QUESTIONQuick question, we are doing another hotel and making sure we follow all appropriate guidelines. Looking at some of your articles online I was trying to determine the recommended soft joint application that's within TCNA guidelines and it's a bit confusing.
Attached is a layout with 23"x47" tile installed on 1/3 offset. I assume we would follow the grout lines as close as we could to TCNA recommended distances. The Architect is asking that we cut through all of the tile with a straight line as illustrated in the attached drawing. This would obviously look terrible and defeats the purpose of using large format tiles because they are all going to be cut into large and small pieces? Thoughts?
ANSWERThe TCNA EJ171 now allows for zipper or sawtooth generic movement joints in tile installations, where you follow the grout joints within the tile assembly, not into the mortar bed.
It is not uncommon for the movement joints go straight across, which would be more practical if the movement joint extends into the mortar bed if this is a mortar bed installation.
The joints are suppose to have a compressible closed cell back up strip with an ASTM C920 Traffic Grade sealant. It should be tooled to achieve a slight recess so the foot traffic doesn’t touch the sealant. They should be installed very 20 to 25 feet in each direction for interior applications that are not subject to direct sunlight. Exterior and Interior applications subject to direct sunlight are to be placed every 8 to 12 feet in each direction.
Be sure to include movement joints at all the perimeters, change of plans, and where you are tiling up to restraining surfaces. You need at least a ¼” wide joint. It can be left open if there is a tile base going over it. Otherwise you need to install the backup strip with the ASTM C920 sealant over it.