This is a picture of the master shower in my sister's house. It's all slate, and they told her they sealed it, but I couldn't find a trace of any sealer on it.

You'll notice that the area all around the drain is still wet, and there are a couple of spots where the floor meets the wall that moisture is wicking up the wall, particularly on the right side of the photo.....and this is about 10-12 hours after the shower had been used. I also found at least three areas where the floor was either flat or sloped away from the drain, and water was either still standing there, or the floor was still damp.

My guess? The liner is flat on the floor, and the wall board (no telling what it is) is sitting on the liner.

Before anybody asks, I told her what to watch for while they were building the shower, but I don't think she did. Probably in two or three years she'll be asking me to fix it all for her.

On a side note, the whole 3500 square feet of this house has wood flooring. I warned her against that in the wet areas, but she didn't listen to me on that one either.

Sisters.....

Update: My sister said the installer called her the other day and told her he would re-seal the shower, but if that didn't work, he promised to tear it out and start over.

I told her it had nothing to doing with sealing the tile, but I guess she wants to let him try once more before tearing it out.

Yep ... he should have done it right thr first time.
But now she has her brother's insight to arm herself with.

I had my builder say it was the tiler's fault! Everything done here was pretty much done at my place, and well before I was around to see it done wrong. Nails through the liner, no preslope, mortar blocking the weep holes, and the winner?
fiber board used to build the shower dam