Hi folks, thanks for all the replies. My interest in green is that it makes me sick to pollute the planet-- thats about my whole philosophy. So, I want to go as green as I can. My confusion with the bathroom is that on one hand you want surfaces to be waterproof and on the other hand you want them somewhat permeable so the walls can "breathe". I'd like to use a natural insulation (at my last house I used chopped up recycled denim--i can't remember the name), but since this is going to be near water I thought maybe this would be too mold friendly??? But maybe not??? So far what I have looking in through my bathroom from the roof is roof shingles, then wood, then about 5" of air, then the remaining wood laths from the interior wall. So if someone were me--what would you use? Am I supposed to put some kind of flashing against the inside of the roof? Or is that not necessary? I'm thinking i would use insulation, then sheetrock, then backerboard, then tile. Do I have it right and if so are there natural alternatives to those items. Also, someone mentioned lime plaster but I think that takes time to cure? Thanks a bunch.