We encourage you to follow along on our Living Building journey. Stay tuned to this space to see the challenges that arise from this project and how we approach and solve them, as well as how we approach the education and equity petals of the LBC. 

The Spray Foam Blues – a Middle Way

Written by Owner Todd Vogel and Chris Hellstern, Living Building Challenge Services Director at Miller Hull Partnership

Remodeling a house as a Living Building can require some big moves, such as installing solar panels or triple-pane windows.  But, then, we can engineer the world’s tightest building envelope, and defeat all that work by neglecting a hole some place in the wall or roof just the size of a quarter. It’s the small, day-to-day construction methods that can make or break a project.  

The result of this cruel truth is that we need to be aware of the potentially big consequences of seemingly small, day-to-day decisions.  We – Todd and Karen and Chris Hellstern, AIA, the Miller Hull Partnerships’ Living Building Challenge Services Director – wanted to team up for a blog post about one of those unexpected, but important stories. The real story, in the end, is about how a well-thought-out compromise can make dramatic differences in our building’s impact on the climate and fellow human beings.

The topic is spray foam insulation. On the surface, it sounds like a dull subject. Things get more interesting, however, when you consider the fact that spray foam is the building industry’s version of a Faustian bargain:  it does an amazingly effective and low-cost job of providing insulation that reduces energy bills, but it is one of the most toxic, greenhouse-gas producing products known.  

Even if spray foam created a remarkably tight envelope for Todd & Karen’s house, the greenhouse gases generated would damage the climate more than the project could ever hope to save through energy conservation. From the start, the design team worked hard with the aim to eliminate all spray foam from the house.  But we learned, even with spray foam’s toxic chemicals, that we couldn’t be absolutists.

First, we turned to rigid, blown-in cellulose and batt insulation. Cellulose and fiberglass insulation contain relatively few toxins that damage kid’s IQs or cause cancer. Each of those products does boost chemical pollution and global warming and they make for thicker walls, but none is as earth-and-person damaging as the foam. Check out this chart from the Health Building network and the Natural Resources Defense Council in its report, Making Affordable Multifamily Housing More Energy Efficient:  A Guide to Health Upgrade Materials.  And notice that spray-foam isn’t even the most cost-effective solution, when measured as cost per R-value – the capacity of the material to insulate the building.

NRDC Chart Insulation Replacements.jpg

Now for the really bad news. Scientists have 30 years of research showing spray-foam’s health effects.  The chemicals in the foam – most of which have other-worldly names like isocyanates, formaldehyde and phthalates – disrupt the body’s hormones, which can cause tumors and birth defects. These chemicals, as well as the flame-retardants baked in to the foam, also cause diseases like asthma. 

The damaging chemicals affect not just those who live or work in buildings with these spray-applied insulations but also the workers who make them and the craftspeople who install them.  Look here, for example, to see the Center for Disease Control’s summary of 14 years of study on the impact of isocyanates on workers. 

Justin Ansley, Clark Construction’s Superintendent for Loom house, screws up his face at the mention of spray foam. He is used to seeing spray foam on the job and watching sub-contractors pull on protective suits and respirators. But the process is still brutal, he says.  The perils are inherent in the chemicals added to create a spray method of application. “What you have to do to liquify foam is going to be disgusting,” he sighs. Until the product chemistry changes, it will be unsafe. 


The effect of the chemicals continues to ripple into wider and wider segments of society. Those chemicals have to be produced before they mix to make the foam.  Neighborhoods near chemical plants – which are often are low-income and predominantly filled with people of color – live with higher levels of these pollutants in their schools, their playgrounds and their homes. Making matters worse, these chemicals don’t eventually go away. Scientists call them persistent bioaccumulative toxins, meaning they remain in the environment and in any species that encounters them.  

When you have a minute, check out this clear-eyed overview by a scientist of how these chemicals accumulate in our children, harm them and even pose a threat to our society as a whole:

Embed Simon Fraser video on damaging children: 

Spray foam’s toxins led the Living Building Challenge to prohibit it in new buildings. However, the LBC acknowledges that remodels like ours are tougher to insulate than new buildings.  Loom House, for example, is 50 years old, and, although it was well constructed and well cared for, the years have made the walls and every other angle less straight or exact.  This makes cutting a piece of insulation for each crack a painfully customized job. 

Todd and Karen could have a carpenter cut a piece of insulation to fit in each spot exactly. Or, they could have a less skilled hand walk by with a can of spray foam and close the gap tightly in a fraction of the time. A home like Todd and Karen’s would typically require about three cases (36 cans) of spray foam to fill cracks. The cost of the materials and the labor would run approximately $3,000.  Customizing the insulation was quoted as costing nearly three times that.

Environmentally friendly insulation used at Loom House

Environmentally friendly insulation used at Loom House

But there’s at least one more cost to account for: the greenhouse gases that spray foam creates. The global warming potential of spray-applied insulation can be staggeringly high.  It produces hydroflurocarbons (HFC’s) and hydroflurooelefins (HFO’s), which can be more than 1,000 times as potent as carbon dioxide.  That’s why a building’s spray foam might cause more greenhouse gases over its life than it would save through the insulation’s ability to help it save energy. 

In fact, it may be better for the environment to have a building that uses more energy rather than one that uses spray foam.  We had to have a careful, targeted plan for any use of spray foam in the Loom project or a seemingly small off-the-shelf product creates devastating consequences.    

Karen and Todd did not want to choose between spewing out the greenhouse gases and endangering workers on one hand and paying a 300% increase for custom-cutting of insulation everywhere. 

Nevertheless, we needed to make sure the small cracks and pinholes were closed off, or all the time and money we had put into insulation would be wasted. (Remember that a hole the size of a quarter would undo all our work.) 

The solution rests not in making spray foam an either/or decision.  Instead, Justin and his crew used spray foam only as a last resort. They set about cutting strips of insulation for the easy-to-reach places.  When a place was extremely difficult to reach or fit – and no other option would do so well – out came the spray foam.  In the end, Justin and Clark reduced the amount of spray foam from 36 cans to *three*. Yes, the labor involved cost more, but not very much more. In fact, it added less than $1,000 to the budget – and reduced the greenhouse gases and those toxic chemicals by 90 percent.

While the Loom House strives for the ambitious goal of full Living Building certification, the project’s most important lessons may well lie in the way it navigates between the twin challenges of cost and responsibility to the environment and our fellow humans.  

Spray foam is an excellent solution for some problems. That doesn’t make it an excellent solution for the entire house. If we restrict spray foam to the places where it does its job best – those few hard-to-reach, small, awkward gaps – we can cut our use of this toxic material enormously. Cutting it out completely, of course, would be terrific.  But even if we spend just a little more money (and use spray foam sparingly), we can create huge benefits for the health of our families, our workers, our communities and for the environment.

And ultimately, the Living Building Materials Petal strives to create market demand for safer products. Can we one day have the energy saving and labor efficient benefits of a spray foam but avoid the toxic ingredients and throwing gas on the planetary fire of global warming?  Hopefully yes. But even now, by thinking strategically, we can improve our choices and our future.

Written by Owner Todd Vogel and Chris Hellstern, Living Building Challenge Services Director at Miller Hull Partnership

todd vogel