I've remodeled the bathroom and I'm installing new tile and have a single water control valve. What do you do to seal around the single water control The valve cartridge is what extends through the opening.
There is trim that goes over it, however, I didn't know if it was necessary to seal off the wall opening other than with the trim.
Over time the seal will dry out. To keep it sealed, I run a small bead of clear caulk around the perimeter of the plate. If you visualize the plate as a clock face, I run it from 7 0'clock around to 5 o'clock leaving the bottom open for drainage.