Hardibacker 500 Ceramic Tile Backerboard is an example of a fiber-cement underlayment designed for tile installations

Bonsal's Util-A-Crete underlayment features a fiber-cement core with a fiberglass mesh cover
Whether they are building a new home or simply remodeling their existing dwelling, today’s homeowners are enthusiastically taking control of their living space. Naturally, they are most excited about choosing the design elements, such as decorative tile, wall treatments, and the interior furnishings that will help create a harmonious, comfortable and attractive home.

But in their excitement over the wide array of colors, styles, and designs available, homeowners tend to overlook some of the fundamental aspects of building or remodeling. One that every ceramic tile customer should be aware of is underlayment.

What is ceramic tile underlayment? In the simplest terms, it is a product used as a substrate for ceramic tile. It is available in a wide variety of compositions, and is most frequently used in floor, wall and countertop applications.

In high-traffic, moisture-prone areas of the home, such as bathrooms, kitchens and laundry rooms, using a reliable underlayment is crucial because it provides a solid foundation for the tile, and prevents the underlying deterioration commonly caused by water and steam.

Typically, this deterioration occurs when water and steam penetrate a ceramic tile application through grout joints, which are porous. As a result of this frequent exposure to moisture, many underlayments rot, warp, and swell over time, causing the adhesive bond to fail and the tiles to become raised and loose.

Therefore, even as homeowners explore the myriad of ceramic tile options, it’s important that they give careful consideration to the underlayment product they, or their contractor, will use.

Due to the deleterious effects of prolonged expose to moisture, the direct application of tile to plywood is a practice that should be avoided, as wood-based substrates are extremely vulnerable to warping, rotting and other damage.

One commonly used product consists of a cement core faced with fiberglass on both sides. Another alternative is products based on fiber-cement technology, a durable, lightweight option. Gypsum is sometimes used as well.

Many factors must be considered when selecting an acceptable underlayment, on of the most important being the environment surrounding the installation. Careful consideration of factors such as moisture, heat, and humidity helps ensure a superior bonding system for the tile.

Just as in any step of building or remodeling, selecting tile treatments can be an emotional, costly and time-consuming process. The worst thing any homeowner can do is to forget about what the underlying foundation to their beautiful new investment will be.

Making an informed decision can be the difference between a ceramic tile surface that looks great in the short term and one that will perform beautifully for years to come.