Buy a latex modified thin set one brand is flexbond and mix it in small batches to keep it from skinning over.
Tiling over marble floor.
But i wouldn t consider tiling over a stone as porous as marble.
Tiling over an uneven surface will give you less than stellar results so level out any globs of dried grout with a sander and secure loose tiles with fresh.
If you want a long lasting durable floor then install a porcelain tile over your existing marble floor.
If you want to tile over a marble fireplace you have to address the problem of tile adhesion.
Vacuum the tiles and clean with detergent and water to remove dirt sealers and wax.
Rinse the surface with clear water and let it dry.
This is a mixture of cement fine grain sand and water that will adhere the new tile to the old.
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.
Using your notched trowel apply an even layer of thinset or mastic to the cultured marble.
The modified mortar creates a stronger bond between the surfaces.
Only spread a small area at first until you have set a few tiles in order to ensure that you do not spread too far ahead of yourself and allow the adhesive time to set up.
This is a bonding mortar with either a latex or polymer additive.
Remove any moldy or loose grout with a rotary tool or carbide scraper.
Prepare the surface for installation.
When laying tile over tile it is best to use a modified thin set.
The marble floor has to be structurally stable because your new floor will only be as good as the existing floor.
Or larger and even more important when you re tiling over tile.
One strategy is to clean the marble with tsp and water then sand it with coarse sandpaper to etch it.
Then if you use the proper mastic the tiles should stick.
You will have to clean and scarify the marble before you installed the tile over it.
Complete adhesive coverage is critical on large tiles 12 in.
Once installed routine maintenance of a marble tile floor is relatively easy it requires the same kind of sweeping and damp mopping you would do with a ceramic tile floor.
Yes it s possible to go over a stable tile with a good substrate.
Also consider that doors cabinets and other hardware might need to be reworked or replaced with new ones to compensate for the higher floor.
However unlike ceramic tile marble is fairly porous so you shouldn t allow water to puddle and stand on the surface.
As for tiling over it.
When it comes to mortar latex or epoxy options are best for installing tile over tile.
Use a thin set product to install ceramic tile over existing tiles.
You can also install cement backer board.