Roof/ceiling insulation for new home in climate zone 2a
Designing house to be built, general contractors and insulation salesmen all telling me they all do this and it's fine.
5.5 inches of open cell foam at 0.5 pound density in under-roof rafter cavities.
Depends on one's definition of "fine."
But the code says to insulate to R30, and 5.5 inches of a foam such as that is only to deliver R16 to R20.
The contractors and the insulation salesmen say not to worry, because R does not mean as much as air sealing, and that the water-blown open-cell product they use has "superior" air sealing capacity.
Are they wrong? What should be done?
Posted Wed, 08/28/2013 - 15:45
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