The ever-changing world of vertical tile installations
Because vertical installations can pose interesting challenges to architects and designers, it is critical to use proper bonding material and consider the substrate that is in place
Not all that long ago, 4 ¼-inch wall tile was the standard issue for many commercial projects, maybe spiced up with a few random brightly colored feature tiles or a contrasting border. Now we see the technological advances in tile production yielding tile designs that challenge even the trained eye to determine if it is the actual product it represents. Not only do these tiles look like the genuine product, they have the texture and depth to further enhance their appearance.
Another by-product of this technology surge is the ever-increasing tile size. What was considered a large tile in the past, say a 12- x 12-inch, is now dwarfed by the 24- x 24-, 39- x 39- (one meter square) and even 48- x 48-inch tiles that are beginning to populate the market in the U.S. And this does not include the extremely popular rectangular tiles that capture the eye of many designers and decorators. These rectangles can simulate marbles, granites, metals, linens and even wood. Placing them on vertical surfaces presents fabulous visuals, and mixing these mediums further extends the possibilities.
With its beauty and diversity, glass tile was introduced to the market several years ago and was installed based on the tile manufacturers’ recommendations — if and when they were available. Many times, the mortar manufacturers were called on to provide installation recommendations for bonding these products. But until mid-2012, this category did not have a standard established, which meant there was no means available to define the type, the performance levels or installation procedures. The ANSI A137.2 American National Standard for Glass Tile now addresses the criteria for each item.
Thin panel porcelain products presently are 1 x 3 meters — or approximately 3 ¹⁄³ feet by just under 10 feet — and cover 32.3 square feet. Considering the size of these panels, they are relatively light in weight at just over 50 pounds each. Currently, they are being used on walls only, but as time and testing progress, this usage may change. The thin panel tiles have opened up an entire new market, including exterior facades, cladding, restroom walls, cabinet facings and countertops. This category is so new that it is evolving as this article is being written.
Each of these products functions well, providing many years of trouble-free performance, beautiful appearance and ease of maintenance as long as proper installation methods and best practices are followed. The main obstacle occurs when the “We’ve always done it this way and never had a problem” mindset creeps into the picture. Every one of these products has their own specific installation and handling requirements.
Vertical installations create some interesting challenges to the architect as well as the installer. The largest issue is that wall applications defy gravity. When tile in placed vertically, safety issues are paramount. The tile needs to stay tightly bonded to the substrate. This sounds like a no-brainer, but liability concerns must be addressed. Keep it in place permanently.
Primarily, the proper bonding material must be specified to hold the tile in position. Consideration must also be given to the substrate. Is the bonding material suitable for both surfaces? This may seem to be an easy task, but not necessarily. We will look at each product individually.
Large-format tile on the wall presents two issues: full coverage to promote a secure bond and gravitational slippage. The addition of medium-bed mortars with thixotropic (non-slip, non-sag) characteristics has met both challenges. As with any mortar, they are keyed into the substrate for a good mechanical bond and then spread with a trowel that places more mortar on the surface than used with a thin-bed mortar. Many manufacturers recommend a trowel such as a ¾-inch U-notch. The properties of these mortars provide excellent coverage to the back of the tile while holding the tile in place with no sagging away from the initial placement.
Glass tile, even with the new A137.2 standard in place, continues to present challenges to its installation. Glass products vary so widely that it is impossible to cover each potential scenario in this article. Most mortar manufacturers today offer a mortar specifically for glass. However, these products cannot be considered “one size fits all.” For instance, one of these high-quality mortars may work well with both cast and fused glass, but will not work well with low-temperature coated glass. Until the new standard gains its legs and garners more wide-spread support, always consult the glass and mortar manufacturers for their written installation instructions and follow them to the letter. This needs to be done BEFORE starting the installation.
Thin panel tile has hit the pavement at full speed and is gaining acceptance very quickly, especially in the commercial realm. Many thin panel producers have been working feverishly to develop installation methods that will support the panel. Mortar coverage must be as close to 100% as possible — with this being achieved through the use of a trowel design that differs from most being used today. The combination of a zipper-notch trowel to apply the mortar to the substrate and a V-notched trowel to back-butter the panel works best when both are spread in one direction, being parallel to each other when installed. Additionally, to minimize edge lippage, the use of mechanical edge-leveling systems is strongly recommended.
Another crucial factor to consider when installing any tile on walls is the structure behind the substrate. Whether it is wood or steel stud, proper code-compliant framing is vitally important. Verify with the design professional and the general contractor that the structure is adequate to support the weight of the tile. Deflection issues are not solely relegated to floors. The weight of the wall tile can cause the wall framing to bow in or deflect, which almost always will cause the tile to crack. This condition can be exacerbated by increasingly tall walls, such as two-story fireplaces in homes and large accent walls in commercial projects. The higher the wall extends, the stronger it must be designed and constructed.
While this situation is not the responsibility of the tile installer, it is incumbent upon him or her to be absolutely certain that the surface provided is “tile ready” and “tile supportive.” This statement may seem elementary, but can be disastrous if left to chance.
The beauty and longevity of a high-quality wall tile installation is best achieved when it is designed and specified properly. The use of a qualified tile installer who is committed to their craft and has taken their time to stay abreast of the latest materials and methods is strongly recommended to complete the project. Accepting the lowest bid should not be the determining factor, but rather the most qualified person to perform the scope of work specified.