Common Tile Fitting Problems: Hollow Sound, Lippage and Cracks

Many of the calls we receive are not for new floors but for floors that have gone wrong. A tile that sounds hollow when you walk on it, an edge that catches your foot, a crack running diagonally across a living room tile. These common tile fitting problems are frustrating because they usually appear after the furniture has moved in, and because the cause is hidden under the surface.

This guide explains the main problems we see, what causes them, and what can be done about each one. It is also a useful list of things to watch out for while new tile fitting is in progress.

Hollow sound under tiles

If you tap a tile with a coin or the handle of a screwdriver and it sounds dull and drum-like instead of solid, there is a void between the tile and the bed. Some hollow spots are small and stable; others grow over time and lead to cracking or loose tiles.

Common causes

• Spot fixing with dabs of adhesive or mortar at the corners and centre instead of full coverage.
• Plain cement on vitrified tiles, which does not bond well with low-absorption tiles.
• Mortar bed drying before the tile was placed, so it never bonded.
• Adhesive skinned over because too large an area was spread at once.
• Wrong trowel size for the tile, leaving gaps between ridges.
• Uneven base where the tile bridges a low spot.

What can be done

A small hollow area on a tile that is not cracked or moving can sometimes be left and monitored. Where tiles are cracking, rocking or the hollow area is widespread, the right repair is to cut out the grout, lift the tile, clean the old bed, and refit with fresh adhesive and full coverage. Injection methods are sometimes offered, but they do not always fill the void reliably. This is why keeping spare tiles from the same batch is so important.

Lippage: uneven tile edges

Lippage is when one tile edge sits higher than the next. You feel it underfoot and see it as a bright line when light falls across a glossy floor.

Common causes

• A floor that is not flat before fitting.
• Slightly bowed tiles, more common in large and plank formats.
• Inconsistent pressing of tiles during fitting.
• Not using levelling clips on large-format tiles.
• Offset patterns that place the high centre of one tile next to the low edge of another.

What can be done

Minor lippage is sometimes acceptable within limits, especially on non-rectified tiles. Noticeable lippage on a new floor usually means lifting and refitting the affected tiles. Prevention is far easier: flat base, levelling clips, and checking with a straight edge as work progresses, as covered in our article on spacers and levelling clips.

Cracked tiles

Cracks can appear soon after fitting or months later. Where and how a crack runs gives a clue to its cause.

• Cracks over a hollow area usually mean the tile had no support underneath and broke under a load.
• Cracks continuing across several tiles in a line often follow a crack in the slab or a junction between two different bases.
• Corner cracks can come from impact, or from tiles with no joint pressed tightly against each other.
• Cracks near walls or doorways may be from heavy furniture, construction loads or movement where no perimeter gap was left.

Single cracked tiles can be cut out and replaced. Where cracks follow the slab, the underlying movement must be addressed, and a movement joint or crack-isolation approach may be needed before tiles are refitted.

Tenting: tiles lifting in a ridge

Sometimes tiles pop up along a line, forming a small tent, often with a loud crack. This usually happens when tiles are fitted without enough joint width or perimeter gap, and the floor expands with heat or moisture. Floors near large glass windows and on terraces are especially prone. The repair involves lifting the affected tiles, creating proper movement joints and perimeter gaps, and refitting.

Grout cracking and discolouration

Grout that cracks, crumbles or turns dark is a common complaint, especially in bathrooms and kitchens. Causes include joints that were not cleaned of adhesive before grouting, grout mixed with too much water, movement in a hollow tile, and the porous nature of cement grout in wet areas. Raking out the old grout and regrouting, often with epoxy grout, solves most surface grout problems, provided the tiles themselves are firmly bonded.

Water problems in bathrooms

Standing water and damp walls usually point to an incorrect slope or failed waterproofing rather than the tiles themselves. Fixing it may mean lifting the floor tiles, correcting the slope and redoing waterproofing. Our guide to bathroom tile work explains how to avoid this on new work.

Inspection checklist for any tiled floor

1. Tap each tile and mark any that sound hollow.
2. Run a straight edge or your palm across joints to check lippage.
3. Look for cracks and note whether they continue across tiles.
4. Check that a gap or sealant joint exists along walls.
5. Inspect grout for cracks, gaps and colour changes.
6. In bathrooms, pour water and watch where it flows.

Repair and correction of faulty work is a regular part of what we do, for tiles as well as marble and stone. If your floor shows any of these problems, send photos and a short description on WhatsApp at 9468916422. Hemaram Kumawat and team will suggest whether a repair or refitting is needed. You can also learn more about our tile fitting and flooring service or contact us directly.