In the first part in our 4 part guide on how to soundproof a room, we’ll tell you everything you need to know to make your room more soundproof, and what you need to buy to do it.
In part one we cover the basic techniques you can use to make your room more soundproof. We’ll also show you how you can soundproof a wall at home. In part two you can learn how to soundproof floors and ceilings, in part three you can learn how to make windows more soundproof, and in part four learn about treating doors.
You can do all of these with some basic DIY skills, and it doesn’t have to break the bank either.
You can use the quick links below to navigate to your place of interest. We’d recommend reading the “How to Soundproof a Room: Basics” section first though.
Content Quick Links
Part 3 : How to Soundproof Windows
Part 4: How to Soundproof Doors
How to Soundproof a Room: Basics
In today’s claustrophobic cities, soundproofing your home has never been more important.
With some basic DIY it is actually possible to remove the sound of the buzzing scooters, the noisy neighbor next door, or even the nearby train line.
Furthermore, if you’re a musician, a bit of soundproofing work can stop those noise complaints, and leave you free to perform whenever you want.
By reducing the noise coming into (and out of) your home, you can substantially increase your quality of life.
Soundproofing a room is not as difficult or as expensive as you might think. Using some basic science, we can target the noises we want to reduce or remove, and create a tailor made solution to our own noise problems.
Luckily, the science isn’t complicated and I can talk you through the whole process step by step. Let’s start by learning about each of the ways we can stop noise from traveling.
We discussed two reasons for soundproofing a room: keeping unwanted sound out, and keeping sound in. The process for each of these reasons is similar. In short, we want to stop vibrations (sound) from traveling through surfaces like walls.
There are 4 key ways to stop unwanted sound from traveling like this:
- Absorb Sound
- Add Mass
- Dampen Sound
- Decouple Surfaces
Let’s take a look at what these things mean, and how you can implement them in your home.
1. Absorb Sound
Sound waves will retain more of their energy when traveling the path of least resistance. Sound travelling the same distance through air, will be louder to your ears, than sound that has passed through a wall.
There are probably gaps in your room where sound can easily enter. So how do we find these “holes” in your room?
Imagine your room was flooded with water, right up to the ceiling (stay with me here, there’s a point to this).
Now picture where the water would leak out of your room. Windows, the bottoms of doors, power outlets, vents…. These “holes” in your room are prime locations for sound to leak in or out of your apartment. By treating these weak points we can reduce the noise entering/exiting your home.
How to Treat a Room For Air Gaps
We mentioned the prime locations of air gaps in a room. These are probably doors, vents, windows, power outlets etc. Now, we can’t easily treat them all, but tools do exist to resolve most of them. Doors are especially bad at letting noise enter our homes.
Acoustic sealants come in many shapes and forms. They work by filling air gaps with a super dense material that is great at absorbing sound energy.
These are some common types of acoustic sealant readily available to you at home:
Acoustic caulk is easily applied using its tube. It can be used to seal any holes or cracks in your home. It comes in single packs, or huge multi-packs for more liberal use. Once applied to a gap it will take a few days to to dry and become effective.
Acoustic putty is an effective tool for sealing holes. It is a very dense substance that will add a lot of mass to objects. This reduces how effectively sound travels through them. It can easily be molded into any shape, and is flame retardant.
These are attached to the bottom of doors to provide a seal. This stops air from easily passing under the gap at the bottom of a door. They’re easily attached with a few screws.
These door seals have an adhesive strip which allows them to seal the air gaps around the perimeter of a door frame. They are really good at reducing airborne noise.
2. Adding Mass
For sound to pass through a surface (like a wall), it has to actually move or vibrate the surface ever so slightly.
A heavier wall is harder to move than a light wall right? It sure is, and the same principle applies when soundproofing a room.
If we add mass to an object, we make it much harder for sound to be transmitted through it.
This kind of treatment is more effective for higher frequency sounds. These sounds have less energy than low frequencies, and will be absorbed much more effectively by adding extra mass.
Adding mass to a room pre-build is simple. We can use dense materials like concrete for example. Adding mass to a room retrospectively is harder, but tools do exist.
