Spray Foam Odor Remediation
We had our attic in the Chicago suburbs done in 2019 to create 2 spaces:
1. A finished space with closed cell foam applied directly to the roof deck, finished with drywall, carpeting, and an HVAC supply
2. An unfinished space with open cell foam applied directly to the roof deck that contains our HVAC that services the 2nd floor.
In the spring of 2020 we noticed a “chemical” smell as it began to get hot and humid (seems stronger in the unfinished open cell section), and I can see from the forums here that we are not alone with this issue. We’ve had the installer out a few times to test the foam, and they are convinced it is fine and that the smell is coming from something else in the attic (I don’t quite buy this, as the attic is conditioned and so the materials up there – such as the insulation that remains underneath the attic floor – never gets hot). Absent a better explanation, I assume that a chemical reaction is taking place in the foam as it gets hot and sucks up moisture from the living space.
I’ve been dealing with this to date by using a duct fan to exhaust the air from the back of the unfinished section out of a window, the theory being that I’ll pull air in from the living space, through the smelly section, and out of the house, ideally before it gets sucked up by the HVAC return and dispersed to my 2nd floor. I’ve also now tried placing a dehumidifier in the attic to try and keep the moisture level lower, and will see if I notice an improvement in the spring after doing this all winter.
The intensity of the smell seems to be growing weaker, but I’m also not sure if I’m just getting better at ventilation, and this is obviously difficult to quantify.
I’m hoping for a more permanent solution, and from what I’ve read, removing the open cell foam would be possible, but it will be messy and might not solve the problem if the smell has leached into the wood of the roof deck.
I’m likely due for a new roof within the next few years, and I was wondering about adding some insulation from above, my theory being that if I can keep the foam from getting too hot, I can keep it from reacting and stop the smell without removing the existing foam.
Does anyone have any experience with this? I have no idea at this point how much it would add to the cost of my roof, but I’m definitely willing to spend a few bucks to never google “spray foam odor” ever again.
Any product recommendations? A friend brought this to my attention, https://www.gaf.com/en-us/products/thermacal-1. I’m hoping to avoid any mistakes like the one I made when I had spray foam installed on my roof deck. I’m also considering solar panels if I’m going to do all of this work, so I’ll want to make sure that whatever I choose leaves me with this option.
Thanks for your time!
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