As a general rule floor tiles should have grout lines of 1 8 inch or larger depending on the type and size of tile.
Marble subway tile grout line.
How to grout marble tile.
Because of this minimizing the width of grout lines is advisable.
I try to use the smallest grout lines the tile will allow.
Note that using the smallest grout possible will increase installation time.
We recommend a 3 16 grout size for our ceramic tile line.
Finished grout lines will vary from 1 16 to 3 16.
If you are going for high contrast or retro style wider grout spacing gives you the opportunity to make a statement with your grout.
The best thing to do is use the smallest grout line your particular tile will allow and get a grout that closely matches the tile.
Grout lines for floor tiles.
Special types such as slate or quarry tiles often do not have edges uniform enough to look good with tight spacing.
Thinner grout spacing for subway tile creates a more subtle effect and wider grout lines a more dramatic one.
For most granite and marble tile i install i use either 1 32 or 1 16 inch grout lines.
Most floor tiles are 8 inches by 8 inches but larger versions are available.
Although tile installations can be installed in groutless format the traditional method calls for grout to be placed in the joints between the tiles.
If smaller spacers like 1 8 are used it will accentuate the size difference of handmade tile.
In most other tile i will use 1 16 or 1 8 inch lines.