The short answer
Subfloor Movement
When the wood or concrete underneath your tile flexes, the tile has no give and cracks. This often happens because the subfloor was not stiff enough for the tile thickness, or because joists have sagged over time. In a kitchen, a leaky sink or dishwasher can soak the subfloor, making it swell and shrink as it dries.
If you notice cracks that follow a straight line or appear near seams, subfloor movement is likely. Press down on the tile to see if it moves. You might also see grout cracking along the same areas. Fixing the cause, not just the tile, is important to prevent the new tile from cracking too.
- Check for squeaky or bouncy floors
- Look for gaps between baseboard and floor
- See if cracks align with joist lines
- Probe for soft spots with a screwdriver
- Watch for doors that stick after rain
Water Damage Underneath
Water is a silent enemy of tile. A slow leak from the refrigerator ice maker, a worn seal around the sink, or a pipe in the wall can drip onto the plywood underlayment. That wood swells, loses strength, and then shrinks as it dries, which pulls the tile apart. You may not see the water until the tile cracks.
Look for clues like a musty smell, dark stains on grout, or a slight give when you walk. If you suspect moisture, a water damage inspection can map where the water is coming from. Catching the leak early saves you from replacing a larger section of flooring.
- Dark or damp grout lines
- Musty odor near cabinets
- Tile that sounds hollow when tapped
- Warped or stained baseboards
- Moisture meter readings above normal
Poor Installation
Tile needs a full bed of thin-set mortar under it. If the mortar was spread with gaps or allowed to skin over before the tile was set, the tile does not stick evenly. Over time, the hollow spots flex and crack. This is more common with large-format tiles that need extra care.
Another installation issue is not leaving enough space for expansion. Tile expands and contracts with temperature changes, so grout joints and perimeter gaps are essential. Without them, tiles press against each other and crack. If your cracks appear shortly after installation, this is a likely cause.
- Cracks that start at corners
- Tiles that sound different when tapped
- Grout that crumbles easily
- Cracks radiating from a single point
- Loose tiles that rock slightly
Heavy Impacts
Dropping a heavy cast-iron pot or a full jar can crack a tile, especially if the tile is thin or the subfloor has a soft spot. The impact creates a point load that the tile cannot absorb. This is often a single crack or a spider-web pattern from the impact point.
If the crack is isolated and the tile is otherwise solid, a simple replacement may work. But check the surrounding area for hidden damage. A crack from impact can let water seep down to the subfloor, which leads to bigger problems later. Seal the crack promptly to keep moisture out.
- Spider-web crack pattern
- Crack in the center of a tile
- No other tiles affected
- Recent drop or heavy object nearby
- Tile still firmly stuck down
What You Can Do
Start by identifying the source of the crack. If you see water or suspect a leak, shut off the water supply to the kitchen and look for puddles under the sink or fridge. Dry the area with fans and a dehumidifier to prevent mold. If the crack is from movement, you may need to reinforce the subfloor before retiling.
For water-related cracking, address the leak first. A plumber can fix the pipe, and the pros can dry out the structure and assess the damage. They can also remove water-damaged flooring and prepare the surface for new tile. If the damage is extensive, a full inspection helps you understand what is safe to keep.
Water damage does not wait
Call (801) 383-0232 any time, day or night, and describe what happened.
Call Now (801) 383-0232Frequently asked questions
Can I just replace one cracked tile?
Yes, if the crack is from a single impact and the subfloor is solid. Remove the grout around the tile, break the tile carefully, and scrape out the old mortar. Install a new tile with fresh adhesive. If the crack is from movement or moisture, replacing one tile will not stop the problem.
Will the crack get worse over time?
Cracks from movement or water often spread. As the subfloor shifts or rots, more tiles can crack and grout can fall out. Moisture can also weaken the adhesive further. Fixing the underlying cause soon prevents a larger repair later.
How do I know if water is the cause?
Look for dark stains on the grout, a musty smell, or a hollow sound when you tap the tile. You can also place a dry paper towel over the crack and press down; if it gets damp, water is seeping up. A moisture meter can give a clearer answer.