December 29, 2017

Reason Foam Fails #8 – Hypersensitive On-Site Manufacturing

The construction industry has been making more and more building parts in the factory – through panelization, modular construction, and complex component fabrication. Factories are great at providing predictable environments that optimize construction quality while protecting workers.  It’s just smart. So we see this trend growing.

And when chemical compounds are manufactured, the manufacturing environment is even more critical – we see this with the pharmaceutical industry, where good manufacturing practices are nearly sacrosanct – and across the vast chemical industrial complex as well. In these factories the chemicals are stored in climate controlled spaces, worker protection is reliable, the equipment is clean and well maintained, supervision is close by, and quality checks are well documented.

And then there’s the spray polyurethane foam industry – moving in the opposite direction, against the trend toward greater quality control.

Spray foam production in a factory is a tricky enough thing – with volatile compounds, complex equipment and worker protection requiring constant vigilance.  It’s chemistry.  And by moving the manufacturing process to the building construction site, the “chemists” are relatively low paid construction workers with little training and typically without an industry certification, while often working in difficult conditions.

The result has been destroyed homes and lives.

The Process is the Product

If a factory had the record of defects onsite spray foam manufacturing does – it would have been shut down.  Yet these job site factories are metastasizing across the country.  How is this possible?  Obviously, one answer is there is a ton of big money in it.  The chemical companies care about selling chemicals.  Like big tobacco, it’s a pretty straightforward calculation that big profits can be made regardless of the inherent problems.  And the defenders of construction site spray foam manufacturing assure us that the product is good and the product works.  They say the problem isn’t the product – the problem, instead is in faulty installation work.  It’s the installers fault!

Or first response is to say: That’s a ridiculous defense – it’s a shitty product because it’s a shitty way to manufacture something.

You can’t separate the process from the product! Back to the pharmaceutical industry – the quality of our drugs is protected by having rigorous processes.  If the process is compromised the product is too.

And if ever we’ve seen a compromised process it is construction site spray foam manufacturing.  It seems as if it’s almost been set up to fail.  We call it hypersensitive manufacturing because you’ve taken all the inherent difficulties that exist in making the product that exists in a factory environment and magnified the risks.  But never mind that – the installers declare that they know what’s best and they’ve fought hard to keep onsite spray foam manufacturing unregulated.

So we have roaming toxic manufacturing plants without regulatory oversight.  Of course the chemical giants could require that all installers of their products are properly trained, but clearly, the money is just too good to bother.

What the Experts Tell Us

To dive into the almost mind-boggling very real onsite hypersensitivity we are going to lean on industry experts.  First is Henri Fennell.  Henri is a consummate professional and a leader in construction forensics and in particular an expert around issues about spray foam installations.  We attended Henri’s presentation at the 2016 Better Building by Design conference in Burlington Vermont with great interest.  It was titled “The challenges of creating the perfect conditions for properly machine processing polyurethane foam” (see his presentation slides here).  Second is Mason Knowles, a former executive director of the Spray Polyurethane Foam Alliance, whose article in JLC, Troubleshooting Spray-Foam Insulation, is one of the more succinct rundowns of the typical problems one can find with onsite chemical manufacturing.  And third is Paul Bennett, an engineer and consultant in Colorado, writing Spray-Foam Problems in Fine Homebuilding magazine.

We appreciate their candidness and just wish more people would fully contemplate the devastating implications of what they describe.


Let’s start with Mason’s opening words “Most spray-foam insulation is installed correctly…”  In what other business is “most” an acceptable threshold for industry-wide adoption….of anything?  Most car engines work correctly?  Most airplane engines?  Really?

What makes spray foam manufacture hypersensitive?  There are three general parts of the process we’ll take a look at.

  1. Preparation – is the area of application, clean, dry and in right temperature range?
  2. Processing of the chemicals – to get correct 1:1 ratio of A and B sides, and a complete reaction.
  3. Installation issues – how the chemicals are applied.


There is precision involved in even the site preparation.  If surfaces are too wet or damp, off-ratio foam can adhere poorly and can crack.  Moisture content must be measured.  If surfaces are too cold, delamination is possible. The temperature must be monitored.

Even the relative humidity, which can change over the course of the day on a jobsite, must be measured several times a day. As Paul Bennett notes, “no spraying within 5 degrees F of dewpoint.”

If there’s a moisture problem, as with wet concrete – the installer must wait, test the area with plastic or a test spray.  Will they?

The preparation is akin to baking not barbecuing.  Does your spray foam contractor bake?


Fennell notes that chemical “manufacturers require the installer to be responsible for proper processing, but often do not provide adequate information (or training) about how to do this.”

The temperatures at the drums, the pumps, the hoses and at the guns must be maintained.  Same for pressures.  This requires weekly calibration as recommended by Fennell and constant vigilance.  The pressures and temperature must be adequate to assure a complete chemical reaction.

Fennell notes: “Temperature differences between gun & truck is a problem.” He adds: “The control panel readings in the truck don’t tell you what’s at the gun.”  Bennett writes: “Even if the drums are stored in a heated trailer and the job site is heated, what about the hose lying in the snow between the trailer and the building? The product could cool in the hose, producing an off-ratio or improperly reactive mix.

If foam goes off ratio and becomes A-rich it can embrittle and crack.  If it goes B-rich it won’t fully cure, will become soft and off-gas.

