Cracks in a slab can print through bonded tile
When tile is bonded to concrete, movement in the concrete cracks the tile layer. The Tile Council calls a crack that follows a slab crack reflective cracking. A control joint that was tiled over does the same thing. The FAQ says the Tile Council does not recommend that installation. Even a small shrinkage crack can keep moving as the slab cures, and the line shows in the tile.
Two ways to avoid the direct path
The page says this cracking is avoided by setting tile on a mortar bed over a cleavage membrane, or by a thinset installation over a crack-isolation membrane. An inspection is still required before anyone names the cause of a particular crack. The FAQ lists those mechanisms and says the exact cause cannot be guessed from a description alone.
The name is the mechanism
Reflective cracking is not a hollow sound and it is not grout that crumbled in place. It is the slab's crack continuing into a tile that was stuck directly to that slab.
Source
Fetched 2026-10-11 from Tile Council cracked tile FAQ. The sentences above follow that page. They are not a contractor promise.
Related notes
- Tile notes index
- Tented tile is often compression from a slab that kept shrinking
- Tile over laminate depends on the layers under the laminate
- Shower photos
Send photos if you want another person to look at the area. This note does not set a response time.