There are a lot of reasons to avoid foam, but its high performance can make it a hard habit to kick, as designers are finding out.
by Tristan Roberts
Bora Architects is designing a 22,000 ft2 early childhood center addition for the Earl Boyles School in Portland, Oregon. Bora has switched to mineral wool as its standard insulation material for rainscreen walls like this one, in part because of toxicity concerns with foam insulation materials.
Rendering: Bora Architects
If you’ve ever held a Styrofoam cup comfortably in your hand, only to scorch your tongue sipping the piping-hot coffee inside, you know that plastic foam is a really good insulator. It’s also lightweight, generally impervious to moisture, relatively cheap, and strong.
With all that in its favor, it would take some effort to find a contemporary, high-performance building that doesn’t incorporate foam insulation into key parts of its assembly. But a dark side to foam has come into focus over the last decade. To name a few issues, its manufacturing process can be polluting, its global warming impact can be stratospheric, it is laden with toxic flame retardants, and it is highly flammable, even with those chemical additives.
While there are moves outside the industry as well as within it to clean up foam, some projects aren’t waiting for that: they’re designing and building without foam wherever possible, looking to mineral wool, cellulose, cellular glass, cork, aerogel, and other products to provide high performance with what they perceive to be fewer environmental and health tradeoffs. After talking with numerousprofessionals who have worked to avoid foam insulation, here are the war stories that we heard, along with our research on cutting-edge insulation materials.
