No need to Google. This came from Daltile, but it came to them from TCNA. Ask and you shall receive: Rectified Tiles What Is The Appropriate Grout Joint Width? Rectified tiles continue to increase in popularity, particularly in the commercial arena. For years, the industry and Dal-Tile have recommended that Rectified tiles can be installed with a 1/16" grout joint. However, from the contractorÂs perspective, installations have become more time consuming and difficult to ensure compliant installations when attempting to install a Rectified tile with a 1/16" grout joint. In response, the new TCNA (Tile Council of North America) Handbook addresses this issue by recommending that the width of the grout joint used be determined by the ANSI A108.02 specification which states that the actual grout joint size shall be at least 3 times the actual variation of facial dimensions of the tile. To simplify: Rectified tiles, regardless of size, shall have a grout joint width no less than 1/8". As a result, Dal-Tile is changing its recommended grout joint width to be 1/8" for all of its Rectified tiles. In addition, we will no longer recommend in our literature that Rectified and Non-Rectified large format rectangle sizes (Ex: 12" x 24") can be installed in a brickwork or running bond pattern where the overlap is 50% [normal brick joint]. The reason for this is that the allowable warpage for a tile based on ANSI specifications can create an installation issue when large format rectangular tiles are installed in a brickwork/running bond pattern. This allowable warpage can create a scenario where lippage is inevitable given the overlapping pattern. To mitigate this effect, Dal-Tile will be removing the brickwork pattern from our catalogs and literature. This will be replaced by a new pattern that will be referred to as a "Staggered" brickwork pattern where the overlap does not exceed 33%, and the grout joint width must be a minimum of 3/16". Also-- grout was Mapei's Pearl Grey.

I don't think I would do it unless I was wanting to accentuate the dimension of the room in one direction -- say, make the room look longer. But there would be a continuity or similarity -- I think it would depend on the other visual aspects of the room, what you want to accentuate and what you like. I've seen some things I wouldn't normally think I would like be perfect for the right space or done with the right flair and attention to details.

The TCNA industry standard term ''large format tile'' refers to any tile that is 16'' or larger in one dimension. That means a 16x16 or a 4x16 are both large format and follow under the TCNA recommendations for being set as large format. All large format tile will have droop. Because it's so large. It shrinks unevenly as it's fired. Rectified or not. That's why tile manufacturers will not warrant a random set, or a 1/2 offset. Stacked, herringbone, or 1/3 offset are all fine, as that minimizes the high/low contact point between the ends and body. 1/32 is also the usual recommended minimum grout line, on a medium bed mortar, with a leveling system. Without the leveling system, 3/32 is as small as you'd want to go. That medium bed provides more support for the mass and makes it easier to level over the distance. Many leveling systems have also come on the market to help with the lippage issue, but they work best with the medium bed mortar and no less than 1/32 grout lines. Lot's of installers have not kept up with the advances in tile manufacturing and are unfamiliar with the requirements for large format tile. And some don't want to invest in technology when they think they won't see a return in labor costs. Very few set out deliberately to do a poor job. They are just ignorant of the requirements. Or, they see themselves pricing themselves out of their market if the do a proper install. Consumers have to realize that setting large format should be about twice as expensive as a standard 12x12 tile. Just the mortar is twice as expensive alone! Then add the extra time, and the investment into a leveling system. If you want a good job, you have to pay those additional costs. You won't be hiring the low bidder on the job and getting even a half decent job. Here is a link that might be useful: Tuscan Leveling system.

I‘lol comment on the “quality” aspect a little. My previous house had tile throughout the main living areas and it was laid on the diagonal. Initially when we looked at (&bought) the house we too thought it was different/special/unique/whatever. Friends commented on it looking nice. However, it just really sucked. Rugs and furniture placement always looked bad bc it was hard to get them lined up with the angle or exactly perpendicular to it. It quickly became a PIA. It never just blended away as a floor. I know yours is a bathroom but I would still rethink it. It could easily end up looking like you just couldn’t make a straight line. Maybe use a smaller rectangle tile for herringbone or another interesting layout or find some interesting tile and do a stacked or offset pattern. I think you’d find it nicer and less “unique”. Sometimes unique is the equivalent of bless your heart.