A well-installed tile job and a poorly installed tile job can look identical the day they are finished. The differences reveal themselves over time — in cracking grout, lippage between tiles, hollow spots that develop into loose tiles, water intrusion at transitions, and staining in grout lines that were never properly sealed. Knowing what to look for — during installation and after — gives you the ability to assess quality before problems become permanent.
Lippage
Lippage is the difference in height between the edges of adjacent tiles. Some lippage is normal — tile is a manufactured product with dimensional tolerances — but excessive lippage creates an uneven surface that catches toes, collects dirt at the high edges, and looks unprofessional. Industry standards (ANSI A108.02) allow a maximum lippage of 1/32 inch for tiles with a grout joint width of 1/16 inch or wider. For large-format tiles (any tile with one side longer than fifteen inches), a leveling system should be used during installation to keep tiles coplanar as the thin-set cures.
Run your hand across the tile surface. If you can feel distinct ridges at the tile edges, the lippage exceeds what industry standards allow. This is most common with large-format tiles installed without leveling clips — and it is not correctable after the thin-set has cured.
Hollow Spots
A tile should be fully bonded to the substrate — meaning the thin-set mortar behind the tile makes complete contact with both the back of the tile and the surface it is being set on. When the thin-set coverage is incomplete, hollow spots develop — areas where the tile is not bonded and flexes slightly when stepped on. Over time, these hollow spots lead to cracked tiles, especially in floor applications where foot traffic and furniture create point loads.
You can check for hollow spots by tapping the tile surface with your knuckle. A fully bonded tile produces a solid, dull sound. A tile with a hollow spot behind it produces a distinctly different, higher-pitched, hollow sound. This test is simple, non-destructive, and can be done on any tile surface at any time.
Grout and Caulk Transitions
Grout belongs between tiles on the same plane. Caulk belongs at every change of plane — where walls meet floors, where walls meet walls (inside corners), and where tile meets a different material (tub lip, shower pan edge, window frame). This is because buildings move — thermal expansion, settling, structural flex — and rigid grout will crack at these transitions. Flexible caulk absorbs the movement. If your installer grouted the inside corners and the tub-to-tile transition, those joints will crack. It is not a question of if — it is a question of when.
The caulk should be color-matched to the grout and should be a sanded caulk if the grout is sanded, so the transitions are visually seamless. This is a detail that separates professional-quality work from average work.
Where To Start
- Run your hand across the tile surface to check for lippage. If you feel ridges at tile edges, the installation does not meet industry standards.
- Tap tiles with your knuckle to check for hollow spots. A hollow sound means incomplete thin-set coverage — a bond failure that will worsen over time.
- Check that caulk — not grout — is used at every change of plane. Inside corners, tub-to-tile joints, and floor-to-wall transitions should all be caulked, not grouted.
Reading a tile installation is not about finding fault. It is about understanding quality — knowing what to look for so you can confirm that the work was done right, or catch issues early enough to address them. This is knowledge that serves you in every home you will ever own.
Have you ever tapped a tile in your shower and listened to whether it sounds solid — or hollow?