QUESTION

Why is limestone debonding from floor? I have installed 24x24 in. limestone tile in a residence on three levels with a multipurpose thin-set mortar. we finished the job with no problem. later on the home owner hired a company to clean and seal the floor. The company came with a machine that cut and cleaned the floor with a liquid and then sealed the floor with a inpregnating water base sealer. then the floor started debonding from the mortar. can you please advise on the cause of the problem.

I have installed similar tile with the same thin-set mortar in other jobs with no problem. There have to be other conditions that might have contributed to the debonding. Because the same tile installed on the floor is installed on the walls it is not debonding.

ANSWER

ANSWER - This suggests that the tile was not bonded well to its substrate for some reason. So when they started grinding the floor it caused the tiles to debond. There are many potential reasons why the tile did not bond well.

What you installed before and what you installed on the walls is a different substrate than what you installed on the floor.

When there is a failure it is never for only one problem/deficiency, but rather for compounding reasons. e.g. there may be a contaminate on the substrate, there may not be adequate thin-set coverage, there may be too much deflection in the floor, there may not be adequate expansion joints. The primary problem is that the thin-set did not bond adequately to something. The only way to understand what caused the debonding is to perform an investigation if it is practical.
For information, visit our Forensic Investigations page.