Posted on

Silence is music to the ears of underlayment producers

How they create serenity while adhering to regulations

by Lou Iannaco

In acting as the ambassador of silence in the flooring industry, reliable underlayment is crucial, especially in multi-family and office environments. Underlayment producers strengthen their reputations and help make sales by keeping things quiet.

How exactly is underlayment manufactured? What needs to be done to create the best product and reduce noise? How does technology play a role in the world of underlayment?

When sound hits a material only three things can happen, noted Ray Rodriguez, president and CEO of Starline Associates, maker of Silent Blue underlayment. “First, the sound can be reflected where it bounces off the material and is redirected. Secondly, sound can be transmitted through the material, and finally, the sound can be absorbed.

“When sound is absorbed by a material,” he explained, “it is converted into a very small amount of heat. When developing Silent Blue we simply looked to the auto industry and found closed cell foam material was being used to keep the loud traffic noises out of new vehicles. Testing proved that it’s very effective for absorbing sound when placed under laminate or wood floating floors and nail down wood floors.”

Screen Shot 2013-06-03 at 1.55.06 PMIn relation to sound transmission, specifically blocking sound travel to lower level rooms, Bob Cummings, flooring sales and marketing manager for Pak-Lite (PLI)—a private label manufacturer of foam underlayment—believes PLI products assist with sound issues through a combination of factors. “The first is the quality of the core underlayment material itself. In the past 20 years, we’ve effectively designed products through testing and product development. The other factor to consider is thickness, but not all materials produce better results because of it.”

Similar to Silent Blue, MP Global Products’ fiber acoustic underlayment absorbs sound in the filaments of the pad and converts it into a small amount of heat, which is then dispersed noted Duane Reamer, the company’s technical director.

As regulations always play a role in how product is created and tested, Rodriguez noted that different high-rises have slightly different acoustical minimum standards that vary nationally. “We found just the correct amount of density to use when manufacturing Silent Blue. Many years ago, we created a much denser pad believing it would outperform our current model, but after sending the prototype to various independent testing laboratories, we found this did nothing but raise cost and lower sound absorption. Since then, we’ve kept the original formula for maximum sound control.”

One test recognized by the International Building Code (IBC) that evaluates for sound traveling from one living area down to another is the Impact Insulation Class (IIC) test. “Performed in a controlled laboratory environment, the IIC test determines the ability to block impact sound by measuring the resistance to transmission of impact noise or structure-borne noise,” noted Al Collison, founder and president of MP Global.

Another evaluation, also performed in a controlled laboratory environment, is the Sound Transmission Class (STC) test, which measures the ability of a particular construction assembly to reduce airborne sounds such as television, stereo systems and vocal noise. “In both tests,” he pointed out, “the higher the score, the higher the resistance. An IIC rating of 50 satisfies the requirements of the IBC though in some residences owners or tenants would want a higher level of insulation from the floor/ceiling assembly—perhaps in the range of 58 or even 60—to minimize footfall noise.”

Underlayment can also be evaluated by field tests such as the Field Impact Insulation Class (FIIC) test after a floor installation is complete. The IBC calls for at least a 45 rating in the FIIC, though some underlayment can, when in-stalled over a standard concrete subfloor, score in the 50s or even 60, he noted.

The higher the IIC number, Cummings explained, the better the impact sound attenuation qualities will be. “But you have to pay attention to exactly how the flooring assembly is constructed in the testing. To put it into perspective, most floating luxury vinyl tiles or planks test at around IIC 35 with a 6-inch cement slab,” he explained, “with no underlayment and no drop ceiling assembly. Our LVT underlayment raises the IIC numbers from the mid 30s to the 50s when nothing other than our underlay is added to the previously described assembly. When you add a suspended drop ceiling into the assembly mix, the IIC score can exceed 70.”

According to Andy Stafford, marketing manager for Healthier Choice, while in multistory dwellings an IIC of 50+ is required for all flooring types, “this has become a challenge because the trend toward hard surface forces retailers to find acoustical underlayment that will meet this criteria. Very few acoustical underlayments are approved for use under LVT and ceramic tile floors.”

Stafford explained Healthier Choice has found some companies are willing to publish false test scores for marketing purposes. “We maintain a database of third-party results that are available upon request. Our acoustical underlayment products are different than most others on the market because they’re made of high-density frothed polyurethane, which is guaranteed to not lose more than 2% of its original thickness over time. Others are made from lighter weight PE foam and don’t have the same resiliency.”

MP Global recently introduced two products for the category: VersaWalk underlayment and VersaStick adhesive. VersaWalk is a VOC-free, odorless and non-allergenic sound reduction impact isolation and insulation system engineered for installation under wood, laminate and LVT, noted Jack Boesch, director of marketing. “It suppresses noise within the room and inhibits the transfer of noise into rooms below.”

VersaStick is a VOC-free and solvent-free premium, pressure sensitive flooring adhesive that can be used both “to glue VersaWalk to the subfloor and to glue a wood or LVT floor to the underlayment,” he noted.

Starline’s newly developed Silent Red was created for a nearby micro distributor.  “It is very similar to Silent Blue,” said Rodriguez, “only it has a little less sound control for a reduced cost. We learned that homeowners rarely want the cheapest alternative when buying underlayment for their own homes or offices. They prefer paying a little more for better quality. Silent Red will provide much higher quality at a midrange price-point.”

PLI continually upgrades a variety of formulas and products for its customers. Finally, Healthier Choice has created acoustical underlayment in the past year-and-a-half that is approved for use under laminate, wood, LVT and ceramic tile.