I concur with Jim, there's really no need to seal around the valve body.
Just study the situation and seal the trim ring to the tile by whatever
means you like. I just did the three in my house (The ubiquitous Symmons
Temptrol valves). I just replaced the foam "weather stripping" around the
back of the trim ring and made sure the new stuff stood proud by about 1/8
inch. I put a little clear silicone caulk on the foam where it would contsct
the tile, for good measure.
If you happen to have Temptrols, you should be aware that when the "shaft"
seal O-ring on the diverter valve gets hard or worn, the resultant leak
occurs BEHIND the tile wall. I had quite a mess to fix up because of just
such a leak about a month ago. After I replaced the diverter valve seal
O-ring I made up a little sheet brass "chute" stuck on with silicone caulk
which will direct any similar future leaks to the user side of the tile
wall, where it can run out the notch at the bottom of the trim ring and down
the tile surface into the tub.
While I was at it I sealed the spaces around the chromed shower arm and the
tub spout pipe with Bondo. Not so much to prevent leaks through the wall at
those points as to stabilize the plumbing which the original installer had
left sort of "springy". The movement annoyed me because handling the shower
head caused the trim plate to move out on the pipe and not stay tight up
against the tile, and having the tub nozzle move around when cleaning it
just didn't feel right to me.
Happy New Year,
Jeff Wisnia (W1BSV + Brass Rat '57 EE)
"If you can smile when things are going wrong, you've thought of someone to
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