The new TCA handbook informs us that the American National Standards Institute (ANSI) A108 Committee on Ceramic Tile has revised the A108, A118 and A136 designations for the installation of ceramic tile.
In addition to these revisions, the committee has approved new specifications for: the installation of ceramic tile with exterior glue plywood (EGP) latex Portland cement mortar; installation of load-bearing bonded waterproof membranes for thinset ceramic tile and dimensional stone; standard cement grouts and polymer-modified cement grouts; and EGP latex Portland cement mortar.
One of the revisions to the TCA 2003-2004 Handbook is a caution with regard to wood-based panels and a list of exclusions from recommendations. Plywood made with fully waterproof adhesive and with an exposure rating of 1 for exterior applications may be used on residential horizontal surfaces when installed in accordance with ANSI guidelines.
In the Interior Floors section of the handbook a new detail has been added -- Detail F135-03 Cork Underlayment on Concrete. This detail is included to provide an above-grade installation where sound transmission is a concern. One of the limitations is that a minimum 6-inch slab must is required for the procedure and only ceramic tile or stone measuring 8 inches square or larger may be used.
RH110-03 is hydronic system with water-filled tubes installed in the concrete slab. The detail specifies that a minimum 3/4-inch layer of concrete must cover these tubes. A crack-isolation membrane is included in the detail, and the membrane manufacturer must approve the use of the product in a hydronic system application.
RH115-03 refers to an electric system installed on the surface of the substrate. The electric system detail does not include a membrane. Both hydronic and electric systems call for latex Portland cement mortar bond coats.
Another revised detail is F144-03, Cementitious Backer Unit/Fiber Cement Underlayment with a thinset installation for floors. This detail is in the Interior Floors section of the handbook under the wood subfloors category. Again, deflection is an important consideration. This deflection cannot exceed 1/360 of the span when measured under a 300 lb. concentrated load.
Yet another revised detail for interior wood subfloors is F146-03, Coated Glass Mat Water-Resistant Gypsum Backer Board to be used with latex Portland cement mortar. In this detail, ceramic tiles must be 2-by-2 inches or larger. This detail is not for areas such as shower floors.
F170-03, entitled Fiber-Reinforced Gypsum Panel Backer Board using latex Portland cement mortar, is a completely new detail. This detail can only be used in dry areas. Another new detail, F151-03 Coated Glass Mat Water-Resistant Gypsum Backer Board over 24-inch o.c. Joist Spacing, is also for use over plywood subfloors. A limitation here is that you must use tiles of 8-inch-square or larger format.
A few other new details worthy of your attention are F152-03, Wood Sufloor 24 inch o.c. Joist with membrane, and F155-03 OBS Subfloor 24-inch o.c. Joist with EGP (Exterior Glue Plywood).
Finally, another detail worth noting is a wall detail, W246-03, which is a Cementitions-Coated Foam Backer Board and can be used in wet or dry areas. This panel may also be used for detail B425-426 03, bathroom walls and shower receptors.
Unfortunately, I haven’t the space to cover all of these details in an exhaustive manner. For a more complete understanding of these guidelines, I suggest that you telephone TCA at (864) 646-8453 to obtain the unabridged 2003-2004 Handbook (and also the current ANSI manual).