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How to Soundproof an Existing Wall
Author: Eric Zuck
Last Updated: February 9, 2024
Read Time: 8 Minutes
How to Soundproof an Existing Wall
Author:
Eric Zuck
Last Updated:
February 9, 2024
Read Time:
8 Minutes
Author: Eric Zuck
Updated: Feb. 9, 2024
Read Time: 8 Minutes
There are plenty of reasons for wanting to soundproof a wall in your home. Maybe your neighbors are college kids that are always partying until dawn, or you and your rock band want to “turn things up to eleven”. Whatever your reason, you will need to learn the process to soundproof a wall before embarking on this endeavor. When deciding to soundproof an existing wall, the variables are just different than when building an entirely new wall, so in this article, we will go over some of the options you have for soundproofing an existing wall.
There are plenty of reasons for wanting to soundproof a wall in your home. Maybe your neighbors are college kids that are always partying until dawn, or you and your rock band want to “turn things up to eleven”. Whatever your reason, you will need to learn the process to soundproof a wall before embarking on this endeavor. When deciding to soundproof an existing wall, the variables are just different than when building an entirely new wall, so in this article, we will go over some of the options you have for soundproofing an existing wall.
Core Principles of Soundproofing any Wall
When looking to soundproof an existing wall in your home, studio, or office, there are a couple of things you will need to know before you get started. The first is that there are two types of noise that we deal with when soundproofing a room: airborne noise and structural (or impact) noise. For a wall, we’re usually soundproofing for airborne noise.
Airborne sound travels through air instead of vibrationally through a structure. Examples of airborne noise you may hear through your walls include loud music, people talking, dogs barking, loud sirens, and… you get the idea.
Depending on the building’s age and the quality of the construction, you may or may not have a wall already built to keep out as much airborne noise as possible. On the other hand, the older and/or more dilapidated the building, the less likely it is to have music studio quality soundproofing.
The standard wall in a residential or commercial building looks something like this:
- A barrier (generally drywall)
- Insulation filled air cavity between studs
- Another drywall barrier
A wall that has been constructed with attention to its sound blocking properties will have additional features, some of which include:
- Acoustical sealant to ensure all gaps, cracks, and seams are well-sealed
- Additional density to the walls with mass loaded vinyl and multiple layers of 5/8” drywall or soundproof drywall
- Create a larger airspace in your wall cavity
That list is not exhaustive, but it give you an idea of the variables we have to play with! The next section will more specifically break down the steps needed to soundproof an existing wall.
How to Soundproof Existing Walls
The majority of the time, the actual structural properties of the wall are not the soundproofing issue. Rather, the gaps, holes, or other imperfections are the cause of airborne noise traveling through the wall. You would be surprised by the amount of noise that can travel through a tiny gap in your wall.
When soundproofing of an existing wall, there’s one approach that stands above the rest – using Green Glue, acoustical sealant, and a new layer of 5/8” drywall. It’s high performing; it’s cost-effective; and it doesn’t require you to remove the drywall that’s already up.
Steps to Soundproof Existing Walls
- Step One: Seal all edges and gaps: Use acoustical sealant to fill any gaps, cracks, or seams. These weak points are typically around the perimeter and any penetrations in the wall. Weak areas are places in the wall like light switches, outlets, or a gap behind the baseboard. Sealing these gaps will block sound from freely escaping these open areas.
- Step Two: Add another layer of drywall: For all wall soundproofing projects, we recommend ⅝” thick drywall; as the additional mass is much more effective at blocking airborne sound. The additional layer of drywall should be coupled with Green Glue Noiseproofing compound. Using the Green Glue to between the two layers of drywall decouples the drywall sheets, which increases your STC rating, the measurement used to determine how good a product or assembly is at soundproofing.
