September 14/21; Volume 30/Number 7
By Nadia Ramlakhan
Underlayment is an integral part of the floor covering installation process; without it a floor may reveal a “clacking” sound when walked on, feel cold and harsh underfoot or allow noise to travel from room to room. Although often taken into consideration at the last minute, choosing the right underlayment for a particular application is vital in order to achieve optimal results. “Density, stability, durability and acoustic performance all play a part in selecting the correct underlayment,” said Bas Vangenderen, managing director for InstaFloor.
Generally, end users look for a few things in an underlayment, including sound reduction, leveling of subfloor imperfections and comfort underfoot. Regarding luxury vinyl tile, some qualities are more important than others. “All underlayments are designed to meet specific needs,” said Bob Cummings, sales and marketing, hard surface, resilient and carpet tile, Pak-Lite. “Vinyl flooring underlayments are specifically designed for vinyl flooring. They need to have very high compression-set and compression-strength attributes to support the flooring joints, while also providing enhanced sound transmission attenuation.”
Because LVT is known for being a softer and more flexible product, its compatible underlayments come with different requirements than other hard surface products. “The laminate industry as represented by manufacturer members of NALFA [North American Laminate Flooring Association] helped determine standards for underlayment beneath their floors,” said Jack Boesch, director of marketing at MP Global Products, who explained that no such regulations exist for LVT underlayments.
“What might work well for one type of flooring may not work well for another,” said Duane Reimer, technical director at MP Global Products, noting that LVT underlayment can be installed under other hard surface flooring but not the other way around. Some manufacturers have addressed this by creating a product that adheres to the requirements of multiple hard surface products. For example, InstaFloor’s InstaLay 25hg is suitable for LVT and can also be used for engineered and solid hardwood as well as ceramic and porcelain tiles.
“There are no industry standards for LVT underlayment, so the characteristics that an installation requires may vary from job to job,” Reimer continued. Despite the lack of these standards, manufacturers agree the product’s most important attribute to note is its density.
“LVT is a softer product than laminate, so the underlayment has to have a great deal of resilience and density vs. what may be used under a laminate floor,” said Andy Stafford, marketing manager for Healthier Choice. “[Other hard surfaces] can use foam that is soft and easy to crush. Because the potential of denting is commonplace with vinyl flooring, you need a high-density, heavy-duty material under it.” In other words, underlayment that is compatible with LVT cannot be too soft otherwise denting can occur and interlocking floating LVT tiles can uncouple.
OmniChoice by Healthier Choice is one example of a high-density acoustic underlayment with a heavy weight construction that ensures it will remain resilient and functional as an acoustic membrane, outperforming other lightweight acoustic underlayment that can crush and fail from the weight of heavy foot traffic.
Another rule of thumb to remember is underlayment for LVT must be thin. “What we’ve found in all of our testing is any underlayment thicker than 1mm tends to fail over time due to the compression characteristics necessary,” said Jeffrey Castor, national sales manager, North America, Diversified Industries. “Compared to laminate, we had to make our product half the thickness and more than twice the density in order to withstand typical LVT activity over time. Anything thicker than 1mm provides too much cushion and cannot handle the wear and tear.”
LVT is also known for its moisture resistance, a quality that makes it attractive to consumers for various spaces in a home; underlayment manufacturers have created products that don’t compromise LVT’s moisture-resistant capabilities. In fact, due to its composition, FloorMuffler LVT by Diversified Industries works as a moisture barrier without an additional film, complementing the similar attributes of LVT. It can be installed with both floating and glue-down floors and its lip-and-tape system offers a complete seal against moisture as opposed to roll-out formats that leave room for seams and tapes that aren’t moisture resistant.
Although some manufacturers recommend installing underlayment in all applications above ground level, it is not typically required under LVT unless there are sound requirements or building codes to be met. “Single-family homes normally do not have any acoustic requirements to meet,” Boesch said, “however multi-family housing such as condominiums and apartment buildings often require specific IIC or STC test scores to deaden sound between floors.”
OmniChoice Universal by Healthier Choice is specially designed to abate airborne and impact noise associated with hard surface floors. It also works to reduce noise levels as well as floor-to-ceiling sound transmission in multi-family homes.
“When it comes to underlayment for vinyl flooring, it is all about room-to-room transmission sound control,” Cummings said. “Vinyl flooring works well to dampen in-room sound, however it is poor at controlling sound transmission to the rooms below.”