Tiling directly over existing marble requires using the correct adhesive over a properly prepared surface. The key is selecting a high-quality, flexible thin-set mortar specifically designed for bonding tile to challenging substrates like existing tile or stone.
Choosing the Right Adhesive
Based on professional recommendations for tiling over existing surfaces like marble, the adhesive choice is critical for a successful bond.
- You should use a polymer modified thin-set mortar adhesive for this type of application.
- This adhesive must meet ANSI A118.4 standards.
- For a better, more robust bond, it is recommended to use a mortar that meets ANSI A118.15 standards. These standards indicate higher bond strength and performance characteristics.
- Flexible thin-set mortars are particularly recommended for bonding tile over tile or stone surfaces like marble due to their ability to accommodate slight movements and reduce the risk of bond failure.
Using a mortar that meets or exceeds these standards ensures strong adhesion between the new tile (such as porcelain, as mentioned in related contexts) and the existing marble surface.
The Process Overview
While the reference focuses heavily on the adhesive, tiling over marble generally involves these steps:
- Surface Preparation: The existing marble surface must be cleaned thoroughly, free of sealers, waxes, oils, and any contaminants. The surface may also need to be mechanically abraded (roughened) to provide a proper profile for the adhesive to grip onto. Existing grout lines should also be addressed.
- Surface Soundness: Ensure the existing marble installation is sound, flat, and well-bonded to its substrate. Any loose or damaged areas must be repaired before tiling.
- Adhesive Application: Apply the recommended polymer modified thin-set mortar (meeting at least ANSI A118.4, preferably A118.15) using the appropriate trowel size for the new tile being installed.
- Tile Installation: Set the new tiles into the wet mortar, ensuring proper coverage and leveling.
- Grouting: Once the mortar has cured according to the manufacturer's instructions, apply grout designed for the type of tile and joint width.
Choosing a flexible thin-set mortar that meets the stringent ANSI A118.15 standard provides enhanced performance and durability when tiling over a non-traditional substrate like polished or prepared marble.
