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Old 08-09-11, 08:17 AM   #10
S-F
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Most of the recycled sheets of polyiso are 2.25" which are something like R 15.7. They are called R 16 boards.
There is a growing body of evidence suggesting that spray foam , while nothing like UFFI, may still have some negative qualities. The catch is that once it cured it's supposedly completely neutral, but only when mixed properly. Apparently when it's not mixed properly there can be a lot of issues. And also it appears to be pretty difficult to get the mix correct. Even for seasoned professionals.

And besides, cellulose is awesome. Sure the R value is a little bit lower but the other benefits are fantastic. The hygroscopic value of it is amazing. I wish my walls were 12" of cellulose. It's also probably the greenest insulation there is.
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