Frequently Asked Questions About Movement Joints
(By the way, nobody frequently asks any of these)
- I’m tiling a small floor. Do I need movement joints? Yes!
- I’m using Ditra which is an uncoupling mat. Do I need movement joints? Yes!
- I’m tiling over cement board. Do I need movement joints? Yes!
- My concrete floor doesn’t have expansion joints. Do I still need them? Yes!
- I’m not tiling over a concrete floor. Do I need movement joints? Yes!
- I’m tiling shower walls. Do I need movement joints? Yes!
- Is a movement joint the same as an expansion joint? No
- Is it the same as a control joint? No
What are movement joints?
These are the kind that every tile installation should have. When you place a tile next to a wall it should have a gap between it and the wall. That’s a perimeter joint. There should be a gap around the entire floor (or wall). Typically this gap doesn’t get filled with anything. Typically it’s covered by baseboards around the room.
If you are butting up to another hard surface- like hardwood floors- then there should be a small gap between the tile and the hardwood. This you will probably want to fill with caulking. More on that later in the post.
Movement in the field
Where to place the field joints
How to install movement joints in tile floors
You need to leave yourself a gap that is ungrouted. This space needs to be clean down to the substrate. So you don’t want thinset or anything else in the joint.
Take some backer rod and stuff it in the joint. Backer rod is a stringy foam product. Typically it’s found in the door/window/insulation section at the big box store. I use 1/4 inch which works for most tile applications but it does come in bigger thicker sizes.