Hello All,
I have a remodel project where we would hope to install 16"x16" travertine over an existing marble tile floor. We have a whopping 1800+ sq. ft. of ugly marble at the lower level, so we would surely like to avoid a messy tear-out. The sub floor is a slab on grade. The existing marble is 12"x12", 3/4 thick with 1/8" grout joints. It is in California where there is not any freeze/thaw cycles to affect the slab. The current install has no visible defects, and was installed in the early 90's. I also chisled a few existing pieces out and it was very difficult, indicating the overall existing bond is very sound.

I would hope to use a mechanical buffer/sander to scuff up the existing floor to except a bond for thin-set. I could aso use Ditra membrane if suggested ro required.

Any input would be greatly appreciated.