If all your talking about is 3 16 then thinset is a good solution.
Tile over tile thinset.
Then i will mud with thinset and lay tile.
However it may be worth noting that you may need to wait a little longer between laying the tile and grouting to allow the thin set to properly cure.
Thinset over thinset robert thinset will adhere to thinset just fine.
Without a somewhat smooth surface it will be difficult to properly trowel out new thinset.
The modified mortar creates a stronger bond between the surfaces.
Thinset with small amounts of latex added are primarily used for large format tiles and stone tiles to help absorb flex from floors and walls.
This is a bonding mortar with either a latex or polymer additive.
This could lead to difficulty getting the new tiles level and fully supported by the new thinset.
The big issue is going to be the smoothness.
The surface of the existing tile should be free of mold and mildew completely level including grout and.
If this is not a good idea i can just pack the thinset thicker in that corner at the time that i lay the tile.
You can add extra thinset under your new tiles if needed to ensure they re level.
You can tile over exiting tile with latex modified thinset mortar but the bond might not be as sound as.
Epoxy tile adhesive may bond with almost anything and requires special solvents to remove.
How to install tile over old thinset grind it down.
When laying tile over tile it is best to use a modified thin set.
First clean and then sand the surface of the old tile until it feels rough.
This helps to prevent tiles from cracking.
Ideally tile should be installed directly on top of a surface like cement backerboard which is stable.
As you re installing your tiles use a level to make sure the new floor remains even.
Position your tiles according to the layout you choose.
So in short you can tile over tile as long as you re working on a fairly sound surface.
Or larger and even more important when you re tiling over tile.
Thinset with large amounts of latex added are used with glass tiles which are unable to flex on their own.
Tile needs a smooth level surface to be installed on.
Working in small sections spread the thinset over the existing tile using a notched trowel.
Complete adhesive coverage is critical on large tiles 12 in.
Some installers prefer to flatback each tile with the flat edge of the trowel before applying the tile to the combed thin set.
If the substrate and thinset is solid then you can go over the top with new.
Others prefer to use a larger notched trowel 1 2 x 1 2 in to apply the thin set.