I've just about completed a bathroom remodel, and it looks great. But the new concrete backer-board and new 18x18 tile is about 3/8 thicker than the old drywall and 4x4 tile. I've got a single-handle shower valve (pull-on/push-off, left to right for temp). The thicker wall puts the valve too far into the wall for the knob to properly engage. This is (I think) a Delta valve that was existing in this 1980's house. It has the replaceable cartridge. I need an extension for the stem, so I don't have to re-open the wall, destroying the wall tile (after removing the all glass frameless shower enclosure).
I've already cut the outside shell of the knob, so the center extends deep enough to turn the cartridge, but when pulled out, it doesn't engage the stops, so you have no idea what temperature you're shooting for.
Someone before me just have made this error, and someone must make an extension for the valve stem, I hope!