If your home has been flooded, floor tiles may come loose. Standing water does not damage ceramic floor tiles. However, it damages the grout between the tiles, loosens tile adhesive and saturates the subfloor. The subfloor may be particle board or plywood sheet. The wood soaks up the water and expands, causing the tile floor to buckle or tiles to become loose. Damage may not become evident for several weeks or months after the flood waters have subsided.
A slow leak, from a dripping pipe or from a malfunctioning dishwasher or washing machine, may have existed for some time before the homeowner notices the leak and the problem is repaired. The leak may have been small enough that a plywood or particle board subfloor soaked up the water. Dark staining or mold may appear before tiles become loose. Damage from a slow leak may not be evident for several months or even years.
If the installer used a water-based mortar adhesive, exposure to moisture can cause the adhesion to fail after a period of time. Condensation or excessive humidity can soften the adhesive, and it may not appear loose until heavy foot traffic or furniture movement causes a tile to shift, become loose or break. Tiles installed on a concrete slab will stand up to flood or water damage better than tiles installed on a wooden subfloor that can absorb water.
Extreme changes in temperature can contribute to tiles becoming loose and breaking. As humidity and heat build up in the structure, condensation develops and can cause moisture to permeate the grout around the tile. Cold weather can cause the dampened subfloor to contract and cause tiles to "tent" or break loose. Tile should not become loose if the floor was properly installed with expansion joints. Expansions or "soft joints" are period joints composed of latex caulking that expands and contracts when exposed to moisture or temperature extremes.