Vapor barriers and vapor retarders are two different beasts: http://www.energysavers.gov/your_hom.../mytopic=11810
If asphalt-coated paper (vapor retarder) on the insulation, it is vapor variable
Your Zone requires a Class 1, or 2: R601.3 Vapor retarders. Class I or II vapor retarders are required on the interior side of frame walls in Zones 5, 6, 7, 8 and Marine 4.
It is not a vapor barrier- Class I: R601.3.2 Material vapor retarder class. The vapor retarder class shall be based on the manufacturer's certified testing or a tested assembly.
The following shall be deemed to meet the class specified:
Class I: Sheet polyethylene, unperforated aluminum foil.
Class II: Kraft-faced fiberglass batts.
Class III: Latex or enamel paint.
So any vapor from the inside will not condense due to the foam board (1") on the attic side. You don't even have one vapor barrier to "trap water". The foam board would need to be 9"
or so thick to stop all moisture movement.
You want to stop air/moisture from getting to the cavity from the conditioned space (inside room):http://www.buildingscience.com/docum...wall-approach/
Sounds as if it already done, at least air seal the drywall bottom edge to the floor- as per Code minimum, with caulking or canned foam; number 6: http://publicecodes.citation.com/ico...002_par021.htm