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Does Spray Foam Insulation Off-Gas Poisonous Fumes?

Open- or closed-cell spray foam insulation is a great way to get air sealing and insulation in a single step, but the health implications are fuzzy

Posted on Feb 17 2010 by Daniel Morrison

Spray-foam insulation has become a weapon of choice for many builders and homeowners trying to build tight, energy efficient houses. And with its long list of attributes, that's no wonder. It fills tiny cracks and fissures in walls and roofs to form an effective air seal. The high R-values of closed-cell foam pack a lot of punch in a small space, and closed-cell versions can block the movement of moisture into wall and roof cavities. Expensive as it may be, it's at the top of its class.

But does this miracle material have a darker side? Dan Fette's question about the potential hazards of spray foam launched an extended thread containing enough anecdotal information to give a few readers pause for thought and dissuaded others from using foam at all.

Polyurethane foam is a two-part compound mixed at the job site as it's sprayed from a high-pressure gun. Although some of its ingredients are nasty at the time of application, when it cures the foam becomes an inert material that should not off-gas any harmful chemicals. That, at least, is our common understanding and the word from manufacturers and installers.

Typical are these words of assurance from Foam-Tech:: "Urethanes are non-toxic and only require protection for our operators during installations, but the finished product is completely safe and has no formaldehydes."

Some dissent from the field

But that sunny expectation doesn't always pan out. An anonymous poster reported developing a serious chemical sensitivity while building an "uber-green" house, which included non-toxic wood finishes and closed-cell polyurethane foam.

"I became ill after moving into the house two years ago, and had to move out," Anonymous wrote. "Any exposure to the indoor air induces neurological symptoms...I never had these sorts of problems before that I know of."

Not far behind was Marlene, who said her 66-year-old brother had experienced a "very dire situation" after IcyneneOpen-cell, low-density spray foam insulation that can be used in wall, floor, and roof assemblies. It has an R-value of about 3.6 per inch and a vapor permeability of about 10 perms at 5 inches thick. (a brand of open-cell foam) was sprayed in his house. Marlene said her brother was told he would probably have to sell his half-completed home after investing his life savings in the project.

David Posada said a strong odor persisted two months after Demilec Sealection 500 foam was sprayed into a 95-year-old house in Oregon during a retrofit. Julia, who suffers from chemical sensitivities, says her building materials consultant "won't allow her clients to use spray foam insulation of any kind."

More study is needed

William Swietlik, who identified himself as a member of the Federal Interagency Spray Polyurethane Foam Worksgroup and co-chair of the EPA's workgroup on spray foam, said that both open- and closed-cell foams are made with diisocyanates, among other ingredients, a leading cause of workplace asthma and a "well-known sensitizing toxicant to humans." He added: "Once an individual becomes sensitized to diisocyanates there may be no safe exposure level."

Swietlik said this is why occupational health authorities recommend personal protective equipment for installers, and that any unprotected workers or occupants leave the building while the foam is being sprayed and not return until "all residual vapors are ventilated and all dust particles (from shaving the finished foam) are cleaned up to safe levels."

Just what is "safe?" That's not clear. Swietlik had this to say: "The exact timing of this is not known for each specific building application as this depends on the amount of vapors and particles generated to begin with, the amount and type of ventilation, the size and configuration of the building, the foam curing factors and the installation and clean up techniques of the workers."

More reserach is needed, he said, not only on the problems posed at the time the foam is applied, but also on "whether or not there remains off-gasing from the finished foam that was applied days or months earlier that could affect sensitive, or sensitized individuals who occupy the building."

Application is the wild card

If spray foam is designed chemically to morph into an inert material after it cures, could the problem be the installation itself, an improper balance of Part A and Part B? This, at least, was the suggestion of David Posada, who raised the question after following two threads at

There was no unanimity on this question, but Posada added this: "Much of the published information regarding low density spray foams addresses the low- or non- toxicity of 'properly cured' or 'properly installed' foams; little seems to be said about what constitutes a improper curing or installation, what chemicals can be released, what hazards (if any) may be present, and what remedies are appropriate."

A bad mix may be only one potential problem. A poster named B. Kolodziej recounted his experience with BASF Comfort Foam during a remodel of his California home. The installer exceeded the 2-inch per-pass maximum set by the manufacturer, which causes the foam to overheat as it cures. The result is a discolored insulation layer of insufficient density that just happens to smell like rotten fish. Although Kolodziej believes the product will work as advertised if installed correctly, he now regrets he used the stuff in the first place. Further, because the foam sticks tenaciously to whatever it's applied to, removing it will be a nightmare.

Tracy Nelson summed up the dilemma this way: "Here is the simple truth of spray foam in an existing building: Mixing this material in the field can be inconsistent and as mentioned many times above, completely depends on the skill level of the installer (don't confuse the actual person who shows up at the property with the company who sells you the product and promotes themselves as experts)."

An anonymous poster said a variety of factors affect the reaction of parts A and B on application, making it "very difficult, if not impossible, to get a full and complete A+B seldom ever equals C."

The poster included a link to an American Chemistry Council site with information on spray foam for consumers.

Making a case for natural materials

Just what were you expecting when you chose a petrochemical over a natural insulation, like cellulose, wondered Robert Riversong?

"As I've stated more times than anyone here cares to remember, there is nothing either 'green' or healthy about petrochemical foams, or any of the 80,000 petrochemicals that never existed on earth before we created them.

"Unfortunately, most of American society is brainwashed into believing in the 'magic' of chemistry, as the advertisers and marketers have impressed on us for generations. Every product produced since the start of the petrochemical age is toxic, either to people or the environment or both."

