As you already know, TCNA Handbook methods W242-18 (Organic Adhesive) and W243-18 (Cementitious Bond Coat) are for installing (direct bonding) ceramic or glass tile on a substrate of gypsum boardfastenedtowoodormetalstuds. In these methods, the Preparation by Other Trades section states: “Gypsum board… to be installed per GA-216.” and “Gypsum board face layer joints – treated with tape and joint com- pound, bedding coat only (no finish coats). Nail heads, one coat only.” I break down (and paraphrase) those statements in this way: • Gypsum board is to be properly installed (by the gypsum board installation contractor) as described by the Gypsum Association’s GA-216 (which further references GA-214). • The face layer joints of the gypsum board are to be treated with (joint) tape applied to a bedding coat of joint compound. • Nail (fastener) heads are to receive one coat only of joint compound. • No additional finish coats of joint compound are to be applied (to the face layer joints or to the fastener heads). • These instructions say nothing about painting the gypsum board, which indicates it is not to be painted. In other words: • The board is not being prepared for painting, papering or any other surface finish. • The board must be fastened and The LATICRETE® SUPERCAP® Ready-Mix Delivery Service is a turnkey service that delivers blended self-leveling underlay- ment (SLU) through the com- pany’s patented pump truck technology, allowing an unmatched volume of premium cementitious SLU to be deliv- ered directly to the job site. With the ability to blend and pump up to 30,000 pounds (13,608 kg) per hour – the equivalent of 600 small bags per hour – the SUPERCAP Ready-Mix Delivery Service benefits the entire project from design to completion by provid- ing predictable results. Thanks to its computer-controlled system, a consistent, quality blend is ensured every time, shaving weeks off a project schedule while delivering a flat floor for subsequent trades to build out on within 24 hours. www.laticrete.com. ASK THE EXPERTS –––––––––––––––––––––––––––––––––––––––––––––––––––– 26 TileLetter | January 2019