The ceramic floor tiles in the kitchen and dining room sounded hollow to walk on and some were lifting. The homeowners thought that maybe their neighbor’s landscaping or irrigation system was the cause. GEI was hired to get to the root of the problem.

A leak check test was performed and provided for our review. The leak detection report identified that there was no evidence of water leaking from plumbing systems under the slab. In addition, their report identified that a neighbor’s irrigation system overflow may have been running across the rear yard and under their slab.


Our expert then visited the property and was escorted through the home by the homeowner. The property was a single-family residence as part of a condominium complex, constructed of timber framing with stucco exterior finish and plaster interior finish under concrete tile roof, constructed circa 2002, according to the County Assessor’s web-site.



Showing overview of area where tiles were hollow-sounding and raised or “tented”

The ceramic floor tiles were buckling and our expert lifted a few up to inspect the surface underneath. He found that the tile was laid without the benefit of a vapor barrier. This allowed ground moisture to penetrate up through the porous concrete and to counteract the adhesive properties of the adhesive used. The Tile Council of North America (TCNA) is a manufacturer’s trade group that publishes specifications for the proper method of laying ceramic and stone tiles. The TCNA recommends that ceramic tile be laid over a vapor barrier. This is to ensure that the adhesion is not defeated by moisture rising by capillary action through the minute pores present in normal concrete. In addition, the TCNA recommends that ceramic tiles not be laid in large areas without benefit of an expansion joint within the field of laid tile and around the perimeter of that field. The tiling at this home was laid without benefit of either a vapor barrier, an expansion joint, or the benefit of a perimeter baseboard expansion joint.


Evidence of adhesive laid over floor without a vapor barrier

This lack of ability for the tile to expand during normal use resulted in breakage of the adhesion, creating a hollow sound when the tiles were stepped on, and finally “tenting” or lifting of the tile in the center of the field or in areas where the tiles and grout could not move laterally.

Contrary to the leak detection report, there was no evidence of moisture movement over the slab from the neighboring property. If it were the case that the sole source of water intrusion were from the neighbor’s irrigation overflow, then the tile and flooring adjacent to that area of the floor (by the rear door) would have first been affected and not in an area that was located several feet away from it. In addition, failure to properly lay the floor (no vapor barrier, improper expansion prevention) will normally result in lifting of the tiles, whenever the floor is subjected to expansion. Expansion occurs as a result of heating and cooling, together with migration of moisture into the expandable grout from under the tile, and affects tiles whose adhesion has been lost to moisture intrusion. Expansion of the framing is not a consideration when the tiling is properly laid with an expansion gap under the baseboard instead of being filled with grout, as was the case in this flooring.


Floor tile abutting the kitchen unit, instead of leaving a gap or running under the baseboard to allow for expansion

Based on the foregoing, the approximate age of the cause of that damage was the original date of installation and the predominant cause of the damage observed was faulty installation of the ceramic tile.