Flash And Batt (Climate Zone 2)
GoBuildItRight
| Posted in Energy Efficiency and Durability on
I’m in the middle of remodeling my house and would like to air/bug seal the exterior fiberboard sheathing from the interior. In order to do this, I’m considering the Flash and Batt insulation technique. {Flash (1/2″-1″Closed Cell Foam) and Batt (mineral wool)}. I know there’s serious concern with this building technique in the northern climate zones due to condensation but was curious of anyone’s thoughts or personal experiences with Flash/Batt in Climate Zone 2 and how much Closed Cell Spray foam thickness should be utilized?
The existing exterior wall makeup is:
2″ Brick Facade, 1″ Air Gap, 1/2″ Fiber Board, 2×4 Stud Walls, 1/2″ Gyp
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Replies
GoBuildItRight,
There is no minimum thickness for the foam in climate zones 1, 2, or 3.
It's going to be nealy impossible to get an even layer of closed cell foam applied only 1/2" thick. 1" is probably about the minimum installed thickness that is achievable in practice, and it's not going to be particularly even, even if you have a professional crew do the installation.
You may want to consider doing a full fill of open cell spray foam here and see if it's about the same, or even less, money than the flash and batt you're considering.
Bill