Riversong points to studies suggesting that not enough is known of the impact on health by spray foam insulation. Moreover, he adds that the foam creates a sealed building that can't breathe, making humidity control more difficult and raising the potential for mold.

"I would suggest considering environmentally-friendly, non-toxic, fire-resistant, insect-proof, rodent-resistant, and mold-resistant cellulose, which is also significantly hygroscopic and assists with natural moisture management (as long as the thermal envelope can breath - i.e. no vapor barriers)," Riversong writes.

Where does this leave us?

The many performance benefits of spray-in polyurethane foam no doubt will continue to make it popular, particularly as the cost of energy goes up. Canadian insulation installer Dwaine doesn't dispute the problems cited elsewhere in the thread, but he also admits he is "completely in awe" of what spray foam can do.

"The blame is being laid in the wrong places," he writes. "When someone like myself sits back and reads these various comments, it is easy to see they are all for the most part human error. The biggest problem reputable companies are having right now in the foam industry is companies who are trying to make a quick buck and not follow proper manufacturer guidelines and installation instructions. I blame the governing agencies."

Dwaine thinks there are lessons to be learned from the Canadian Urethane Foam Contractors Association. Although it's not a perfect approach, it could help consumers feel confident in using foam.


Image Credits:

  1. Daniel Morrison

Feb 17, 2010 10:24 AM ET

Caveat emptor...
by Lucas Durand - 7A

I can understand the initial appeal of using spray foam products as they seem to present a solution to many design problems at the same time. I'm surprised though that more consumers don't seem to be taking a more active role in researching the pros and cons of insulating this way. I know guys that have literally taken years to decide on what TV to buy but after only one or two episodes of their favorite renovation show are ready to seal their homes up with spray foam.
To the pros:
Is it common to have knowledgable customers that want to be part of the process of design and material selection?
Is much effort put into involving customers at the design stage when material choices are still being made?

Feb 17, 2010 10:31 AM ET

And you want to use this where?
by Lucas Durand - 7A

From the NRC document cited above:

Polyurethane is best used in a cool, dry environment. A good design
will ensure its protection from extremes in temperature and from becoming
wet. It will also keep the foam dry by providing a vapour barrier that
will keep excessive moisture from entering the material and condensing
or freezing in the colder parts of the foam. Polyurethane does not have
good freeze-thaw resistance. If the material is wet and is subjected to
freeze-thaw cycles it may disintegrate after only a few dozen cycles.

Is this really the best product for insulating roofs?

Feb 18, 2010 1:22 PM ET

Recent EPA, OSHA, NIOSH,SPSC web-seminar on SPF app safety
by Kyle

Here is a PDF of presentations made during an EPA web-seminar from December 2nd on SPF safety concerns. Pay attention to pages 68-77 as these pages summarize regulators current concerns. This topic is something to follow as proper safety guidelines evolve over the next few years.

Feb 18, 2010 1:27 PM ET

Concern of off gassing in basement applications?
by Kyle

Building Science Corporation often uses SPFs (as described on this site) in bellow grade applications as part of a foundation wall sealing strategy. Does moisture concerns in this type of application pose additional off gassing concerns, especially if ground water levels change in the future?

Feb 18, 2010 1:35 PM ET

Yellow Press at Work ???
by Bill Clark

So start with a tainted headline, then add a few comments from "anonymous" posters and follow up with misinformation about spray foam's suitability to be used in building anywhere? You could just as well run this story in the National Inquirer...

I hate to ruin a good story with "Facts", but just for fun:

Spray Foam Insulation uses an "A" and a "B" raw component. When these two materials are combined they form a completely different material that no longer has any of the hazards of the of the original raw materials used to make the final product, which is pretty much inert after it is formed! A+B=C the chemical reaction transforms the raw materials into an entirely new composition.

Yes, the raw materials have some hazards listed on the MSDS sheets and must be handled correctly with proper worker protections, but once they are properly applied, the hazards no longer exist and any "off-gassing" that may occur is not detectable 24 hours after application.

The "Canada" study is from 1977(!) and lists foam raw materials not used for many many years, but is used to support his idea of improper testing and "Potential" problems...

The EPA study lists the dangers of the "raw materials" and health issues to installers IF they do not follow widely know and simple steps to protect themselves from contact with the materials in their "raw" form, not to mention that these effects and/or safety precautions are not even valid AFTER the spray foam is installed.

Yes - vapor barriers are required in some climate zones on EVERY type of insulation sold today. Vapor Diffusion is the only force that could allow small amounts of moisture to slowly enter spray foam, but in residential construction, it is a force weak force/drive. To insinuate that spray foam insulation could "disintegrate" after being installed into a home's roof system due to these conditions, is simply untrue and could not happen except for highly unusual conditions, or massive design flaws.

Zero air leakage on a home is the correct target amount, then supply the proper amount of ventilation AND performance test all combustion appliances for proper operation under "worst case" pressure conditions. This is the only way to create and operate an energy efficient, healthy indoor living environment.

Feb 18, 2010 2:42 PM ET

Now Comes a Foam Fundamentalist to Attack the Heretics
by Riversong

Bill Clark: "This is the only way to create and operate an energy efficient, healthy indoor living environment."

Whenever anyone insists that there is only one proper way to do something, you can be sure that he's an advocate (propagandist) rather than an objective commentator.

I agree that the outgassing poblem is largely overblown (except for those few who have become chemically-sensitized and have to spend the rest of their lives avoiding the world), but there are many legitimate arguments against the use of a petrochemical, high-embodied energy, non-renewable, non-recyclable, non-permeable, difficult to remove, problematic for renovation, and expensive insulating material.

