Grout staying wet 8 hours after shower
A remodel of my master bath was completed on 12/20/13 and my first shower was that night... Fast forward to a couple of days ago when I first noticed that the floor/wall grout joint, on the shower head wall, was still wet/dark 8 hours after showering. This could have been happening all along, but I only just noticed it a couple of days ago.
The shower head, diverter and handheld shower are all on that wall (see photo), but the control valve is located, waist high, on an adjacent wall where PEX wraps around 3 corners before it gets to the 3-way diverter. A good exhaust fan runs during the shower and continues for another 20 minutes.
There is no dampness visible in the rest of the grout after only 2-3 hours, just the joint below the shower head.
What I think may be happening is one of two things; either water remaining in the pipes after shutoff is slowly leaking somewhere around the diverter valve/shower head/HH elbow, or water is getting behind the diverter valve and/or sprayer elbow when the HH sprayer is used to rinse down the walls after showering, but I think this is less likely because the holes in the tile are very tight to the pipes. To test this, for the next few showers I'll only rinse BELOW these two areas to see if there is any change.
I installed the TRIM for the fixtures, but I had the plumber install both elbows where they screw into the main plumbing in the wall. Didn't want to take the chance I would not attach them properly and end up with a leak I couldn't see.
The plumber used only Teflon tape to wrap the threads on the elbows, no pipe dope, when I think the Delta instructions said to use both. I questioned this, but he said the dope was not necessary. He also didn't install the plastic washer between the HH elbow and the tile saying it was too thick and wasn't necessary anyway.
Any suggestions on how to determine what is causing the damp grout would be greatly appreciated.
Thanks in advance,