How to Soundproof a Floor
Author: Eric Dellolio
Last Updated: June 6, 2024
Read Time: 10 Minutes
How to Soundproof a Floor
Author:
Eric Dellolio
Last Updated:
June 6, 2024
Read Time:
10 Minutes
Author: Eric Dellolio
Updated: Jun. 6, 2024
Read Time: 10 Minutes
Table of Contents
Footfall noise is some of the most irritating and distracting noise out there and can easily ruin anyone's day.
Soundproofing the floor to quiet impact noise and even airborne noise travelling between both spaces will bring notable improvements to focus, peace, and stress levels.
Whether this is an existing floor or you’re planning ahead to meet building code, continue reading to learn the basics of soundproofing a floor, recommended floor-ceiling assemblies (with test data), and the expected impact of each one.
Footfall noise is some of the most irritating and distracting noise out there and can easily ruin anyone's day.
Soundproofing the floor to quiet impact noise and even airborne noise travelling between both spaces will bring notable improvements to focus, peace, and stress levels.
Whether this is an existing floor or you’re planning ahead to meet building code, continue reading to learn the basics of soundproofing a floor, recommended floor-ceiling assemblies (with test data), and the expected impact of each one.
Watch to Learn the Secret to Floor Soundproofing
How to Soundproof a Floor
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:
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- 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!
- Mass – the more mass a barrier has, the more airborne sound it can block.
- 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
Floor soundproofing comes down to two things. Isolate the floor and block airborne sound.
Step one: isolate the floor to solve for Impact Noise
Isolating the floor from the building's structure to prevent impact energy from transferring to the space below is the key to building a soundproof floor. 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.
We measure a floor-ceiling structure’s effectiveness at stopping this energy with another metric, Impact Insulation Class (IIC). A structure’s IIC rating is the lab-tested effectiveness of how it isolates impact noise and prevents transmission of vibrations. The good news is that many of your flooring options for improving the IIC rating will improve the STC rating at the same time because the materials also have mass – a key component to sound blocking!
Using a rubber floor underlayment across the entire subfloor will greatly reduce the impact noise through the floor ceiling assembly. Install at 100% coverage, leaving about 1/8" around the perimeter (to later be filled by acoustic caulk). If you are looking to block airborne noise more and not necessarily impact noise, you'll want to increase the STC rating by at least 5-10 points to notice the difference.
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.
Recommended Floor-Ceiling Assemblies
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:
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- 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.
- 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.
- 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.
Floor-Ceiling Assembly Examples | Construction | Ratings |
| LVT Flooring 10mm UnderBlock™ rubber underlayment 3/4" Gypsum Concrete 3/4" OSB 18" Open Web Truss 3-1/2" R-13 Fiberglass Insulation RC Deluxe (16" OC) 1 Layer 5/8" Drywall (Type C) | IIC: 55 STC: 60 |
| LVT Flooring 1" Gypsum Concrete 1/4" Hacker SCM-250 3/4" OSB 18" Open Web Truss (24" OC) 3-1/2" R-13 Fiberglass Insulation RSIC-1® Isolation Clip (24" x 48" OC) 25 ga Drywall Furring Channel (24" OC) 1 Layer Drywall (Type C) | IIC: 56 STC: 62 |
| Floated Wood Floor 2mm UnderBlock™ rubber underlayment 3/4" Gypsum Concrete 3/4" OSB 18" Open Web Truss (24" OC) 3-1/2" R-13 Fiberglass Insulation RC-1 Boost® (16" x 24" OC) RC-1 (16" OC) 1 Layer 5/8" Drywall (Type C) | IIC: 57 STC: 60 |
| PET Polyester Carpet and Pad 23/32" OSB 11-1/4" Open Web Truss (24" OC) 3-1/2" R-13 Fiberglass Insulation RSIC-1® Isolation Clip (24" x 48" OC) 25 ga Drywall Furring Channel (24" OC) 2 Layers 5/8" Drywall (Type C) | IIC: 73 STC: 56 |
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:
Floor-Ceiling Assembly Examples | Construction | Ratings |
| Ceramic Tile 2mm UnderBlock™ rubber underlayment 6" Concrete Slab 3-1/2" R-13 Fiberglass Insulation Wire Hung 1 Layer 5/8" Drywall (Type X) | IIC: 59 STC: 61 |
| LVT Flooring 10mm UnderBlock™ rubber underlayment 6" Concrete Slab (No Ceiling) | IIC: 55 STC: 52 |
| LVT Flooring 3/8" UnderBlock HD™ rubber underlayment 6" Concrete Slab (No Ceiling) | IIC: 60 STC: 60 |
What Kind of Floor Soundproofing Project Do You Have?
