I have a shower that is leaking out underneath the fiberglass pan. Just a small amount. The walls are tile. I have had numerous people ( plumbers and tile people) look at it. Some think the plumbing is leaking. Some say it is the tile. My house is 17 years old. The shower is on the second floor ( no leakage in the ceiling down below). We can't see any leakage in the plumbing to the faucet. I am ready to pull the entire thing out and start from scratch. Any ideas? The problem started about 10 years ago. We just stopped using the shower, but now it is time to sell. I really hate to spend $2500 if I can solve the problem.