Assuming the shower was tiled properly in the first place - there's a cement board, the shower pan formed properly and a proper liner was used and there are no visible cracks in the tiles and grout, take a look at the sliding door tracks - they can be a nice channel for all the water that's coming down the door. They are supposed to have holes that let the water escape back into the shower pan but the holes may either be clogged or perhaps even accidentally sealed. Since this is from 5 years ago, there may already be some discoloration around one of the ends of the track (the one that just happens to be slightly lower than the other one) that can be a telltale sign of the path the water is taking.
Which floor is this at? Do you have any damage directly below?
Before I moved in, I had a tub/shower with sliding glass door replace with a tiled shower. The renovation was done in 2009. The shower is the whole side of the room (as was the tub/shower with sliding glass door). The floor in the corner of my closet (on the other side of the wall that butts up to the glass shower wall/door) is damp under the carpet. Had plumber out. He cut a square out of each wall making the corner. No noticable dampness in walls. He could not identify with any certainty where the water was coming from, but thought it a good bet it was the shower. He does not do tile or wallboard repair, so we left it at that. The dampness is not much, but is definitely there. What is my my next step and what type of repair person do I call? Any help would be greatly appreciated.
My unit is 1 story on a slab. the holes are open. It looks like there might be a slight discoloration in the grout at one end of the glass wall/door. I appreciate your time and effort in answering.