What is the recommendation for minimal grout lines ?
Nobody likes to see dirty dark lines in their floors that can’t even be cleaned without professional help.
Also, grout lines are the seams that we would love to get rid of since everybody’s goal is to have seamless flors. So what is the answer ?
The answer from factories is 2mm. Which is 5/64
Our recommendation is not closer than 1/16 by using a good quality, heavy duty grout.
Let me explain why ?
There are three requirements for tiles to be installed with no grout. A perfectly leveled floor, perfectly flat floor tiles, and a perfect installer
Lets assume that you or your contractor is working with a great installer and your floor is perfectly leveled prior to the installation. If you bought natural stone for your floor such as marble, travertine or limestone, your tiles are as flat as a tile can be. On the other hand if you decided to go with porcelain tile, your sales person has probably told you about rectified tiles. And by putting two tiles next to one another, has already demonstrated to you how close those tiles can be installed. However, she/he forgot to tell you that porcelain tiles are baked products coming out of an oven and for that nature they cannot be perfectly flat. They all bow. Even in the factory, they are fired with a certain angle to prevent them from bowing upward. So, they need to be installed with a certain distance for your floor to not the have lip-page.
However, even natural stone should not be installed without grout because grout is the product that is used to cover the gap between tiles. If there is no grout between the tiles, in the long run, all the liquids used for cleaning will slightly leak under the tiles and create mold, which will then eat up the concrete causing damage and poisoning the air that you breathe. Or, if the gap between the tiles is too thin, it cannot be properly filled with grout, resulting the grout to pop up from the corners leaving little holes in the floor that will cause the same issues.
Factory recommendation for grout lines is 5/64th of an inch. If this is not thin enough for you, you may be still okay pushing it up to 1/16th of an inch by using a heavy duty grout.