1 Helpful?

Post-cure/long term off-gassing with Bayer’s Bayseal closed cell spray foam insulation (“SFI”)

I am considering having Bayer’s Bayseal closed cell spray foam insulation (“SFI”) installed in the attic and basement rim joist at my New Jersey home. I am interested in hearing thoughts on the recent concerns over off-gassing of the SFI that I have been reading about. My questions assume SFI installation gets done correctly (I have read about the improper installation problems causing odors). Anyway, the issue of concern/interest for me is long-term off-gassing AFTER a properly done SFI job. None of the information on off-gassing I have seen draws a bright line between (i) the risks of SFI off-gassing during installation/before the SFI materials cure VERSUS (ii) risks of off-gassing in the post-curing period – the long run, i.e., a few days after the SFI cures and the ensuing months and years when the home is occupied.

It makes perfect sense to me that during spraying of SFI and a few days after the cure, there will be odors and off-gassing. But it seems to me that a few days after the SFI cures, there should be a dramatic drop in off-gassing as the SFI becomes highly stable. If one were to graph off-gassing, it would seem to me there would be an asymptotic decline in off-gassing after a few days post-installation.

A webpage within this very website (i.e., gba.com) seems to confirm my belief as stated above when it says: “Polyurethane is in a lot of stuff, from foam mattresses to bowling balls. When it is fully reacted or "cured," it is stable and its chemistry is not a significant concern. However, some products, however, such as adhesives, coatings, and spray foam, react while being applied by builders or homeowners doing insulation retrofits, and continue to react for some hours afterwards, and may contain "uncured" isocyanates to which people may be exposed.”

Other sources seem to corroborate that post-cure, SFI should be highly stable/inert. With regard to SFI's main ingredient, polyurethane, Wikipedia states that "Fully reacted polyurethane polymer is chemically inert." and cites to "Health Hazards Associated with Polyurethane" from the "Journal of Occupational and Environmental Medicine (1966)". But, as cited, the article is from 1966; there has got to be more current info on off-gassing post-cure. Moreover, SFI is more than just polyurethane (SFI is also has halogenated flame retardants, etc.) so perhaps a clean bill of health on polyurethane does not equal a clean bill of health on SFI.

So, assuming a properly done SFI installation, I would like to hear comments on off-gassing and lingering chemical odors in the SFI POST-CURE PERIOD (weeks, months and years down the road). Of note, the SFI project I am contemplating on my 30 year old house which is presently insulated entirely with fiberglass is:

1. ATTIC - SFI (6”) on the floor of a vented, non-living space attic (vented via (i) vents (openings) on both gables; and (ii) a whole house fan (“HHF”) that vents through the attic and results in evacuation of attic air when the HHF is turned on (intermittent/when we feel like it); and

2. BASEMENT - SFI (2”) on the whole perimeter of the basement’s rim joist. Basement has no passive or automatic ventilation; one would have to open a window if one wanted fresh air.

3. Nothing else in the house to be changed (i.e., all other fiberglass presently in the walls to remain in the walls, etc.).

So is the concern with off-gassing (whether it be any of the ingredients in SFI or additives thereto (flame retardant additives (halogenated flame retardants in the B-side component that have been conclusively linked to birth defects and loss of fertility))), and other chemicals leaching a concern DURING install and the day or two thereafter, or are these concerns LONG-TERM, post-cure? I am already committed to leaving the home for a few days during and after installation so the question is to long term off-gassing. I thank everyone in advance for their insight and comments based on science and experience.

Asked by D S
Posted May 14, 2014 9:56 AM ET
Edited May 14, 2014 10:30 AM ET


9 Answers

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As far as I know, every case of lingering odors has involved installation errors. For more information on these problems, see Spray Foam Jobs With Lingering Odor Problems.

Builders routinely use spray-foam insulation to insulate rim joists, and the vast majority of homeowners are completely satisfied with these rim joist insulation jobs.

If you are at all worried about lingering odors, however, there is no reason to specify spray foam where its use is unnecessary. Most green builders would advise you that it makes more sense to use cellulose insulation rather than spray foam insulation to insulate an attic floor. You will get a higher R-value at a lower cost if you use cellulose rather than spray foam.

Of course, it's always a good idea to perform air-sealing work before installing cellulose on an attic floor. For more information on this topic, see Air Sealing an Attic.

Answered by Martin Holladay, GBA Advisor
Posted May 14, 2014 10:09 AM ET


Dear Martin,
Would you also suggest using cellulose insulation under the floor? Or maybe mineral wool?
Thanks a lot!

Answered by Ohad Coen
Posted May 15, 2014 2:04 PM ET
Edited May 15, 2014 2:04 PM ET.


I notice that you have already started a different thread with insulation questions:

It can be confusing for one person to scatter questions in several threads.

If your house is on piers, you can find guidance on insulating the floor assembly here:
How to Insulate a Cold Floor.

If your house is over a basement or crawl space, I recommend that you insulate the basement walls or the crawl space walls, not the floor assembly.

