Hi everyone. I'm new to the forum and it seems there is a wealth of great information here.

I'm currently working on a masterbath remodel and I'm ready to install the cement backer (Durock) for the shower walls. It is a corner shower. The interior wall will be insulated with r-11 unfaced insulation. The exterior wall has the same insulation. My question is should I put a vapor barrier up between the insulation on the exterior or interior walls? When I called USG they seemed a little vague stating that the vapor could cause mold build up if water got behind the Durock but it was common to install the vapor barrier.

The Durock will go up about 6' from the shower floor. I'm using green board for the last 2' of the wall on both walls. I am not installing a vapor barrier behind the green board.

Thanks for your advice,