Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 52 Page 53 Page 54 Page 55 Page 56 Page 57 Page 58 Page 59 Page 60 Page 61 Page 62 Page 63 Page 64 Page 65 Page 66 Page 67 Page 68 Page 69 Page 70 Page 71 Page 72 Page 73 Page 74 Page 75 Page 76 Page 77 Page 78 Page 79 Page 80 Page 81 Page 82 Page 83 Page 84 Page 85 Page 86 Page 87 Page 88 Page 89 Page 90 Page 91 Page 92 Page 93 Page 94 Page 95 Page 96 Page 97 Page 98 Page 99 Page 100 Page 101 Page 102 Page 103 Page 104 Page 105 Page 106 Page 107 Page 108 Page 109 Page 110 Page 111 Page 112 Page 113 Page 114 Page 115 Page 116 Page 117 Page 118 Page 119 Page 120 Page 121 Page 122 Page 123 Page 124 Page 125 Page 126 Page 127 Page 128STONE ––––––––––––––––––––––––––––– Ongoing mystery: discoloration in marble shower installations A recurring situation that installers encounter is this: the stone tile they install in shower floors and walls often becomes discolored, or “stained.” This is a confounding problem, with much investigation, theories and speculation on what causes this, which can also be seen in some translucent glass tile. Martin Brookes, of Heritage Marble & Tile in Mill Valley, Calif., NTCA 2nd vice president, and Five Star Contractor, has worked with Steve Young of Steve Young & Associates, White Plains, Ga., and NTCA’s 2016 Tile Person of the Year, as sleuths to explore this problem. Brookes explained that in their dis- cussion, the problem seems to stem from several conditions. 1. Direct-bond shower waterproof- ing issues. “I have personally seen this happen with both glass tile and stone tile,” Brookes explained. “The troweling techniques need to be perfect with no valleys in the thinset to prevent moisture from congregating beneath the tile sur- face. I refer to this as ‘aqueducts‘ that allow free movement of mois- ture between the waterproofing and the underside of the tile. Over time this will manifest into a cloudy appearance within the tile and may eventually wick up the wall.” It’s believed this also happens with other types of tile but due to their ability to resist absorption – or because of the color – it is not vis- ible to the naked eye. 2. Drain flange issues. “The second issue is a traditional water-in/ water- out method with a traditional clamp- ing ring type drain,” Brookes said. “If this drain flange is not set flush with the top of the substrate, it will cause moisture to also congregate around the flange until it reaches the height of the bottom clamping ring. Over time this will create “puddling” and eventually a dark spot around tile at the drain, which will then wick to the rest of the tile and sometimes up the wall tile.” 3. “Bird Baths”. If a manufactured pre-slope is used with the tradi- tional water-in/ water-out method using a traditional clamping ring type drain, and indentations are made from knees or other forms of weight, it can also produce “bird baths” in which water will pool and eventually evaporate through the stone or tile leading to a dark spot. 4. Inadequate weep allowance. sponsored by 64 TileLetter | February 2017