Quote Originally Posted by dj1 View Post
First solve your leak problem before you start any repairs.
I'm 95% sure that the leak is caused by the shower water running down the bath walls. I had my son downstairs watch for leaks, while I was upstairs running the shower with a plastic collar around it so it wouldn't splash onto the walls. He saw no leaks, verifying that it isn't the incoming water pipes causing the leak.

Soon after I removed the collar off the shower and let it sprinkle in its normal fashion, we started having a leak in the basement. To me, this signifies that the leak occurs when the water hits/splashes/collects on the tiled walls. It also does not leak when the tub is in use, so I concluded that it's not the incoming water pipes nor the outgoing drain/fittings.

Quote Originally Posted by HoustonRemodeler View Post

Tile + grout + sealant is NOT waterproof. In fact none of those elements are waterproof. The tiled area should be waterproof (not just water resistant) without any tile on the walls.

How was your tile substrate constructed?
I honestly couldn't tell you how or what the previous homeowner did; we haven't remodeled the house and it's from the 50s, so for all I know -- the tile/grout could be that old. Not sure if it was sealed; is it possible to tell by its appearance? I assume that sealed grout looks a little slicker/smoother than the chalky/rough/porous stuff I've got.

Looking behind the soap dish that's falling off, I can see what appears to be plywood, not some vapor barrier, plastic, drywall or otherwise. It also looks like they used a ton of white stuff (grout maybe?) to stick the soap dish onto the wall.

We don't use the soap dish so I'd have no problem removing it if I knew how to put up 2 tiles in its place; we've found a few matching tiles in the basement that we could install.

Right now, we need to keep the bathroom moisture/leak from getting worse. We eventually plan on remodeling the bathroom & perhaps enlarging it within a year or two, so I'm not too keen on ripping out all the tile and starting over right now... but we'll definitely do a vapor barrier and "the works" when we remodel/enlarge the bathroom.