Grout joint widths are also an important factor in a successful tile installation. When choosing spacer size, consider the aesthetics of the installation, the type and size of tile, the edge style of the tile and the type of grout.
3/16″ is a standard-size joint width. Wider joints may be needed with installations of very large tiles. Even installations of small tile require a minimum of 1/16″ grout joint. Note: Installations with tiles tightly butted together (zero grout) are not recommended and will likely develop serious issues over time.