Feb 18, 2010 5:03 PM ET

Information for all
by Lucas Durand - 7A

It's true I do have my own personal reservations about the use of spray foams (most of which are described by Mr. Riversong's list above) and maybe I should be less careless about how I express those reservations.
The point I was hoping to make was that the consumers that buy these products should have adequate factual information to base their desicion on. As you pointed out, the NRC study above is perhaps out of date but there is very little other impartial information to read on the subject. This obviously isn't the fault of the spray-foam industry but the better the information, the better things are for everyone.
I'm not a chemical engineer but your assertion that A+B=C is hard for me to believe. Regardless of how good a mixing system you have, I doubt it's 100% efficient at making C from A and B (therefore there must be some small amount of A and B left over).

Feb 19, 2010 6:50 PM ET

Mr. Riversong
by Bill Clark


If you are going to Quote people, please use the entire quote:

Zero air leakage on a home is the correct target amount, then supply the proper amount of ventilation AND performance test all combustion appliances for proper operation under "worst case" pressure conditions. This is the only way to create and operate an energy efficient, healthy indoor living environment.

I never indicated what system was best, just the steps that need to be taken...

Feb 22, 2010 3:11 AM ET

Does Any Post-Installation Data Exist?
by Stephen Colley

Has any independent party actually taken air samples from the interiors of homes insulated with spray foam and compared the samples with similar samples taken from "control" or conventionally-built homes of similar age to determine whether there are toxic elements present in the spray foam house samples? Look first for the presence of the compounds "A", "B", or "C" or other chemicals listed in the MSDS's of spray foam.

Remember though, that the spray foam house will likely be much tighter than the "control" homes and may likely trap chemicals picked up from wood sheet goods, framing, insecticide, etc. at a higher concentration than the non-foam houses with higher air changes per hour.

Feb 22, 2010 10:10 AM ET

Safety is in the proper use.
by Michael Park

I have used Spray Foam on several projects and it has been bery successful with no repercussions. We well ventilated the ares during application and the applicators wore the proper protective clothing and breathing gear. It was left to cure for several days before enclosing. AS with any product proper safety practices should be followed. I prefer to use this over fiberglas bats and other insulations.

Feb 22, 2010 11:04 AM ET

by Anonymous

Frankly, I've no axe to grind, but Clarks comment makes sense, and Riversong's comment makes it look like he doesn't understand anything.

Colley above has a very good point - foam makes a tight house. Therefore all the other offgassing will remain. Is this foam's "fault"? No, but its clearly an issue that must be managed. And yet another example of why energy recovery ventilators should be mandatory.

In my personal experience, I've been pleased with foam, and continue to use it, though not for everything. I have chemical sensitivity issues, much as I hate to admit it, as most people who focus on them are raving loons. So I don't hang around while the foam is installed. After installation I have noticed precisely zero effects, and have it in my own house.

Its still a bit on the cost prohibitive side - framing from scratch I'd think seriously of using ICFs and thus being able to ignore the whole issue.

Feb 22, 2010 11:49 AM ET

Not a tough answer to get
by FlownOver

Getting good hard data should not be very difficult. Build a large number of test installations, monitor the atmosphere under different conditions. It would be difficult to recreate all of the ways this stuff has been used, so such data could be rigorous, but not exhastive. If some conditions produce higher outgassing, build more test installations, and find out what variables have the most effect. Really, just basic science. Of course, facts can often kill a fun arguement.

Feb 22, 2010 12:53 PM ET

My experience and opinion
by Jim

I agree with much of what Bill has stated. Nothing is perfect, but it must be tested. I'm not an expert, but I have used cellulose, fiberglass, and foam. Fiberglass and cellulose require protection, also.
Are they as bad as foam offgas? I don't know. I can see little strands of fiberglass and cellulose floating in the air when I'm working after a installation. Does that mean that I should be wearing protective clothing and mask to keep from itching from the fiberglass and breathing both? In reality, I don't think many contractors do. They come down from the attic and shake off the fiberglass to float around the air.
I'm not a chemist, but I could see A+B=C. I would think that it is plausable. When the two parts of epoxy are mixed together they form a something that is hard and unlike the two parts orignal parts. I think cured epoxy is realitively safe.
I agree that more up to date research should be done. Why isn't there something more current than 1977?
I like the way foam adds more rigidity to a structure when sprayed on framing members, so I like it's permanence. Should it be more recycle friendly? I don't think fiberglass is recycled, and it is probably the most common type of insulation. How does the foam made from soybeans stack up?
Just my thoughts.

Feb 22, 2010 1:40 PM ET

chemical combos
by john rusnak

Sodium a deadly metal element plus chlorine a deadly gas element= table salt NaCl. I have never been exposed to either elements shaking table salt on goodies like fries. Foam is the SAME.

Feb 22, 2010 2:09 PM ET

High -embodied enrgy, petrochemical, etc.
by Kevin Brodie

Mr. Riversong makes a good point about "petrochemical, high-embodied energy, non-renewable, non-recyclable, non-permeable, difficult to remove, problematic for renovation, and expensive insulating material." However, the long term benefits of less energy consumption should outweigh these concerns. I assume that as spray foam becomes more prevalent it will one day be recyclable. The same long term benefits outweigh the "expensive" comment as well. I just used this on an interior renovation with 2x4 studs, 2x6 rafters, and existing radiant heat. The client wanted a cathedral ceiling and using spray polyurethane allowed us to keep the existing framing so it pretty much evened out cost wise. My client was in disbelief that the room went from 40 degrees to 68 degrees in about 20 minutes after the foam was applied. Now that zone barely calls for heat anymore compared to the fiberglass batt used previously. All insulation is covered by 1/2" gypsum and latex paint film. I can't imagine a lot of off-gassing from this. A whole house using spray foam should have an HRV system anyway.

