I have an extra bathroom that the shower is not being used. The hot water valve broke and was stuck on so I had to remove the whole thing and cap the water lines. I had someone tell me they would fix it for $500 but I would like to attempt it myself. I would guess I need a new shower insert, how much in parts do you think this would cost? I have access to the water lines in a closet behind the tub. Any tips/suggestions would be much appreciated.
While you have referred to a "shower", the photo shows only where the taps/faucets and a "spout" for the BATH previously existed. (i. e. There is no indication of a previously existing SHOWER.)
Replacing the tile board would be a mistake.
You need to demo down to studs.
Replace valve.
Install Durock, Kerdi Board, Denshield and waterproof accordingly.
Tile
Grout with Mapei Flexcolor.
However, to install a shower you need to do much more than "Replace valve"
At least you need to install either a "Riser Bath and Shower Assembly" like this one
https://2ecffd01e1ab3e9383f0-07db7b...x800/04ea789b-140d-44b9-8e63-98d5f1368866.jpg
or a Bath/Shower diverter valve/tap/faucet.
However, there are many other devices that you could use, which may include mixer valves and hand-held/adjustable showers.
Check "riser bath and shower" for images - While most of these show external plumbing, such plumbing can be placed within the wall(s) if you wish.
There is another consideration in that it is a good idea NOT to have the shower "Head" above the faucets that control it, but to place it to the side (for which you do not have room) or on the wall to the right. (Of course, this is NOT the cheapest option.)
You will also need to install a shower-screen (or, at least, a shower curtain.)
I am not sure about where the transition from the tiles in the rest of the bathroom and the shower tiles meet though, I am guessing I can put some kind of divider in place
This suggests that you intend to re-tile only one wall - which raises questions about "waterproofing" the vertical junction between that wall and the others.
However. If you cannot now purchase matching tiles, just purchase tiles of the same size of a corresponding or contrasting colour and make the repaired wall a "feature wall".
Of course, if you do move the shower head onto the side wall, it will be necessary to repair/re-tile that wall also.
The existing silicone at the wall junctions and along the edge of the bath is poorly done. The wall silicone will be removed when you re-sheet and that along the bath should be cut-out and replaced. However, if you cannot remove every trace (and there are potent chemicals to do this), new silicone will not stick to the old. You could use a white or coloured acrylic sealer instead.