An Inside Look into the World of Underlayments
With so many different types of underlayments available today, it’s imperative to know which product is best to use and why
For a good-looking, long-lasting tile installation, it is essential that every aspect of the job be completed according to tile industry standards. A fundamental element in every tile installation job is the levelness of the floor. Ensuring a strong, even foundation for any type of tile can prevent a multitude of problems, such as cracks or lippage. Uneven subfloors, cracks and other surface irregularities must be corrected to avoid these tiling complications.
Obtaining a level, tile-ready floor can be achieved by incorporating self-leveling underlayments (SLUs) into the installation plan. SLUs are designed to level a floor’s surface prior to installing tile. The floor’s surface must be properly prepared and primed with the manufacturer’s recommended product(s) and allowed to dry before application.
SLUs typically fall into two categories: synthetic gypsum-based and cement-based. Each offers its own benefits depending on the need for the job. Synthetic gypsum is reclaimed from calcium sulfate, a by-product of coal. Because it’s an inorganic material, it does not support any growth of mold. Synthetic gypsum-based SLUs, such as Schönox AP and APF, are flexible, non-shrinking, and contain 5000+ PSI.
Cement-based SLUs are also ideal for fast self-leveling. These compounds typically contain cement, aggregate and chemical additives to enhance their flow and strength. Schönox US is a great example of an industry-trusted, cement-based SLU offering installation above 1/8 inch up to 3 inches with 4,250 PSI. This compound is not only ideal for leveling a subfloor, but also for creating a shower pan.
Some jobs may also require sealing and uncoupling membrane systems. Schönox iFix is a rollable, waterproof sealing adhesive for bonding a sealing and uncoupling membrane in residential and commercial wet areas. Schönox iFix is based on self-crosslinking, special acrylic, and approved in heavy-loaded wet areas. These systems are intended to cover smooth, sound substrates like those provided by a SLU.
Synthetic gypsum-based and cement-based SLUs can both be barrel-mixed, machine-mixed or pumped, while moisture systems are usually rollable materials. The mixing and pouring method is typically dependent on the job site. For smaller areas, a full machine mixer may not be ideal, just as a barrel mix is not fitting for a larger, ground level project. Knowing your jobsite is critical when planning your tools for a SLU application.
Regardless of how helpful tools can make the process, all SLUs require professional installation. These compounds require training to ensure consistent application. Schönox offers classes for professional contractors, installers and applicators, as well as on-site assistance. Organizations such as National Tile Contractors Association (NTCA), Installation Standards Training Alliance (INSTALL™) and Certified Flooring Installation (CFI) also have training classes for professionals and those interested in learning the expertise of the trade.
However, each project is different. The necessary requirements for SLUs and moisture systems are generally included in the project’s speciﬁcations and may vary from the recommendations set forth by tile manufacture.
Successful tile installation may require a few elements to be used alongside each other to provide the desired surface for a quality result. No matter the substrate case, following manufacturer’s guidelines and using qualified, knowledgeable installers can best prepare the foundation for the tiling installation.