Expert: Stephen Hayes - 2/13/2009

Question
We are homebuilder in Tulsa and have had 5 house in the past year that the ceramic tile has lifted from the concrete slab. Most of the homeowners have said they hear a 'pop'. When you step on these floors it sounds like sand is under them. One house actually had the tiles lifted in a triangular fashion. There are no signs of structural, no seperation of trim or sheetrock cracks. Any suggestions? Thanks Kevin  

Answer
Hi Kevin;

There could be a lot of reasons for your problem, however I will list a few possibilities;

1. A moisture problem in the concrete.
2. The concrete was not properly prepared for the ceramic installation.
3. The installer used an improper mortar adhesive.
4. The installer applied the adhesive with an improper trowel size or did not keep cleaning the trowel which would result in a sparse application of the mortar adhesive.
5. The installer did not allow the adhesive to properly set up before installing the tiles.
6. The mortar adhesive was not fully dry before the tiles were walked upon.
7. The HVAC system was not in the proper temperature and/or humidity range before, during, and forever after the handling and installation of the tiles.
8. Since flooring MUST be the last trade in, that MUST was not followed and other tradespeople were allowed to walk on freshly installed tiles.
9. If there was any preparation coat applied to the concrete, such as a leveler, that leveler was not compatable with the concrete, not fully dry before the mortar adhesive was applied, and/or the concrete was too wet so the leveler could not properly set up.
10. If grouted, the grout was not properly mixed.
11. etc.

If you have any unused tiles and grout left from an affected installation, it might be wise to carefully crack a tile and see what you find under it.  The pour of the concrete may have been erroneous, an improper concrete mix was delivered, etc.  If a popping sound is heard, without being able to see the installation, however I would guess that there may be a mortar adhesive, mortar adhesive application, and/or moisture problem with the concrete.  Another possibility is that no ground cover was put down, so moisture is being allowed to seep into the concrete.  The land surrounding the homes may not pitched away from the foundations (I believe the pitch should be 2 inches in 1 horizontal foot), allowing
moisture to seep into the foundation, and since moisture seeks its own level, it could be negatively affecting the concrete quite a distance from the actual area of the moisture source.

Once a tile is lifted, you may want to have a certified, independent, floor covering inspector view the areas of concern and issue a certified report of his or her findings.  

That's about all the guesses I could give without being on site to see the installation.

If you have any other questions, please feel free to get back to me.

Cordially,

John Michaels