Feb 22, 2010 5:03 PM ET

Is there such a thing as 100% certainty?
by Lucas Durand - 7A

Phenol Formaldehyde is an adhesive chemicaly unique from either of its components, phenol and formaldehyde. MSDS for products using Phenol Formaldehyde indicate some very small amount formaldehyde off-gassing.
A chemical reaction that is 100% efficient must be a rare bird. How efficient is the reaction between A and B ingredients? Is it as effecient as the process of thermosetting Phenol Formaldehyde resin? If not then there must be some (small) amount of A or B left over after the reaction has occured and the foam has cured.

Feb 22, 2010 7:50 PM ET

by Wayne

John Rusnak may be correct when he talks about NaCl or table salt but the analogy does not carry over to the foam case. The question is are the components A and B mixed precisely in the proportions required to make C. If not there will be some A or some B left over and where small amounts at the parts per million level are important the ratios have to be that precise. I doubt any foam equipment is that accurate in their mixers. The real question is what happens to the leftovers.
In the table salt case, any leftover raw Na or Cl has long left the scene since the material was deposited millions of years ago.

Feb 22, 2010 8:58 PM ET

Lingering odor from low density SPF
by David Posada

I'm witnessing an insulation retrofit using low-density spray foam, Demilec Sealection 500, in an old house in Oregon where there is a strong odor two months after installation. It is a somewhat sweet ammonia-like smell.
8" SPF was sprayed to the exposed underside of the roof sheathing in the attic and crawlspace, and the rim joists in the basement. A low-rise mix was blown into to the exterior walls.
The odor is strongest in the attic and crawlspace and spreads into the second floor area through small penetrations in the ceiling and attic hatch. Installation was done in med-December with temps in the 40's.
The occupants have been running a fan in the second floor bathroom 24/7 to reduce the odor since installation and cracking a bedroom window to negatively pressurize the house and ventilate the sleeping area. The attic hatch has occasionally been left open to the second floor during the day to provide some ventilation of the attic air.
Some sources have suggested that an improper mixing of the A and B components during installation can cause long term odors. Two spray foam discussion threads suggest that too much amine catalyst in the B component, poor ventilation of the area, and possibly too thick an application of the foam can emit odors for long periods of time. Some have suggested it may be cause to remove and re-install the foam, others disagree:
Much of the published information regarding low density spray foams addresses the low- or non- toxicity of "properly cured" or "properly installed" foams; little seems to be said about what constitutes a improper curing or installation, what chemicals can be released, what hazards (if any) may be present, and what remedies are appropriate.

Feb 22, 2010 11:25 PM ET

Wayne, Well said. That's
by Lucas Durand - 7A

Well said. That's exactly my thought.

Feb 24, 2010 6:16 PM ET

What David Said, Plus--
by Mike O'Brien

There's also the immediate issue of small droplets of foam entering the air during installation. While they probably fall out quickly, applicators are supposed to wear protective clothing and masks to avoid inhaling, so is that completely safe?

In the long term, unlike fiberglass or cellulose, foam sticks to some components in assemblies, which may make them hard to deconstruct.

Feb 24, 2010 8:03 PM ET

Foam Insulation
by David Aronson

All the comment has been about sprayed insulation. Has there ever been any comment about sheet goods applied to the exterior of the homes sheathing ?

Feb 24, 2010 8:59 PM ET

by Bill Burke

Would anyone consider Air-Krete? My understanding has been that this would be an excellent choice for a home for a chemically sensitive individual. I've watched it being installed in one building, but have no experience with it personally.

Feb 24, 2010 10:53 PM ET

Long term benefits?
by ben graham

When I think of a good long term solution to insulation or any enclosure materials what comes up for me is renewable, non-toxic, affordable, high-performance. Foam gets 1 out of 4 here for me. When comparing insulation performance, foam may have the best per inch but I have seen plenty of structures insulated to a higher degree than foam insulated structures I've seen, albeit thicker walls. This seems to be more of an issue of design.
So while its important to know the facts about how toxic a material is both in structures and in the landfill(is this another long term benefit of foam?), if we were to think about long term performance in a wholistic way, foam just doesn't stand up.
If all this energy efficiency hype is based on concern about carbon in the air and created a balanced carbon cycle. One of the best ideas I have heard is to keep the long term carbon stores in the ground.

To chime in on the efficiency of getting A+B to equal C, I know a local contractor that didn't get it right on a roof installation. This is not a regular occurance though. I have never heard of an situation where people ended up with toxic air from a cellulose, or wool batt or strawbale installation. Just the potential for a mistake will turn folks off, just look at the nuclear debate. I think once someone has figured out how to make foam with something other than petroleum that is non-toxic with no risk, then there won't be any more debate. Until then, I think there will always be two sides.

Feb 24, 2010 10:57 PM ET

Obtaining information on foam insulation
by Richard

I am going through an upgrade now in areas of my house to cure insulation problems such as a large knee wall area where the ceiling insulation was never completed. I thought originally it could all be done by foam. One bid by an installer mentioned the brand of open cell foam he was going to use. I made a Google search and found - hidden deep - some cases of sensitization and related problems. The literature is dominated by the manufacturers and installers claiming safety among many other things. If older people have asthma or allergy problems, then let the installer explain how they will vent the areas to be sprayed and let them explain their qualifications and maintenance of equipment. Nothing was ever said to me about ventilation or when it would really be safe to go back into the house.

