The quality and integrity of the tile covering is only as good as its foundation. Many substrates are unsuitable, especially in areas with high moisture, requiring com- prehensive preparation and water- proofing. Multifunctional foam building panels provide the tile setter with control over the instal- lation by providing the means to simply and easily create ideal sub- strates for tile. Control of the substrate Originally the tile setter was responsible for building substrates using mortar. While this demand- ed significant skill and labor, the results were flat, plumb, and level surfaces with square corners for high-quality finished applications. As the thin-bed method became predominant, fewer installers were able to remain competitive or float mortar at all. Building the sub- strate shifted from the tile setter to other trades, and the results were often not suitable for tile, whether dimensionally unstable, moisture-sensitive, or poorly con- structed. Comprehensive prepara- tion by the tile setter became para- mount. When foam tile backers emerged, control of the substrate was returned to the tile setter. The foam board Typical foam boards consist of a foam plastic core (e.g., XPS, EPS, or polyiso), sandwiched by rein- forcing layers to provide stiffness. The reinforcing layer may serve as the bonding surface, or another layer may be added for this pur- pose. Panels are waterproof, stable, lightweight, and easy to handle, cut, and install, making them an excellent substrate for tile. There is often a wide range of thicknesses to suit various applications. Multifunctional foam building panels offer a myriad of advantages to the tile setter TECHNICAL FEATURE –––––––––––––––– By Sean Gerolimatos, Director of Research and Development, Schluter Systems 70 TileLetter | November 2018