no larger than 1'16!

0- 1/16"

Contractors need to learn how to do groutless tile installation. I have seen it elsewhere in the world. I need to be educated why it cant be done here.

We have 12x24 vein cut travertine in our FR/guest bedroom/ground floor entryway. Our tile guy did a super-tight grout joint for us (1/32? 1/16?) and it looks fabulous!

Grout width is a function of the uniformity of the tile size. The grout width should be at least 3 times the difference between the largest tile and the smallest tile, and no less than 1/16". Take measurements from a good sample of your tiles to find the variance. For example, if your largest tile is 1/32" larger than your smallest tile, the grout width would be 3/32".

1/16 is what we will be doing with our 12x24 tiles. We also picked the grout color to be similar so the grout doesn't show up as much.

I believe what Catbuilder said is the standard set by the tile associations. The flatness of the surface will also be a factor, as the wall undulates so do the distances between tiles. Ask me how I know this :)

If the tiles are rectified then you should be able to do a 1/16" grout. I really love the look of less grout and I wondered why tile installers tend to like to use wider grout than most people like.

It turns out that grout does serve a purpose -- it allows the tiles and the subfloor materials to breathe. All building materials will expand and contract due to temperature and moisture -- even stone, cement and porcelain. Grout lines allow for the movement without stressing the material.

I also wonder about the large tiles and thin grout here in California. It's pretty common to need to do some grout repair after a quake. Fixing grout is a lot easier than replacing fissures in a tile.

cat_mom, and others, do you find that you can stub your toe on height variations? Is the tile very flat and smooth when using a very thin grout line?

Our tile guy(s) is super-meticulous in general, but especially so with regards to lippage--making sure there is none. He and his helper will pop out a tile (or more) that they had just installed, to add or scrape off thinset as needed in order for the tile(s) in question to lay very flat and smooth.

What color grout looks the best with this tile?

Ours is Ocean Beige (a silver travertine variation from ArtisticTile; with beige toned background color). We used TEC XT grout in Antique White. Blends in well. For caulk (for base of wood staircase), it was suggested we use TEC Pearl color instead, as that color in the caulk is a better match to the Antique White grout, than the Antique White caulk. Go figure! LOL

The only time grout joints(natural stone) can be less than 1/16th of an inch is in a grind in place installation. These types of installations are where the stone(generally 3/4" stock) is installed on top of a mud bed. The stone is butt-joint to each other and the ends are buttered with mortar or Portland cement.
This is done so that even when completed the floor looking monolithic still has a grout joint.
Then the entire floor is ground flat and either honed finished or polished by diamond grinding machines.
These type of installations were done in this country by Italian craftsmen in the 1920-30's.
Just walk into a NYC brownstone and look at the floors.
They have been down for almost a hundred years and are easily serviced and maintained.
Anyway back to todays installations-besides the expansion and contraction of a modern floor the grout also seals the floor. If you didn't have a solid grout system every time you cleaned your floor you wood be trapping moisture underneath the stone.Think of issues that will cause not to mention it will damage the stone eventually.
Marbles and Granites grout joints should always be unsanded grout. While most installers will tell you sanded is stronger a true marble installer wouldn't even consider using sanded grouts. While sanded could be used in marbles that are honed we still think unsanded just makes more sense.The joints just need to be 1/8" or smaller.
If you look closely at a stone tile you will see a bevel on top of the edge. if you join these two tiles together in an installation and then try to grout it the grout will only sit in the bevel. It will fail and the grout will dislodge leaving you with grout lines that look dirty.If you slide a razor thru them
you will see they are empty. This can put your floor at risk.
When working with grout you need to be able to fully push the grout into the joint.