in the northeast (climate 5A) and during a renovation had my roof spray foamed with 2-3 inches of closed cell and 4-6 inches of open cell to make the attic “conditioned space”.  The HVAC unit is also located in the attic.  Since I have access to the attic I was told the code required the entire surface of the foam be coated in fireproof paint (DC-315 was used which is also a water based paint that is supposed to be low VOCs).  The spray foam and paint was applied at the end of March along a roof which is ~50 feet long.

When going into the attic I have smelled a paint like smell and assumed it would dissipate prior to moving back in.  Fast forward to now and the smell is still present when in the attic.  I have also smelled the paint smell when working on some audio video boxes towards the ceiling in the living space from air being pulled into living space.  I wanted to understand the level of VOCs so put an Eve Room air quality sensor in the attic and it initially reported ~270 PPB.

I installed a couple fans with vents out the attic hatch through a window in the living space.  This has been running for a week or so and the VOC count has dropped to 20-60 (a little higher when attic warms up slightly but then drops with temp so may be the quality of the sensor).  With the venting and low VOCs I still smell the paint smell in the attic.  I contacted both the foam / paint installer and the paint manufacturer who said the paint may not have been fully cured from lack of ventilation and to continue to vent for some more time.  The paint manufacturer said that the attic should have a vent since any stale air will start to smell with any paint.

Now with the questions… 🙂

– Is it normal to have a lingering paint smell after an installation like mine?
– Can this smell be dangerous and if it is not a VOC what can it be?  Are there any companies that can tell me how “bad” the air is?
– With a sealed attic should I be installing a vent?  This goes against what I thought a sealed attic does so not sure if the paint manufacturer understood my setup.

Thanks for any help or suggested next steps!  Happy 4th all!

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  1. walta100 | | #1

    A have to ask why you seem to suspect the smell is from the paint and not the foam.

    Spray foam is much more complex chemistry and the installers are under pressure to get the foam installed even when the temp and humidity fall outside of the manufactures recommendations.

    We see lots complaints about smelly foam mostly without any paint. We almost never hear how the stories end. My guess is generally with a legal settlement and a non disclosure clause.


  2. Expert Member
    BILL WICHERS | | #2

    You need to ventilate the attic temporarily to allow the smell to dissipate. Ideally you want a can one side of the attic blowing out, and a vent on the opposite end allowing air to come in. It’s important the fan blow out to depressurize the attic, which will ensure none of the smell gets forced into the living spaces of your home.

    I’d leave this system in place for a few weeks to be safe, then shut it off, wait a few days, and go see if you smell an improvement.

    I disagree with Walter regarding his risky spray foam is. You typically only hear about the problems, you don’t have people posting as often about positive experiences. There are LOTS of spray foam installs that go just fine, so spray foam isn’t the imminent disaster that some people seem to think.


    1. BluePixel | | #5

      Bill, Thanks for your response. I have been venting sporadically but will do as you suggest and see how it goes. I just setup two exhaust fans toward each end with hoses going out a window in the living space. For inlet air I put a box fan in the hatch opening to push fresh air in.

      Walter, At this point I am assuming the paint as I had foam sprayed in multiple parts of the house and have no smells outside of the attic. Plus it has a latex paint type smell.

      Will follow up with what happens after the venting.

      Thanks for all the responses.

      1. Expert Member
        BILL WICHERS | | #6

        Ideally you want more air flow going out than going into the space being ventilated. That will keep the problem space under a slight negative pressure to keep the smell from getting into your living space.

        With more air going in than going out, you pressurized the space, which means any air leaks allow the smell to go into places you don’t want it to.


  3. walta100 | | #3

    I never said the smell was from the foam!

    I agree most foam install the work goes as planned and when it does not people complain loudly as they should.

    Can we agree there are more possibilities of mistakes to be made in applying different types of foam than applying a coat of paint?


    1. Expert Member
      BILL WICHERS | | #4

      >” Can we agree there are more possibilities of mistakes to be made in applying different types of foam than applying a coat of paint?”

      Absolutely! Spray foam application is much more involved than painting. That’s why it’s so important to have an experienced spray foam installer. I think most of the problems are due to inexperienced installers.


  4. ma524 | | #7

    Did you ever resolve this issue? I have the same problem and the couple threads I have found on the topic never end in resolution. Would appreciate any help from your experience.

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