Spray Foam and Indoor Air Quality
We have a wine room underneath the front stoop of our 2-year-old house that has mold problems, likely from wetness coming through the poured concrete walls.
Our builder wants to seal the walls and ceiling w/ CC spray foam (Dupont Froth-Pack). I’m not a fan of it from an environmental (GW or IAQ) standpoint but I’ve already lost that battle and we have it in our exterior walls and ceiling.
How risky is this from an IAQ standpoint? We are living in the house and it’s furnished. How much risk is there of VOCs from applying the foam, or off-gassing while curing, getting embedded in fabrics and other materials? Other IAQ/Health risks?
It seems to me that applying this inside an occupied home is extremely risky but perhaps not.
Thanks,
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It is imperative that you are not in the house while it's being insulated and during fan-assisted ventilation for 24-72 hours after installation. The biggest risk is from airborne isocyanates emitted while spraying and shortly afterwards. You or the insulation company should cover anything you don't want to get a fine mist of foam droplets.
Assuming the foam cures properly, there should be little to no health risk, though some people (including me) seem to be very sensitive to the protein-like odor that lingers. In rare cases, the foam doesn't cure properly and needs to be remediated.
Thanks Michael.
Any thoughts on if this seems a reasonable solution? https://www.greenbuildingadvisor.com/question/mold-in-poured-concrete-lower-level-of-new-house
Those frothpaks have recently been reformulated and now use a more environmentally friendly blowing agent. That addresses your GW concerns.
The IAQ issue is related to the polymers used though, so that’s still something to be concerned with. It is possible to seal off the area where you’ll be spraying, and run it under negative pressure, then be in the home during installation, but I wouldn’t recommend that. I usually recommend to have spray foam work done on a Friday, then take the weekend to travel while leaving some windows cracked for ventilation. When you come back Monday things should be mostly aired out. You can acquire a sensitivity to the isocyanate compounds used in spray foam if you’re exposed to it for a long enough amount of time, so it’s best to not be present during application or the next few days after.
Note that you might not need spray foam here. You could seal the concrete with something like drylok, then insulate with rigid foam. Depending on the severity of the moisture issue, you might want to avoid polyiso here and use EPS instead. If you use rigid foam, you won’t have any of the issues you’d have using spray foam, and you could stay in your home during and immediately after installation of the insulation.
Bill
If you go the spray foam route, read this recent article: Spray Foam’s Impact on Indoor Air Quality. Among the takeaways: 1. Manufacturers recommend that ventilation be provided before and after the installation. Most installers will bring a single fan to the job, not nearly enough to ventilate adequately. 2. The only way to know whether there’s a toxicity problem in the home is with lab testing and an evaluation of the results by someone with medical credentials if the data isn’t overwhelming. But to get useful results, the lab has to know exactly what formulation was used so they know what compounds to test for. Labs in some states may not be allowed to test for all of the compounds used in spray foam.
Note that fans need to be setup properly. I've heard of crews just putting a fan in the room they're working in, which doesn't really accomplish anything. Idealy you need crossflow type ventilation, and I usually recommend that be done with a fan sucking air out at one end of the jobsite, and an open window (or other way for fresh air to get in) at the opposite end. With this arrangement, the fan continously pulls new air through the entire jobsite, helping to exhaust any fumes. Setting the fan to blow out, instead of in, keeps the jobsite under slight negative pressure, which helps to ensure air leaks IN to the jobsite, not out, which also helps to keep fumes contained.
When I said "keep the site under negative pressure", I meant doing what the asbestos abatement crews do -- use a POWERFUL blower to pull air out continuously. These aren't what people usually think of as "fans" though :-)
It's certainly safest to just not be present at install time though, when cocentrations of fumes are highest. After installation is complete, a few days of ventilation is usually enough to get things under control, although I agree testing isn't a bad idea if you have someone in your family who is especially sensitive.
Bill
You should read this recent article and comments, if you have not already read it:
https://www.greenbuildingadvisor.com/article/tracking-down-problems-with-spray-polyurethane-foam
You have "mold problems likely from wetness coming through the poured concrete walls"
Spray foaming the inside is not going to solve this problem; I'd be concerned it will just add to it.
First - you need to stop the moisture from coming in.
1. Is the exterior side of the wall waterproofed?
2. Is there a foundation drain around the foundation, and is it functioning (ie not clogged)
If those two things are proper, moisture should not be migrating through the poured concrete wall. If those two things are not properly address, spray foam is just a big bit of lipstick on the pig...Yes it may be expensive and a pain to address those issues (may involve digging up front yard) but that is the way to fix it.
Second, have you confirmed the moisture is not migrating into the wine room from above - you said this in under the front stoop, so presumably under an unconditioned area that possibly gets rainfall.
Third, have you put a thermostat and humidity sensor in the room and in the adjacent rooms? Do you condition this room to keep it colder than the other adjacent rooms? If not, what is its relative humidity compared to the adjacent rooms?
Fourth, have you taken moisture sensor readings of the walls and floors to try to identify the exact source of the moisture?
I would require the builder to focus on solving the issue, not masking it. If you keep that room considerably colder than the adjacent areas, it might just be due to the variation in dew point at different temperatures, and the solution might be a dehumidifier. But if moisture is migrating through the walls, the solution is to stop the moisture migration.
My experience is Froth Pack chemicals will not kick off unless the concrete is warm but if the foam gets too warm it will shrink/crack.
We used to spray (not pour) foam it outside of tanks for flotation. We only did a few times until we figured out the foam would saturate with water. I'm surprised contractors are (trying to) using it for waterproofing.
This is a band aid for an issues that should have been addressed on the outside.
Pour in place foam is not the same as spray foam, and there are multiple kinds of pour foam too! You are right that too cold surfaces are a problem. Ideally you want the surfaces up around room temperature or so, but spray foam is supposed to be OK down to around 50F or so. When you really have problems is if you try to apply spray foam in the winter to a surface that is near freezing. That's something to avoid.
Bill
Thanks all. I've been following from bed. Back on my feet today. In response to some questions above:
There are a few photos here: https://www.greenbuildingadvisor.com/question/mold-in-poured-concrete-lower-level-of-new-house. I'm going to pull some more together and post on a blog.
There is currently no ventilation in this room (it's a wine room so don't want the Temp/RH changes that come with that) beyond what happens opening the door to enter. Without the unexpected excess moisture entering this shouldn't be a problem?
Joe Lstiburek found that about 1 change every 2-3 days is about right.
We've an IQAir AVP in the room measuring Temp, RH, CO2 and PM2.5. Image is from 2 days ago. Temp and RH stay fairly constant which is currently 73°f & 51%. During winter the temp is about 50°f & 50% RH. These are not ideal (it's all red wine) but are actually quite good. Stability (temp & RH), darkness and no air movement is more important than perfect temp/rh and from that standpoint we've achieved what we want (other than the mold).
My understanding of mold is that it would take a RH of 70% @ 70°f for over 400 days (or 71% @ 65°f for 120 days, or …) to induce mold growth from humidity. We've never been close to any of the conditions required for mold from humidity thus my thought that the mold is from wet walls.
It seems that DryLok would be a much less toxic alternative? Would DryLok seal the walls & ceiling just as well as CC foam?
I agree that fixing the problem on the exterior is what should be done. Unfortunately I think that might require legal action given the response from our builder (willing to do the interior fix, but will not do the exterior fix) and I'd rather not make our relationship with our builder adversarial unless absolutely necessary. If we can find a mutually agreeable solution, even though not ideal, I'd prefer that.