Sleep in house same day unfinished walk-up attic is sealed with open cell spray foam?
I’m thinking of sealing an unfinished walk-up attic with open cell spray foam (R-38, climate zone 4a). The attic has one window in each gable and I was planning to leave the windows open and put some fans up there to circulate air for at least a day or two after the project is complete. Maybe even attach a 20×20 activated charcoal air filter to a box fan and run it for a few days.
Bedrooms are on the floor beneath the unfinished attic. Currently, the ceiling between the bedrooms and the attic is insulated to R-38 with fiberglass batts, and tongue & groove OSB floors the unfinished attic. We are not planning to remove the fiberglass or the OSB.
I’m trying to get a sense for how strong the smell from the attic spray foam will be on the bedroom level of my house (assuming, of course, that the foam will be installed correctly). Are we talking a smell about as strong as the smell of fresh paint? Stronger? Less strong?
Again, assuming a correct installation, would most people in my situation sleep in the house the same day that the foam is installed? Or would they plan to be away for a few days?
I’m hoping that because my attic has windows in it and I will be able to ventilate it during and after the foam installation, that the smell would not be too strong on the bedroom level and we would be able to sleep in the house the same day that the foam is installed with no issues.
Is that realistic or am I kidding myself?
Many thanks to anybody who can offer any insight.
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Replies
I think even with open cell spray foam insulation, you should follow the EPA recommendations for safe re-entry: https://www.epa.gov/saferchoice/vacate-and-safe-re-entry-time-spray-polyurethane-foam-application#determining.
I do think that depressurizing the space to be insulated is a good idea; I used it consistently to good effect in my own 12-year long room-by-room deep energy retrofit. And when we did open cell spray foam in our basement, done while we were gone, that acrid taste in the back of our throats when in the basement persisted until I HEPA-vacced every surface in the basement. We THINK the problem was that when they shaved the walls down to the outside face of the basement exterior wall framing, it generated very tiny specs of spray foam that clung to surfaces in the basement. AFTER the HEPA-vaccing, no problems.
Peter
If you have to wonder........
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The problem isn’t that it smells bad. The problem is that your body can build up a sensitivity to one of the compounds in the spray foam (isocyanates if I remember correctly) and it acts as an irritant. Once the spray foam has fully cured, the chemical mix is effectively locked in the foam and there is nothing to worry about.
I would strongly recommend staying out of the house for at least maybe two days immediately following the application of a large quantity of spray foam if you apply the foam in any of the living spaces. While you’re out, leave some windows cracked open so that the house can air out. I like to recommend doing the spray foam on a Friday and then leaving town to visit relatives over the weekend. Usually when you get back Monday, most of the smell will be gone as will any lingering irritants in the air. I make the same recommendations at work when putting down epoxy floors and I do it for the safety of my crews.
If you have to live in the house, try to seal off the foamed area as best you can, and leave that area open to the outdoors so that it can ventilate. Make sure to seal off any forced air vents in the affected area if you have a forced air furnace.
It sounds like your attic is pretty well isolated from the living spaces so you can probably seal it off pretty well. Close the hatch, leave the windows open, stay out of the attic for a few days. Try to keep the attic sealed off from the living spaces during the application too. You should be ok. I’m not sure the fans are really necessary, but they won’t hurt. I’d probably put one big box fan in one of the windows so that it forces air to flow through the entire attic, in one window and out the other.
Bill
Thanks for the replies.
To be clear, the unfinished attic is not part of the living space, and it is isolated from the living space. We do have some recessed can lights in the ceiling between the living space and the unfinished attic, but the doorway to the stairs that lead to the attic is an exterior door that is well sealed.
In any event, sounds like best practice would probably be to try to be out of the house for a day or two, even in this situation where the attic is fairly isolated from the living space and has windows for ventilation.
+1 on putting a box fan pointing outward in one of the open gable windows (to create a negative attic pressure). With this, there shouldn't be anything making it into the living spaces.
If this were a case of sleeping in a sprayed room, I'd be conservative (say 72 hours with open windows).
I see no mention of where you intend to use the open cell foam in your attic. If you intend on it being applied to the roof deck, I suggest you read further. Several contributors on this site, including Martin, have posted much on this exact topic/application.
Be sure that whomever is doing the spraying addresses the depth of spray properly. I do not think R-38 can be done in one pass with open or closed foam. If not sprayed in properly timed stages, you will be risking failure of proper curing, bubbles and more. Search the GBA site for more on foam installation and be aware of how they can go bad if done wrong. Even a CEO of a big spray foam company had his house burned down when the foam applicators messed up.
I often wonder about this. Back in 2017 I used a closed cell spray foam to do two exterior walls in a bedroom and a couple of years later I did two other walls in another bedroom. While spraying I was the only one in the house, I kept the door to those rooms closed while spraying, I had an exhaust fan in a window well sealed around the edges with plastic sheeting and tape to prevent recirculation blowing air out of the room and another window on the other side of the room cracked as an air intake while maintaining negative pressure. After spraying I kept the fan running for at least 4 hours or more and the door closed for days except for quick entry snd exit. Apparently my son has sports induced or exercise induced asthma but no other issues but I find myself second-guessing could have been the foam? I'm the one who sprayed it although I wore a mask with filters but neither my wife or I have any issues.
