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How would you handle this problem after receiving this response?

Richard Beyer | Posted in Energy Efficiency and Durability on

Here are the facts about this house first;

The home is vacant and contains no household chemicals, furniture or paint cans, etc. Empty as it can get for many month’s now. The consumer purchased the home many month’s ago and wanted to make the home energy efficient. The home is conditioned meaning, heated and air conditioned. House is @1400 sq ft single floor with an attic. The contractor of record convinced the consumer open cell spfi was the best solution. The spfi contractor removed all of the existing visible cellulose and installed open cell spfi during the early winter of 2014. (New England on the shoreline.) Area’s sprayed included the attic roof, gable ends and bedroom walls. The product was sheet-rocked over in the bedrooms and the attic received an intumescent paint covering. The intumescent paint was not installed in accordance with the manufacturers coverage specification. (mil thickness, leaving the foams natural color exposed in the folds) The spfi had retracted from the sheathing but, remained in tact with the rafters and studs and is off gassing a sweet musty chemical odor. Large sections removed clearly showed spray lines on the back side of the foam, voids, 1/8″ pinholes and spider legs. (spider legs meaning…when you spread glue on a floor to install a vinyl floor and when pulled back showing glue legs remaining.)

The response below was sent to the consumer after this major chemical manufacturer inspected the home and retrieved their own samples.


As we discussed, __________ does not have the capability to perform gas phase analysis and so our evaluation of your foam samples was limited to visual inspection and any obvious residual odor in the samples. Our inspection resulted in the following observations: 1) foam quality: good, no indication of improper mixing or improper spraying, 2) no abnormal odors were detected in the foam samples. Based on these simple evaluations, we saw nothing to suggest a problem with the spray job.
> We also had core samples bagged and sent to ____for similar evaluation. Their message to me was that the coating was fully cured, and they smelled nothing abnormal in the foam sample.
> I pointed out in our recent phone conversation, that since you had indicated a sweet smell in the attic air, the source of that odor was likely not originating in the foam. I also indicated that sometimes paints can contain coalescing agents that can have a sweet smell. I have no reason to believe that this sweet smell was coming from the ____ coating – especially after they evaluated their core sample. The source of the sweet odor is truly a mystery.
> I should point out that when a space is air sealed, as has occurred when spray foam was applied within your attic, other household odors that went previously undetected due to the higher levels of fresh air infiltration, can sometimes now be detected. These odors can come from the HVAC system, via kitchens, pets, laundry rooms, hobby rooms, garages, basements and the like. Some of which may provide a source of sweet smells such as cooking, antifreeze, hobby paint or the like – pure speculation and brainstorming here – I’m not pointing fingers at anything without data.
> I hope this information helps to eliminate your concerns.


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  1. user-869687 | | #1

    There are various other threads here on the subject of improperly mixed or degraded foam and chemical odors, but I don't recall any mentions of a sweet smell associated with foam. What does come to mind is a type of fiberglass batt with a sweet smell, see this .
    Is there any of this product in the house?

  2. GBA Editor
    Martin Holladay | | #2

    You have described the type of insulation that was installed, but you are rather vague when it comes to providing any details to show that this house has any problem.

    The only reference to a problem was in this short phrase: "The SPFI [spray polyurethane foam insulation] ... is off gassing a sweet musty chemical odor."

    This type of odor complaint can be hard to pin down. You haven't told us how long this odor has persisted; whether every visitor to the home notices the odor, or only some visitors; whether the owners of the house have tried to ventilate the house with fans; or whether the odor is correlated with high outdoor temperatures.

    It's possible that the house smells so bad that it is unlivable. It's also possible that the odor is subtle and open to interpretation. It's hard to know what's going on here without more information.

  3. Richard Beyer | | #3

    Your right, odor is left up to interpretation. Considering the only party who knows fact from fiction with these associated odors is the chemical companies who designed the product, we may never learn the truth about the chemical odor. The cost to them would be considerable and possibly bankrupt many. We all know sometimes it works and sometimes it does not. We also know the installer will always be blamed. In this case, we know the problem remains with the installer because the installed end configuration supports the facts known about the foams properly installed end configuration.
    The question was how would you address the problem with the chemical manufacturer after receiving such a letter of denial from them knowing the facts about the finished product? How can they dismiss what is so clear since the finished product shows all the signs of installation error? Is this just typical protocol for these chemical companies to deny there's a problem or have they changed their approach to leave it up to the consumer to prove the product is bad with a substantial cost to the consumer in experts?
    Let's move forward a bit so I can answer your questions.....
    Martin asked; "whether every visitor to the home notices the odor, or only some visitors; whether the owners of the house have tried to ventilate the house with fans; or whether the odor is correlated with high outdoor temperatures."
    The homeowner can not smell the odor all the time, but the children can when they enter the home. Two mold remediator's brought in to investigate, one can and one can't. Contractor brought in to remove the foam can not, some employees can. This gives you an idea that senses are not created equally. A couple of people knowing nothing about the problem entered the home and stated they felt strange, disoriented/confused/brain fog after a short visit and later reported headaches. This was after @45 minutes of conversation inside the building.
    The owner hired a company to ventilate the home. It did not work. This odor is not correlated with the outdoor temperature. That's not to dismiss it couldn't get worse with high temperatures and humidity. We already know this can happen.
    Fiberglass was not an issue as TJ ELDER suggested above. The previous "cellulose" was removed by the insulator as noted. TJ Elder also mentioned about the previous articles written in reference to this subject on Unfortunately none of them provide a solution. They all finger point or attempt to draw conclusions...could be this or could be that.
    In this case, the insulator and the chemical company was provided the opportunity to test the finished product once the problems were learned about. This is noted in their final letter received about testing posted in the original question above. The letter generated above came from the chemical company (name omitted).
    However, a previous letter from the chemical company blamed the odor on the intumescent paint and their representative is the one who used their own nose as the measuring device to make this decision. The contractor claims the chemical company thinks the intumescent paint may not have cured properly and may be the cause of the odor. Keep in mind the intumescent paint had been installed many month's previously. They also suggested installing a hydroxyl generator to strip the odor from the air, meaning a permanent installation and cost passed onto the consumer and for the consumer to maintain it. Another suggestion if this did not solve the problem was to install a dehumidifier which is another costly appliance past on to the consumer. The consumer refused to accept any further additional expenses.
    Then the final letter came forward from the chemical manufacturer. Now this is where I'm confused. How is it that a chemical manufacturer does not have the appropriate testing equipment to test their own proprietary chemicals?
    Now lets move inside the product... Aside from the odor, we know the foam was not mixed correctly by comparing the finished product to published industry documents relating to foam failures. As I pointed out previously the separation (shrinking) of the foam from the sheathing is one of many tell tail signs, 1/8" plus pin holes, spider legs (adhesive stretch) and the fact the intumescent paint was not installed to manufacturer spec (ie; mil thickness and visible foam color in all the folds) are all signs of installation error. We also know the foam installer did not use ventilation during installation and had trouble with their equipment. We know this project failure is installation error.
    I have read all the previous articles written over the years on this subject matter from this website and hundreds of other documents published by industry, it's members and government papers. It seems no one has the answer when odor comes into the equation.

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