It’s time you eliminate all that unwanted noise leaking in your home. You know what we’re talking about — noisy neighbors, nearby traffic, airplane noise. All forms of unpleasant noise can affect you and your family’s comfort in your home. Noise pollution has been shown to trigger the body’s stress response, which is why excess noise has been tied to a variety of issues – ranging from heart disease to lower sleep quality to less work productivity. Whatever your reason for wanting to reduce noise, let’s dive into how soundproofing a wall can help.
We say the unwanted noise is “leaking” because sound waves behave like a fluid, moving to the weakest points and sneaking into your home through cracks, holes, and gaps. That’s why we recommend a two-pronged approach to soundproofing the walls in your home:
We’ll go into the specifics later on. For now, consider how much better a quieter home life can be. Having a little peace-and-quiet goes a long way in reducing stress, improving sleep, and promoting focus. For business owners, reducing workplace noise has the same effect for employees — lower stress, better concentration (fewer errors), and higher reported job satisfaction.
As you’ll soon find out, soundproofing the walls in your home can be very labor-intensive, but even larger projects are doable. With the right tools and good information, a quieter home is within your reach.
Whether you’re looking for a way to drown out the noises keeping you up at night, want a private quiet room, or are dying to mute the beautiful sounds coming from your neighbor’s house, soundproofing a door may be your savior.
The doors in your home don’t just let you in and out of different rooms, they’re the easiest access points for air – which means they’re a weak point for sound. Unfortunately, we can only dream about a remote to control the volume of loud roommates or family members, and noises from construction and city life don’t just turn off when you want them to. That’s where sound deadening technology comes in. By addressing the weakest spots in your home, soundproofing will help keep unwanted noise out and turning the disturbance level down for good. It won’t always be a quick fix, but the added peace and quiet is often worth the extra effort.
Overview of Wall Soundproofing
There are two main categories of noise control. The first is improving acoustics, which is all about the quality of sound and improving speech intelligibility. Acoustics control techniques use a variety of sound absorption materials and other strategies to reduce the echoes inside of a room and the reverberations that come from sound bouncing off the walls. Acoustics control improves the quality of the sound within a room (think of a music recording studio), but DOES NOT prevent noise from entering or exiting the room.
The second category is soundproofing or sound isolation, which calls for the installation of sound blocking materials. Sound isolation creates a space in which most exterior sounds are blocked out and most interior sounds stay put. By preventing sound from getting into or out of a space, you reduce or eliminate the disruptions and distractions unwanted noise can create. Sound isolation projects are time-consuming and require precision, but anyone can do them with basic knowledge and a little attention to detail.
To put it simply, optimizing acoustics in a room is a bit of an art, taking a good bit of experience and know-how, but soundproofing a room with sound isolation techniques is more straightforward and requires careful installation.
Key Terms to Know for Wall Soundproofing
We’ll dig deeper into what it really means to soundproof a wall, but first, let’s review let’s make sure we’re talking the same language with some key principles.
- Sound Transmission Class (STC) rating. STC rating is a measurement of how effective a barrier is at stopping the transmission of sound across a variety of frequencies. Though they are calculated in a lab under ideal conditions, STC ratings are the best we have to understand how effective materials can be at soundproofing. Visit our guide on STC ratings to go deeper.
- Transmission Loss (TL). TL is a measurement of the difference in decibels on two sides of a barrier. For example, if you’re listening to music in the kitchen (let’s say 50 decibels of sound) and it can be heard in the room on the other side of the wall (30 decibels), there would be a 20-decibel transmission loss through the wall. Keep in mind that TL and STC rating are NOT the same thing.
- Flanking. Flanking paths, or flanking sound, refers to the noise that indirectly travels over, under, or around sound barriers. Think of flanking path as the route noise creeps in through, such as the gap in your ceiling tile you cut out to accommodate an exposed pipe.
