I have a question on the best practice for installing 12″ x 24″ large-format tile in a 1/3 offset pattern. If layout results in alternating small cuts – no less than 3″ occasionally on one end and larger – is that acceptable as best practice? When laying out to 1/3 offset pattern, the center tile was divided with equal cuts on each side for the bottom course.
The tile industry standards address your question like this:
ANSI A108 (American National Standard Specifications for the Installation of Ceramic Tile Section .02 (General Requirements; Materials, Environmental, and Workmanship sub-section 4.3 (Workmanship, cutting, fitting and grout joint size) states:
- A108.02 4.3.1 – Center and balance areas of tile, if possible.
- A108.02 4.3.2 – An excessive amount of cuts shall not be made. Usually, no cuts smaller than half size should be made. Make all cuts on the outer edges of the field.
This isn’t a lot of information to go on, but it is essentially defining the standard/best practice as ensuring there is not less than 1/2 tile wherever possible. The easiest way to adjust for small tiles is usually to shift the layout from the center of the tile to the center of the grout joint. On a 1/3 offset, this usually offers more than one alternative for centering to avoid small cuts at the ends of the field.
When it comes to layout, the installer or designer should confer with the owner to ensure the final layout is acceptable. If the owner is not available, we advise the installer to ensure their layout is defensible, in other words, that all layout options were considered and the layout installed was the best one that met the criteria for centering/balancing/no small cuts, and it also considered the most prominent focal point of the installation.
I found the section you quoted helpful about standards/best practice as ensuring there is not less than 1/2 tile wherever possible, especially the statement of “wherever possible” and “centering the tile” or shifting the tile, as key components to achieving the best layout for a 1/3 pattern.
In my case, I explored shifting the centered tile on the first course and it still resulted in smaller cuts on the alternating ends. I’m working with 12″x24″ large-format tiles on a shower wall that is 59-1/2″ in width. I started my layout for the first course by using the center of the wall and tile, which resulted in two side cuts on each side of the full 12″x24″ centered tile of approximately 18-1/2″. I began the 1/3 offset install starting from left to right. This resulted in the first end cut being 4-1/2″ to start the 1/3 offset. The right end cut resulted in a 3-1/2″ cut, which equals 1/3 of the 12″x24″ tile. This is the layout I chose to go with in order to control not having any smaller cuts on the ends.
One of the workshops NTCA conducts is titled “The Ins and Outs of Layout.” At this workshop, we are involved with discussing a wide variety of layout issues similar to the one you are working on, as well as others. We’d love to have you attend this program when we are near you. Follow our schedule here and keep checking back as we will be adding many more programs for 2023 soon https://bit.ly/3CHK79H – or go to the Community Calendar at www.tile-assn.com under the Training & Education tab.