TECH TALK –––––––––––––––––––––––––––––––––––––––––––––––––––––––––– cal resistance, reduced porosity, improved flexibility, and freeze/ thaw stability. These additives are either already in the grout as re- dispersible powders or are added in liquid form. In both cases, grout mixed with too much water or cleaned too soon, or cleaned with excess water, can cause the polymer to migrate to the sur- face. In many cases (but not all), these polymers are white in color. When the excess water evaporates, the white polymer is exposed.” While some minor whitish deposits are likely to come from excess water in the grout mix, the serious disfigurement that keeps returning and which is identifiable by having a clear, sticky com- ponent that has a characteristic acrylic odor, is from water under the tile, that carries uncured addi- tive to the grout joints. See photos 1, 2 and 3. While the problem of latex leaching has been known about for decades, its increasing inci- dence can be attributed to several changes that have crept into the tile and construction industries over the decades. These changes are: 1. Larger, denser tiles 2. Increased use of latex/polymer additives 3. Thicker adhesive layers 4. Increased use of screed iso- lation layers (membranes and uncoupling mats) Larger, denser tiles There has been a world-wide uptake of large-format tiles. 35” x 35” and 48” x 24” porcelain tiles are now commonplace, and the use of “thin tiles” such as Laminam and Kerlite are increas- ing. These tiles generally have less than 0.5% water absorption, and Photo No. 3. Latex leaching often devel- ops as small eruptions from the joints. Photo No. 1. Latex leaching can be mis- taken for efflorescence. Photo No. 2. Latex leaching, while often white, always has a clear, sticky compo- nent that has an acrylic odor. 80 TileLetter | 2018