- In simpler terms, you add thickness and density to your wall with the extra drywall, and the Green Glue prevents the sheets from acting as one barrier. The Green Glue makes it harder for the sound energy to travel through both sheets of drywall. If you aren't interested in using Green Glue, read our article on our recommended Green Glue alternatives
- Step Three: Seal the edges again: Once the second layer of 5/8” drywall is installed, you’ll want to seal around the edges and penetrations in the wall again with the same acoustical sealant. Sealing both layers of the drywall will ensure there are no pesky gaps for noise to escape, allowing you to enjoy the tranquility of your soundproof room.
Other Options for Soundproofing a Wall Between Rooms
Soundproof a wall from scratch - Remove Existing Drywall
Use “BlocknZorbe” to Soundproof Your Existing Wall
As the name suggests, our BlocknZorbe panels are designed to BLOCK and ABSORB sound.
Most acoustic panels only absorb sound, with no ability to block sound. The absorptive properties are only useful for improving the sound quality and reducing echo and reverb within a room. But the additional absorption will not stop sound from traveling from one room to another (soundproofing).
BlocknZorbe is different from a standard acoustic panels, because it is STC rated to block sound. By 100% covering your wall with BlocknZorbe, you will reduce sound through that wall by 8-10 decibels.
To install BlocknZorbe, fasten the panels to the wall using screws or construction adhesive. Remember, 100% coverage or don’t bother putting these panels on the wall.
Using Blown In Insulation to Soundproof an Existing Wall (Often Not Helpful)
We felt that we had to comment on blown in insulation as a soundproofing method because so many other websites reference it as a potential solution.
Insulation is an important component of a high-performing wall assembly. But if your wall already has insulation, you won’t improve the wall’s STC rating by blowing in more. In fact, it’s possible to even overstuff the wall with insulation and reduce the soundproofing of the wall.
So, here’s the rule. If your wall does not have insulation, YES. Add insulation and the wall will block more sound. If your wall already has insulation, then NO. We would not recommend using blown in insulation if you already have insulation in your walls that is properly installed.
It is uncommon to see a home with no or damaged insulation, but it does happen in old homes or in homes that have had water damage. For more on insulation and if soundproof insulation works, check out our article on the topic.
Using Mass Loaded Vinyl for Soundproofing interior walls
Mass loaded vinyl is another option you may hear about for soundproofing an existing wall. MLV is a great soundproofing material because it is super dense, versatile, and great at blocking sound.
Although mass loaded vinyl can be very effective at soundproofing a wall, we typically do not recommend it for an existing wall unless you are planning to remove the current drywall and install the MLV directly on the studs.
If you are dead set on adding MLV on top of your drywall, just make sure you consider the following first:
• Mass loaded vinyl is very dense, meaning it is HEAVY. To install MLV to an existing wall, you must screw it into the studs (which are hidden behind the drywall). If you don’t attach it to the studs, the heavy MLV is relying on drywall to hold it up and is likely to fall.
• Adding mass-loaded vinyl to your drywall doesn’t look very good. It is possible to install drywall over the MLV to get that finished look, but at that point, it’s a lot easier and of similar effectiveness to just use Green Glue and a new layer of 5/8” drywall.
Stay Away From Other Acoustic Panels
Standard acoustic panels are not designed to soundproof. In order for a product to have sound proofing qualities, it must block sound by adding density to the wall or sealing off any exposed areas of the wall. Installing a couple of acoustic panels on your wall will not accomplish either of those goals. So don’t waste your money on acoustic panels if you are soundproofing, with the exception of 100% coverage of BlocknZorbe.
We will say it again... acoustic panels are useless for blocking sound through a wall.
Any Questions of Soundproofing Interior Walls?
Now that your walls are properly soundproof, you can sing along to all of your guilty pleasures without a care in the world! If you have other areas to soundproofing in a condo or home, we have all our soundproofing guides in our Owners Manual. We have all the materials you could possibly need to start your soundproofing project today, and the soundproofing experts at Second Skin are available to answer any questions you might have.