teamed up with a reputable set- ting-material manufacturer. You are aware of the amount of moisture in the slab to be covered – use the appropriate setting materials that can handle that level of moisture. There is no mention in the TCNA Handbook of suitable moisture lev- els in concrete measured using the relative humidity or calcium chlo- ride test. In most of the TCNA meth- ods, under requirements, it states “Check with manufacturers of membranes and setting products as not all are suitable for concrete with excessive moisture vapor transmission.” There is one paragraph in the membrane section of the NTCA Reference Manual on page 74 that references this situation. It states “Moisture flow under 12 pounds per 1,000 feet is normally not con- sidered detrimental to ceramic tile installations installed with standard dry-set mortar. Tile set with latex Portland cement mortar need not be concerned unless the moisture flow is above 10 pounds per 1,000 square feet. This is because ceram- ic tile installations set with Portland cement products can ‘breathe’ allowing moisture to escape with- out doing damage to the instal- lation. There should be concern when moisture flows in excess of 12 pounds per 1,000 square feet are encountered. Many times this is an indication of hydrostatic pres- sure, green (uncured) concrete or moisture being introduced to the The LATICRETE® HYDRO BAN® pre-formed shower sys- tem products include an expan- sive line of pre-sloped shower pans, linear shower pans, nich- es, seats, benches and acces- sories – all made with a high density polystyrene core. Complemented with a variety of adhesives, grouts and seal- ant caulk options, including HYDRO BAN, HYDRO BAN Sheet Membrane, HYDRO BAN Board and HYDRO BAN Adhesive & Sealant, LATICRETE shower systems provide every- thing needed for a flawless shower installation, backed by the industry’s best warranty. www.laticrete.com ASK THE EXPERTS –––––––––––––––––––––––––––––––––––––––––––––––––––– 22 TileLetter | September 2017