Imagine you move into a new apartment complex only to realize your upstairs neighbor does a Zumba workout every morning at 5 a.m. Sound issues are the bane of any multi-family dweller’s existence, and sound isolation issues are most effectively addressed during the design phase of a project. 

Unveiled in 2018, Sound Advisor by Shaw Industries showcases the impact ceiling and floor construction, as well as flooring and underlayment selection, have on room acoustics. The web-based tool helps users make more informed design and interior product selection decisions by pairing a sound file of an actual, controlled IIC lab test with their selected specifications with the IIC rating and data. 

Impact sounds are measured and reported using an Impact Insulation Class rating, or IIC rating. To develop the rating, a standardized machine taps on the floor repetitively with metal hammers. A receiving device is placed in the room below to measure the sounds in decibels and across a range of frequencies.

sound transmission diagram“In a real-life multi-family setting, that might be reflective of an upstairs neighbor pacing in high heels on a hardwood floor, a child or pet bouncing a ball on the floor, or a heavy chair being dragged across that floor,” said Layne Dugger, vice president of national accounts, multi-family, Shaw Industries. “All of these are impact sounds, resulting from contact with a barrier—in this instance, the floor.”

IIC ratings can range from as low as 25 up to 110. The higher the score, the more impact sound is reduced. The International Building Code requires a minimum IIC of 50—or 45 in a field test—however, most people can still hear sounds through a barrier up to a score of 65.

Impact sounds transmitting through the floor are a major concern for property managers with multi-family residents, student housing, and hotels. According to property managers, noise is among the top three most frequent complaints made by residents. These complaints aren’t just idle chatter. Twenty percent of residents say they would move if there were noisy or annoying neighbors.

According to real estate expert Edward Kelley, one turnover on a rental rate of $1,120 costs the owner $3,360 in lost revenue. So, the emphasis on noise and acoustics in the multi-family space is understandably a significant business consideration.

For example, the owner of a large apartment complex used the same flooring construction and different types of flooring covering in different buildings. Results showed that simply adding carpets in bedrooms reduced the percentage of complaints from 3.2% to 1.9%.

Using underlayment can also have a big impact. As an example, depending upon the floor and ceiling construction:

  • A bare concrete floor, with no insulation, can score an IIC of 29. That sounds pretty loud.
  • Adding 2 millimeters of luxury vinyl tile (LVT) with no underlayment can increase the IIC to 45.
  • Simply adding an underlayment can increase the IIC to 68.
  • Switching from LVT to engineered vinyl plank (EVP) at 5.5 millimeters with no underlayment, the rating could be an IIC of 56.
  • Add an underlayment to the EVP. The IIC rises to 68.

Dugger said Sound Advisor can help specifiers and project planners choose flooring solutions that help with sound reduction in multifamily structures. 

“With the growing market interest in acoustics, it’s easy to get caught up chasing numbers,” he said. “IIC ratings have been the only thing on the market to help flooring specifiers and others estimate the sound performance of a product and its ability to meet acoustical standards, guidelines and code minimums.”

Published acoustical levels can be misleading. “In a quest for the highest number, it can become tempting to set up a lab test scenario that will produce the absolute best result—i.e., the highest number in a controlled environment,” he said. “This lab result is usually a poor predictor of real-world performance. The reality is the lab environment cannot be replicated in the real world. Plus, many of the common lab setups used to achieve the high acoustic performance are not often used in real world settings. The result is a confused marketplace.”

This can create a tremendous discrepancy between expected performance and the actual performance of a space. Lab tests should be good indicators of what results will be achieved if an acoustic field test is performed.

Dugger said Shaw’s comparative research provides specifiers with a better understanding of the impact that floor and ceiling construction have on IIC ratings and how flooring products perform in each of those spaces. Sound Advisor provides the ability to showcase to customers a more realistic representation of how a product will perform in the field.  

For reference, hard surface products typically range between 45 to 60 IIC, while soft surface products range from 58 to 80 IIC. 

“If a product is significantly out of this range, I’d encourage buyers and specifiers to explore further to ensure a product’s IIC ratings are accurate to real world scenarios,” Dugger said. A few questions to consider:

  • Is a test result available for the product?
  • How was the product tested?  
  • Did the lab environment use a floor and ceiling construction similar to the space in which you are designing / this product will be installed?

Sound Advisor, which won a Silver Davey Award for digital excellence in website construction, can be accessed via the following sites: