Noise is one of those things we don’t always think about until we can’t get away from it. Whether it’s the neighbor upstairs stomping around, traffic outside your office window, or conversations heard through walls, sound has a real impact on how comfortable and functional a building feels. That’s why soundproofing should never be an afterthought. At BLUE RIDGE FIBERBOARD, we help simplify the science of acoustics with our complimentary INSUL Predictor Report, a powerful tool designed to take the guesswork out of soundproofing.
BREAKING DOWN SOUND SCIENCE
There’s more to controlling noise than simply adding insulation or thicker drywall. Depending on the kind of noise you’re trying to reduce, whether it’s airborne like voices or music, impact sounds like footsteps or machinery, or even exterior noise like traffic – there are different measurements and strategies to consider. That’s where understanding sound ratings comes in handy, and it’s where we often start when talking to architects, contractors, and building owners about their soundproofing goals.
For starters, STC (Sound Transmission Class) is one of the most common ratings you’ll hear about. It measures how well a building assembly, like a wall or ceiling, blocks airborne sound. The higher the STC rating, the better the performance. A good rule of thumb; for apartments, hotels, and schools, a wall or floor-ceiling assembly with an STC of 50 or higher is generally considered acceptable. But higher is often better, especially in high-end multifamily or hospitality spaces.
Then there’s NRC, or Noise Reduction Coefficient, which tells you how well a material absorbs sound within a space; basically, how much it prevents sound from bouncing around. It’s a scale from 0 to 1, where 0 means no absorption at all (think concrete) and 1 means total absorption. You’ll also hear about OITC (Outside Inside Transmission Class), which specifically measures how well a wall or window blocks noise from outside, and IIC (Impact Insulation Class), which focuses on impact sounds like footsteps; something anyone living below a hardwood floor can appreciate.
ENTER THE INSUL PREDICTOR REPORT
Once the type of noise is identified, the process can begin to determine how best to correct the intrusion, i.e. how to best design the wall, floor, or ceiling assembly. But there’s a catch – testing every possible material combo in a lab isn’t realistic or affordable. That’s why we use the INSUL software to create what we call the INSUL Predictor Report.
This report takes the guesswork out of acoustic design by modeling how different assemblies will perform before they’re built. Using your specifications, things like stud spacing, material thicknesses, and layout, we simulate how sound travels through each layer and calculate a predicted STC, OITC, or IIC rating. It’s fast, accurate (within about ±3 dB of lab testing), and incredibly helpful when evaluating different options.
Say you’re working on a multi-unit housing project and want to make sure the walls block enough sound between neighbors. You send us the layout, and we’ll plug in different material options to see how they stack up. Maybe one version uses metal studs with RC (resilient) channels. Another uses our SOUNDSTOP board. We might find that you can actually eliminate the RC channel altogether and still hit the target STC rating by swapping in SOUNDSTOP instead, which can save on both materials and labor. We’ve seen it happen.
Another great example? A client looking to replace gypcrete in a floor-ceiling assembly wanted something lighter and easier to work with. By modeling a new system that used STOMP on the floor and SOUNDSTOP on the ceiling below, we were able to show that they could not only ditch the heavy gypcrete but also improve the overall STC rating. That’s a win all around.
REQUESTING A FREE INSUL PREDICTOR REPORT
To run a report, we need a detailed breakdown of the wall, floor, or ceiling you’re designing – what materials you’re using, how thick they are, how far apart the studs or joists are, and anything else unique to the build. Results vary depending on the exact details and that’s why the more information you can provide, the better. From there, we can usually turn around a report within a couple of hours. And don’t worry, if you’re not fluent in sound science, we’ll walk you through the results and explain what each number means in plain language.
We typically evaluate four to six assembly variations per request to give you a clear picture of your options. If you’re working on a larger project or do this kind of work frequently, it might even make sense to purchase a copy of the INSUL software for ongoing use, but we’re always happy to help pull reports on your behalf when needed.
One thing we love about this tool is that it helps us recommend smarter material swaps without sacrificing performance. For example, some folks assume that doubling up on a soundproofing material will double the STC. Unfortunately, it doesn’t work that way; acoustics just aren’t additive like that. But the INSUL report helps identify where a single strategic change can make a real difference. Sometimes just one layer of SOUNDSTOP in the right spot can boost your STC by 4–6 points. Add a second layer? Maybe just 1 more point. Knowing this upfront can save a lot of unnecessary cost and effort.
At the end of the day, offering this service is just one more way BLUE RIDGE FIBERBOARD supports our customers. We originally started running these reports to see how our own products like SOUNDSTOP and STOMP performed against common alternatives—and we were pleased with the results. Now we offer this as a free resource to help you make more informed decisions and get better results on your builds.
So, if you’re planning a project and want to be sure you’re on the right track acoustically, we’d love to help. Send us your specs, and we’ll get started on your custom INSUL Predictor Report. Let’s turn down the noise – together.
