QUESTIONWill Saltillo tiles experience movement, and in particular - shrinkage, due to moisture intrusion and subsequent drying? Have you seen tiles cracking several days or weeks after moisture intrusion and drying?
ANSWERANSWER - All clay based materials can expand and contract to some degree from being subjected to moisture and drying cycles or being subjected to heating and cooling cycles.
Authentic Mexican Saltillo tiles contain clay from the region of Saltillo in Mexico. Depending on how it is manufactured it can be more or less porous. Mechanically pressed high fired tiles will be more dense and less porous and those that are hand molded and heated at lower temperatures are more porous. The more porous the tile the greater capacity it has to move. Although if the tile is well bonded to its substrate it is restrained from movement under those various conditions.
The typical better quality Saltillo tiles that have been properly installed should not be adversely affected by the moisture in terms of cracking. It could develop efflorescence and spalling. Although if the tile isn't properly installed and doesn't have adequate movement joints to mitigate the movement stresses, there could be cracking. Normally the cracking would be in the weaker grout joints and not in the tile.
Cracking in tiles are normally due to either reflective cracking from its substrate or from the tile having excessive voids under the tile, where it is unsupported and was subjected to point loads greater than it could withstand.