phantom leak
OK, that is good for me to understand. I know that behind the tile is a kind of green board. I know that lots of caulk has been applied, for example at the bottom where the tile meets the tub, around spout, escutcheons, along the shower door. I do not know whether grout or caulk was applied at the base of the green board, where I was thinking there should perhaps be a tile flange. I read in an older Terry Love forum that if this joint isn't done properly, water can wick to the back, back behind the wall, which is where the water begins to accumulate in my case. My understanding from that forum was that the green board is a hard surface, the tub is a hard surface, and there has to be something with a bit of flexibility between the two. Otherwise, if anything moves, a crack would appear in a joint with no flexibility.
I cannot see any obvious cracks in the grout, but I will look again. Other things have also made me wonder about the grout. I am wondering whether the grout could just be poor quality such that small amounts of water can seep through. One plumber mentioned to me that there is some type of grout sealant.
So two possible courses of action at the moment are 1. grout sealant or 2. Take legal action against the tiling guy to have the tub to green board joint redone. It would probably mean essentially redoing the tiling job.
To review the symptoms: When someone takes a long shower (it is a tub with a shower), if you open up from the back behind the shower head wall, you can see water accumulating in a small channel that is in the tub on the other side of the tiled wall. This small channel is just a part of the tub, when the tub goes back of the shower head wall. I believe that the green board sits either in this channel or in front of it. Anyway, the channel fills and then starts overflowing into the basement.
At the moment, I have two shower curtains, one on either side (that is one that runs against the side tiled wall and another that runs along the door). When someone takes a shower, we pull these two shower curtains together at the front and clip them together. We still get leaking. It is very difficult to figure out how. But it seems to me either the front tiled wall itself or perhaps some water is getting around the curtains to the base of the front tiled wall and then getting wicked back.
It is also very hard to "make" the leak happen by splashing water directly on either the wall, eschucheons, wall to tub joint etc, usually you can pour lots of water on and no water leaks over. Then sometimes you pour lots of water and eventually will see a bit of leaking but it is hard to figure out what you did to make that happen. Thanks again for your help. Ruth