I have a leak in my shower/tub that I have not been able see where it is comming from. This is a new install I just did. I took the drywall off the closet, which I guess is OK, needed acess to the plumbing and at least it will always be there.
I have a Danze PB valve with a 4-port dirverter. I run tub, shower and hand shower off the dirverter. From the back I see nothing leaking yet the floor is soaked and you can see the water run out of the grout by the tub [I have not caulk yet]. The water must be comming from a fitting and rolling down the felt paper and then go down side of tub where it reaches the floor. This would explain why I can see any water on the backside of the paper
My guess is two things:
1] I think it is the hand shower. A brass pc threads on the nipple, this pc has o-rings on it and the finish pc slides on that then tighens with a set screw. This is a guess but could the water hit the finish mounting pc and shoot back down the hole cut in the tile, then follow the paper down to the floor?
Problem solved, answer is that Danze is garbage! One thing good is they have great customer service. Almost everything I bought had some defective in some way but the sent good replacements that arrived in a couple of days. So far they have sent me  shower valve trim kits,  shower valve cartiage,  diverter valve cartiage, and one complete angle mount elbow.
I never really found the leak but it was either where the brass pc threaded on the nipple [I used teflon tape and thread compound] or a problem with the o-rings.
I will have trouble buying danze again. The price is good, the trim pcs are nice [brass and nice and heavy], the cartiage are plastic the service was great.