If you have an old shower with separate hold and cold taps, you know the pain if someone flushes the toilet or runs hot water elsewhere in the house. Modern shower valves solve this problem by equalizing water pressure and maintaining temperature if this happens.
I was watching an episode of “Ask This Old House” where they replaced a dual tap shower valve with a newer mixing valve. The trick was to use a special plate which would cover up the hole left by the old handles. I decided to attempt this reno on my own tub but instead of using a plate, I would patch the tile. This would be a “temporary” fix until I could replace the tub and re-tile the walls. Replacing the faucet would need to be done in a complete bathroom reno anyways.
I had access to the back of the shower through an access panel in a bedroom closet which made this job much easier. I was also able to match the almond tile colour with bulk tile found at Lowes (buy a few extra pieces in case of breakage).
One of the trickier parts of the job would be cutting the tile for the openings for both the new valve and spout. I ended up buying a circular tile cutter from Harbor Freight to do this.
I hadn’t soldered pipes before (only electronics) and had a very old propane torch. As with any soldering, surfaces need to be very clean and flux needs to be applied. With the torch, it was a bit difficult to light and took a few attempts so it’s best to do it outside. When soldering pipes, the joint heats up in seconds. You want to apply solder letting the heat of the pipe melt the solder and not the heat of flame. If you make a mistake, you may only have one chance to reheat it to make adjustments.
One problem I had was I dropped the elbow for spout pipe in the floor cavity while trying to re-align it to get it perfectly 90 degrees to the wall. I had to make a quick trip to Home Depot to get a replacement. In hindsight, I should have made sure it was supported properly while I soldered it and temporarily put a pipe into it to judge the angle coming out of the wall.
Another problem I spotted, luckily before I started soldering, was that the original spout and taps were not in line with the drain and centered on the wall (not tub).
Another small mistake I made was applying too much adhesive to the tile. I didn’t dry after a day so I removed it all and tried again with much less.