[Arky217]

For a mixed humid climate (Arkansas),
what would be the minimum thickness or R-value of foam board over OSB wall sheathing to prevent condensation in the colder months on the inner surface of the OSB when the wall cavity batts are R-19 ?

Thanks,
Arky

[Ron6519]

If you're getting condensation on the interior side of the OSB, it sounds like there is no vapor barrier on the interior(or it's leaking,badly).
Ron

[Arky217]

Originally Posted by Ron6519

If you're getting condensation on the interior side of the OSB, it sounds like there is no vapor barrier on the interior(or it's leaking,badly).
Ron

According to buildingscience.com, no interior vapor barrier should be used for a mixed-humid climate; just the vapor retarding of the latex paint over the drywall. Their reasoning is that the wall should be able to dry in both directions in a mixed-humid climate.
The walls haven't been built yet, I just want to keep the osb board warm enough in the cold months, as per their (buildingscience.com) recommendation, to prevent condensation on the inner surface of the osb.

[Gary in WA]

I would not use OSB or R-19; http://www.buildingscience.com/docum...d%20in%20walls
http://bct.nrc.umass.edu/index.php/p...d-and-plywood/
http://www.diychatroom.com/f98/how-b...ulation-90438/

http://www.greenbuildingadvisor.com/...foam-sheathing

Gary