Referred to as a movement, expansion or stress relieving joint, expansion joints are often used when tiling large floors to break up the floor covering in to separate sections. A tiled surface is similar to a sheet of glass in its rigid nature, and this can cause problems when there is movement. Using an expansion joint allows each block or section to move independently from the others.
Why Are Expansion Joints Needed?
In any construction there is some degree of movement, and this can affect the different materials and surfaces that are used within the building. Movement can be caused by:
- Physical movement of the building
- Shrinkage of concrete
- Moisture expansion
- Transitions between materials
- Changes of plane
- Thermal movement
- Movement within the substrate
All tiles will expand and contract due to changes in temperature and moisture, and almost all substrates will move differently to their coverings. These movements can transfer to the tiled surface, causing cracks, bulging, debonding, and/or tenting. By using expansion joints you are creating smaller tiled areas, or ‘fields’, therefore significantly reducing the risk of movement affecting the surface.
When Should I Use Movement Joints
The larger the tiled area, the more the tiles will expand and contract. When deciding whether you need to use expansion joints there are a number of factors to consider. Firstly how big is the space you are going to tile? We recommend using expansion joints at intervals of at least 6m for heated floors, and 8m for unheated floors. Therefore if your room measures only 3m wide but is over 8m long, you will need to add an expansion joint.
The number of expansion joints should be increased in areas subject to significant temperature variations, and you should avoid placing them in areas of high traffic if possible. When using stress-relieving joints on suspended floors, they should be positioned over supporting walls and beams.
For additional protection, expansion joints can be used in conjunction with an uncoupling matting or membrane online at Tile Fix Direct.