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I'm not a pro or an expert and I have no idea what the answer to your question is, but my unprofessional instinct opinion is that if you didn't have smell/VOC problems after installation, I doubt that's the source of your kid's asthma.
As a side note, although we never had any problems with our installation that I know of, I would not do spray foam again, personally, unless it was truly the only option. Even being pretty confident that my install was fine, every smell -- every sickness -- every cough, headache, etc -- I would question whether the spray foam was contributing.
Paranoia? Absolutely. But I could have just chosen a different form of insulation and avoided it all. Which is what I would do in the future, personally. Especially with kids in the house.
So you are saying that you use it as well? Yeah I know what you mean I don't think it's the cause but you do always wonder. I had a fan in the window the whole time and for hours after. No smell etc. According to the company it has no vocs and is a fast cure mix. But I feel the same way if I had to do it all over again which I obviously can't go back in time I would just put in fiberglass. I didn't do the whole house I did two exterior walls in the one bedroom and two in another. Other than that I did a storage room that wasn't part of the living space.
I doubt the spray foam was the cause of your son's asthma. Spray foam, once properly cured, is a very stable material. The only real issue is if it doesn't cure properly, which can and does happen, but is relatively rare, despite the perception some seem to have. I do think spray foam is best used as niche product, where it's really the only option, and not as a sort of "upgrade" to more conventional insulating materials in places like walls though.
Keep in mind that there are people who are sensitive to binders used in batts too, so it's not as if spray foam is somehow the only thing out there that can cause anyone problems. I'd be much more concerned with mold though than spray foam, as mold spores can cause problems for many people (myself included!). Mold can grow regarless of the type of insulating material used if the insulating material isn't used correctly. If you have ongoing health issues that seem to be related to you home in some way, my first thoughts would be to check for mold in the usual places, and to check if you have any open drain traps or other ways for sewer gasses to enter your home. Those two things seem to be the most common causes of "unhealthy in the home" issues that I've seen.
Bill
Thanks for your reply. Yes I only had one small area where it didn't cure probably where their mix wasn't good I tried washing it with Dawn detergent but ended up just cutting it out and throwing it in the trash. FWIW he only has a shortness of breath issue a bit when he is doing something like full court basketball the rest of the time he's fine. The brand I used, tigerfoam e84 claims it is a fast cure product with this description "All of our insulations are manufactured using the best quality blowing agents and fire-retardant chemicals available today and DO NOT contain CFCs, VOCs, Formaldehyde or PENTA-BDEs and avoids their associated environmental and health effects."
Of course it does use isocyanates in the spraying process though. However I was under the impression that if exposure to isocyanates was the cause of an issue what would happen is you developed a sensitivity to them and the next time you are exposed you could have a problem. That's not what happens with him he just gets it when running a lot. Also since I installed it I was exposed more even though I wore a face shield, mask with filters and a tyvek suit. My wife was around it as much as he would have been which couldn't have been much as I kept the room sealed off pretty well for a few days after and she has no issues nor do I.
Thanks
Isocyanates are part of the mix for all spray polyurethane foams, so there's no avoiding those. People can build up a sensitivity to those over time, but you the "over time" part is different for each person, so some people might be sensitized after one exposure, others might never notice anything. I know the guy that I usually use for spray foam contracts has been sensitized, and he uses a setup like a diving rig that blows in air from outdoors to his suit while he's working. I don't notice anything myself, but I'm generally not at the sites while the installation is going on, so I've had much less exposure than the installers.
I always recommend staying out the structure during spraying as much as possible, and giving the structure a few days to "air out" before you reoccupy it. This is a simple safety precaution to take, and reduces your exposure to the structure during the time when the concentrations of the stuff that can be a problem for you is highest. After curing, there should be no further issues.
The problem you had with a bad cure is the one big potential downside with spray foam, and there is no way to "clean" it -- you have to physically remove the problem patch. When using the two-part spray foam kits (and not a commerical rig), it's usually recommended to start spraying into a trash bag and not onto the structure, since then the first blast of stuff goes in a bag that you can get rid of. The very first time you spray, the two spray foam components don't always arrive at the same time (hoses fill at different rates, etc.), so it's possible to get some uncured "goo" this way. If the goo goes in the trash bag, no big deal, but if it goes on your wall, you'll have to remove it and respray that section.
Bill
Thanks, yes I did start out spraying in a trash bag and on a board outside. I had the issue when one can ran out before the other. I did end up removing it and respraying the area.
Yeah as I understand it if you become sensitized to it you have a bad reaction when exposed to it. That's not what's happening he just gets short of breath when running a lot. And he's not obese or out of shape either