When you want to get rid of noise and soundproof a room, understanding the basics of soundproofing is a good place to start. From there, floor soundproofing is pretty straight forward. Let's start by identify a huge misconception (the elephant in the room, if you will): sound absorbing materials do NOTHING to prevent sounds from traveling BETWEEN two 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 try and stop floor noise from the upstairs neighbor. Their specific use is to improve the sound quality INSIDE of a space by reducing reverb and echo. Soundproofing materials are designed to block and isolate sound to prevent it from traveling from one room to another.

basic principles of floor soundproofing

There are three keys to effective floor soundproofing:

1. 1. Decoupling – isolating the floor from the building’s structure will greatly reduce impact noise and increase both the IIC and STC rating by a huge amount!
   2. Mass – the more mass a barrier has, the more airborne 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!

Steps to soundproofing a Floor

Step one: isolate the floor to solve for Impact Noise

Step two: seal the gaps to solve for for Airborne Noise

Airborne noises are sound traveling through the air like voices, car horns, ambulance sirens, music, TV audio, 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 (eliminating sound leaks).

Use acoustical sealant caulk to plug up those gaps and around the perimeter of the underlayment and along the baseboards to keep sound from traveling into the space below. The higher the STC rating of your floor, the more devastating a gap leaking sound will be.

Alternative Step: More Airborne Noise Control

While impact noise is the number one thing folks solve for when floor soundproofing, sometimes there is more airborne noise than underlayment can block. The only alternative is to work on the ceiling-side with isolation clips. Check out our recommended floor-ceiling assemblies below for more help with that.

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. Use a thicker underlayment to further boost that IIC rating, 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 RC1 channel booster 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 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. Thicker UnderBlock™ is best used anywhere there isn’t a finished ceiling, like a large multi-family. Building new construction to meet or exceed 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. After that, your next step is to read up on how to soundproof a wall and how to soundproof a door to prevent sound leaks.

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.