Setting Large Tile Without Lippage: Back-Butter, Full Coverage and Leveling Clips

The short answer: flat tile comes from a flat substrate, full mortar coverage (back-butter plus directional troweling), a sensible offset and leveling clips as a helper. Clips can’t fix a wavy floor or hollow spots.

This is the hands-on companion to What Is Large-Format Tile?.

Start flat

Industry guidance for large-format tile (any edge 15 inches or longer) is no more than 1/8 inch of variation in 10 feet. Grind the highs and fill the lows before you tile. Thinset isn’t a floor leveller.

Full coverage, not dabs

Showers call for about 95% mortar coverage, with edges and corners supported. That means:

• A notch trowel sized for the tile.
• Ridges combed in one direction.
• A thin, flat coat back-buttered onto the tile.
• Sliding the tile across the ridges to collapse them.
• Pulling a tile now and then to check.

Ahh ahh ahh! Beware of cookie monsters. Pancake dots of thinset leave hollow spots behind the tile, so it cracks and pops loose. We back-butter and go for full coverage. Best way? Do your research and hire a pro.

In showers, Mike uses LATICRETE 254 Platinum on the floor and first rows of wall tile, and MULTIMAX Lite (a large and heavy tile mortar) higher up the walls, per LATICRETE’s instructions.

Offsets and warpage

Big porcelain often has a slight bow. A 50% brick offset puts the high middle of one tile beside the low end of the next. Many makers specify a third offset or less on long tiles. Check the box.

Leveling clips: helper, not cure

Clips help hold edges even while the mortar sets. They can’t pull a tile flat over a hump or fill a void. Use them on top of good prep, not instead of it.

Frequently asked questions

What causes lippage?

A floor that isn’t flat, tile warpage with a 50% offset, or poor mortar coverage.

Do I need to back-butter large tile?

Yes for large tile. LATICRETE’s MULTIMAX Lite data sheet calls for back-buttering tiles 8x8 inches or larger.

Do leveling clips stop lippage?

They help, but they can’t fix a wavy floor or hollow spots.

How much lippage is acceptable?

It depends on tile size and joint width under the standards. Ask your installer what tolerance they work to.

See large-format tile in our bathroom renovations in Burlington.

By Mike Bourdages, Burlington Tile. Last reviewed Mike to confirm review date.