Soundproofing Existing Walls: What Worked for Me

Most people desire peace when they are at home. However, that may be hard to achieve when you rent a house with strict renovation rules from the landlord. Despite that, you can soundproof walls without damaging the existing walls.

There are several methods you can apply when soundproofing existing walls. They all have different budgets and give you different levels of noise blocking.

However, you need to understand the basic principles of soundproofing before soundproofing your existing walls. Below are different techniques for soundproofing existing walls.

Basic Principles of Soundproofing

The source of noise will highly determine the soundproofing method you choose. For instance, airborne noise and impact noise need different methods to block. The basic principles of soundproofing help you understand the method you need to apply for any of the two types of noise.

Examples of impact noise, also known as structure-borne noise, including banging on the walls, knocking on the door, or any other noise that causes vibration at the point of impact.

On the other hand, airborne noise may consist of music, TV noise, and voices. As its name suggests, airborne noise is transmitted through the air. For example, through the gaps in the door frames, windows, etc.

Soundproofing seems simple when you imagine it. However, the process is tricky. You need to apply the correct sound principles. Below are the basic principles of soundproofing that you need to understand.

Decoupling

Sound is a vibration that travels through a defined path. The path may be in solids, air, or liquids. It’s only in a vacuum that sound doesn’t travel.

We say you have introduced decoupling when introducing a barrier in the sound path. The barrier creates a vacuum between two surfaces, significantly reducing sound transmission.

Sound travels fast on solid surfaces. Thus, the noise is higher on contact surfaces. Decoupling happens when you introduce spaces between walls; hence noise reduces significantly when you detach the contact surfaces.

Note that decoupling is not an effective method to block noise completely. But it can substantially reduce noise decibels that pass through walls. You can apply other principles to block noise from passing through your walls completely.

Sound Blocking

You can block sound by installing a thick material on the wall. Adding mass increases the thickness of the wall making it harder to vibrate. Sound blocking is the cheapest method you can use to soundproof existing walls.

However, the method’s effectiveness will depend on the frequency of the sound you want to block and the thickness of the mass that you install.

The type of material you use in sound blocking also plays a part in sound blocking effectiveness. One of the most common materials used as a sound blocker is mass-loaded vinyl and green glue.

Absorption

Sound also travels through the air. When you decouple your existing walls, the air between the walls vibrates, passing some noise.

However, you can reduce the vibration in the air if you introduce absorption materials.

Low-density cellulose and fiberglass are some materials that you can use for sound absorption. You can use it on walls and ceilings, but you have to ensure there are no space to prevent airborne sound transmission.

Noise absorption is the best method for high-frequency and medium-frequency noise with higher energy.

A few examples of sound-absorbing materials include acoustic foam panels, acoustic blankets, soundproofing paint, and acoustic wallpapers.

Damping

Damping is the effect that stops vibration when an object is tapped or knocked.

Soundproofing a wall with a damping method requires you to use waterborne and liquid damping materials. Green glue noise proofing adhesive is an example of a damping compound you can use for soundproofing.

How to Soundproof Existing Walls

Soundproofing can be expensive, depending on the methods and materials you apply. It’s always wise to use the most effective way of soundproofing. Assess the condition of your house before you start any soundproofing project.

Adding Drywall

The easiest way to reduce noise in your house is by adding a layer of drywall. The additional drywall thickens the wall’s mass, making it hard for vibration to penetrate. Thus, you achieve some level of soundproofing with a small budget. You can add several layers of the drywall as you need.

When adding a layer of drywall, you will need adhesive to connect the two wall layers. One of the most popular and recommended is QuietRock Drywall Soundproofing. Drywall will help reduce sound transmission and help in fireproofing your walls.

Add Blown-In Insulation

Blow-in insulation, also known as loose-fill insulation, fills joist cavities or studs with loose material that has insulating and sound absorption properties.

The most common type of blow-in insulation is cellulose material. However, using Styrofoam or fiberglass fibers is highly recommended, especially if you want to achieve both sound and heat insulation.

You can do blow-in insulation yourself; however, you need a professional hand to make perfect blown-in insulation in most cases.

The expert uses the right tools to access the spaces between the drywall. They blow in low-density cellulose foam in the loose spaces in the wall.

The foam then traps air pockets within air pockets that block the vibrations of sound waves. These air pockets in the walls are responsible for sound transmission, and filling the pockets or gaps with cellulose or fiberglass will help block airborne noise transfer.

Soundproofing Foam Panels

If you’ve been to a recording studio, you’d have noticed that the walls are covered with acoustic foam panels. The foam layer helps to reduce echo and keep the recorded voice smooth and clear.

Additionally, soundproofing foam panels prevent the noise from leaving the recording studio into other rooms.

One of the most popular foam panels is the self-adhesive acoustic foam panels by Dmsky since they are cheap and easy to install.

They are available in different sizes and colors. Thus, you can get panels that can suit your interior decor.

The panels are sold alongside a special adhesive spray to fix them on the wall, making them easier to attach.

Soundproofing Paint

Unlike regular paint, soundproofing paint is specially designed for sound absorption. Like acoustic wallpapers, acoustic paint won’t block noise but absorb sound, especially reverberations and echoes.

Soundproofing paint is one of the easiest methods for soundproofing existing walls. First, applying the paint is similar to using regular paint. You start by applying a primer. It helps in holding the base coat and the paint in place.

Apply a base coat after the primer dries out and let it dry. If you want better results, apply another layer of base coat.

