"Javier" wrote in message
...
I seem to have me a leaky shower stall...

It's lined with ceramic tiles, both the floor and the walls, there's a
single drain in the center of the stall. The bathroom is upstairs, above
the garage, which is finished with drywall, including the ceiling. A few
weeks ago I noticed some water stains on the ceiling in the garage right
below where the shower is, so I cut a large-ish square hole, and it was
indeed wet. Through the hole I see the joists, supporting OMB boards. I
guess those OMB boards are the floor of the bathroom. I see the drain pipe
coming from the shower and going wherever it goes, but the pipe feels dry
to the touch. I don't see leaks at the elbow joining the pipe coming down
from the drain to the one going sideways. The OMB board was damp to the
touch.

I took out the grille covering the drain, and looked down the pipe. I
didn't see anything other than, well, white PVC pipe.

I didn't use the shower for a few weeks to let things dry out, meanwhile I
applied some silicone caulking around where the drain fixture joins the
floor tiles (the drain fixture is plastic), and at all around where the
floor and walls join (the grout didn't look broken at all, but I figured
it couldn't hurt...)

A few days ago I resumed using the shower, and the OMB board feels damp
again.

What steps could I take next to troubleshoot this, besides calling a
plumber?

If you are lucky, you have a leak in the drain piping, or
around the faucet controls or where the shower head
screws into the wall. More likely, you have a failure of
the shower pan, which would require tearing the shower
floor apart and rebuilding it. Searching on mud set
shower repair or tile shower repair might get you more info.

http://www.thetiledoctor.com/repair/leakypan.cfm for instance.

Bob