Many homeowners have asked me, “Why do tiles come loose?” It amazes me that, with advances in floor preparation and modified infills, tiles can still come loose. It is possible to understand why your floor tiles are loose without using the help of a flooring professional or general contractor. Let me tell you why this happens.
First, it’s important to understand what holds the tile to the floor. Tiles, whether ceramic, porcelain, slate, granite, or marble, are held in place by a substance called thinset. Thin set is a Portland cement-based material that contains a special blend of additives that give the mix the ability to flex smoothly under stress and return to its original position. This tension, also known as load, can be the result of climatic changes, such as the passing of the seasons, or of a physical nature, such as the weight of a person or an item placed on the tile.
Sometimes the stress or load can be too much for the thin layer. If a heavy object is placed on the tile floor, such as a piano, it is very possible that an individual tile will be overloaded. If this happens, the bond between the tile and the thinset may break and the tile may flake off. Once cut, the tile will never be reattached to the thin layer. The result is a loose tile that is only held in place by the grout that surrounds all four sides.
Next, the structure of the floor must be considered. Before any type of tile floor is installed, the subfloor must be inspected by the contractor or flooring professional. The subfloor must be built rigid enough to support its own weight, the weight of the tile, and the weight of items placed on it. Most local codes state that if the floor is framed with 2×8 floor joists, 16″ on center and sheathed with a 5/8″ plywood material, it can be tiled. Remember, before beginning any construction project, check with your local building code officials. Better safe than sorry.
In many homes, the floor simply isn’t built or framed strong enough to support its own weight and the weight of a tile floor. When floors are not framed enough, they tend to move perpendicular to the ground plane. This up and down movement stresses the bond between tile and backer by applying too much weight or load to one area.
The bond between the tile and the thinset may very well be strong enough to accept multiple times overload. The number of times is directly related to the quality of the thin layer. Inevitably, even the most expensive slimline assemblies will fail if subjected to continuous overload.
Lastly, the most common reason for a tile to loosen from its thin layer is improper installation. Careless contractors tend to tile weak floors. The thin set must be mixed according to the manufacturer’s specifications. If you mix too wet or too dry, the thin coat will not cure properly. This inadequate curing results in a weak floor.
Over time, most tile floors will loosen. This is to be expected and can be fixed. If during the life of a floor, many tiles come loose, the cause is a more serious problem. In my experience, human error is the cause.
