Hello there, I'm in need of a recomendation for insulating an exterior bathroom wall (shower enclosure) that is gutted to the 2x3 studs as part of a bathroom remodel. I intend to use cement board and subway tile to finish the enclosure but need to figure out the insulation before I proceed. Because of the 2x3 construction I'm having trouble as I originally figured I would install faced batts; which would have to be compressed to fit thereby affecting the R-value. I've asked around and some suggest hiring a professional to spray closed cell foam, while others have suggested using rigid foam board insulation. I'm not sure how a vapor/moisture barrier or retarder will come into play here. I certainly don't want to grow any beasties in my walls (once I have some again .) Thanks in advance!