What is the best way to soundproof an existing wall?

How do you stop noise coming through shared existing walls?

1. Add Mass to the Wall

Acoustic Plasterboard: Adding two layers of Acoustic Plasterboard with FlexiSound sandwiched in between, when used with ReductoClips will significantly reduce unwanted noise from passing through a wall.

Mass Loaded Vinyl (MLV): This is a dense material that is used as part of direct to wall soundproofing panels such as SoundBoard 4. Particularly effective at soundproofing existing lightweight stud walls.

2. Decoupling

Create a physical gap: Isolate the soundproofing by creating an air gap and building an independent stud frame (a minimum of 10mm) in front of the existing wall. This delivers the highest level of soundproofing.

Sound Isolation Clips: These can further improve soundproofing by providing additional decoupling. ReductoClips are extremely high performing and are the slimmest on the market.They can also be attached directly to the existing wall.

Resilient Channels: Furring bars are metal channels that clip into the ReductoClips and help to create a gap between the wall and the build up of soundproofing which helps in breaking the path of sound.

3. Damping

ReductoClips, FlexiSound and Closed Cell Foam: Are effective damping materials to help absorb sound energy and vibrations.

4. Sealing Gaps and Cracks

Acoustic Sealant: Use this to seal any gaps, cracks, and perimeter edging of the wall. Small openings or cracks can allow sound to pass through.

5. Absorption

Acoustic Panels: These panels absorb sound waves, reducing echo and noise, but don't soundproof or stop noise from travelling through an existing wall. Learn more about Acoustic Panels.

Key soundproofing materials when soundproofing an existing wall

How not to soundproof a shared wall with your neighbour

Here are some key things to avoid when soundproofing an existing wall:

1. Using Thin Materials:

Simply adding a layer of plasterboard to a brick wall without using a proper soundproofing system or specialist soundproofing materials such as Acoustic Mineral Wool, Acoustic Plasterboard, FlexiSound and ReductoClips and bars, will not soundproof the wall.

2. Not Sealing Gaps and Cracks:

Make sure the soundproofing is properly sealed around the perimeter of the wall, along with any gaps using Acoustic Sealant

3. Leaving Outlets Unsealed: Leaving gaps and creating weak points around e.g. electrical sockets. Be sure to use surface mounted socket boxes, or Acoustic Socket Putty Pads to ensure these aren't weak points in the soundproofing.

4. Not Decoupling: With no decoupling from the existing wall the soundproofing performance will be limited. Creating a physical air gap between the soundproofing and the existing wall and using ReductoClips will give the highest level of soundproofing.

5. Not Using Isolation Clips: Without using isolation clips it is hard to achieve the best soundproofing results. Using isolation clip and bar systems like the ReductoClip and bar system will achieve the best results when soundproofing an existing brick wall

6. Not Adding Mass: By not adding mass to the wall, such as Mass Loaded Vinyl (MLV), FlexiSound and Acoustic Plasterboard it will be hard to block unwanted airborne noise

7. Simply using more of the same material: Use a combination of high mass materials as different materials block different frequencies of sound

Make sure to follow the key principles of soundproofing, otherwise the wall will remain ineffective at blocking sound, leading to poor soundproofing results.

The 3 main principles of soundproofing an existing brick wall

1. Isolation

Concept: Isolate or 'decouple' soundproofing by leaving a physical gap between the existing wall and the soundproofing layers to create a sound breaker.

Top-Tip: ReductoClips are highly effective at isolating soundproofing layers from the wall, preventing sound transfer.

2. Damping

Concept: Use elastic or damping materials like FlexiSound and Closed Cell Foam to absorb sound energy and vibrations.

Top-Tip: ReductoClips provide excellent sound damping, helping to reduce sound energy and vibrations and reduce sound transmission through an existing wall.

3. Mass

Concept: Increase the density of walls to reduce unwanted airborne noise. Utilise materials like Mass Loaded Vinyl, FlexiSound, and Acoustic Plasterboard.

Top-Tip: Combining different types of mass can effectively block a wider range of sound frequencies.

Key steps to soundproofing a wall that is already built

1. Identify the Source: Is the noise coming through the wall airborne (talking and voices) or impact noise (footsteps and banging) or a combination of both?
2. Use Decoupling Methods: For the best performance in sound reduction and a necessity against impact vibrations and low bass frequencies (such as deep voices, snoring and music) use isolation clips (ReductoClips) and resilient furring channels (Reducto Furring Bars) on an independent stud frame
3. Insulate cavities: Use Acoustic Mineral Wool to insulate cavities between the decoupled structure, which separates the soundproofing layers and the existing wall. Mineral wool doesn't soundproof the wall, but absorbs sound within the cavity to stop it amplifying within the space
4. Seal Gaps and Cracks: Use acoustic sealant to seal the perimeter of the soundproofing layers and in any gaps around windows, and doors.
5. Add Mass to the Wall: Add a layer of Acoustic Plasterboard, a layer of FlexiSound and a second layer of Acoustic Plasterboard. The combination of these different layers of mass work better when soundproofing an existing wall, as the different materials block different sound frequencies
6. Install Soundproofing Panels: Direct to wall soundproofing panels like SoundBoard 4 can be added to the wall to help block unwanted airborne noise. These are particularly effective on internal stud walls
7. Final Touches: Use a plaster skim and decorate the wall as usual

These key soundproofing steps are important if you want to achieve the best soundproofing results.

