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.

4 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.

  2. Bill says:

    On a project I am doing there is about 500 sf of 24x48x3/8” black porcelain tile to install at a 3 story high stairwell wall. Above the entire stairwell wall is a skylight approximately 10’x20’. It is above the upper two story’s of the stairwell. Because of the direct sun light I am concerned about grout joint size and movement joints.

    I’ve consulted the tile supplier and the thinset manufacturer and they both recommended a 3/16” grout joint, but, obviously, say to follow TCNA guidelines. In reviewing the TCNA regarding movement and expansion joint, it gives a lot of information for interior areas without direct sun light.

    However, the information is very limited for areas have direct sunlight. From what I read, the only guideline is the movement joints have to be a minimum of 1/8”, there is a 2:1 ratio for width to depth and the movement/soft joints have to be between 8-12 feet apart. Am I reading this correctly? Are there any other guidelines I’m not aware of? Would you recommend mechanical fasteners above a certain height.

    We are planning to float the wall, use a primer recommended by our thinset supplier and thinset over with an S2 thinset. We will have a soft joint around the perimeter. I’m looking for advice as to grout joint size ( the designer would like the grout joint to be 1/8” or less) and are there guidelines in regard to width and spacing of movement joints?

    • Donato Pompo says:

      In ANSI A108.02 where they talk about off-set tiles of 50% vs 33%, they do recommend a 3/16” grout joint to minimize potential lippage with staggered layout on tiles with one edge 15” or larger.

      If the warpage isn’t bad and you are installing over a plumb substrate you should be able to set with 1/8” wide grout joints and not get more than 1/32” lippage.

      For a 1cm thick porcelain tile you don’t need to mechanically attach unless you are doing soffits. Using an ANSI A118.15 thinset like Laticrete 254 Platinum and getting full thinset contact between the back of the tile and substrate it won’t go anywhere. Assuming you have a good structurally sound substrate to go over.

      Movement joints where tile gets full sunlight from windows EJ171 suggests have movement joints every 8 to 12 feet. Technically at 12’ they want a 3/8” wide movement joint and a ¼” wide at 8’. If you place them every 4’ then you can have a 1/8” movement joint. These are only recommendations. Chances are if you do the math in terms of coefficient of expansion of the various materials you can problem do a 1/8” wide movement joint at 8’ or 12’. With that large of tile you might consider caulking all of the grout joints with an ASTM C920 non-sag silicone. It will increase the strength of the attachment to the wall and give you maximum movement mitigation.

      With a 5/16” thick tile you aren’t going to meet the 2:1 ration width to depth. The sealant joint manufacturer wants at least ¼ thick sealant. You are suppose to have bond breaking tape in the grout joint so you have only two point contact, but with a 1/8” joint on a wall it is problematic. I would just fill the joint with sealant so it does bond to the substrate that increases the strength and resiliency of your attachment.

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