Vapor Variable Air Barrier over existing kraft-faced fiberglass batts in my rafter bays?

I have a finished attic space with HVAC ducting behind the kneewall in a vented, unconditioned area (I know, not ideal, but not my design either, and I can’t relocate… I have a finished attic space with HVAC ducting behind the kneewall in a vented, unconditioned area (I know, not ideal, but not my design either, and I can’t relocate…Read MoreGreenBuildingAdvisor