Tiling directly over an existing marble surface requires specific materials and preparation to ensure a strong, lasting bond. The key is using the correct adhesive designed for bonding tile to dense, smooth surfaces like marble.
To tile on marble, you should use a high-quality, polymer-modified thin-set mortar.
Essential Steps for Tiling Over Marble
When planning to install new tiles over existing marble, preparation and the right materials are crucial.
Surface Preparation
Before applying any adhesive, the existing marble surface must be properly prepared. While the reference mentions a "prepared marble surface," this generally involves:
- Thorough cleaning to remove all dirt, grease, wax, or sealers.
- Ensuring the surface is sound, level, and free from cracks or loose areas. Any repairs should be made beforehand.
- Depending on the specific adhesive product instructions, the marble surface might need to be lightly abraded or primed to enhance mechanical bond.
Choosing the Right Adhesive
The type of adhesive you use is paramount for successful tiling over marble.
- Recommended Mortar: You should use a polymer modified thin-set mortar adhesive that meets ANSI A118.4, or better yet ANSI A118.15, to bond the new tile (such as porcelain tile, as mentioned in the reference) to the prepared marble surface.
- Flexible Options: The reference also notes that there are flexible thin-set mortars that are recommended for bonding tile over tile too. These flexible options can accommodate slight movement or differences in expansion between the layers.
Using a mortar that meets or exceeds these ANSI standards ensures it has the necessary bond strength, flexibility, and durability required for tiling over a non-porous surface like marble.
Application Process
Once the surface is prepared and the correct mortar is selected:
- Mix the polymer-modified thin-set mortar according to the manufacturer's instructions.
- Apply the mortar evenly to the prepared marble surface using the appropriate notched trowel size for your new tiles.
- Back-butter the new tiles (apply a thin layer of mortar to the back of the tile) for optimal coverage and bond.
- Set the tiles firmly into the wet mortar, using a slight twisting motion to ensure full contact.
- Maintain proper grout joint spacing using tile spacers.
- Allow the mortar to cure fully according to the manufacturer's guidelines before grouting.
Using the specified polymer-modified thin-set mortar is the critical factor in achieving a durable installation when tiling over marble.
