It is recommended that you err on the side of caution and use the smaller measurement.
Tile expansion joint.
Expansion joints are a necessary installation on large areas of tiling.
A movement joint is in the tile only.
The larger the tile field the more it will expand and contract and be vulnerable to failure.
Tile expansion joints tile doctor ceramic porcelain and stone tile expands and contracts with thermal and moisture changes in the environment.
Including movement joints in floors enables the tile bed to move in unison with the individual substrates.
In almost every case the substrate will move differently to the covering material.
Schluter systems prefabricated movement joint profiles protect tile edges and prevent sound bridges and surface water penetration resulting in a permanent maintenance free installation.
Placement of expansion joints is very important.
It s quite common to see controlled breaks in concrete and those are usually expansion joints.
Learn all about expansion joints here.
Latham standard loc strip hard flooring expansion joints are capable of absorbing extension and compression equivalent to 16 or 20 of the undeformed width of their elastic neoprene cores.
According to the tile council of north america a body that helps set standards for tile installations when installing outdoor tile there must be an expansion joint every 8 feet to 12 feet in each direction.
Recognizing that tile is a facade movement joints are needed to eliminate stresses that can occur between the substrate and the tile due to differing amounts of expansion and contraction.
According to the ntca national tile contractors association reference manual an expansion joint is a joint through the tile mortar and reinforcing wire down to the substrate by integrating these stress relievers into the tile assembly expansion and contraction takes place without compromising its integrity.
Thus 12mm joints can be compressed to about 10mm and extended to about 14mm 6mm compressed to about 4 75mm and extended to about 7 25mm.
An expansion joint is in the substrate for instance in concrete.
The tcna handbook recommends allowing for expansion and contraction in every tile installation.
If you tile over an expansion joint then you need to honor that joint in the tile as well.
Where should movement joints be placed.
Movement joints are an integral part of any tile assembly and must be incorporated within the tile field at doorsills and at transitions to walls and other restraining structures to allow movement of the assembly and prevent stresses that can damage the system.