You can put new thinset on top of old but only if.
Tile over tile thinset.
Complete adhesive coverage is critical on large tiles 12 in.
You can add extra thinset under your new tiles if needed to ensure they re level.
Some installers prefer to flatback each tile with the flat edge of the trowel before applying the tile to the combed thin set.
This could lead to difficulty getting the new tiles level and fully supported by the new thinset.
So in short you can tile over tile as long as you re working on a fairly sound surface.
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.
Ideally tile should be installed directly on top of a surface like cement backerboard which is stable.
The surface of the existing tile should be free of mold and mildew completely level including grout and.
The modified mortar creates a stronger bond between the surfaces.
First clean and then sand the surface of the old tile until it feels rough.
Tile needs a smooth level surface to be installed on.
Thinset with large amounts of latex added are used with glass tiles which are unable to flex on their own.
Or larger and even more important when you re tiling over tile.
If all your talking about is 3 16 then thinset is a good solution.
This is a bonding mortar with either a latex or polymer additive.
When laying tile over tile it is best to use a modified thin set.
You can tile over exiting tile with latex modified thinset mortar but the bond might not be as sound as.
The big issue is going to be the smoothness.
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.
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.
Second apply a very thin coat of thin set mortar filling in the current grout lines.
Without a somewhat smooth surface it will be difficult to properly trowel out new thinset.
Thinset over thinset robert thinset will adhere to thinset just fine.
This helps to prevent tiles from cracking.
Epoxy tile adhesive may bond with almost anything and requires special solvents to remove.
How to install tile over old thinset grind it down.
Others prefer to use a larger notched trowel 1 2 x 1 2 in to apply the thin set.
Then i will mud with thinset and lay tile.
Unlevel floors can eventually cause both layers of tile to crack the following steps are helpful tips when installing tile over tile.