The issue of cracked tiles on floors and walls is a difficult problem. In most cases, the problem is not with the tile but with the material below the tile. Because the cause is hidden below tile, you cannot easily investigate this cause or fix it.
Following are seven reasons why your floor tile has cracked, ranging from the remote and obscure (sub-standard tile and heavy dead loads) to the most common (sharp blows, improperly cured concrete, etc.).
01 of 07
Tile Received a Sharp Blow
If the crack is located in one area, extending across only a single tile, this is probably the case. Sometimes, you will see a chip taken out of the tile where the object hit.
In kitchens, especially, where heavy objects such as cans, pots, and pans get dropped, ceramic tiles frequently break. Building standards (ASTM C648) do not regulate sharp blows to tile, only heavy dead loads. Doorways are another common spot for impact-related tile cracks because items may be dropped while opening the door. In general, these types of cracks will be found near the periphery of the floor, not the center.
02 of 07
Tile Cracked Under Heavy Loads
Did the refrigerator's dead weight do it? Perhaps.
Most tiles are in compliance with ASTM C648 Breaking Strength standards. In this test, floor tiles are run through a machine that exerts load on an unsupported 1-inch square area. As long as the tile does not break under 250 pounds of pressure, it is considered compliant.
Most tiles meet the 250 pound minimum. In fact, some specialty tiles greatly exceed the minimums. Durabody brand tiles from the manufacturer Interceramic have a breaking point of 400 pounds per square inch.
A sizable refrigerator such as a 22 cubic foot side by side model weighs about 300 pounds, representing about 75 pounds per square inch of breaking force on each of its four legs. This is far less than ASTM standards.
However, keep in mind that this is dead weight. Should an errant mover let a fridge, table, dishwasher, or cabinet land too hard on the floor, this is considered a sharp blow and could easily crack the tile.
03 of 07
Tile Was Installed Over a Control Joint
Control joints in concrete are essentially pre-planned cracks. Since it is almost certain that concrete will crack, why not place those cracks where they can be kept track of? Furthermore, they are intended to create a weakened area in the concrete and regulate where cracks will occur, normally in a straight line.
So, it is not prudent to use tile to bridge a line that you know in advance will expand.
04 of 07
Tile Was Installed on Improperly Spaced Joists
With tile, the less deflection, the better. Wood is flexible; tile is rigid. So, if you have a floor with flex, your tile will suffer.
Joists are the long wood "girders" under the subfloor that hold up everything: subfloor, mortar, tile, contents of the room, people. Joists that are spaced too far apart will allow for deflection in the plywood subfloor, thus allowing the finish floor tile to bend, which it does not want to do. Joist spacing must conform to the International Residential Code.Continue to 5 of 7 below.
05 of 07
Tile's Concrete Substrate Has Cracked Over Time
You've seen concrete basement floors, driveways, or patios. Chances are good that this concrete, if it is a few years old, has a long crack or two running through it.
Even though concrete seems like the perfect substrate for tile, it too has its own problems. When concrete substrate cracks, this is transmitted to the tile above in the form of a reflective crack.
If the tile cracks are long, continuous, and extending across multiple tiles, likelihood is high that the concrete below has cracked.
The way to eliminate this from happening is to strip the tile and then install a crack isolation membrane such as Ditra prior to installing tile again. These membrane are designed to uncouple tile from concrete substrate, allowing tile to move separately from the concrete.
06 of 07
Tile's Concrete Substrate Did Not Cure Long Enough
Newly poured concrete is full of water. As the concrete cures, the water evaporates and the concrete shrinks.
It is recommended by The Tile Council of America that you let new concrete cure for "as long as possible" or at least for 28 days. Some thinset manufacturers recommend only 14 days' curing time before installing the tile, but the Tile Council believes that this is not long enough.
If you have a new home and your tile has cracked, there is a distinct possibility that the concrete did not cure long enough.
07 of 07
Tile Is Sub-Standard
Because the tile is cracked, and the tile is the only visible portion of the installation sandwich of mortar and substrate, most homeowners assume that the tile is at fault. Usually, this is not the cause.
It is possible to purchase sub-standard tiles. In fact, tiles purchased at discount shops may have shady origins. But tiles purchased through established retail lines (home improvement stores, reputable online outlets, etc.) tend to be in compliance with ANSI and ASTM testing standards which regulate tile strength.