Cracking in Wall and Floor Tilings

As it has been remarked in the previous sections, particularly in the widespread detachments, arching, and debonding, if adhesion does not fail, ruptures will occur when the stresses to which the tiling system is subjected exceed the strength of the materials.

This large section includes four families of cracks with four quite well-defined generic origins:

• Cracks that affect a single or several consecutive tiles as a result of localised stresses or point aggressions.

• A crack aligned across consecutive tiles owing to a localised stress in correspondence with fitted installations or a weak point, with fracture, in an opening.

• Cracks that usually affect every tile, in one or more propagation direction, in the ceramic wall or floor tiling surface. Here, the assignment usually corresponds to stresses generated by the substrates or structural elements underlying the wall tiling or flooring.

• Cracks displaying random development with a polygonal trend in flooring subjected to compression and strong localised stresses stemming from the levelling layer.

This serious malfunction appears in every type of ceramic flooring, in both the traditional tile installation ‘on decoupled screed’ and in thin-bed fixing. The well-adhered tile does not withstand the localised compression, tries to follow the shrinkage between cracks of the levelling layer, and ends up cracking. Owing to its seriousness, extensive appearance in the last decade, and complex assignment, it will be dealt with monographically here.

In the remaining situations, a distinction is made between the cracking found in wall tilings from that in floor tilings, though in some cases they share the defect assignment.

• In wall tilings

• Longitudinal and isolated

• Widespread cracking with a polygonal development