Organic mastics are either water — or petroleum-based adhesives that consist of a bonding agent and a liquid vehicle. For petroleum — based mastics, the vehicle is a solvent, usually toluene. These formulations are highly toxic and flammable and are not recommended for use in a healthy home.
Organic mastics enjoy widespread popularity because they are inexpensive, stickier than thinsets, and allow the quickest installations. However, they do not have the strength, flexibility, or water resistance of thinset or thickset applications. Because they are applied in a very thin layer, they do not have leveling capabilities and are suitable only for application over flat surfaces such as plywood or dry — wall. When they are used over concrete, the vapor emission rate and pH of the slab must be checked to ensure compatibility with the mastic, which can break down if too much moisture is emitted from the slab. If the slab is too alkaline, adverse pH reactions in the mastic can result in a persistent odor that is strong and unpleasant. Refer to Division 13 for more information on calcium chloride moisture testing and pH testing for concrete. Most mastics are not recommended for areas that get wet. Where mastic applications are appropriate, you may wish to choose one of the following water-based products:
• AFM Safecoat 3 in 1 Adhesive: Low-odor, low-VOC, water-based mastic for hard composition wall and floor tiles
• CHAPCO Safe-Set 88 and Safe-Set 90 Ceramic Tile Adhesives: Solvent-free, nonflammable, freeze/thaw stable, and almost odor-free ceramic floor tile adhesives
• Taylor Envirotec 901 Odyssey Ceramic Tile Type I Adhesive: For ceramic floor and wall tile adhesion
As with tile-setting mortars, a number of additives maybe used in commercial grouts to impart certain performance characteristics such as improved strength and flexibility, increased water or stain resistance, and improved freeze/ thaw stability. Some of these additives, such as epoxies, are quite noxious. In grout applications, they will be exposed to the living space and will continue to outgas until completely cured. Homemade grouts can be mixed onsite by combining Portland cement, sand, lime (optional), and water. They can be colored with the same pigments used to color concrete (see the section on concrete finishes in Division 3). It is important that the person mixing the grout know the proper proportions and sand size for the particular tile application. These applications should be damp-cured for three days. The following commercially available grouts are free of latex additives:
• C-Cure AR Sanded Grout 922: A sanded grout available in a limited selection of colors
• C-Cure Supreme Grout 925: An unsanded grout for joints less than % inch and for use with tiles that are easily scratched, such as marble
• Hydroment: Ceramic tile grout (sanded) and dry tile grout (unsanded)
• Mapei 2V2" to 1: For large grout joints greater than % inch
• Summitville-700 SummitChromes:
Sanded grout without polymer additives, available in 32 colors
Tile Sealers
If an unsealed tile is selected, it is important to specify sealants that are free of harmful chemicals. Many of the commercially available tile sealers are solvent-based, highly toxic products that will emit noxious fumes for a long time after application. If they are used to cover a large floor area, the negative impact can be significant. Consider one of the following specially formulated products:
• AFM Safecoat MexeSeal: For sealing previously unsealed tile floors
• AgriStain for Concrete: Sealer and stain for concrete, plaster, and porous tiles
• Zip-Guard Environmental Wood Finish: A water-based urethane that can be used for sealing very clean, previously unsealed tile floors