And if you’re counting on spray foam to be a Class II vapor retarder, then Bennett recommends doing laboratory tests of samples to confirm the permeance.  Perfectly “good looking” spray foam improperly made can have greatly varied results in permeance.  Bennett reports seeing closed cell spray foam tested with a permeance of 6.  Failing to provide needed vapor control will result in failures down the road.


The risks are heightened enough that Paul Bennett notes that trusting the subcontractor to do the right thing – as a GC might with an electrician or plumber – is a bad idea:

We hire qualified subcontractors and expect that we won’t have to babysit them. With SPFI, however, I advise going beyond this usual standard and becoming educated on the foam that a subcontractor will use. Read the manufacturer’s instructions and the product’s ICC Evaluation Service Report so that you know the limits on lift thickness, shelf life, and temperature for storage and use. You may be surprised at the very narrow allowable ranges. For instance, Demilec says that its HeatLok Soy 200 Plus must be stored between 59°F and 77°F. Don’t settle for a certified foreman who’s rarely present. Make sure the on-site applicators have received formal training. Be leery of an inexperienced subcontractor or one who can’t produce training certifications.”


Too often corners are cut – closed cell foam is spayed too thick, proper equipment and site condition monitoring are overlooked.  And when bad foam results and is found, Fennell notes that “the tendency is to spray good foam over bad foam.”  Just bury the bodies, as we say in Brooklyn…..what could possibly go wrong?


The work of a spray foam installer is not well aligned with construction site work.  The spray foam installation process requires careful multi-point monitoring and controlled site conditions.  But the pressures on the job site are constant, pushing to get the subs in and out.  It almost demands a compromised process.  And as noted above, if you have a compromised chemical manufacturing process you have a compromised product.

The industry defenders quote industry saying that the failure rate is at just 1%, or  1/10th of 1%, or less.  Given that it’s industry speaking, we should reasonably double or triple the estimated rate.  Still low?  What if it’s your house? Would you play Russian Roulette voluntarily? Why let the chemical companies put a gun to your head? Are you invincible?


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2 Responses to Reason Foam Fails #8 – Hypersensitive On-Site Manufacturing

  1. Mark Pollard January 20, 2018 at 3:03 pm #

    Couldn’t the same be said for poor installation of any insulation product? As you stated in the opening paragraph, factories are a great place to control and monitor the product and workers doing the installation. BUT each and every component installed in our homes, factory or site built, are touched by human hands. It doesn’t really matter if there is a chemical reaction taking place to make or break a products success. At the end of the day, it is up to the human installing the product to give a damn and the people up the chain of command to give a damn.

    Dense pack cellulose, DPC, is dependent on the operator’s experience and “touch”. Yes, samples can be taken to ensure it was installed to the proper density but verification of each and every stud, rafter, and/or joist bay is not practical. I understand your argument that poorly installed SPF can lead to a number of consequences due to the SPF itself being used primarily as an air control layer, ACL. DPC is usually used in tandem with an interior or exterior ACL, or both. BUT it still performs poorly as a thermal control layer when installation is botched.

    The membranes and tapes you sell through this website are just as susceptible to poor installation practices as SPF. Dirty and damp are commonplace at jobsites and they are definitely not compatible with adhesives.

    Let’s be honest here, builders of the types of homes you wish to market your products to are not the type to use SPF. SPF is an expensive product but far less expensive than the materials and labor used to build a foam free home. A well detailed interior/exterior ACL is far more costly than blasting a 2×6 wall full of SPF and stapling some lumber yard variety WRB over the exterior sheathing. Is the latter a high performance home? No, but it will outperform the average code built house, if done reasonably well.

    Reasonably well is the sad truth of the vast majority of the home building industry. This is not meant to be insulting to those in the trades, it’s just a reality. Until we start placing real value, not lip service value, on these professions we will continue to see products poorly installed.

    • Ken January 22, 2018 at 5:35 am #

      Hi Mark,

      Appreciate your comments.

      Totally agreed that quality control is a struggle across building industry and no matter where one is building or with what one is building.

      Yet the chemical reaction of SPF does change things fundamentally – and raises risks both in the production of quality construction and in the repairability of poor construction.

      SPF installation is like a rocket launch – with a myriad of factors that can make it fail and one chance to work once you hit “go”. If it’s perfect – great! If it’s not – “Houston, we have a problem”.

      Other insulations and air sealing techniques are more like recording music, let’s say, or more like construction. Many parts must be practiced and come together to make the whole work – but there is time to train, work and correct and realize the proper job – then you test/record.

      If i’m doing the equivalent of a rocket launch I’d want it to happen in factory like conditions…..

      And a botched chemical reaction can make the home completely unlivable, and has for many. A botched cellulose install may make the enclosure performance poor – but it won’t destroy the basic habitability of the home.

      And the experts say that installer training is lacking and industry is basically uninterested in meaningful SPF training requirements.

      As for cost – SPF install job is not cheap – and a quality cellulose/INTELLO install should match it or cost less. Sure there is a learning curve, but we have a growing list of installers that do it very cost effectively – confident that it’s better for the health of their workers as well.

      As you probably know, we are not for the banishment of SPF – just the guiding motto that “less is best”.

      And we share your concern for lifting the quality of construction generally and are very happy to work with conscientious builders like yourself.

      All best,

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