So in short you can tile over tile as long as you re working on a fairly sound surface.
Tile over tile thinset.
Without a somewhat smooth surface it will be difficult to properly trowel out new thinset.
Epoxy tile adhesive may bond with almost anything and requires special solvents to remove.
Some installers prefer to flatback each tile with the flat edge of the trowel before applying the tile to the combed thin set.
Working in small sections spread the thinset over the existing tile using a notched trowel.
This is a bonding mortar with either a latex or polymer additive.
The big issue is going to be the smoothness.
You can add extra thinset under your new tiles if needed to ensure they re level.
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.
If all your talking about is 3 16 then thinset is a good solution.
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.
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.
This helps to prevent tiles from cracking.
Unlevel floors can eventually cause both layers of tile to crack the following steps are helpful tips when installing tile over tile.
The modified mortar creates a stronger bond between the surfaces.
Tile needs a smooth level surface to be installed on.
Complete adhesive coverage is critical on large tiles 12 in.
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.
As you re installing your tiles use a level to make sure the new floor remains even.
If the substrate and thinset is solid then you can go over the top with new.
This could lead to difficulty getting the new tiles level and fully supported by the new thinset.
Ideally tile should be installed directly on top of a surface like cement backerboard which is stable.
You can put new thinset on top of old but only if.
The surface of the existing tile should be free of mold and mildew completely level including grout and.
When laying tile over tile it is best to use a modified thin set.
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.
Thinset over thinset robert thinset will adhere to thinset just fine.
Others prefer to use a larger notched trowel 1 2 x 1 2 in to apply the thin set.