How to soundproof an existing wall cheaply?

So called 'cheap' soundproofing hacks although mentioned online, really don't exist. You will end up wasting money on things which yield no soundproofing results and will be disappointed with the results. There are many supposedly cheap ways to soundproof a wall and highlighted below are the most popular, along with the reasons as to why they won't work:

Add Mass with Furniture and Decor

• Bookshelves and Cabinets: Placing heavy furniture like bookshelves or cabinets against the wall to add mass and absorb sound is a misbelief. For a wall to be soundproofed the whole wall needs to be soundproofed with tried and tested soundproofing materials. Noise will simply travel through, around the back and over the top of bookshelves and cabinets

• Curtains or Tapestries: Hanging thick curtains or tapestries on the wall to help stop sound is also a misconception. This will deliver zero soundproofing. What it might help with is absorbing sound within the room. Think of the acoustics within an empty room compared to a room with carpet and soft furnishings. However, it is important to stress again that this will have absolutely no soundproofing benefits whatsoever at blocking sound from passing through an existing wall.



Use Soft Furnishings

• Rugs and Carpets: Adding upholstered furniture, cushions and pillows to the room to reduce echo. Again, adding soft furnishings will help absorb some of the sound within the room, rather than it reflecting off hard surfaces, but this is not soundproofing. Sound will still pass from your neighbour through your wall and vice versa.

DIY Acoustic Panels

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• Egg Cartons: The idea that attaching egg cartons to the wall will help with soundproofing is a complete fallacy. Adding something lightweight to the wall won't block airborne noise from passing through the wall.

Many 'cheap' soundproofing options don't soundproof, they won't block unwanted noise from your neighbours room from passing into your room and vice versa. They simply help with the acoustics within the room. There are also dedicated acoustic panels and solutions to help reduce echo and noise within a room and this is separate to soundproofing.

How can I sound proof my wall cheaply?

Many of the 'cheap' soundproofing options which come up time and time again (as mentioned above) aren't remotely effective at soundproofing a wall. It is much better to save your money and to soundproof the wall properly using a tried and tested soundproofing system and doing it once and doing it right. Based on an average wall size of 3m x 2.4m for the highest performing ReductoClip Independent Wall System the cost would be around £900 including delivery and VAT.

For the same size wall and for the ReductoClip Direct to Wall System (without the independent stud frame) the cost would be around £835, including delivery and VAT.

For the SoundBoard 4 which is an excellent direct to existing wall soundproofing panel for studs walls, the cost would be around £570.

The 3 best ways to sound proof an existing brick wall

Conclusion: How to soundproof an existing wall

Soundproofing an existing wall can significantly enhance the comfort and privacy of your living space by reducing unwanted noise, especially from noisy neighbours. The key to effective soundproofing lies in understanding and applying the three main principles: isolation, damping, and mass.

1. Isolation involves creating a physical gap between the existing wall and the soundproofing layers using methods such as building an independent stud frame 10mm away from from the existing wall and using ReductoClips and resilient channels. This decoupling is crucial for breaking the path of sound and preventing it from travelling through the structure.
2. Damping focuses on absorbing sound energy and vibrations using materials like FlexiSound and Closed Cell Foam. ReductoClips also contribute to damping, further reducing sound transmission.
3. Mass requires adding dense, heavy materials like Mass Loaded Vinyl, Acoustic Plasterboard, and FlexiSound to increase the wall's density and block airborne noise effectively. Combining different materials can block a wider range of sound frequencies.

By following these principles and using proper soundproofing materials and techniques, you can achieve significant noise reduction in your existing walls. Avoid common mistakes such as using thin materials, neglecting to seal gaps and cracks, and failing to decouple and isolate the soundproofing layers.

Although some "cheap" soundproofing hacks might seem appealing, they often yield disappointing results. Investing in a tried and tested soundproofing system is more effective in the long run. Depending on your budget, noise reduction needs and space you can lose from the wall, systems like the ReductoClip Independent Wall System, ReductoClip Direct to Wall System, or SoundBoard 4 can provide excellent levels of soundproofing performance.

Ultimately, proper soundproofing requires a thoughtful approach and the right materials to ensure the best results. By understanding the principles and following best practices, you can transform your space into a quieter, more serene environment.

Author

Phil Lyons heads up the technical team within The Soundproofing Store, bringing with him a wealth of expertise in the field of soundproofing and acoustics. With considerable experience in addressing a variety of noise-related challenges, Phil plays a crucial role in assisting customers in finding effective solutions to all types of unwanted noise problems.

Phil also serves as the head of the studio department, specialising in soundproofing music rooms and band practice spaces. His proficiency extends to regularly collaborating with builders and specifiers on projects that require compliance with Part E Building Regulations. Phil regularly demonstrates his versatility and extensive knowledge of soundproofing across all situations.

An authoritative voice within Soundproofing, Phil also fronts The Soundproofing Store YouTube channel, sharing his extensive knowledge and expertise with people all over the world.