What grout joint width should you choose for rectified tiles?

Reading time: approx. 4 minutes

Rectified tiles are popular because of their clean appearance and narrow grout joints. But how narrow can a grout joint actually be? Is a 1 mm joint possible, or is it better to choose 1.5 mm or 2 mm?

In this article, you'll learn the recommended grout joint width for rectified tiles, the factors that influence your choice, and why a minimum grout joint is always essential.

What are rectified tiles?

Rectified tiles are ceramic tiles that are mechanically finished after the firing process. During rectification, the edges are precisely cut to size using diamond tools. This gives the tiles perfectly straight edges, accurate 90° corners, and exceptional dimensional accuracy.

Unlike non-rectified tiles, which come directly from the kiln, rectified tiles undergo an additional finishing process to achieve highly consistent dimensions. Thanks to this precision, the tiles fit together perfectly, creating a sleek and uniform appearance.

What is the minimum grout joint width for rectified tiles?

Because of their precisely cut edges, rectified tiles can be installed with narrower grout joints than non-rectified tiles. As a general guideline, a minimum grout joint width of 1.5 mm is recommended for wall tiles and 2 mm for floor tiles.

These recommendations apply to most installations but are not absolute. Depending on the tile size, edge finish, dimensional accuracy and intended application, the tile manufacturer may specify a larger minimum grout joint. Always check the technical data sheet before installation.

The following minimum grout joint widths are generally recommended for rectified tiles:

Rectified or non-rectified?

The difference between these two tile types has a direct impact on the required grout joint width.

Non-rectified tiles have slight dimensional variations, requiring wider grout joints to achieve an even and consistent finish. As a result, they are generally installed with at least a 2 mm joint on walls and a 3 mm joint on floors.

Why are grout joints still important with rectified tiles?

Although rectified tiles are highly dimensionally accurate, grout joints remain essential. Even rectified tiles have very small manufacturing tolerances. The grout joint absorbs these minor variations, preventing tile edges from pressing against each other and reducing the risk of chipping or stress.

Grout joints also prevent dirt, moisture and other contaminants from penetrating between the tiles. In addition, they absorb thermal movement caused by temperature changes, such as with underfloor heating or dark-coloured tiles exposed to direct sunlight.

For these reasons, rectified tiles should never be installed without grout joints.

Why is a tile levelling system recommended?

Rectified tiles are often installed in large formats, making even the smallest height differences immediately visible.

A tile levelling system keeps adjacent tiles perfectly level while the adhesive cures, reducing the risk of lippage and creating a perfectly flat tiled surface.

A levelling system also ensures a consistent grout joint width throughout the installation. The thickness of the clip determines the spacing between the tiles, so choose a clip that matches your desired grout joint width, such as 1.5 mm or 2 mm.

Key takeaways

Thanks to their high dimensional accuracy, rectified tiles can be installed with narrower grout joints than non-rectified tiles. As a general guideline, use a minimum grout joint width of 1.5 mm for wall tiles and 2 mm for floor tiles. However, always consult the tile manufacturer's technical data sheet, as larger minimum grout joints may be required depending on the tile size, edge finish and application.

For the best results, use a suitable tile levelling system to maintain a consistent grout joint width and achieve a perfectly flat, professional finish.