Raymond; It is conceivable that an existing crack was in movement after the tile was done and was existing before the tile was done.
In most cases the tile setters would notice these potential problem cracks and use this over the cracks.
Thin set adhesives are usually installed with 3/8" notch trowels.
Pretty hard to screw it up.
Many specifiers call for anti-fracture membranes today. Anti-fracture membranes are designed to protect ceramic tile floors from cracking. The rubberized asphalt membranes are installed over floor substrates (concrete or wood). A latex modified thinset mortar bed is installed over the anti-fracture membrane, and finally ceramic tile is installed.
Anti-fracture membranes protect ceramic tile by providing a stress absorbing layer between the substrate and the tile. If the concrete substrate underneath cracks, the stress of the crack is not transferred up to the brittle ceramic tile. The stress is absorbed by the rubbery nature of the rubberized asphalt.
Tileguard is Polyguard’s anti-fracture membrane. Tileguard is a 40 mil “peel and stick” product, with a fabric on top, to which the thinset mortar bed adheres.
You might also be interested to know that before anti-fracture membranes were used for ceramic floors, they were used for many years to reduce cracking in highways. Additionally, the same anti-fracture stress absorbing properties are used in Polyguard’s Underseal™. Underseal™ Underslab Waterproofing Geomembrane, a much heavier duty version of Tileguard, protects concrete slabs from cracking, and provides a permanent barrier against moisture, toxins, gases, and insects.
[size=5][size=4]Tileguard™ Anti-fracture Membrane [/size][/size]
Click image to view full size](http://www.polyguardproducts.com/images/tileguard_OPT.jpg)
Tileguard anti-fracture membrane is a 40 mil stress absorbing membrane which protects overlying ceramic tile from cracking. Cracks in the substrate (concrete or other) generate a cracking force upwards, but the cracking energy is absorbed by the elastomeric rubberized asphalt in Tileguard.
***Tileguard’s ***fabric backing bonds to latex modified thinset.