How to Add Mass to a Surface
We want to make a surface (wall, ceiling, floor) as heavy as possible. Common materials for this, that don’t break the bank are: plywood, drywall, oriented strand board, and cement board. Drywall is one of the cheapest materials for this. 5/8 inch drywall is commonly used for this purpose, and it can be found at any lumberyard or home center. A readily available material that is designed to reduce sound levels is acoustic vinyl.
Acoustic vinyl (or mass loaded vinyl) is a barrier used to block sound between walls, ceilings, floors, pipes and more. It is very dense, weighing one pound per square foot. Besides stopping noise transmitted through walls, it can also be used to make covers or curtains for windows. Windows are a major culprit when it comes to noise leaks.
3. Damping Sound
We mentioned before that sound needs to vibrate a surface to travel through it. Well, an effective way of stopping unwanted noise is to reduce the amount of vibrating a surface can do. That is exactly what acoustic damping does. We want to stop a surface from being able to vibrate freely, and therefore stop it from transmitting noise.
How to Dampen Sound
By adding a dampening material to the inside of walls, or by hanging a new sound proof wall (see below), we can effectively dampen sound.
A popular solution is to hang a new wall inside the room (we’ll tell you how to do that further down the page). Using two pieces of drywall, with noiseproofing compound sandwiched in-between, we can make a really effective dampening system.
Here are four products that can help us dampen sound vibrations:
Green Glue is an extremely effective dampener of sound. It can be used to plug holes, but is more commonly used to provide a layer of protection between walls. It is fire resistant, and even effective at reducing those problematic low frequency noises.
Noiseproofing Joist Tape
This noiseproofing tape is most commonly used to reduce the sound of footsteps and squeaky floors. This tape will dampen foot traffic by creating a seal at joists. It doubles up as an extra layer of insulation too.
Anti vibration pads are the perfect solution to speaker vibrations. Place these under or around a loudspeaker, washing machine, or AC unit, and you can say goodbye to those annoying noises and vibrations.
Like the pads but on a larger scale. One of these mats is designed to fit under a large appliance like a washing machine or electricity generator. It prevents the vibrations from travelling through floors and ceilings.
4. Decouple Surfaces
Sound is little more than a vibration of particles. When surfaces are in direct contact, then sound can travel more easily between them. If we remove the point of contact then we decouple the surfaces.
Think about the “walkie-talkie” you made as a kid. Two cans joined by a piece of string can transmit sound through the string from one person to the other. Remove that string and we have decoupled the cans.
Decoupling surfaces in a room is probably the hardest soundproofing treatment to implement, but also one of the most effective.
How to Decouple Surfaces in a Room
To decouple surfaces in a room we have to isolate the walls, ceiling, or floor. We want to create a “floating” surface, where its contact with the building structure is minimal. By creating an air gap between surfaces, we make it much harder for sound to pass through.
There are various tools that allow us to create new walls, ceilings, or floors that are decoupled from the building. By attaching a new layer of drywall in this way we can reduce sound transmission into a room. We have an in-depth guide to soundproofing walls further down the page.
Here are some commonly used tools to help decouple a surface:
These sound isolators are used to decouple floors. By placing these under a new floor you can achieve the “floating” floor effect, so desired by recording studios. They are inexpensive and a great way of reducing sound transmission through floors.
A resilient channel is a special metal bracket that is used to hang drywall. It is specifically designed to reduce sound transmission through a wall or ceiling. By using resilient channels you significantly reduce the amount of direct contact between surfaces, and create an effective air gap. These are a must for decoupling walls and ceiling.
Resilient Sound Isolation Clips
Much like a resilient channel, these sound isolation clips are used to decouple walls and ceilings. They are said to reduce noise transfer by between 75 and 100%. They attach to hat channels or furring strips, and decouple the surfaces and add damping. There is a similar product called a whisper clip.
Its not cheap, but it’s incredibly effective. This vinyl material is 6dB more effective than lead at stopping the transmission of sound. It is thin but very dense, and is used to help decouple walls, ceilings, and floors.
We’ve now looked at the 4 ways of reducing sound coming into and out of a room. Remember, each of these methods can be effective, but you should try and use all of them. Next, we we will learn how to use all of these techniques together to soundproof a wall.
How to Soundproof a Wall
If you have used some of the soundproofing techniques in the previous section, but still need more help, then perhaps you need to improve your existing walls.
We are going to learn how to make an effective “floating” wall for a room. This does not alter the structure of your home, but adds an extra barrier for sound to pass. If you want to reduce noise transfer through a wall, then this is your most effective solution.
