Tile lippage is the small height difference between the edges of two neighboring tiles. It is the ridge you feel under a sock or see as a shadow line when light comes across the floor from a window. This guide explains what lippage is, what causes it, how much the industry standard accepts, how to measure it and, most important, how to prevent it while you set tile.
What is tile lippage?
Tile lippage is a difference in elevation between the edges of adjacent tiles, so one tile sits higher than the one next to it. Industry documents define it the same way: ANSI A108.02 describes lippage as differences in elevation between edges of adjacent tile modules. On a finished floor it shows up as a raised edge, a toe-catcher or a visible shadow along the grout joint.
Lippage meaning in plain words: the tiles are not in one flat plane. A little of it is normal, because every tile has some thickness variation and warpage from the kiln. Too much of it looks sloppy, collects dirt at the raised edge, and on a floor can chip the high corner when something heavy is dragged across it.
What causes lippage between tiles?
Most lippage comes from an uneven substrate or uneven thin-set under the tile, followed by warped tile, tight grout joints, offset patterns and side lighting that exaggerates small differences. In other words, the floor or wall underneath and the way the mortar is spread matter more than the tile itself.
The LATICRETE technical data sheet on lippage (TDS 164) lists the main factors: allowable thickness variation of the tile, allowable warpage, the width of the joint, the angle of natural or artificial light, and highly reflective surfaces. It also states that, overwhelmingly, most lippage is caused by an uneven substrate or by trying to fix that unevenness with extra thin-set.
- Substrate flatness: humps and dips in the slab, plywood or backer board transfer straight into the tile.
- Mortar coverage: hollow spots and thick spots let one tile settle lower than the next as the thin-set cures.
- Warpage and crown: a tile that is slightly domed or has edge curl puts its center high and its edges low, or the other way around.
- Layout: a 50% running bond lines up the high center of one plank with the low ends of its neighbors.
- Light: raking light from a sliding door or wall-washer fixture turns a tiny step into a long shadow.
How much lippage is acceptable?
Under ANSI A108.02 (section 4.3.7), allowable lippage is 1/32 inch for most floor tile set with joints from 1/16 inch to under 1/4 inch, and 1/16 inch when joints are 1/4 inch or wider. Gauged porcelain tile and panels are held to 1/32 inch at any joint width.
The table below follows the chart reproduced in LATICRETE TDS 164, which cites ANSI A108.02 4.3.7. The standard also recognizes that the tile’s own allowable warpage and thickness variation affect the result, and the chart does not apply to floors sloped to a drain, where some lippage is expected.
| Tile type | Grout joint width | Allowable lippage |
|---|---|---|
| Glazed wall tile and mosaics (1×1 to 6×6 in) | 1/16 to 1/8 in | 1/32 in (0.8 mm) |
| Quarry tile (6×6 to 8×8 in) | 1/4 in or wider | 1/16 in (1.5 mm) |
| Pavers, all sizes | 1/16 in to less than 1/4 in | 1/32 in (0.8 mm) |
| Pavers, all sizes | 1/4 in or wider | 1/16 in (1.5 mm) |
| Gauged porcelain tile and panels | All | 1/32 in (0.8 mm) |
For context, 1/32 inch is roughly the thickness of a credit card, which is why many installers run a card across the joint as a quick check. Treat that as a field test, not a measurement.
Why does large format and plank tile show more lippage?
Large format and plank tile show more lippage because a long tile spans more of the floor’s highs and lows, has more room to warp along its length, and is usually set with tight joints that hide nothing. Small tile follows the floor; big tile bridges it and exposes every mismatch.
That is why the substrate requirement tightens for big tile. TCNA guidance quoted in TDS 164 allows 1/4 inch in 10 feet for tile with all edges shorter than 15 inches, but only 1/8 inch in 10 feet (and no more than 1/16 inch in 24 inches) when any edge is 15 inches or longer. Plank layouts also have an offset rule: for tiles where the offset side is longer than 18 inches, ANSI A108.02 4.3.8.2 limits a running bond offset to 33% unless the tile maker says otherwise. Our guide to large format tile spacers and leveling covers this in detail.
How do you measure lippage on a finished floor?
Measure lippage with a straightedge across the joint and a feeler gauge, a lippage gauge or a dial meter at the low tile’s edge. Check several joints in different areas, measure at the tile edge rather than the center, and judge under normal lighting before reacting to shadows.
Place a short straightedge on the higher tile so it overhangs the joint, then measure the gap down to the neighboring tile. A dedicated lippage gauge does the same job in one step. Raking light is good for finding suspect joints, but it exaggerates everything, so confirm with a measurement. Our article on tile leveling tools shows the inexpensive options.
