HVAC in unvented, spray foam insulated attic?

[jbreazeale]

Really informative thread, guys. I'm almost convinced! But I'm with Kenton concerning moisture trapped in the sheathing. Guess we'll all find out eventually.

[William D. Miller]

I'm new to Icynene, but I understand it's an "open cell" product that allows moisture to slowly penetrate. I'm told that any roof leak would manifest itself as a slow leak through the icynene directly below the leak. Can anyone confirm?

[Blaine Wiley]

I ran into an insulation contractor yesterday that was spraying the attic. He assured me that any moisture from a leak in the roof will travel through the foam insulation.

He joked that it will show up more readily because the sheetrock ceiling will have a stain on it real soon!

None of the older attics or homes I've inspected with this type of insulation have had any moisture issue. Of course, we have no humidity near the coast here in FL....