Quite often the reason for uneven tiles is an uneven layer of thinset mortar holding tiles on the floor.
Uneven tile wall.
To do so make sure all of the tiles are intact and secure.
What is the allowable warpage of a tile.
If you put a 48 straight edge up against the most sunken areas there s a gap of almost a 1 2.
If existing tiles are beyond repair remove the tile and install a piece of wallboard in its place.
Remove the tile and prepare the wall according to the corresponding instructions above or tile over the existing tile.
The ansi a137 1 standard defined allowed warpage according to the type of tile.
Comb walls then back butter tiles accordingly if they are really bad holes etc you can build out wall in layers using rapidset adhesive which will set in 3hrs which will then allow you to use your tub stuff after priming make sure you smoothe the rapidset otherwise you are giving yourself more hassle.
If you are using cove at the bottom put it in as normal then do your cuts on the bottom of the bottom row of regular tiles so the uneven height row of tile sits right on top of the cove.
The problem is that the wall is uneven.
There is also a spot near the window trim where the wall appears to be built up too much enough so that the tile could end up proud of the trim which i m pretty sure won t look so hot.
For a paver tile commonly used on floors the allowable warpage is defined as follows.
Wash the wall with tsp tri sodium phosphate or an ammonia based cleaner to remove any grease or oil.
In many cases when tile is installed by the thinset method over an uneven substrate the installed surface will not meet lippage standards.