Whether used under floating wood and laminate, glue-down and nail-down solid and engineered wood, luxury vinyl tile or even ceramic tile flooring, a well-matched, high-performing acoustic floor underlayment can noticeably improve sound control between dwellings or floors.
Demand for quiet between floors is rising, with less intrusion of neighbor noise seen not as a perk but as an expected paradigm. Increasingly, facility managers often pay a steep price when residents complain about noise, forced to take action after the fact-when the new floor is already being walked on. Acoustic underlayment can address both airborne noise, which travels through floor/ceiling assemblies and walls, and structure-borne noise, which travels through the building itself.
Airborne noise results from speech, music, TV, etc., and travels through the atmosphere, while structure-borne noise is caused by impact sounds from walking, fallen objects, or the moving of chairs or other furniture in the unit above.
There are a number of underlayments currently available, each boasting features specifically engineered to enhance sound performance in the type of floor for which it is marketed. For example, a fiber acoustic underlayment designed for laminate flooring not only can provide good sound absorption but can also help make laminate floors sound more like real wood. A fiber acoustic underlayment designed for under ceramic tile may include crack suppressing capabilities.
KNOW THE NUMBERS
There are two popular, widely accepted tests recognized by the International Building Code, both performed in a controlled laboratory environment, for sound that travels from one living area down to another: Impact Insulation Class (IIC) and Sound Transmission Class (STC).
IIC tests the ability of a particular floor/ ceiling assembly to block impact sound by measuring the resistance to the transmission of impact noise or structure-borne noise.
The typical range for an IIC rating is a single number between 20 and 80; the higher the number, the better the sound attenuation performance. The International Building Code minimum standards for multi-family dwellings are 50 for new construction, tested in a controlled laboratory environment.
Condominiums and high-rises commonly require an IIC rating of 50 as well. Field tests for the same properties may be conducted in an actual building after the floor installation is completed. The UBC calls for a rating of at least 45 in these tests.
WHEN PERFORMANCE IS NOT ENOUGH
However, that performance does not necessarily satisfy students of residence halls, who are likely to still notice and complain about footfall noise. Products that, in a floor-ceiling assembly, can achieve a higher score, say 60 or even 70- plus, would buffet sound transmission that much more effectively.
The STC test rates the ability of a specific construction assembly (e.g. floor, window, door) to reduce airborne sounds, such as from voices, stereo systems, and TVs. The higher the number, the higher the resistance.
COMPARING UNDERLAYMENT FOR ACOUSTIC PERFORMANCE
When comparing underlayment for acoustic performance, another way to compare is to evaluate product certifications, which can be addressed in any of three ways: First- party certification is self-certification by the manufacturer. Second-party certification typically involves assessment by a trade organization. Third-party certification is conducted by an independent, unbiased laboratory and is generally the most rigorous.
Beyond performance, there are other benefits to consider. There are acoustic underlayments made entirely or substantially from recycled materials and feature a composition that minimizes or eliminates the effects of off-gassing not only during and soon after installation but also throughout the life of the finished floor. Some products incorporate antimicrobials. And under any hard surface finished floor, firm underlayment can provide proper support to prevent premature wear and tear, extending durability and longevity of the installation. Acoustic underlayment designed for laminate flooring can, in some cases, help smooth out minor imperfections in the subfloor and enable the top finish surface to lay flat.
A quality product can also add to the insulation of the flooring assembly, helping keep floors warmer in cold weather and cooler in warm weather. Some feature moisture management systems that wick subfloor or incidental perimeter moisture and disperse it through the pad, with moderate amounts of moisture eventually dissipating over time by evaporation, provided the source of water such as a leak is stopped.
DIFFERENTIATING AMONG UNDERLAYMENT OPTIONS
Factors that help in differentiating among various underlayment options include the following: the type of floor (e.g. glue down or nail down hardwood, engineered wood, laminate wood, floating wood, composition) and the performance goals for the underlayment as part of the floor assembly. Some underlayment manufacturer websites provide detailed information about attributes, specifications and benefits of each of their product lines.
CHARACTERISTICS OF HIGH PERFORMING UNDERLAYMENT
The characteristics of high performing underlayment can vary widely among options. But paramount among them should be sound abatement and reduction in sound transmission between floors.
Sound absorbing, or acoustic, underlayment quiets impact sound and inhibits noise from traveling into the room below. Manufacturers offer acoustic underlayment in various materials, including polyethylene or polystyrene film, cork, rubber and fiber.
Fiber underlayment, often made from textile fibers, can render an upgrade in performance over "foam" pads and can furnish sound-deadening benefits similar to those offered by cork and rubber at lower cost.
In addition to sound abatement, upgrade capabilities include insulating qualities that enable the underlayment to act as a thermal break, helping keep a room warmer in the winter and cooler in the summer and the ability to smooth minor floor imperfections, and moisture protection.
Acoustic fiber underlayment with built-in moisture management will reduce the possibility of mold growth under a finished floor and can wick away subfloor or incidental perimeter moisture that might otherwise ruin the finished surface. Finally, some acoustic underlayment enables engineered wood and laminate floors to sound more like real wood.
In a renovation project where a new glue-down or engineered wood floor will replace old vinyl composition tile as the finished surface, if the VCTs are secure, acoustic underlayment that can be glued directly atop them eliminates the need for potentially hazardous tear out that could release dangerous fibers into the air.
Additionally, for flooring installations that are part of green building projects, eco-friendly underlayment is available that is manufactured without any VOCs and/or is third party certified to meet high standards for low emissions. Some underlayments of this type are manufactured substantially or totally from recycled fibers, diverting material otherwise destined for landfill and further helping preserve the environment.
Photography provided by MP Global Products
is the Director of Marketing of MP Global Products. A well-respected, well known voice in the underlayment industry, Jack is a two-time recipient of the LAMMY Award, Associate Member of the Year, both for 2007 and 2011, given by the North American Laminate Flooring Association (NALFA) for exceptional contributions to the laminate flooring industry.