Expansion Joints

Expansion joints should be used where the surface to be tiled is made from different materials. This will most commonly be the join between a concrete and a wooden floor where the whole area is to be covered in tiles. Different backgrounds move at differing rates during changes in temperature. If a tile is fitted across one of these joins, it will be under great pressure which will cause it to break or cause the grout to fail around it. Expansion joints are fixed along stress lines to allow the floor on either side to behave in different ways without affecting each other.

On very large floors expansion joints should be used to surround uninterrupted areas of 64 square metres. (8m x 8m)

It is less likely to install an expansion joint on the wall unless there is a movement joint already present or the area to be covered is an uninterrupted 9 square metres. Expansion joints on the wall are usually constructed with a continuous bead of silicone between the tiles. The silicone is able to deform under pressure and reduce any stresses building across the face of the wall.