When I have watched shows like "This Old House" or even more recently "Holmes on Homes" almost always there is either a new house or large cleared areas being corrected and refurbished. Particularly in "Holmes on Homes" he uses foam a lot and has expert contractors doing the work. Neither show talks about the safety issue vis-a-vis the occupants. Also both shows are atypical since they always have real experts and professionals doing the work.

In our project we thought the risk was too great so we went back to having contractors bid with conventional materials. I do not want people to proclaim to me that A+B=C, therefore there is no problem, particularly when they know the guns may not be well maintained and the mixing may be incomplete, and when they know the operators may have all sorts of different training. The cannisters may have bad batches, etc., etc. If everything goes right with real pros doing the job, foam appears to be an excellent material. I just cannot take that chance in a closed-in home with some upgrades being done. Will the contractor warranty to me in a written contract backed by a big insurance policy that my family will have no post-install contamination problems? Well if A+
B=C, as some have previously stated, that should be a no brainer, and we can proceed.

Feb 25, 2010 2:35 AM ET

spray foam chemistry
by Wenzel Bartlett

There are some really good points made in this discussion about spray foam insulation. Here are a few important details on the chemistry. I hope it helps the discussion.

My understanding is that spray foams used in residential construction are all polyurethanes. The polyurethane spray foam is made by mixing the A and B components. The A component is a highly reactive and toxic chemical that has at least two isocyanate functional groups (i.e. PMDI). The high reactivity of the isocyanate is a desirable property when manufacturing polyurethane materials, including residential spray foam insulation, but it is also the property that makes isocyanate chemicals toxic. The B component is primarily made of polyols, but there are many other additives mixed with the polyols (i.e. catalysts, antioxidants, uv inhibitors, etc). The formulation of the B component has a big influence on the properties of the polyurethane (i.e. are you making a car seat, mattress, shoe sole, insulation for walls, refrigerator, ice chest, packaging material, and many, many more products that we use every day). Polyols can come from many different sources including renewable crops and petroleum. However, the manufacture of polyols from petroleum is typically less expensive and typically produces a polyol with properties that are easier to control.

Ideally you do want complete reaction of both the A and B components, hence they are typically mixed in stochiometric ratios. A chemical reaction between an isocyanate functional group and a hydroxyl functional group forms a urethane functional group and carbon dioxide. The reaction is extremely fast, exothermic (releases heat), and not reversible. Since the A component has at least 2 isocyanates in its chemical structure and the polyol in the B component has numerous hydroxyl groups in its chemical structure, mixing components A and B will form polyurethanes and carbon dioxide gas. In the few seconds that it takes for this chemistry to occur, carbon dioxide gas bubbles through the polyurethane as it grows, cools, and turns into a solid plastic material. Hence, carbon dioxide creates the foam.

Since you can't really mix the perfect stochiometric ratio, it is safer to add a slight excess of component B to the mixture. Component B is not a very reactive material (other than with isocyanate). It is highly unlikely that the low level off gassing in the polyurethane foam is the isocyanate of component A. Isocyanate reacts with many other chemicals, including water. In fact, it reacts with water even faster than it reacts with polyols. Hence, if the isocyanate were off gassing it would react with water vapor in the air. It is far more likely off gassing is either excess polyols or some of the additives in component B.

When we insulated our new house with spray foam insulation, I thought the smell from the foam followed a similar trend as fresh wall paint. The smell was strongest when first installed and then it went away over time. Supplemental ventilation in our HVAC system helped remove new construction odors from our house to the point where I don't smell any odors except in the attic, which smells more like wood with a slight hint of spray foam. We've been living in the house for 2 months.

Feb 25, 2010 10:57 AM ET

Open Cell Spray Foam & Vapor Barriers
by Christopher Vlcek, Littlewolf Architecture

It appears most of this thread is aimed at Open Cell Spray Foam - the soft kind you can crush in your hand. It goes by the trade names of Icynene, Bio-Based, Demilec, and others. It is vapor permeable and so requires a vapor barrier, and many building codes make that a requirement. In heating climates, the vapor barrier is put on the inside of the insulation.

For walls, Open Cell Foam is generally over sprayed and shaved flush with the studs. Drywall and latex paint form an effective barrier, though gaps around outlets and such often get little attention. For unvented cathedral roofs, or vented attics with the insulation at the ceiling, the same applies. That is, when drywall & paint are in contact with the foam, they serve as a vapor barrier.

But, for attics where the foam is sprayed to the underside of an unvented roof, Open Cell foam requires an additional vapor barrier. Typically, 2 coats of latex paint can be sprayed directly to the foam. This provides the required vapor barrier IN CONTACT with the insulation, and also serves to seal the off-gassing potential. The same is done for Open Cell foam used in band-joist applications where the basement is left unfinished.

Feb 25, 2010 2:28 PM ET

To the Skeptics - Especially Mr. Bill Clark
by Marlene

I really don't appreciate labeling the health probelms my brother has experience as "yellow press".
He has saved his entire life to build this house and hired a licensed contractor to install the Icynene. He is in the process of seeing doctors since this installation because he has been chemically sensitized. As for the chemical process, we sent samples of the "cured foam" curing since December 2009 to a chemical company for testing. There is definitely remnants of icynene in the foam. Mr. Clark, why do you think anyone at 65 years of age would make this stuff up?!? My brother is trying to build a home to live in during his "golden years" which have turned into "hell" as a result of this product. Whether it is due to improper mixing of the two-part components or to a problem with the chemical itself, someone needs to be held responsible for this travesity!

