When it comes to stone and tiles for walls and flooring, a proper grout joint is an important part of the project. When you look at any floor, you’ll notice that the tile is greatly affected by the grout joint. While many architects, designers and DIY enthusiasts like the idea of a thinner grout joint, it’s important to understand why a thicker grout joint may be better.
1) A proper grout joint will reduce the likelihood of tiles chipping if and/or when the subfloor moves.
2) A proper grout will minimize the appearance of inconsistencies in the tile – and many tiles do have inconsistencies from tile to tile.
3) A proper grout will minimize the likelihood that the tile pattern will be thrown off upon installation. A thin grout line emphasizes any tile that’s slightly offset. A thicker grout joint is more forgiving.
Many stone and tile manufacturers suggest grout joints be no less than 1/8” and not more than 3/16”.
Large-format tiles create more lippage, or unevenness in the surface. Therefore, a thicker grout joint may be necessary.
Tile variation - differences in size: grout joints must accommodate differences in thickness and tile size. Standards for tile manufacture allow for size variation from one tile to the next – often up to 3/32” difference between the largest tile and the smallest tile in the box. Grout joints need to be thick enough to accommodate this variation.
Tile variation - differences in shape: there is less variation in rectified tiles, which produce the same size tile. Non-rectified, hand-crafted or artisanal tiles, on the other hand, have variation in shape from tile to tile and also within the same tile. A thicker grout joint will accommodate these irregular edges.
The plane or surface – Grout accommodates differences in the angle of the surface. As the plane of the tile changes (i.e. where the floor or wall is not level) the grout will slope from one tile to another. When tiling over a bump, the grout joint opens up: and when tiling across a depression the top of the grout joint narrows.
When tiles are set too close together or have a grout joint that’s too think, any variance in that grout joint may be visible. This is especially noticeable in a thinner grout joint.
Once you understand the benefits of a proper grout joint, it’s up to you to make the decision.