How Should Movement Joints (expansion joints) be Installed in Tile Installations?

QUESTION

Quick 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?

ANSWER

The 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.

2 thoughts on “How Should Movement Joints (expansion joints) be Installed in Tile Installations?

  1. Donato Pompo says:

    We have a large 20,000sf kitchen we will be installing with Daltile Quarry Que Tread 6”x6”x1/2” tiles, see below in yellow. The architect is asking us what our recommendation would be for expansion joints, what are your thoughts for this large of an area? Your help is much appreciated.

    • Donato Pompo says:

      Expansion joints is a type of a movement joint as described in TCNA Handbook detail EJ171.

      If you are floating a mortar bed over the substrate to establish a slope to drain for the waterproof membrane to go over and for the tile to bond directly to the membrane, then the movement joints need to be continuous from the structural slab up through the tile. The membrane then needs to be looped into the movement joints to be continuous. A closed cell compressible back up strip is inserted with an ASTM C920 Traffic grade sealant installed over it. The sealant needs to be up to ½” thick and at least ¼” thick. The sealant should be tooled to a slight concave finish so that foot traffic does not come into contact with it to prevent it from getting excessively dirty.

      Movement joints on interior applications should be installed every 20 to 25 feet in each direction. You need to have movement joints that are ¼” wide at all perimeters of the tile areas and where it changes plane. Normally if you have a shoe base then you can leave the movement joints open and place the base over it so you can’t see it. But since this is a commercial kitchen, then I would fill all perimeter joints with the ASTM C920 sealant (silicone or polyurethane) as a water stop to help prevent water getting inside the walls. Your waterproof membrane should be going up the wall at least 6” as you know they normally use water hoses to wash down the tile during cleaning at the end of the night.

      Since cracks tend to occur at outside corners of walls and doorways. I would lay your movement joints out to be at those locations even if you have to add additional movement joints.

      If the tile is being installed in a running bond pattern (staggard) you can install them in a zipper or saw tooth pattern following the grout joint if you are installer over a concrete substrate. Otherwise you should lay them out in a lineal geometric pattern.

      I assume you will be grouting it with an epoxy grout that is chemical resistant.

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