Feb 25, 2010 2:35 PM ET

Correction -To the Skeptics - Especially Mr. Clark
by Marlene

Specifically the chemical component remaining was "Isocyanate".

Feb 25, 2010 3:24 PM ET

People with Chemical Sensitivities are Raving Loons?
by Marlene

This is also a rather ignorant comment. My brother is a Vietnam vet who fought for his country and has worked his whole life. He has saved to build this house, pay cash for it and used the Icynene, as it is supposed to be superior for insulation and be good for people with sinus problems. He is definitely a good conservative Republican and really doesn't like Governent intervention as a general principle. the icynene company advertises as being able to inhabit 24 hours after installation, yet I see many entries regarding waiting several days/weeks to get rid of any potential off gassing. Being unable to breathe after being exposed to this stuff definitely does mark him as a "raving loon", but a good man who has had the unfortunate experience of believing the advertised claims of this product.

Feb 26, 2010 12:01 AM ET

Spray Polyurethane Foam Health and Safety Information
by Neeva-Gayle Candelori, Director of CPI

I’d like to share some information that may be helpful. As mentioned earlier in the dialogue, spray polyurethane foam (SPF) is a highly efficient insulation product and without question, it is critically important that it be installed safely and according to model and local building codes which provide guidance and requirements on the safe use of materials and systems used in buildings. Interest in this product is likely to grow right along with increasing demand for greater energy efficiency in homes and buildings. The makers of SPF know that this interest is growing, and want to provide further education and outreach about the safe use and handling of this product. That’s why the Center for the Polyurethanes Industry (CPI) and the Spray Polyurethane Foam Alliance (SPFA) have launched an industry product stewardship program enhancing national health and safety practices for the SPF industry in the United States.

If you haven’t already seen our new SPF health and safety website, take a look, and I encourage you to visit it often. You’ll find many guidance documents related to SPF ranging from personal protective equipment during SPF installation, ventilation techniques, good safety practices, health and safety Q&A’s for interior or exterior SPF application, preparing a site for SPF application, “green” marketing claims, and more. There’s a lot of useful information and guidance regarding SPF product stewardship and the website will be continually updated as new health and safety information becomes available.

Neeva-Gayle Candelori, Director
Center for the Polyurethanes Industry
of the American Chemistry Council

Feb 26, 2010 11:30 AM ET

spray foam under roof decking
by Wenzel Bartlett

I have an alternate opinion on the need to apply paint to spray foam that is applied to the underside of roof decking. When the underside of a roof is insulated, you essentially create a semi-conditioned space in the attic. In my house, the attic is just a few degrees warmer than the rest of the house. That means that I am willing to go up in the attic any time. For this reason, I had the framers deck the entire attic so I could use it as extra storage space in the house. If there is a leak in my roof, then I want to know about it so I can get it repaired as soon as possible before it damages any of the wood. If the underside of the roof is covered with paint or some other vapor barrier, then it will be more difficult to tell if and where the leak is located. That said, I did use a roll plastic roof underlayment on the top side of the decking instead of roll felt paper. So it is true that I do have a vapor barrier on my roof.

A couple of other issues have been brought up about the attic during my house construction. One is that spray foam will discolor and degrade if left exposed to UV light. I have windows in the gables of my attic. I leave the windows closed and they have a good rating for blocking UV light. So far I have seen no discoloration of the foam.

The other issue is regarding ventilation of the attic. My HVAC guy believes there is enough leakage through ceiling fixtures to ventilate the attic, but my energy efficiency consultant believes that I need to provide mechanical ventilation by adding a very small air flow from the HVAC system. The intention is to dehumidify the attic since the wood is still drying out. I'm planning to add the mechanical ventilation.

Feb 26, 2010 6:03 PM ET

A Poisoned World
by Steve Dearlove

I am about to install spray foam in my new house and so I find all this discussion of great interest. I do believe the benefits outweigh the detriments: prudence, with anything these days, is always wise.

Feb 26, 2010 7:38 PM ET

by Anonymous

There are two issues at hand here...1.) health concerns prior to the foam insulation being created, 2.) health concerns after the foam insulation is manufactured and cured.

1.) Obvious safety risks here. A building product is being custom manufactured in your home for each wall cavity. Yea, there are going to be some health concerns here.

2.) Once the foam has cured - IT IS CHEMICALLY INERT. Foam insulation is the same product in your pillows and mattresses.

A lot of information above has the health and safety concerns confused. FYI foam insulation is recommended by the American Lung Association for healthy homes (that is because foam insulation is chemically inert and does not sprinkle nano sized fiberglass shards in the air). If your an installer, wear the proper safety equipment while installing. If your a building occupant of a foam insulated house, there are ZERO health concerns related to indoor air quality or dermal absorbtion.


Feb 27, 2010 7:38 AM ET

Thermal barrier
by Martin Holladay

Your installation raises questions being debated elsewhere on this site — namely the question of requirements for a thermal barrier. It sounds like you have exposed spray foam in an attic with a floor that you visit frequently because the attic is used for storage. Some building officials require a drywall layer covering the foam in attics like yours.

