First time builder here building a 13’x23′ shed roof cabin with my dad in central West Virginia. Three weeks ago I had 2″ of closed cell spray foam installed in the walls/floor and 3″ in the ceiling. Walls are 2×6 and floor joists 2×10.
I recently started spending more time inside with a heater running and notice a slight paint/chemical smell. If inside for 30-60 minutes I can feel it in my throat/lungs, like when you use a strong cleaner without good ventilation.
The installer came out and cannot detect any odor but wants to put 6 mil poly on the walls and ceiling.
A couple questions:
– Will the odor go away with time?
– Will plastic sheating block the odor?
– Will adding this plastic cause any problems with moisture getting trapped in the walls? I plan on adding a mini split but will not continually condition the space.
Thanks for any help!
Bill
Replies
Hi Bill,
First things first, you mentioned a heater running. Is this a gas heater? If so are you sure this isn't the smell, and that CO isn't a culprit here? Secondly, I wouldn't be surprised to be getting a smell from newly installed spray foam. Third, a vapor barrier should never be used to control smells. Vapor barriers control water vapor, and to quote Corbett Lunsford, "water vapor is like a teenager, if you try to stop it from doing what it wants to do it will make your life a living hell." Use it only in extremely cold climates with no air conditioning (generally speaking). Sufficient ventilation is what you need to get rid of the smell, both immediately to get rid of the freshly installed smell and continuously forever, which is as long as the foam will off-gas. Another thing that will help is when you install the drywall over the spray foam, as is required by fire code when spray foam is used in a habitable space.
Thanks! I have an electric heater running when I'm out there. But if weather cooperates I leave open as many widows as possible.
Eventually (in a month or two) I'll be installing tongue and groove pine walls and ceiling. Maybe this will help cover the odor?
Until then I'll keep ventilating.
Everyone should understand that the feedstock for poly foam is toxic. imperfect mixing will leave these toxins. if your installer has been spraying an imperfect mix, his ability to smell the feed chemicals is likely gone.
that being said, ventilation and time will reduce the problem. as will covering.
the only issue with a layer of poly is if/when you get a leak from the roof or walls. may delay your identifying the problem.
https://www.epa.gov/saferchoice/chemicals-and-production-spray-polyurethane-foam-why-it-matters
Bill,
What type of heater? Any combustion appliance will take any non smelling (in the cold) thing like paint, varnish etc and burn off what you didn’t smell before. An electric heater will do this less.
But, any chemical smell can’t be a good one. Makes you wonder what’s being done to you when you don’t smell it.....
Hey Calvin, this is an electric heater I'm using only when I'm working out there. All other times I'm ventilating as much as possible.
The smell is one thing but I do worry about long term health issues.
Best of luck in this.
I don't have direct experience but I know that lasting odor and respiratory irritation are possible signs of a bad mix.
A poly vapor barrier is neither a good idea or a way to fix this.
If it is a bad mix (and I'm not sure how you'd find out for sure that is is), it has to be removed, which is a difficult-to-impossible task.
The company owner came out looked at the foam and said the mix was good. This was just a visual inspection and no core samples taken. He wants to try the poly first and if that doesn't work then recomends a full removal.
He seems to think I'm just extra sensitive to the odor.
If I knew the smell would go away in a year or two I could put up with it. But I hate to finish the inside and then have to remove everything.
I'd say it's time to get a second opinion on the problem. Anyone else do spray foam in your area? The poly idea is just an attempt to bury the problem and buy time. Also, it's not your fault for being too sensitive – another attempt to evade responsibility. I doubt you'll get satisfaction from this outfit. If you talk to another foam installer you might get a better explanation and a better solution (and an installer with a better sense of smell). Ask if applying another inch of properly mixed stuff over the stinky stuff will contain the smell. More cost, but more insulation so not a total loss.
As I rethink, perhaps you could find a sealer of some type to spray over the surface of the foam. There are products for painting over smoke damaged interiors to kill the smoke odor, but I don't know how well that type would seal against chemical off gassing.
Thanks for the help.
Getting a second opinion around here may be difficult but worth pursuing.
I'll look into a spray sealant. If ventilation does not seem to help I'll try anything.
FWIW: I had several attics foamed with closed cell a couple of years ago. All odor was gone within 24 hours.