12 2018 | TECH TECHNICAL FEATURE (continued) Because spot bonding leaves larger voids under the tile, cracked tile over voids is a typical observation. Spot-bonded tile is also generally not as well-bonded to a substrate so loose/debonded tile could also occur. However, while workmanship may be an obvious cause of hollow sounds and tile and grout issues, it may not be the only cause. A thorough inspection is required to discern. To inspect or not to inspect A 2013 TileLetter article, well before the TCNA Handbook revision was made, outlined a process of removing tiles and substrate from vari- ous areas of a hol- low-sounding floor to determine whether tiles have debonded. It also addressed why and whether indi- vidual tile replace- ment or entire instal- lation replacement might be needed. The subsequently-added TCNA Handbook lan- guage suggests a more conservative wait- and-see approach: no action necessary in the absence of actual issues. A destructive inspection will require repairs resulting from the inspection itself at the very least, and could cause new debonding or weakening of bonds. This might necessitate later repairs that would not have been need- ed had a destructive inspection not been performed. Furthermore, a premature destructive inspection mud- dies the waters with regard to the reason or responsibility for later repairs, should such be needed. Accordingly, the physician’s “first, do no harm” guideline may be advis- Spot bonding high up on walls can be dangerous. NTCA’s Trowel and Error video shows how to properly embed tiles in trow- eled out mortar. Gain peace of mind... protect your investment. Industry leading 3/8” crack protection! Consultants, contractors and architects prefer the membrane that works best, ECB® ! ECB® membrane protects hard surface flooring from structural movement. The perfect solution for malls, airports, condominiums, hotels, high-rise office buildings and any commercial or residential installation requiring crack protection. For use over concrete or wood ECB Classic ® Crack Isolation Membrane 1 ( 8 0 0 ) 6 3 3 - 4 6 2 2 w w w . n a c p r o d u c t s . c o m