Are you soundproofing between floors that already exist?
Wherever you have multiple story buildings, you have the potential for noise between floors. After years of solving noise issues, we can confidently say that any true floor soundproofing solution involves decoupling.
Option #1: Floor Side
Regardless of whether or not you have access to the ceiling below you, proper installation of a rubber floor underlayment will guarantee excellent soundproofing. UnderBlock™ is an incredible bang for your buck and can be used with most any unfinished or finished floor. UnderBlock HD™ can also be used for up to an additional 5 IIC points and pairs particularly well with tile floors, which can be laid directly on top to save on other building materials and labor.
Option #2: Ceiling Side
If you have access to the ceiling below you, use sound isolation clips to decouple the ceiling from the structure, preventing any vibrational noise from travelling down into your space. RSIC-1™ clips are your new best friend! You can construct a decoupled, two-sided barrier with airspace to substantially improve IIC and STC ratings.
Maybe you are on the ceiling side. Read our article on how to reduce noise from upstairs neighbors and soundproofing a ceiling for more information on sound isolation clips, RC-1 boosters, and general ceiling soundproofing.
Are you soundproofing a new construction floor?
Getting in at the ground floor (pun intended) is the best case scenario with any soundproofing project if only for the fact that there’s no deconstruction required. When soundproofing a new floor, you’ll need to know your desired IIC rating. From there, you can use our recommended assemblies above to meet your specific requirements.
If you are building new construction and plan to install resilient channel in your floor-ceiling assembly for isolation, you can add RC-1 Boost® Enhancers to improve generic resilient channel an additional 5 IIC points. These are hugely cost effective, a multi-family friendly option, and the best way to ensure the spec’d performance is actually what gets built in the field.
For more on soundproofing between floors new construction, check out our article or contact us to talk through a floor-ceiling assembly that works for you.
Are you soundproofing a wood floor?
Wood floors are easy to clean and highly aesthetic, but there are a few caveats. The first issue is that they don’t do much to stop footfall noise. So, if you have hardwood floors on a second story, without proper soundproofing, you’re going to hear every step like thunderous applause. Secondly, they’re incredibly reflective surfaces, causing sound to reflect off it. It can make a room noisy. While the latter issues will require some acoustic room treatments, the former can be resolved with UnderBlock™ rubber floor underlayment on the floor side or RSIC-1® clips on the ceiling side.
For more on hardwood floor soundproofing, read our article or give us a call!
Are you soundproofing a concrete floor?
Concrete is dense, making it a capable sound barrier! A 6” thick concrete slab alone can have up to an STC 54. You still need to solve for structural noise, though. Your approach to soundproofing a concrete floor will mostly depend on if there’s a ceiling below it or not. It’s not uncommon for a concrete floor to have an unfinished ceiling. While finishing the ceiling below will gain IIC points, that doesn’t work for every situation. In that case, we would recommend UnderBlock HD™ rubber underlayment to substantially improve the IIC rating to 55+, even without a finished ceiling.
Are you soundproofing a tile floor?
UnderBlock HD™ is the best soundproof underlayment for tile. It works by adding mass to the floor to block airborne noise and by decoupling the finished floor from the structure to stop impact noise. Simply roll the mat on your subfloor and cut it to size. UnderBlock HD™ can go under any ceramic, marble, or porcelain tile. For projects on a budget, the 2mm UnderBlock™ gives excellent performance and costs less than $0.60 per sq ft. Tile can go directly on top of the 2mm UnderBlock™ as well.
Check out our article for more on building a soundproof tile floor!
Are you soundproofing under carpet?