If you need to install insulation because your joist bays include hydronic tubing for radiant-floor heat, you can use a wide variety of insulation products. Check out these three previous threads:

Heat Transfer Plates for Radiant heat under floor joists

Reflective barrier and insulation for radiant heat

What is the best method to insulate beneath PEX pipes installed under floor joists for radiant heat?

Answered by Martin Holladay, GBA Advisor
Posted May 15, 2014 2:31 PM ET


FYI: EPA considering action on certain chemicals associated with spray foam insulation, such as MDI & related polyisocyanurates


Answered by Terry Sopher Sr
Posted May 15, 2014 4:42 PM ET


This is the original questioner, DS, responding to Terry Sopher, Sr. who posted Answer #4. Terry, you seem to have missed the point of my question. The issue is SFI pre-cure versus post-cure dangers from off gassing. Certainly there are SFI pre-cure (during installation) dangers, but I could not find evidence of SFI post-cure dangers. SFI post-cure (long term) dangers, if any, is my issue. The EPA webpage you linked to says nothing about post-cure, but only discusses risk pre-cure. The EPA webpage says, "but EPA is concerned about potential health effects that may result from exposures to the consumer or self-employed worker while using products containing UNCURED (unreacted) MDI and its related polyisocyanates (e.g., spray-applied foam sealants, adhesives, and coatings) or incidental exposures to the general population while such products are used in or around buildings including homes or schools." (emphasis mine). The EPA is speaking of pre-cure (during installation) times, not post-cure, post-install. Regardless, thank you for your input.

Answered by D S
Posted May 21, 2014 4:30 PM ET


FWIW: Closed cell BaySeal is blown with HFC245fa, which has a global warming potential (GWP) of about 1000x CO2, whereas the open cell version (like most open cell) is blown with water:


The 2" shot on the band joists is not going to be a crime against the planet, but 6" on the attic floor probably is- it will probably never recoup the GWP impact of the blowing agent in the reduced energy use over the life of the building when going with that much foam.

It doesn't take anything like 6" of foam to air-seal an attic floor, and there are much cheaper lower impact methods of getting higher R values there. Some amount of spray foam for air-sealing may make sense there, but unless it's a cracked/crazed plaster & lath ceiling below, it won't take a full coverage to air seal it. (Even a 1" flash shot of closed cell would be good enough if it's too tough to air seal otherwise.)

Answered by Dana Dorsett
Posted May 22, 2014 3:11 PM ET


This is DS, the original poster of the original 5-14-14 question, updating the original question with a request for input with regard to the following. This website: http://sprayfoamdangers.com/tag/epa/ which seems to be the anti-SFI "blog" of a concerned mom, asserts, "Spray foam also off-gases a toxic soup of other known carcinogens, endocrine disruptors, ect ect. [ sic]" I am not overly concerned by statements from someone who does not even know that the correct abbreviation for et cetera is "etc.", but is there any evidence for concerned mom's allegation in the case of properly-installed closed cell SFI?

Answered by D S
Posted Oct 9, 2014 3:07 PM ET


The rate of off gassing and your ventilation rates are what determines the your exposure/concentration.

Even geniuses make typos- wouldn't use that as a measure of credibility.

Download the MSDS pages for the product in question, and do some online research on the toxicity or other bioactivity of the potential offgassing, and at what concentrations. There are nasty materials in all sorts of things we use daily, but the dose & response doesn't necessarily rise to clinical illness. The dyes and binders of newsprint ink can be unhealthy, but not easily absorbed when dry. Should we be worried about the offgassing in cellulose insulation too? (Some people are, but it's mostly about some of the fire retardents used.) SFAIK there haven't been clinical cases where long term exposure to outgassing polyurethane insulation at the extremely low doses you would find in a home where it was A. properly installed and B . the house is properly ventilated. But that's not to say there is zero tail-end risk associated with SPF.

There is evidence of occupational exposures to some of those chemicals causing health issues. The foam installers and chemical manufacturing workers may carry some risk.

If there is a general health issue with houses with polyurethane insulation the problem is nowhere near the order of magnitude of experienced with urea formaldehyde foams offgassing back in the 1970s. Some of those houses had to be condemned, but many are still standing, with the foam still there (though pretty much completely outgassed, decades later.)

Answered by Dana Dorsett
Posted Oct 9, 2014 5:51 PM ET


In my opinion, I have an impression "D S" is not a concerned individual, rather a troll for industry hoping to stir the bee hive.

D S if you were a concerned citizen, builder or architect you would read what the concerned Mom has on her blog as she is personally living the life of a spray foam victim. If you take pleasure in insulting the author for her own personal experiences your not seeking truth. The concerned Mom has one of the most truthful and informative web pages out there about SPFI and the people who have been personally affected.

If I'm wrong about you and your seriously considering any SPFI product, your seeking answers in the wrong forum. You should be asking these questions of the chemical provider directly and from your selected installer. Almost all SPFI chemicals have hidden proprietary ingredients of which they will never disclose to you or I. With that said you ned to draw the line as to what you consider safe and what your willing to risk.

Here's your warning from the EPA......

and a warning from CPSC on properly installed SPFI's amines....(the unknown)

Answered by Richard Beyer
Posted Oct 9, 2014 10:56 PM ET

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