This just in: Glass tile is no longer a trend in the tile industry. Like porcelain tile before it, the use of glass tile continues to increase at an astronomical pace. In researching this article, I called several leading distributors of tile and stone from around the country. Every single one of them maintains that glass tile continues to play a more significant role in their product offerings. Designers and consumers love the versatility of colors and sizes. It is safe to say that glass tile is here to stay.
For the last several years, the National Tile Contractors Association has offered seminars on glass tile installation. Scott Fleming, Technical Director at Oceanside Glasstile, (www.glasstile.com) and Greg Andrews, a tile contractor specializing in glass tile installations in Southern California, have generously donated their time on numerous occasions to help educate an industry in need of this knowledge. Much of the information in this article comes from their seminars and from Oceanside Glasstile's Installation Guide. Until our industry formally adopts specific glass tile methods, it is imperative you rely on specific recommendations from the glass and setting material manufacturer.
Due to its nature, glass tile does pose some concerns in relation to proper installation. As an industry, we are rushing to catch up to the growth of the product in developing acceptable methods and standards for its installation. The problems with installation currently stem from a lack of understanding of the nature of glass as compared to ceramic tile. However, installation materials and glass tile manufacturers have been collaborating with one another to create solid installation recommendations.
Glass tile contains no clay whatsoever. It can be transparent, translucent or opaque and ranges in sizes from less than 1" to 24"x24". It may come in either mounted (usually mosaics up to 3"x3") or non-mounted (usually larger modules). As is the case with ceramic tile, a specifier or salesperson must understand the characteristics of glass and where it should or should not be installed. If you are unsure about how glass will perform in a certain area, consult the manufacturer for their recommendation.
Other products, such as gypsum board, may be acceptable in dry areas only. YOU SHOULD NOT USE GYPSUM BOARD in any areas subject to continued moisture, for any tile products. Glass is no exception. Besides, there are numerous backerboard products that will perform in areas exposed to moisture. Consult with the Tile Council of America Handbook for the Installation of Ceramic Tile for suitable backerboard methods and definitions for products recommended in wet areas. In wall tile installations subject to continued moisture, a membrane should be installed behind the backerboard. Applying alkaline resistant fiberglass mesh tape embedded with the recommended mortar is also essential for the successful installation of glass tile.
Other important items to consider include the selection of the proper adhesive to bond the glass to the substrate. Organic adhesives (mastics) will likely not be recommended due to possible discoloration or yellowing of the material that can affect the aesthetic appearance of transparent glass tile. Many mastics also lack the adequate bond strength required for the glass tile. Grey mortars can also bleed through some glass tiles. For this reason, it may make sense to use white mortars for most glass tile installations. Epoxy is also not recommended as a setting material or grout due to its low flexibility and potential degradation in UV sunlight.
You should treat glass tile similarly to ceramic tile in relation to color variation. Work out of different boxes of the material and establish a range of control of color. Inspect the material and get it approved by the end-user prior to installing it to protect yourself and your client. Paper face-mounted glass mosaic sheets should be installed with the paper side up.
Some glass tiles are transparent (you can see right through them). When considering transparent tiles in wet areas, it is very important to consult with the manufacturer regarding the use of a waterproof membrane. There are differing opinions and recommendations in these applications, so you must protect yourself and follow both the tile and installation material manufacturers' directions. Create an installation folder with these instructions that protects you and your client.
Pay close attention to both mosaic and large module installation instructions. Glass is also popular in numerous specialty tiles, such as liners and moldings. As is the case with all tile, superior coverage of the mortar is crucial to the success of the installation. Follow troweling instructions to the letter. Use the recommended trowel size as instructed by the manufacturer. You must first key in the mortar with the flat side of the trowel. This is a step that is often skipped, and this is a big mistake. With mosaics, use a wooden beating block and a hammer to properly smooth out the surface. Specialty pieces and larger glass tile should be backbuttered to achieve maximum coverage of the mortar.
Andrews and Fleming will continue to partner with NTCA and other Associations to provide as much education as possible. Many installation material manufacturers are also beginning to publish recommendations for glass tile with their products. The entire industry needs to take a proactive approach to learning more about glass tile specification and installation. Glass tile adds beauty and value to the home and can be highly profitable. A successful installation is vital to the growth of this vibrant product.