Feb 27, 2010 10:34 AM ET

Let's get rid of confusion
by Lucas Durand - 7A

Agreed, properly installed and CURED foam (C) is probably not a health concern.
It's not clear to me that even in perfect laboratory conditions, there are ZERO unreacted remenants of either A or B (or both) ingredients after mixing.
If there are unreacted remenants of A and/or B after an installation, where do they reside? Do they all dissipate completely into the environment? Is it at all possible that some of those remenants remain within the cured foam?
Though the cured foam itself is inert it may be trapping toxic compounds that may then escape to the outside over time. This may be an insignificant amount of off-gassing to most people but it seems that there are some cases where it is not.
If someone has specific information that either supports or refutes this thinking I would love to see it.
There needs to be more unbiased and impartial information provided to consumers. The people who are to actualy live sealed inside the foam bubble need to know exactly what the potential risks and benefits are before the installation occurs.

Feb 27, 2010 10:58 AM ET

Health concerns aside
by Lucas Durand - 7A

There are plenty of other issues that consumers should also be informed about when making the decision about whether or not to use spray foam.
The concept of providing high R and air sealing in one step is appealing but for the cost there are other ways to air seal and insulate to high levels.
The sustainability of using petrochemicals to make homes more energy efficient is debatable.

Mar 1, 2010 10:21 AM ET

Lucas Durands Comments
by Steve Dearlove

As usual, the industry touts the benefits; the skeptics ring the alarm bells and nothing ends up being definitive... until after the damage has occured. (Toyota. Ford Pinto. Thalidomide along with countless other pharmaceuticals)

"for the cost there are other ways to air seal and insulate to high levels"

What are these other tried and true tested/safe methods? (Fibreglass is out and not strawbale as it's too late for that for me.)

Mar 1, 2010 10:27 AM ET

What's your question?
by Martin Holladay

Please give us details about your insulation project.
1. New construction or retrofit?
2. Basement walls? Above-grade walls? Sloped ceiling? Flat ceiling with attic above? Somewhere else?

Mar 1, 2010 11:07 AM ET

Thanks Martin. It's new
by Steve Dearlove

Thanks Martin. It's new construction. Spray foam for all above-grade stud framed walls as well as the rim joist perimeter. (2x6 construction with 2" of poly extruded on exterior.). All roof construction is SIPS. Region is Southern Ontario.

My mechanical design is hinged on the high R values.

Mar 1, 2010 11:20 AM ET

by Martin Holladay

You asked about alternatives to spray foam — "What are these other tried and true tested/safe methods?"

1. If you are planning to use open-cell spray foam, then you should know that dense-packed cellulose will provide the same R-value.

2. If you are considering the use of closed-cell foam, then you will need thicker walls to provide the same R-value with cellulose. That can be accomplished by installing horizontal interior strapping or by using double 2x4 stud walls.

3. It's hard to beat closed-cell spray foam for rim joists. It's the best material for this area.

4. No matter what insulation you choose, you need to do a meticulous job of air sealing. Spray foam does not address many potential leak sites.

Mar 1, 2010 11:47 AM ET

Help Appreciated
by Steve Dearlove

Thanks Martin. I think I'll stick with the closed cell and face the potential risks. (There's too much water under the bridge regarding framing at this point.)

I have exposed areas of spray foam installed in my current home (as retrofit) for over 5 years and cannot claim any negative effects... mind you, my memory is failing, but I suspect that's got more to do with stress and age!

I wil be diligent about the air sealing. ;-)

Mar 1, 2010 3:54 PM ET

Just for the record...
by Lucas Durand - 7A

The building code of Canada suggests that any of the following materials can form part of an air barrier system:
OSB, plywood, drywall, rigid insulation, polyethylene, metal or glass.
Of course many other materials are suitable as an air-barrier as well.
Many of these materials may already be specified for use within your new home and could be installed so as to provide the function of an air barrier. Air-tight drywall is a good example.

Mar 2, 2010 8:50 PM ET

closed cell in the cold
by reis

i am currently remodeling my attic space. (i'm in portland, or) I am vaulting the ceilings and have 2x4 rafters. I really want to use close cell SPF, but am not yet convinced for a couple reasons. The main thing i'm confused about is the vapor barrier question. If the closed cell acts as a vapor barrier and doesn't allow the outside air in, or inside air out, would there be a moisture build up on the interior of the house? Especially in the winter, when it's cold outside and warm inside and any vapor in the air inside the house could condense against the colder ceiling. I've always assumed there needs to be some built in venting for the ceiling/attic space, however basically all literature i've read about closed cell says you don't need to vent the roof.

any thoughts on this matter?

Mar 3, 2010 5:30 AM ET

Interior moisture build-up
by Martin Holladay

Whether or not a house has high or low indoor humidity during the winter depends on several factors, including the number of occupants, the home's volume, the frequency of certain activities (showering, cooking), the number of houseplants, whether there is a fish tank, and whether or not the occupants store firewood indoors.

Ventilation channels adjacent to roof sheathing and attic ventilation were never intended as remedies for a house with high indoor humidity problems. Oddly, though, some builders treated them that way. If you ended up building a leaky ceiling, and indoor humidity escaped into your attic or got between the rafters of a cathedral ceiling, then the ventilation chutes were supposed to help carry away the moisture. But the fact that the moisture was even there was evidence of sloppy building practices.

The usual remedy for high indoor humidity during the winter is mechanical ventilation (bath exhaust fans, a supply ventilation system, or an HRV). Once your ventilation system is installed, you can adjust your ventilation rate to meet your home's needs.

If you choose to install closed-cell spray polyurethane foam, the foam (if properly installed) will act as an air barrier and a vapor barrier. There shouldn't be any risk of interior air or interior water vapor contacting your cold roof sheathing.