Carpet is the best soundproof flooring because it’s so good at limiting impact transmission. The thicker the better. Usually, one of two things would lead you to add soundproofing under carpet:
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- You need a higher STC rating. Carpet doesn't have a ton of mass so it’s not as good at blocking sound as a lot of other flooring options. Using RSIC-1® clips on the ceiling side will greatly improve your STC rating. UnderBlock™ rubber underlayment will add that much-needed mass on the floor side of the assembly. Both will also improve the IIC rating.
- You want a maxed out IIC rating. Carpet is already so good at stopping impact noise. If you want to max that out, go for it! Adding rubber underlayment or sound isolation clips will get you to an even higher IIC rating.
Contact us for assembly recommendations or any questions about under carpet soundproofing!
Are Any Appliances or Objects the Cause of the Noise?
In your home, it could be an exercise bike, a drum set, or a washer/dryer. In a commercial building, it could be stages, risers, pumps, or motors. Energy is traveling through the object’s structure and into the floor. The result is creaks, groans, rumbles, and rattles as the two objects make contact with one another. The reason we ask is because, if footstep noise or airborne noise aren’t the problem, we want to save you the trouble of potentially unnecessary construction!
Soundproofing a specific object can be a lot simpler than soundproofing a whole barrier. If it’s causing vibrational noise, decoupling the object from the floor will do the trick! In some home applications, good, carpeted floors are all you need. Any floor mats or carpet will help, but a thicker carpet is a better soundproof carpet and will do more to prevent that impact sound from transferring downwards.
If you need a drum mat or have an area rug under your drum kit, consider The Stomp Mat™. If you’re soundproofing a washing machine or other equipment, rubber vibration isolation pads like our Super W Sound Isolation Pads™ are a great option for targeted applications under equipment or an appliance that's vibrating. If you need even more durability for bigger equipment, a 100% rubber vibration isolation pad will fix your issues. Put them under exercise equipment, appliances, a stage, or even heavy machinery to decouple vibrating structures from the floor.
Floor Soundproofing FAQ
What is the best flooring to absorb sound?
Carpet is the best flooring material for absorbing sound because it’s impact resistant and helps reduce sound reflections because it's soft and pliable. The thicker the carpet the better. As far as airborne noise is concerned, it's worth noting that carpet does not have a lot of mass compared to other flooring alternatives, making it a less effective sound blocker.
Maybe carpet isn’t your style. Adding rubber underlayment to the subfloor beneath your finished floor of choice will help reduce impact noise and block noise transmission. However, this won’t help reduce sound reflections.
Do rugs help with soundproofing?
A rug, a carpet, a rug, a carpet . . . the answer is yes, but it's not that simple. First off, if you're referring to an area rug, you will not see any airborne noise reduction. Impact noise reduction, however, will be contained to that specific area, and it depends how think the rug is. If you're thinking about carpet, then yes, a carpet will help with soundproofing, but most specifically for impact noise due to it's lower surface density.
Will acoustic foam help with noise from above?
No, acoustic foam will not help reduce noise from above because it is not a sound blocking material. Depending on your construction, putting up acoustic foam or acoustic panels on your ceiling may help moderately reduce noise transmission by dissipating the noise within the space. However, we would not recommend this as a means of reducing noise between spaces.
Do I have to do construction to stop impact noise?
Yes, in order to reduce impact noise transfer, construction is necessary. With the right tools and the right information, it's easier than you might think. Give us a call and speak with a Second Skin noise control specialist for help with your construction project!
UnderBlock HD™ Rubber Underlayment for Better IIC and STC
UnderBlock HD™ rubber underlayment stops impact noise and airborne noise through floor-ceiling assemblies. Install it under just about any type of flooring for best-in-class noise reduction. This superhero is ready to save you from footfall noise with the best IIC and STC ratings you can achieve between floors.
- Propriatary formula engineered for maximum IIC
- Choose between 3/8" and 1/2" thick underlayment
- Useable with floating floors, nail down floors, and glue down floors
- Guaranteed 50+ IIC with a consultation from a Second Skin expert
Soundproofing Floors: Final Thoughts
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.