Spray-foam insulation has become a weapon of choice for many builders and homeowners trying to build tight, energy efficient houses. And with its long list of attributes, that’s no wonder. It fills tiny cracks and fissures in walls and roofs to form an effective air seal. The high R-values of closed-cell foam pack a lot of punch in a small space, and closed-cell versions can block the movement of moisture into wall and roof cavities. Expensive as it may be, it’s at the top of its class.
But does this miracle material have a darker side? Dan Fette’s question about the potential hazards of spray foam launched an extended thread containing enough anecdotal information to give a few readers pause for thought and dissuaded others from using foam at all.
Polyurethane foam is a two-part compound mixed at the job site as it’s sprayed from a high-pressure gun. Although some of its ingredients are nasty at the time of application, when it cures the foam becomes an inert material that should not off-gas any harmful chemicals. That, at least, is our common understanding and the word from manufacturers and installers.
Typical are these words of assurance from Foam-Tech:: “Urethanes are non-toxic and only require protection for our operators during installations, but the finished product is completely safe and has no formaldehydes.”
Some dissent from the field
But that sunny expectation doesn’t always pan out. An anonymous poster reported developing a serious chemical sensitivity while building an “uber-green” house, which included non-toxic wood finishes and closed-cell polyurethane foam.
“I became ill after moving into the house two years ago, and had to move out,” Anonymous wrote. “Any exposure to the indoor air induces neurological symptoms…I never had these sorts of problems before that I know of.”