How do you prevent lippage while setting tile?
Prevent lippage by flattening the substrate first, spreading thin-set with straight trowel ridges and full coverage, back-buttering larger tile, keeping offsets at 33% or less for long tile, and using a tile leveling system to hold neighboring edges in one plane while the mortar cures.
- Check the floor or wall with a long straightedge and fix highs and lows before you mix any thin-set.
- Get coverage right. NTCA’s TileLetter notes that 80% mortar coverage is required in most applications and 95% in wet areas and exteriors. Pull up a tile now and then to check.
- Dry-lay and sort tile. Look down the edge of a few pieces to spot crown or edge curl and rotate pieces so they match.
- Use leveling clips and wedges. A tile leveling system that prevents lippage pulls adjacent edges into the same plane and holds them there until the thin-set sets. The Next Level system uses break-off leveling clips in 1/32, 1/16 and 1/8 inch with reusable wedges. Step-by-step instructions are in how to use a tile leveling system.
A leveling system does not flatten a bad floor. It controls the edges between tiles; the substrate still has to be within tolerance.
Can you fix lippage after the grout is in?
Once grout is in and the mortar has cured, lippage can only be reduced, not truly fixed: either remove and reset the offending tiles, or grind the high edges on suitable tile. Grout cannot level tiles; it only fills the joint, so a grout fix just disguises the step.
Resetting means cutting out the grout, breaking out the tile and setting a new one at the right height, which is practical for a few tiles. Grinding with diamond pads can work on through-body porcelain and natural stone, but on glazed tile it cuts through the glaze and changes the look. That is why prevention during setting is far cheaper than any repair. On walls the same rules apply; see using a tile leveling system on walls and showers.
Frequently asked questions
What is lippage in tile flooring?
It is an uneven step between the edges of two floor tiles. You see it as a shadow along the joint and feel it as a raised edge.
Is some lippage normal?
Yes. Because every tile has some thickness variation and warpage, standards allow a small amount, typically 1/32 inch with joints under 1/4 inch. Light can make acceptable lippage look worse than it measures.
Does wall tile get lippage too?
Yes. Lippage on wall tile is common in showers and backsplashes, where light hits the wall from the side and makes every step visible.
Key terms
- Lippage: a difference in height between the edges of two adjacent tiles.
- Lippage tolerance: the maximum height difference a standard or contract accepts between adjacent tile edges.
- Raking light: light that hits a surface at a low, grazing angle and exaggerates small height differences.
- Warpage: the natural bow of a tile from firing, measured as a percentage of the edge or diagonal length.
- Substrate flatness: how close the floor or wall under the tile is to a true plane, measured over a set distance.
- Offset pattern: any layout where each row is shifted so joints do not line up from row to row.
- Running bond: a brick-style offset layout, often used with plank tile.
- 33% offset: shifting each row by one third of the tile length, the maximum ANSI A108.02 allows for tiles over 18 inches unless the maker specifies otherwise.
- Credit card test: a quick field check where a card is slid across a joint to feel for a step of roughly 1/32 inch.
- Lippage gauge: a small tool that measures the height difference between two tile edges directly.
- Edge curl: warpage in which the edges of a tile turn up or down relative to its center.
- Crown: a tile whose center sits higher than its edges, like a shallow dome.
- Flat trowel coverage: mortar ridges that have collapsed into a continuous layer under the tile, leaving no voids.
- ANSI A108.02: the American National Standard that sets general requirements for installing ceramic tile, including lippage and joint guidance.
- Grinding lippage: removing a high tile edge with diamond abrasives after installation.
- Tile grinding: mechanically flattening an installed tile or stone surface, practical mainly on through-body material.
- Plane: the flat, continuous surface all tiles in an installation are meant to share.
- Tile edge: the side face of a tile, which can be square, beveled or rectified.
- Finished floor height: the final top-of-tile elevation, which must meet doors, thresholds and adjacent floors.
- Light source: any window, door or fixture whose angle determines how visible lippage will be.
Sources
- LATICRETE TDS 164, Lippage: Causes and Prevention (cites ANSI A108.02 4.3.7, 4.3.8 and TCNA substrate tolerances)
- TileLetter (NTCA), Large-format tile: know your numbers for installation success
Setting tile where lippage matters? Next Level ships its clip-and-wedge leveling system nationwide, sold by quote. Request a quote for Next Level leveling clips and wedges and tell us your tile size and joint width.