Preventing lippage with rectified tiles: how to achieve a perfectly level finish

Rectified tiles feature perfectly straight edges and precise 90° corners. This allows them to be installed with very narrow grout joints, creating a clean and modern finish. However, this precision also has a downside: even the slightest height difference between adjacent tiles, known as lippage, is immediately visible and noticeable.

For professional tile installers, preventing lippage is therefore essential. A perfectly level installation reduces complaints, improves the quality of the finish, and ensures a durable end result.

What is lippage?

Lippage occurs when two adjacent tiles are not installed at exactly the same height. With rectified tiles, these height differences are much more noticeable because the sharp, straight edges do not conceal imperfections.

Besides affecting the appearance, lippage can also result in:

• a less comfortable floor;
• increased wear on tile edges;
• a higher risk of chipping or damage;
• defects or remarks during project handover.

What causes lippage?

Lippage is rarely caused by a single factor. In most cases, it results from a combination of conditions during installation. Professional tile installers should pay particular attention to the following causes:

Tile adhesive shrinkage: As the tile adhesive cures, moisture evaporates and the adhesive shrinks slightly. If the adhesive bed is not evenly distributed, tiles may settle unevenly, creating height differences.

Insufficient adhesive coverage: Using the wrong notched trowel or applying the adhesive incorrectly can leave voids beneath the tile, reducing support. This is particularly critical when installing large-format tiles. For large-format tiles, nearly 100% adhesive coverage is recommended. The buttering-floating method, where adhesive is applied to both the substrate and the back of the tile, helps achieve uniform support.

Tile warpage: All ceramic tiles are manufactured within certain tolerances. Long plank or wood-look tiles are especially prone to slight warping. When installed in a brick bond (50% offset) pattern, these height differences become even more noticeable.

An uneven substrate: Even the best tile installation tools cannot fully compensate for an uneven substrate. Always check that the floor or wall is level before tiling and use a levelling compound where necessary.

Why manual correction is not enough

A rubber mallet can be used to make minor adjustments during installation, but it cannot guarantee a permanently level surface.

Once the adhesive begins to cure, tiles may shift due to adhesive shrinkage or internal tension. With rectified tiles, even the smallest height difference immediately becomes visible.

For this reason, professional tile installers use a tile levelling system. Levelling clips and wedges keep adjacent tiles perfectly aligned while the adhesive cures, significantly reducing the risk of lippage.

How to prevent lippage

You can greatly reduce the risk of lippage by following these best practices:

• ensure the substrate is level and stable;
• choose the correct notched trowel for the tile size;
• achieve maximum adhesive coverage;
• use the buttering-floating method for large-format tiles;
• install tiles using a high-quality tile levelling system;
• follow the recommended installation pattern for long-format tiles.

A tile levelling system as the professional standard

A tile levelling system does not replace craftsmanship; it supports proper installation. Combined with a level substrate, the correct notched trowel and proper adhesive application, it keeps tiles perfectly aligned while the adhesive cures.

The benefits include:

• reduced risk of lippage;
• a flatter, more professional finish;
• less corrective work during installation;
• faster and more efficient tile laying;
• fewer defects and customer complaints.

Get started

With rectified tiles, even the smallest height differences are immediately visible. By combining a level substrate, the correct notched trowel, proper adhesive application and a professional tile levelling system, you can prevent lippage and achieve a durable, perfectly level tiled surface.

For every professional tile installer, a tile levelling system is therefore not an optional accessory, but an essential part of high-quality tile installation.