My upstairs fiberglass shower doesn't leak when you run water in it, but leaks when someone is taking a shower. I've checked out all possible leaks and it seems the only thing I can figure out is the floor "gives" with the person's weight. How can I fix this without taking the whole floor out?
Have already paid a plumber $400 who has come 4 times trying to fix it -- without success. Installed a new gasket, new caulk in drain area, plumbers glue in drain area... everything but replacing the drain and floor pan. Hole in ceiling below is too small to get tool in there to replace drain, and he is afraid of damaging floor of shower making hole bigger.
What to do??

Hi CJ,

You're caught between a rock and a hard place. The showerfloor should have been bedded down at the time of installation. You wasted your $400 because every time you put weight on the floor it destroys the drain seal a little bit more until you don't have a seal left under the lip of the drain. Short of pulling it out and bedding it with mortar or cement I would see about opening up the ceiling until I could shore the floor up with wood on top of the floor joists or ceiling rafters. If you don't this problem will just continue.
I'm surprised the plumber didn't tell you this before he made off with your 400 bucks. There just isn't any "magic fix" to this. It's something that should have been done and wasn't any now, (through no fault of your own) you're paying for it. Good luck and you have my sympathy for the shoddy workmanship. Regards, Tom

I was afraid you were going to say that! Thank you for your quick response. It appears the shoddy workmanship was from start to finish... at installation and with the master plumber later.
I guess it might be good therapy to demolish the shower and start over rather than "demolish" the plumber, huh?! Either that or make it into a closet!