OK want some opinions, What is everyone’s take on putting a plastic vapor barrier behing the backer board in a tub or shower enclosure. Sounds like a great place for mold to grow in my opinion.
Info here may help you. Keep in mind that if one of those walls is on the exterior, you should have a vapor barrier or unless it is already part of the waterproofing required for a tiled shower.
Your Bathroom Remodel Starts With the Vapor Barrier on the Shower Walls at TileTip.com