post-installation health risks from current generation spray foams?
I was considering the use of spray foam insulation underneath the roof deck on a Texas remodel project to create a sealed attic (effectively placing the attic inside the home’s building envelope) . This is becoming sufficiently popular that now major insulation vendors like John Manville have recently jumped into the market. As production scales, costs will drop, and it will undoubtedly become even more popular, especially with “green” builders or people looking for LEED credits.
However, as part my due-diligence, I ran across this link (which includes fairly recent posts from very credible sounding people like the the Co-Chair of the EPA SPF Workgroup) that raises some serious concerns about the post-installation health safety of current generation spray foams, even if water is used as the blowing agent:
http://www.greenbuildingadvisor.com/…oam-insulation
I can believe that in a laboratory setting, where the A and B components can be perfectly mixed in the right ratio, and fully reacted, the end product might well be reasonably safe after it cures. I presume it tests out that way. However, if that level of perfection isn’t achieved in the field, I interpret the above thread as saying there could potentially be serious health consequences for the homeowners, maybe from outgassing of the unreacted components or other reactive gases, when they return. At the present time there seems to be little or no scientific guidance as to when it’s actually safe to return, possibly because the answer might depend on a multitude of variables. In short, the scientific data is still being developed.
The anecdotes sound sincere, although that by itself doesn’t establish the risk probability. Plainly, not every installation is a Love Canal, even if some of the heartwrenching anecdotes prove accurate.
Meanwhile, what do you think would be the next best alternative in terms of safely retrofitting an equivalent insulated air barrier? For instance, I’m considering sprayed Spyder covered by Thermo Ply. It seems safe enough, although I’m not sure it will perform as well. I welcome any suggestions.
Replies
I have identical concerns
and have not embraced spray foam yet. Green Building Advisor is one of the best sources of info you can get, and I would pay attention to what you are reading there. This is one of those areas where there is no clear consensus. You can do a very good job with cellulose, and although it won't have quite the R value or air sealing of foam, it won't have the possible risks either (provided you understand exactly what's in the cellulose and choose the right product).
best brand(s)/type(s) of cellulose for this application?
David,
What would be your preferred brand(s)/type(s) of cellulose for this application?
Recognize, though, that nearly 100% of the people who get into car accidents have had french fries in the previous month.
Tens of thousands of parents have put their children at risk for deadly and debilitating diseases because someone drew a faulty causal relationship between vaccines and autism.
on the other hand
the toxicity of many commonly used consumer products, mostly plastics and chemical in nature, keeps becoming better and better understood.
Personally I don't think it's crazy to assume that there are potential health effects from spray foam, especially if it is not ideally mixed.
general rule of thumb, if you have to wear a hazmat suit to install it, it isn't fully benign.
given cellulose's cost advantage, relative greenness, and excellent air tightness I prefer it all around at this point. That or a really quality controlled foam like rigid, especially EPS.
maybe not all open cell spray foams are alike
For instance, in its May 27, 2010 press release, John Manville states "Unlike many other open-cell products on the market, JM ocSPF insulation is formulated with 100 percent reactive catalysts to minimize emissions during spraying, resulting in lower jobsite odor and improved safety for installers. "
It sounds promising. However, I'm not enough of a chemist to fully appreciate the differences between the open cell spray foam components produced by different manufacturers or the differences in the end products which they produce.
Which brand of open cell spray foam has the highest chance of being the least toxic post-installation? Or in reality are they really all about the same?
Spray Foam
I too am in the same boat as you, but I think I am going to go the spray foam route. I did a little research and have read some stuff about BASF foam being one of the most benign. I have also been reading different things about closed and open cell, with that I can gather, is that open cell will off gas less if any, because of the catalyst involved.
It is a great and hard to to be going green, simply because we have not had a lot of time to see how some of these products perform over time (10+ years say), but we do have many methods with proven products that help our efficiency.
Keep us posted on what you find out!
SIPs panels have been around 10+ years. How different is the foam sprayed on sight than that in these panels from the factory.
SIPs do have the panel (OSB?) acting as something of a barrier. Of course OSB has also had problems.
Good suggestion
Has SIP outgassing on hot roofs has been well studied?
I've read that XPS, EPS, poly-iso sheets have had outgassing problems. Is that still true, or have those problems been surmounted? If not, is a SIP, except around the edges, able to "contain" the inner foam's outgassing?
not sure if you caught it
If I remember correctly, one of the postings in the above greenbuildingadvisor link specifically noted a problem with a BASF spray foam installation. The author attributed the problem (a persistent dead fish smell) to the installer spraying the BASF ingredients on too thick in a single pass. If that's the case, then I suppose, technically speaking, it's not a BASF problem. However, how does one monitor and control for that to ensure it doesn't happen to you?
Here's BASF's caution regarding its Enertite open cell spray foam: "As with all SPF systems improper application techniques should be avoided. Examples of improper application techniques include, but are not limited to excessive thickness of SPF, off-ratio material and spraying into or under rising SPF. Potential results of improperly installed SPF include: dangerously high reaction temperatures that may result in fire and offensive odors that may or may not dissipate. Improperly installed SPF must be removed and replaced with properly installed materials. "
The instructions for BASF WalltiteECO state "Do not apply WALLTITEeco® in excess of 50 mm (two inches) per pass due to the product's exothermic effect. Allow passes to thoroughly cool before applying successive passes." So, the obvioius question is: how accurately can an installer achieve a 2 inch or less thickness when he's spraying it on? Is he truly allowing it to "thoroughly cool" before applying a success pass? Or, as common sense would say is more likely, is he laying it on thick and fast so that he can be done sooner? Should you even care? i.e. is it mostly a fire hazard during installation, or could it have health or "offensive odor" ramifications on a homes occupants post-installation?
slam-dunk?
In just dawned on me that I may have a slam-dunk alternative to spray foam because I also need to replace the roof shingles. If I put down a suitable air barrier membrane underneath the roof shingles (presently there's 15# felt), then would I get the same benefits as a spray foam installation without the risks if I instead used sprayed spider or sprayed cellulose? If so, what would be the best air barrier membrane to use? The remodel is in Austin, Texas.
In such a scenario, would sprayed Spider or Cellulose be as resistant to convective air currents as spray foam? Or would dense pack rather than sprayed spider or sprayed cellulose be significantly better at resisting convective air currents? I have measured the existing attic air temperature at 130F, so I'm sure the shingles will easily reach 130F to 150F degrees in the summertime.
If what you want
is an air barrier, then you might want to consider Huber's Zip Roof sheathing panels. They are taped together and apparently form a fairly tight skin.