I am remodelling my bathroom. My tub is in a 3 wall alcove with 2 of the walls being exterior walls. The plumbing is on one of the exterior walls. I have read different opinions about using felt paper for a vapor barrier between the studs and cement board. If I use felt paper should I use faced or unfaced insulation on the exterior walls? Also, what needs to be done to the places where the plumbing fixtures come through the felt? Won't this leave holes for water to get into the walls? I can't find any instructions or videos on this. None of the videos show this area which I would think would be the trickiest and most important area. Am I wrong? Do I just cut holes in the felt for the plumbing and not worry about it? I sweat the details, especially the ones that get covered up and are hard to go back and fix if they are wrong. Any ideas, instructions, or links to good sources?