Most tiles available on the market have a size of 8x8 inches and will feature grout lines of 1/8" or even larger if the client prefers. However, larger tiles are also available, so the sizes of grout lines can vary depending on the used tiles. Also, there are special types of tiles, like quarry tiles and slates, that do not feature regular edges, so tight spacing doesn't look good on them. In this case, larger grout lines look best, which can measure 3/16 or can be even larger. In general, plastic spacers are utilized in the corners of the tiles with the purpose of forming even grouting spaces. Larger tiles, of 18 inches or even larger, look best if the grout lines are thinner, and colored with a matching grout color. If you choose this method then the entire floor will look like being made out of one single tile.
In the case of tilling walls in the bathroom or kitchen, small tiles are regularly used. These tiles, which often measure 4x4 inches, don't need to be spaced, as they space themselves. This happens due to the embedded lugs, which are small-sized protrusions present on the edges of the tiles. Thus, when positioned next to another tile, these lugs will create grout lines with sizes between 1/16 and 1/32. When it comes to wall tiling projects, grout lines do not exceed the size of 1/16 inches because tiles required support when being installed on a vertical surface.
Small-sized grout joints are the ones measuring 1/16 inches. This type of joint can be obtained only when tiles have a consistent size, also known as rectified tiles. If you're going to install rectified tiles, choosing smaller grout joints will not just look great, but will also require less maintenance. But, the downside of this aspect is that smaller grout joints are harder to achieve, as there's not that much space to "move" during the installation process. Also, in the case of small grout joints, unsanded grout is recommended.
The size of medium-sized grout joints ranges between 1/8 and 1/4 inches. These grout joints will need sanded grout and will become an option when the tiles feature lugs or when there are size differences among the tiles. Both experienced professionals and DIY homeowners choose these grout line sizes because it is easy to work with them and can hide any imperfections tiles may have.
Large grout lines are the best option for tiles that have different sizes and shapes. These joint sizes range between 3/8 and 1/2 inches and will required sanded grout. Tiles made out of marble, which feature different sizes, or patterns that repeat themselves, such as the Versailles pattern, will need large-sized grout joints. This is why it is worth checking adequate guidelines before choosing a size for grout joints. But, at the same time, it is also about how you like to see a tiled floor or wall, from an aesthetic point of view.