Take your soundproofing paint and apply it to the dry base coat. Ensure you stir the paint well before application.

The paint is thicker than normal paint and has a texture. You can achieve better results if you apply two layers of paint.

Separate the layers for 40-60 minutes to ensure the first layer has dried off. Finish your work by applying a layer of finishing coat.

Soundproof Wallpaper

You can buy Yataihui Foam wallpapers in large rolls. It helps save on the final cost rather than buying a few pieces at a time. Since the seams where the wallpapers meet are visible, you can apply some sparkle. It adds some glamor and gives the wallpapers a seamless finish.

Acoustic Blankets

The noise outside your house may be temporary. Thus, you don’t need a permanent soundproofing solution. In such a case, you can have some acoustic blankets until the noise source is withdrawn.

It’s important to note that acoustic blankets are not the same thing as soundproofing blankets. The former is designed to absorb noise (echoes and reverberations), while the latter blocks sound transmission.

Acoustic blankets are unappealing, and hence I would recommend them if you value the aesthetic decors of your home.

Soundproofing Curtains

When your landlord is strict about renovations, you can leave the walls in peace and apply soundproofing methods that do not interfere with the wells. NiceTown High-end, Thermal, and Soundproofing curtains are made of thick and dense materials that help reduce noise transmission.

Hang soundproofing curtains in the same way as regular curtains. You can also select the colors that match your interior decor. The dense material of the curtains blocks any noise from passing through them.

The curtains should be wider than the walls to get the best results. Thus, the extra width covers the curves the curtains assume when you hand them. Also, get curtains that cover from top to bottom. That way, the curtains will be more effective at dampening noise.

Wall Covering

Sometimes you may find foam unappealing in your rooms. Thus, you opt for a more presentable alternative.

Wallcovering has similar material to acoustic foam panels. However, they differ in their finishing. Wallcovering has a stylish finish and more colors to choose from.

Sealing Holes and Cracks

Airborne noise passes through the slightest gap they find. Thus, it would help if you sealed all the cracks, holes, and crevices on your walls, doors, and windows.

Green glue can help you patch up holes and cracks on the wall. Sometimes, the spaces are too small that you can seal them with a layer of paint.

Use green glue to seal all the cracks and gaps on the walls as the cracks create a vulnerability through which sound can travel.

Also use green glue to seal up any holes and cracks you create when applying other methods of soundproofing existing walls.

Add Mass Loaded Vinyl

Mass-loaded vinyl is a thin sheet of soundproofing material. The primary materials are PVC and calcium carbonate or barium carbonate. It also has some infused metals that make it high density and adds to its soundproofing ability.

Using MLV between two drywall dampens any sound going through the wall by stopping the vibrations.

You can also install it on top of an existing wall without adding a layer of drywall. In this case, you should overlap the seal to seal out any gaps where sound can pass through.

Use QuietRock

Adding a layer of the wall to an existing wall can reduce the noise in your room. However, you need several layers of drywall to dampen a significant amount of noise in your room.

Instead of regular drywall, you can use the latest technology called QuietRock. According to study, a single layer of QuietRock has the effectiveness of four layers of drywall.

Once you screw the QuietRock on an existing wall, you should seal the seals between the sheets with noise-proofing glue. Remember to seal switches, electrical outlets, and corners with latex caulking.

Other Methods to Soundproof Existing Walls

Plaster the Walls

If your walls are made of bricks, most available soundproofing methods would not fit. However, you can plaster the walls to add thickness to your walls. One layer of plaster can add soundproofing properties to your wall. Some people opt to plaster both sides of the wall (interior and exterior) to boost the soundproofing ability of the wall.

Add Strips on the Doors

The gap beneath the door can be the path to the noise sneaking into your room. Thus, it’s easy to soundproof by sealing the gap under the door.

Nail-in or adhesive strips are great at sealing that gap. All you need is to attach them to the base of the door.

Change the Doors

Some doors are made of two thin panels of wood attached to a thicker wood by buttons. Thus, they are hollow and amplify any noise that passes through them. You can opt to replace such doors with solid doors. It’s an expensive method but effective for soundproofing your room.

Get Creative with Furniture Placement

Spaces in your room amplify the noise that gets in. You can reduce the noise by playing around with spaces between your furniture and wall fittings.

Place heavy and oversized furniture close to the wall you need to soundproof. They will add some mass and absorb some sound waves. The furniture will absorb some airborne noise that passes through the walls. If you place the furniture against the walls, they will transfer the vibrations to your room.

Softer furniture helps absorb the waves that make it through hard furniture. With this arrangement, you will reduce the noise in your room significantly.

Use Sound Absorbing Fabric to Cover Walls

Sometimes soundproofing blankets and curtains are not as effective as you’d wish. You can cover walls with sound-absorbing fabric to enhance or substitute blankets and curtains.

Sound absorbing fabrics are not soundproof. However, they reduce sound waves and echoes within a room. Thus, when sound passes through the walls, the material absorbs the vibrations, dampening the noise.

Final thoughts on Soundproofing Existing Walls

The methods above offer you the simplest and most effective techniques for soundproofing existing walls. Assess the needs around your home and the budget before you select any technique. Sometimes, you can apply more than one method to achieve better results.

Sometimes, you can opt for more expensive methods of soundproofing. Replacing doors, windows, and types of walls can help you achieve some levels of soundproofing. However, the decision will depend on the homeowner and your budget.

DIY methods are the best since they are cheap and straightforward. Also, they help address some temporary noise – especially from construction or other heavy machinery work outside your house.