St. Louis has high humidity in the summers and then cold, dry winters. I've had one local "expert" tell me that because of this, no vapor barrier should be used in my particular situation - complete shower remodel with one of the 3 shower walls on an exterior wall. While another said it is required.
When I pulled the old fiberglass shower there was no vapor barrier between it and the 2x4 studs that make up the exterior wall. The pink insulation had mold on it. BUT...I can't be certain of the cause because the old siding on the house had been so neglected, I'm told, that there were holes everywhere. Whatever the material is that the old siding was attached to has all sorts of water stains on it. So I don't know what ultimately caused this.
All I want to do is remodel my bath in the way that makes the most sense for my climate. Is there anyone in the St. Louis area, or even the region, that has experience with this and can point me in the right direction?