A version of this article appears in the January/February 2009 issue of Home Energy Magazine.
January 02, 2009
Where’s the High-Density Foam? I was looking over your article in the Nov/Dec ’08 issue (“The Long Island Green Homes Program,” p. 6) and noticed that the description of the picture on p. 8 is incorrect (see photo below). In the rim joist I can see a kraft-faced Certain-Teed fiberglass batt installed, not 4-inch high-density foam. On the facing of the kraft-faced material it notes you cannot leave this material exposed because it’s flammable. David C. James Santa Barbara, California Author Rich Manning replies: That is a good observation, but let me explain. The foundation is an 8-inch concrete block wall and the house was built in the 1920s; therefore it had balloon framing. The picture that I took was taken before the work was completed. We had sprayed 4 inches of high-density foam along the rim joist, not only to insulate the rim joist and underflooring, but also to use it for fire blocking. We wanted to finish it with the Thermax so it would look uniform and not be recessed, so we filled the space between with fiberglass to fill the void and help slow down air movement. It doesn’t&...
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