When you want to get rid of noise and soundproof a room, understanding the basics of soundproofing is a good place to start. Before we get into soundproofing, we want to identify a huge misconception (the elephant in the room, if you will): Lesson #1: sound absorbing panels do NOTHING to prevent sounds from traveling BETWEEN two spaces. Their specific use is to improve the sound quality INSIDE of a space by reducing reverb and echo. Soundproofing is the isolating and blocking of sound travelling between spaces. Unfortunately, we can’t tell you how many times someone has wanted to use (or already used!) acoustic foam or acoustic panels on a ceiling to stop floor noise from the upstairs neighbor.

Soundproofing materials, on the other hand, are designed to block and isolate sound to prevent it from traveling from one room to another. There are three keys to effective soundproofing:

1. 1. Decoupling – isolating drywall from the building’s structure, increasing both the IIC rating and the STC rating by a huge amount!
   2. Mass – the more mass a barrier has, the more sound it can block.
   3. Airtight Construction – poor sealing and air gaps are the antitheses and undoing of any soundproofing project.

To solve for all 3, you need the right materials and the know-how to know which material is best for your situation! We’re here to talk through any project to get you set up for success. As we go along, if you have questions about the cost of soundproofing a floor, read our article on the topic!

Soundproofing a Floor for Airborne Noise

There are two types of noise to consider when soundproofing. The first type of noise is airborne noise. Airborne noises are exactly what you’d think: sound traveling through the air. Examples include your voice as you talk, car horns, ambulance sirens, music from your stereo, any sounds from your TV, dogs barking, cats yowling, your mother-in-law calling… you get it. You are constantly bombarded with airborne noises. The key to stopping airborne sounds is to block the sound energy with high STC rated materials installed as airtight as possible.

A Sound Transmission Class - or STC rating - is a number value assigned to how much airborne sound a material or partition is able to stop. When evaluating STC ratings, a rule of thumb is +3 STC points is barely noticeable, +5 STC points will be obvious, and +10 STC will be half as loud. Remember, eliminating sound leaks (gaps) is extremely important too, because the higher the STC rating of your floor, the more devastating a gap leaking sound will be.

Soundproofing a Floor for Impact Noise

Now onto the main focus for most floor soundproofing projects: Impact noises. Unlike airborne sounds, impact noise is caused by physical collisions, like slamming doors, loud footsteps, machinery, jumping, moving furniture, etc., that result in vibrations traveling through a structure. Eventually, the vibrational energy exits the structure and is heard by your ears as noise. Another quick rule of thumb: if two objects make physical contact, you have impact noise. Isolating and preventing impact energy from entering a building’s structure is the key to soundproofing a floor.

We measure a floor-ceiling structure’s effectiveness at stopping this energy with another metric, Impact Isolation Class (IIC). A structure’s IIC rating is the lab-tested effectiveness of how it isolates impact noise and prevents transmission of vibrations. Similar to STC, the higher the rating, the better. And the good news is, many of your flooring options for improving the IIC rating will improve the STC rating at the same time – solving two problems at once.

Whether your construction uses concrete, 18” web truss, or any other of the many various floor-ceiling assembly constructions, there are consistent principles that can be applied to see significant results. Construct a proper two-sided barrier with airspace and use a rubber soundproof floor underlayment. Here are a few assemblies to look at.

18" WEB TRUSS FLOOR-CEILING ASSEMBLY SOUNDPROOFING

You’ll find open web truss floor-ceiling assemblies commonly in commercial applications. While there are different ways it’s done, there are three soundproofing solutions we consistently recommend. Our recommendations have been both lab and field tested, but feel free to reach out to one of our Second Skin experts with any questions or for more information:

1. 1. UnderBlock™ rubber underlayment – adding UnderBlock™ is a very cost-effective way to add density and decouple the floor to give large improvements in IIC and STC. UnderBlock HD™ will boost that another ~5 IIC points, key for open ceiling plans or buildings with high IIC requirements.
   2. RSIC-1® clips - RSIC-1® clips work by isolating the ceiling below from the rest of the assembly. These easy-to-install clips greatly improve STC and IIC ratings, are UL rated, and are the best option if you have a finished floor down already and need to treat the ceiling below.
   3. RC-1 Boost® - these RC-1 Boost® isolators will improve any resilient channel by 5 points of IIC. It's a perfect solution for multi-family and hotels, and at $0.30 per sq ft, they’re the most affordable way to get a 5 IIC point improvement with resilient channel.

6" CONCRETE SLAB FLOOR-CEILING ASSEMBLY SOUNDPROOFING

Another common floor-ceiling assembly is concrete slab. Rubber underlayment is going to be in our spec for soundproofing a concrete floor no matter what, but the type and thickness of the underlayment will depend on whether or not there’s a finished ceiling below, what type of finished floor there is (tile, LVP, LVT, wood, etc.), and what your target IIC rating is.

Again, UnderBlock HD™ will perform about 5 IIC points better than standard UnderBlock™, and it’s best used anywhere there isn’t a finished ceiling, like a large multi-family. An IIC 50 does get you to building code, but we recommend at least an IIC 55 to limit complaints. At an IIC 60, you’ll quiet the complaints from the downstairs neighbor . . . literally. Building new construction to above code is one of the best ways to reduce ongoing operating costs due to tenant turnover. Our tests show the IIC and STC ratings you can expect to see:

Noise coming through the ceiling from the floor above is at the top of the list of complaints. With these tips, assemblies, and materials, you can stop noise leaks in their tracks. When you do that, make sure you take the time to address soundproofing a wall and soundproofing a door.

No matter the approach you take, soundproofing can improve sleep, focus, and overall quality of life. It’s hard to put a value on peace and quiet, but we all want it. Please, if you’ve got questions, give us a call and we’ll be happy to talk you through your project. We know that if the job is done right, you’ll be floored.