Two Basic Principles for Soundproofing a Wall
- A wall is only as strong as its weakest point. And an air gap is the weakest of all weak points. Air gaps could be a poorly-sealed window, a doorway, a gap at the floor, around an electric outlet, or any number of other things. All these gaps are a big problem. A 1% air gap will reduce the max effectiveness of a wall to at best a 20 decibel transmission loss, no matter how expensive and dense the materials used to construct it. While it may seem obvious that having a hole in your wall is a big problem, many are surprised by how small that hole has to be to make a big difference.
That's why one of the most effective things you can do is to seal up your wall with acoustic caulk. You can’t expect your drywall or mass-loaded vinyl to block out all the sound coming from the other side of the wall if the point where the wall meets the floor isn’t properly sealed. Use a non-hardening acoustical caulk to seal the gap between the wall and the floor, as well as the point where the ceiling meets the walls, and around electrical outlets and ducts. A proper caulk seal is the best way to snuff out pesky flanking sound.
- The weak point doesn't have to be air. It can also be the materials. Design plays a large part in the overall effectiveness of a wall’s soundproofing. Introducing multiple materials in the same barrier (like adding a glass window into a brick wall) drastically affects transmission loss. Though you might think that adding one small window will have one-third of the effect of adding three windows, you’d be wrong. The fact is, adding any amount of “weaker” material to a barrier results in a big drop-off in soundproofing that doesn’t change a whole lot even if you adjust the ratios. Consider the following example:
Understanding this principle explains why a door or a window is often the wall's weakest point for sound. Even if you've sealed up all the air gaps, the actual construction of the door or window could be the problem. It has less mass (and a lower STC rating) than the wall itself, so it's dragging down the whole structure's sound blocking performance.
How to Soundproof an Existing Wall
If you come away from this article with nothing else, let it be this — the wall itself may not be your biggest problem. In many cases, it’s the gaps, windows, and other “weak spots” that leak the most noise. You may surprise yourself with how much sound you can block out without demolishing any drywall. That’s why you should begin every soundproof job with a few easy steps. Run through this checklist before committing to a teardown; if you’re not getting the results you want, continue on to the more labor-intensive steps.
Checklist Before Soundproofing an Existing Wall
- Do a thorough inspection. Examine the length of the wall at every connection point (along the ceiling, floor, and other walls). See if you can spot any gaps. Creating a consistent noise on the other side of the wall (turn on a vacuum cleaner, blender, loud fan, etc.,) will allow you to use your ears to find the weak spots.
- Caulk the weak spots you find. If you’ve got enough of a noise problem that you’re researching how to soundproof your walls, your walls have weak spots. After you find them, seal them with acoustical caulk.
- Electrical boxes/outlets/vents: Start here. It’s super easy to remove the covers and seal any gaps. Scrape off old caulk or fill in gaps with fresh caulk.
- Baseboards: If your baseboards are the weak spot, remove them and seal the gap where the wall meets the floor. Reattach the baseboards and test for sound.
- Doors/windows: The average door has 1 square foot of airspace. Caulk is your best friend (again) for the frame. Adding door gaskets and a door sweep (comes together in a door seal kit) will close up the air gap around the door panel.
- Replace doors/windows. If you’ve run several sound tests and have isolated your weak spot to a hollow door or old window, replacing them may be the best option. Replacing a hollow-core door with a solid wood door is effective and a reasonable DIY door soundproofing project. Windows... consult you significant other. :)
While these steps can be time consuming, but it’s less work than soundproofing walls themselves and ultimately may be more effective if you find a different weak point than you expected.
Actually Soundproofing an Existing Wall
We still doing this? Alright, it's game time. Let's soundproof that wall. We've got several options for you. The first two are extremely effective solutions. The third one (Option C) is a partial measure.
Option A (mass loaded vinyl):
- Attach mass loaded vinyl to the existing layer of drywall by nailing it directly into the studs. If your studs are 24" apart, we strongly recommend you get MLV that's 48" wide. Saves a lot of time. Seal all seams and edges with acoustic caulk.
- Install a new layer of drywall on top (or leave the MLV exposed).
Option B (Green Glue + 5/8" Drywall):
- Lay new drywall flat and apply Green Glue in beads on its surface using a standard caulk gun. The pattern doesn't matter. Just get it everywhere. Two tubes of Green Glue is enough for about 32 square feet of coverage (one sheet of drywall).
