I have a leaking shower (two-handle, washers have been replaced by plumber every few years, still leaks), and I was thinking of just putting a shower cutoff valve on the shower head, the one where you turn off the knob while soaping up to save water and then turn on the knob to rinse off, and of course I would turn the knob to off when not using the shower (ie. almost 24/7). But my concern is that with the leak, the hot and cold water would always be mixing behind this cutoff valve - is this true? Any harm in doing so?
I could just get a plumber to replace the old shower faucet and then a tile guy to replace the tiles, but that's a lot of $$. If I do replace the shower faucet, though, should I get a two-handle or a single-handle? The other shower in the house has an old Moen single- handle which works fine. Also, is there any inexpensive way (fiberglass?) to overlay the existing tile wall, so I don't need to clean the tiles and keep re- caulking the seam to the fiberglass shower base?
Thanks.