Tile Stress- Lessons not learned from history!
Tile is a very common floor covering in modern homes. But most do not think much about it and we should. Tiles are very durable and will last a long time if… done correctly.
European builders thousands of years ago understood some basic principle of tile and developed a successful installation method of tiles. The idea was to eliminate the transfer of stresses within the various layers of materials of the overall assembly, thereby eliminating failures.
The builders of yesteryear understood that for a tile surface to be properly installed a forgiving shear interface between the building structure and the tiled surface was necessary. This was to allow the two elements to move independently.
European builders used a "sand strata" method comprising a structural base and a layer of sand. The use of this "sand strata" method is not used today due to the introduction of thin-set mortar in the 1960s. Thin-set mortar has allowed the tile to be bonded directly to the building structure (concrete or plywood, etc…).
However the physical dynamics of the floor assembly in relationship between the covering and the substrate often is not properly addressed.
Direct bonding of the tiles to the building substrate creates what is known as a "force-transfer assembly”. The physical dynamics of the tile in relationship to the substrate will vary due to the differences in their physical properties.
So if the tile is directly bonded to the substrate, naturally-occurring stress cracks, and movement in the substrate can manifest themselves in the tiles. This will be visible as cracks, splits, tenting, or debonding.
Here is a perfect example of this dynamic. The fracture from the concrete curing radiated through the tile causing a fracture of the tile.
How is this corrected? Install what is referred to as an “Anti-Fracture” membrane. These membranes come is various forms from a sheet material to a liquid elastomeric formulation.
It is unfortunate that most will not know if this has been properly performed till an issue arises.