- Carefully hang the new drywall, being sure to install it so the seams do not line up with your first layer of drywall. 5/8” drywall is strongly recommended. Leave a 1/8" gap at the top and bottom of the drywall. Seal those edges with acoustic caulk.
Option C (soundproof curtains):
Hang soundproof curtains over weak spots, like the window or door. BIG CAVEAT HERE: This is a less effective solution, but the install is relatively easy and people need options. Well, don't say we didn't give you options. The main problem with soundproof curtains is it’s very hard to properly seal them to eliminate air gaps. But you can cut a couple decibels (20-30% of the noise) if you get a soundproof curtain with a high enough STC rating (25+). You can cut a few more dBs if you seal the edges with a reclosable fastener like Dual Lock. Simply hang the curtains as you would regular curtains to block out noise coming from the offending window or doorway.
How to Build a New Soundproof Wall
If you’re building a new wall and want it as soundproof as possible, there are a few considerations to make. Question #1 is… how far do you want to go? One key to keep in mind is that whatever you do for the walls, you also need to do to the ceiling. Sound is always looking for the path of least resistance, and if you have a beefy wall with a flimsy little ceiling... you have a flanking path. Bad news, please avoid!! With that said, here are the steps to take for MAXIMUM wall soundproofing:
- Install stud framing. You have a choice between wood and steel framing. Steel is more difficult for many contractors or DIY enthusiasts to work with, but steel studs do provide better isolation than wood. Often the answer is wood, but you can go either way.
- Fill stud cavities with insulation. Just your typical R-13 (2x4 walls) or R-19 (2x6 walls) batting insulation. No need to get fancy here. Don’t overstuff.
- Install mass loaded vinyl. Nail it directly into the studs. Make sure you seal all seams tightly with acoustic caulk before moving on.
- Add resilient sound isolation clips (RSIC). Combine with a 25 gauge aluminum hat channel to decouple the mass loaded vinyl and drywall. By “floating” the drywall with isolation clips, your soundproofing will be much improved due to reduced structural noise transmitting through the walls.
- Attach 5/8 “ drywall to the hat channel. The thicker drywall adds much needed mass to the wall, which aids in soundproofing. Leave a 1/8” gap at the floor, ceiling, and around all surfaces for acoustic caulk.
- Apply second layer of 5/8” drywall. Use the Green Glue damping compound as your decoupler. Be sure that your seams don’t line up. Again, leave a 1/8" gap.
That’s it! Your new wall is now the beefiest wall in town. All the other walls will be gossiping like that time your neighbor got calf implants. If you want to pull back from the MAXIMUM, cut out step 3 and/or step 6. Cutting the MLV or Green Glue will still result in an extremely effective noise barrier.
Speaking of Beefy... Luxury Liner MLV Rolls... So Strong!
Our Luxury Liner Rolls are made of the highest quality MLV and come in a variety of length x width options. A versatile and durable material, mass loaded vinyl can be used for all sorts of residential, commercial, or even classroom (that's right!) projects.
- Offered in two standard thicknesses, 1 lb and 2 lb.
- Extremely durable, Luxury Liner is building grade, automotive safe, flexible, tear resistant, and fire resistant.
- The 1 lb MLV is 1/8” thick and the 2 lb MLV is 1/4” thick. MLV is unmatched in its noise noise blocking ability for its thickness.
- Made in the USA. All prices include free shipping.
Soundproof a Wall. Any Wall Will Do.
Way to go! You made it to the bottom of the wall soundproofing article (unless you just scrolled down here…). The steps we’ve outlined can be handled by many DIY-ers, though if you decide to go for a top performing solution, it will take more time and effort to get the results you want. Just like anything else in life really...
That’s why we suggest starting with the easy stuff though — inspect your wall and caulk up air leaks. Seal up the door with a door seal kit or just replace that hollow-core door. These are the big "bang for your buck" opportunities. If you can identify the root cause of the noise, you can get creative and sometimes avoid the full blown project that soundproofing a wall. But if you’re going to go for it, do it right the first time.