After graduating with a degree in architecture from Carnegie Mellon, Henri Fennell followed the usual path. He became a spray-foam insulation contractor for thirty years. The whole story is more complicated (and illustrious), but that’s the gist. He now consults with architects, builders and homeowners to ensure that their spray-foam projects go smoothly. At BuildingEnergy Boston, he’s presenting a pre-conference workshop called Can You Afford an SPF failure: A comprehensive look at assuring a quality foam installation and a conference session on What Contractors Need to Know About Spray Foam.
Ireton: Both of your sessions are about spray foam. Is it the perfect insulation?
Fennell: Yes.
Ireton: Why?
Fennell: Because it creates a good air seal while also delivering a very high R-value per inch of insulation.
Ireton: But aren’t there environmental concerns about the blowing agents being used in spray foams?
Fennell: Twenty years ago, yes, but we’re now on the fourth generation of blowing agents, and the ones used today have a very low global warming potential (GWP), especially in light of the fossil fuel saved by using spray foam.
Ireton: Okay, so what’s the secret to a quality spray-foam installation?
Fennell: Follow the directions.
Ireton: Really?
Fennell: If you follow all the manufacturers recommendations, you will have no problems.
Ireton: How hard can that be?
Fennell: You’d be surprised. I was recently hired to oversee the application of a spray foam job. I wrote the specs, went over them with the installer and was on site every day. On the first day, when the installer was ready to start, I checked the temperature of the tanks and they were at 50° instead of 90°. I made him warm up the tanks. We did that every morning, and even on the fifth day, he tried to start with the tanks at 50°.
Ireton: Your client should have hired a licensed installer.
Fennell: Unfortunately, there is no licensing for spray-foam installation. The Spray Polyurethane Foam Alliance (SPFA) has a professional certification program for installers. It’s better than nothing, but it’s not a requirement anywhere.
Ireton: So how can I be assured of a good spray-foam installation?
Fennell: The number of failed installations is actually pretty low. But when there are problems, 75% result from how the foam is processed, which is everything that happens from the drum where the chemicals are stored to the nozzle of the spray gun where they’re delivered. The three parameters for proper processing are the heat at which the chemicals are maintained, the pressure at which they’re delivered, and the proportion in which the two-part system is mixed.
The remaining problems are with installation, where air temperature, humidity, moisture content of the wood, and compatibility of substrates all come into play.
Ireton: If it’s so tricky to work with, maybe folks should avoid spray foam altogether.
Fennell: It’s no trickier than concrete, which also has to be mixed, poured and cured properly. For instance, you can’t pour concrete in freezing temperature without taking precautions. It’s the same thing with spray foam. We just have a lot more experience working with concrete.
Ireton: Well, if there is a problem with a spray-foam installation, will the failure be catastrophic?
Fennell: No. The problem is the foam breaking and pulling away from the substrate. In my early days as an installer, I knew I was in trouble when I heard the foam snap, crackle and pop. That means you’re not getting a good air seal, and there could be moisture problems down the road. Is it still better than other insulations? Absolutely, but it’s not what the customer paid for. So that’s what I’ll be talking about at BuildingEnergy Boston, how to ensure a premium installation for a premium product.
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Kevin Ireton graduated Phi Beta Kappa from the University of Kentucky and then, perversely, went to work as a carpenter for 10 years. In 1986 he joined the staff of Fine Homebuilding, and suddenly his odd career choice looked like a well-thought-out plan. A few years later, he became the magazine’s chief editor and held the position for 17 years. Ireton retired from publishing in 2009, but continues to serve the magazine as an editor-at-large. He lives in western Connecticut with his wife and dog, and works as a freelance writer and a builder.
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