More Q&A Spotlight
First developed the 1930s, both open-cell and closed-cell spray polyurethane foams have been widely used in residential construction for more than 30 years. As the name suggests, open-cell foam is less dense, has an R-value around 4 per in., is less expensive, absorbs sound well, and has a permeance (the ability for water vapor to pass through the material) of about 7.5 per in., making it a class III vapor retarder. Closed-cell foam is denser, more expensive, has an R-value of 7 per in., and has a permeance of less than 1 per 2 in., which makes it a class II vapor retarder at that thickness.
Although open-cell and closed-cell spray foams are effective insulation materials, neither is considered environmentally friendly due to their high-carbon manufacturing processes. Until fairly recently, the blowing agents used had a high global warming potential. (High GWP blowing agents have been banned for several years in a number of states, and there is a nationwide ban on making new material with high GWP blowing agents as of Jan 1, 2025, though existing product can be used until 2028.) Another consideration with regard to both versions of spray foam is that correct installation of the products is critical for their performance.
Witness an installation gone wrong
Member “Woodworker99” has posted a question in the Q&A forums about a spray foam failure. Nine years ago, he built his house in climate zone 4A that featured a 30-year metal roof (with no decking or underlayment) and an unvented, unconditioned attic. His contractor sprayed 5½-in. of open-cell spray foam directly onto the underside of the roofing. No vapor barrier was installed, as it wasn’t required by code at the time.
Then things went sideways. He writes, “This year I started noticing major leaks. I assumed bad screws or washers, but after pulling panels I found…
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2 Comments
Sometimes during the manufacturing process, a light lubricant might be applied to the surfaces of metal panels to prevent them from scratching during stacking and transport.
This can sometimes leave a residue that can also cause foams to not properly adhere to a surface ...
You can’t blame spray foam for a poor installation.
You can’t blame it for roof leaks.
You can’t even blame it for elevated indoor humidity.
But when third-party lab testing confirms that the foam itself contains toxic or banned substances, compounds that are not disclosed in the manufacturer’s SDS, TDS, or GreenGuard Gold documentation, then the issue isn’t installation. Its formulation.
These are not workmanship defects. These are chemical formulation failures. No amount of proper spraying can change the fact that a product emitting hazardous or prohibited chemicals may be inherently unsafe and non-compliant with the safety and emissions standards it’s claimed to meet.
Manufacturers and installers routinely point to certifications like GreenGuard Gold and cite third-party emissions testing to assure customers of safety. But when independent testing contradicts those assurances, and the industry responds with silence, blame-shifting, or dismissal, serious questions arise about product integrity, transparency, and responsibility.
Too often, affected homeowners are met not with accountability but with deflection from a tight-knit circle of professionals quick to attribute the issue to anything but the foam itself: ventilation, HVAC design, humidity, even user error.
I’m not questioning the value of spray foam when it performs as claimed. But I am raising a red flag: if a product does not meet the standards printed on its own label and contains compounds that directly contradict its certifications who is accountable?
Consumers aren’t demanding perfection. We’re asking for honesty, transparency, and alignment between marketing claims and real-world performance.
If the industry won’t stand behind its own certifications when faced with credible scientific evidence, then what are those certifications actually worth?
And if installers knowingly misrepresented the chemicals they were spraying, if they lied about the contents, used off-label or unapproved materials, or applied foam that was illegally sourced or mislabeled, then that’s not just negligence. That’s fraud. That’s consumer deception. And depending on the chemicals involved, it could rise to the level of a criminal act.
Homeowners rely on installers and manufacturers to tell the truth about what is being applied in their homes, especially when it comes to chemical products that affect indoor air quality, health, and long-term safety. If that trust is broken, someone must be held accountable.
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