Choosing open-cell foam is more risky, since open-cell foam is not a vapor retarder. There have been reports of wet roof sheathing and wet wall sheathing in cold-climate homes insulated with open-cell foam. This is a vapor-diffusion problem. The usual solution is to install vapor-retarder paint on the inside surface of the cured foam.

Mar 8, 2010 2:43 AM ET

The idea of giving high R and
by Ravi

The idea of giving high R and air sealing in one step is demanding but for the price there are other methods to air seal and protect to high levels.

Mar 13, 2010 8:06 AM ET

by Haris

According to me if there is a leak in my roof, then I want to know about it so I can get it repaired as soon as possible before it damages any of the wood.

Mar 21, 2010 10:15 PM ET

Alternatives to Spray Polyurethane Foam
by Anonymous

I would like to get some ideas about alternative insulation materials which could be used in an unfinished attic of an old Michigan home. The attic rafters are exposed and after insulation I would cover them with dry wall. As I have a husband who is highly sensitive to any chemical smells I want to avoid any toxic material.

Mar 22, 2010 4:19 AM ET

Toxic insulation
by Martin Holladay

As far as I know, products sold as insulation and installed as directed are not toxic. If your husband has special medical issues, the best place to get advice on this question is from your husband's doctor.

Mar 24, 2010 9:38 AM ET

Icenyne - 5 Years No Barrier - Water Standing Open Tastes Bad
by Chris in OK

In 2005 I build my home on a remote Western OK ranch. The walls are ICF, the roof conventional truss, the decking OSB, the roof semi standing seam metal. Given the huge mismatch in thermal mass and insulating potential of ICF versus a 'stick built' roof, I wanted seal and insulate the roof really well in this very hot climate. I don't believe in venting if you can seal a roof solid, so I went for spray-on foams.

Icenyne was installed, fulling filling the 2X10 top chord space, then sawed back flush. I was not here when it was installed. My wife reported that the installers struggled some trouble with their truck during installation, but the foam all looks consistent in cell size and good in all the exposed areas, and we have no detectable residual odors. What is uder the exposed foam, as to some areas blown on way off stoichiometric, I have no way of knowing directly.

This foam has remained standing open these last 10 years with no vapor barrier, and we have only curtains and not doors between the utiltities service runs of the 'attic' and our bedroom and office. One complaint is when we fetch stuff from the attic and rub agaist the underside of the roof, we get 'foam buggers' on our clothes.

For ventillation of this very tight house we have an ERV or energy recovery ventillator, which runs most of the time, exchaging air with the outside.

I have been concerned about outgassing for three reasons:

- After installation something all the exposed copper wires of our electrical work in process

I attributed this to outgassing from the foam during cure. Later, when I heard horror stories about Chinese drywall, I checked that out too. Nope, I have American drywall, and there are no odors.

- My wife and I have noticed that to this day a cup of water standing open next to our bed will have the water tasting funny by the morning, and worse if left there a few days.

This one fact makes me very concerned, because whatever is creating the off taste has to be coming from the air. I will do an experiment (should have done this before) to leave the same water standing open in a space not having icenyne foam as a control. If the water does not change, there is something reacting with the water in the air. That would be scary, as I am mostly made of water!

Now I suppose I could have this water examined, control and experiment, for chemical differences, but don't know where to send the water to. It seems we are talking very low ppm here.

- I have developed a cluster of possible auto immune-related problems.

The first is aching in the joints. This has been with me since before I have lived in this structure, but has gotten worse with each passing year. I attributed this to age (I am 53) and past body abuse. Last year I developed Papulo-pustular Rosacea, a skin problem with some auto immune component. The cause was ascribed to stress at work. The Rosacea responded well to a treatment similar to acne treatment, with a blast of Azithromax followed by daily dosing at sub-therapeutic levels of slow-release doxycylene that is supposed to be more anti inflammatory than antibiotic. I have also developed some sensitivity in the colon to foods. Some irritability. I used to be able to eat anything. Now I have to watch it.

I am otherwise robust and healthy. I understant the human tendency of 'perception is reality', and want to examine this objectively and not get carried away with the kind of blame the other guy thinking that is ruining our society. Objective is to test the water. If something is in there the next step would be a barrier to slow outgassing. Given the very rough surface of the exposed, sawed icenyne, I suspect paint will be a piss-poor sealer, more feel good than anything. The attic does not allow putting up drywall. Just not enough room, and plastic sheating will just get torn off as we pass through.

Any suggestions, comments?

Apr 1, 2010 11:55 AM ET

Response to Confusion by Anonymous and others
by Anonymous

The American Lung Association (ALA) has never approved or endorsed spray polyurethane foam insulation, or any insulation type for that matter. The ALA does have a "Health House" program but they do not specify certain products or types of materials. They have established "Health House" criteria and these are the following, as excerpted from their website:

What are the typical components of a Health House® Home?

Foundation waterproofing and moisture control
Advanced framing techniques
Air sealing and advanced insulation techniques
Energy efficient, high performance windows
Energy efficient and sealed combustion appliances
High efficiency air filtration
Whole house ventilation
Humidity control
Carefully selected and reviewed interior finishes

There have been a couple of marketers of polyurethane spray foam insulation who have claimed it is approved by the ALA in some of their advertisements, but this is not true and is deceptive marketing. In truth, spray polyurethane foam insulation was just used by a builder who built a house according to the ALA criteria and the house was given the Health House designation. And of course, with all the deceptive advertising being spread about this insulation material-- "no off-gasing, green, made from soy beans, eco-friendly, all natural, bio-based, etc.", it is easy to understand how the true health ramifications of this material could be overlooked. The builder himself, most likely didn't know the truth about this material.

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