By adding an extra layer of wall to a room like this, you will make the wall around 100mm thicker. This means you will lose a little space, but you can reduce noise that is transferred through the wall by up to 40 decibels (find out more about decibels).
This method of soundproofing is effective in reducing noises like talking, TV, and radio.
To create an effective soundproof wall we need to combine the four techniques learned previously. If you’re unsure about any of the following terminology, then you should read the last section called ‘How to Soundproof a Room’. To recap, we need to:
Decouple the wall
Add mass to the wall
Step 1: Decouple the walls
The first step is to use resilient channels (see above) to ensure that the surface contact between the structural wall and our new partition wall is minimal. Remember, we don’t want to give the sound vibrations an easy path to travel.
The resilient channels screw into the original wall at the top and bottom, and then at 24 inch intervals. The resilient channels are the long, horizontal metal strips you see in the picture below.
An alternative set-up would be to use 25 gauge 7/8 hat channel and resilient sound isolation clips. This would have the same effect as the resilient channels. Hat channel is similar to resilient channel, but does not decouple the surfaces. That is why the isolation clips are needed.
If there are electrical outlets on the wall we need to prepare for that. The electrical box will need to extend another couple of inches from the wall. We need to make a good seal around the box with acoustic putty, and also seal air gaps at each stage with acoustic caulk .
Step 2: Absorb Sound
The resilient channels leave a small air pocket between the two walls. If we leave this empty, then the sound will resonate in the air pocket and vibrate our wall. We want to stop this, so we need to add a thin layer of sound absorbing material. We can use cheaper materials like mineral wool, cellulose, or polyester. But, just remember not to pack it too tightly as this wouldn’t help our cause. There are also specially designed acoustic materials like acoustic batt, that can do an excellent job here.
We want to cover the whole wall space with our absorber. It’s very important that the thickness of this absorber is less than that of our resilient channel. We need to leave a small air gap between our surfaces. Otherwise, we might compress the absorber, which will aid sound transmission between the walls. By leaving a small air gap we can reduce even more sound transmission between the walls.
Step 3: Add Mass to the Wall
The next stage is to add our wall. We want to use the heaviest possible material we can. As the heavier it is, the harder it is for sound to vibrate through it. A commonly used material for this is 5/8 inch drywall (commonly found at lumberyards and home centers). We can also use materials like cement board, plywood, and oriented strand board. After hanging the first layer of drywall you should fill any gaps with acoustic caulk.
Ideally, we want to hang two layers of drywall. This is to create a lot of mass in our wall. But, between them we need another ingredient. This leads us to step four…
Step 4: Dampen Vibrations
Between our layers of drywall we need to add some acoustic damping. This is to reduce the vibrations that can travel through our wall. As we know, vibrations = sound. Green Glue Noiseproofing Compound is perfect for this, and is commonly used in the building trade for this purpose. Liberally apply a layer of this to the first drywall block before attaching the final piece of drywall.
After attaching the drywall/Green Glue/drywall sandwich to the resilient channel we are ready for the finishing touches.
It’s really important to seal any gaps at this stage with some acoustic caulk.
You can finish the wall in any way you like, just remember not to couple the wall again by using long nails. These would give the sound vibrations an easy route to travel again. If you are particularly worried about sound escaping from the room then acoustic panels can be hung. They offer extra sound absorption and aren’t as ugly as you might expect.
You now have an acoustic partition wall or “floating” wall. This should reduce the sound transmitted through the wall by up around 40dB. That is a significant impact, and should all but eliminate noise from the TV, radio or conversations.
Well that brings us to an end of the first part of our ‘How to Soundproof a Room’ guide. You now know the basic techniques to soundproof a room, and also how to soundproof a wall.
Check out part two where you can find out how you can soundproof your floor and ceiling.
Before starting the process of soundproofing your room, be aware that cities/states/countries all have regulations regarding what acceptable noise limits are. You can monitor noise levels with a special meter to see if they exceed maximum limits set by your local government. For example, the New York City Noise Code states that music coming from any commercial establishment must not exceed 42 decibels of loudness inside any nearby residences. Sound meters are relatively inexpensive, and can be purchased easily on Amazon. Make sure your neighbors are operating within the law before you invest in soundproofing materials.