Installing ceramic tile correctly can be a difficult and complex operation. However, there are certain aspects of a job that are not within the installer’s expertise and should be left to the appropriate person.
The Tile Council of North America (TCNA) Handbook committee has gone to great lengths to provide guidelines and best practices that will help and protect the tile installer. For instance, the Handbook section entitled “Substrate Requirements” states: “For ceramic tile installation, maximum allowable floor member live load and concentrated load deflection for framed floor systems shall not exceed L/360, where ‘L’ is the clear span length of the supporting member per applicable building code. For natural stone tile installations, maximum allowable floor member live load and concentrated load deflection for wood framed floor systems shall not exceed L/720, where ‘L’ is the clear span length of the supporting member per applicable building code.”
Many times, the tile installer is called on (especially in single-family residential) to determine if the structure will support the added weight of a new ceramic or stone floor and to design and install the necessary additional framing. This is not the installer’s job and it could be a really bad choice because the installer will be responsible for the cost of a replacement floor if it fails.
This is where the Handbook becomes your new best friend. It states: “The tile contractor shall not be responsible for problems resulting from any structural subfloor installation not compliant with applicable building codes, unless structural subfloor was designed and installed by tile contractor, not for problems from overloading.”
The tile installer should not get involved in the design of the floor structure. If the owner, general contractor or builder asks for advice, don’t volunteer any information. Politely steer them toward the structural expert and continue to do what you do best—installing tile.