Can You Soundproof A Cavity Wall?

If you have a cavity wall separating you and your next-door neighbors, then you would know how loud it can get. The sound and noise from outside your home can easily penetrate through your walls, and it may be hard to get some quiet time. So, can you soundproof a cavity wall?

Yes, you can soundproof a cavity wall to reduce external noise. Filling your cavity wall with acoustical blankets or isolation blankets is the most straightforward method. You’ll also need to make sure the wall is completely sealed to ensure no sound can make its way through.

There is, however, more to soundproofing or insulation than just getting your cavity wall filled. For one, it has to be filled with the right material to work. You also need to install your insulation properly to make sure your cavity wall is soundproof. So read on to know more about it.

What Is a Cavity Wall and What Are Its Advantages?

A cavity wall features two separate walls with a hollow space between them. These two separate walls are called the skins or the outer and inner leaves and the hollow space is called the cavity.

The outer wall or outer skin, which is usually made of brick, faces the exterior of the building structure. Meanwhile, the inner wall is usually built using brick, reinforced concrete, concrete block, or structural clay. Both outer and inner walls are fastened together using bonding blocks or metal ties, which strengthen the cavity wall.

Having a cavity wall offers certain advantages, especially when compared to a solid wall. These advantages include:

• Better thermal insulation than solid walls because of airspace
• Resistance against wind-driven rain
• Cheaper and more economical than solid walls
• Moisture content in the outer atmosphere cannot enter the house because of the hollow space, thus preventing dampness.
• Better sound insulator than a solid wall
• Less thick than a solid wall, so it reduces the weight on the foundation

The cavity wall helps keep wind-driven rainwater out through weep holes, which are drainage holes on the outer wall. These holes are typically created at the base of the wall system or above the windows. These weep holes allow the wind to create an air stream through the cavity and they also allow the evaporated water to exit.

Why You Should Soundproof Your Cavity Wall?

You will need to soundproof your house if you are living next to neighbors who tend to get loud. Or if you are working the night shift and would rather not deal with the usual street noise while you try to sleep during the day.

Compared to older houses built with very thick walls, more modern homes with cavity walls suffer more noise-related issues. Neighbors’ voices, loud music, stereos, television, and traffic are just a few of the typical noise pollutants that people living in homes with cavity walls get to experience daily. This can cause stress, sleeping problems, and anxiety, which would eventually have a detrimental effect on your health.

Aside from solving your problem with noise, soundproofing your cavity walls will also insulate your home during the cold season.

Soundproofing vs. Insulating

Soundproofing and insulating your wall go hand in hand, according to The Green Age, a UK-based energy saving advice portal that specializes in heating, insulation, and renewable technologies. It says that just insulating your wall will automatically reduce noise coming in from outside, and soundproofing will automatically help insulate your home from the cold.

In other words, whatever solution you apply on your cavity wall will serve both purposes: that of reducing external noise and that of keeping your house warm and cozy. However, the term insulation focuses more on the creation of a thermal barrier for your home.

The U.S. Government’s Take on Soundproofing

Another reason why you should soundproof your cavity wall is that it is highly recommended by the government. The United States Department of Transportation, Federal Highway Administration, has outlined guidelines on how to manage highway noise. In its manual, the FHWA states that noise can be intercepted as it passes through walls and has enumerated noise-reducing materials and construction techniques.

While the FHWA states that the airspace in cavity partitions has better sound insulating properties compared to a single wall, it recommends increasing the width of this airspace. Doing this would provide more significant noise reduction. Moreover, it says that if the leaves of the cavity wall are made of different materials and different thicknesses, the sound reduction qualities of the wall are improved.

Benefits of Insulating Your Cavity Wall

Homes with uninsulated external walls can lose as much as 35 percent of its heat. However, by installing cavity wall insulation, the flow of heat as it exits a room through the wall becomes slower. As such, you will need less heat to keep the required temperature for your house.

The concept of insulating a cavity wall involves filling the cavity with an insulating material to reduce heat loss. This insulating material also works in reverse and keeps your house cooler during the summer. Hot air outside the home won’t be able to get in as easily, so you wouldn’t need to use so much energy just to keep your home cool.

Moreover, aside from helping you save energy that could have been lost through your wall and decreasing your heating bills, insulating your cavity wall will also help reduce your carbon footprint. The Green Age cites the Energy Saving Trust as indicating that cavity wall insulation can reduce carbon dioxide emissions by 560 kilograms. This is because insulation limits the amount of carbon dioxide and other greenhouse gases that are emitted from your home.

In both cold and hot months, cavity wall insulation contributes significant savings to your energy consumption and helps you keep your energy bills down.

How to Soundproof Your Cavity Wall?

The Green Age explains that since an empty cavity wall largely contributes to a loud house, filling up this cavity is a sensible way to reduce external noise. Not to mention that doing so also brings in great thermal insulation benefits.

A good way to reduce sound is either to absorb it or to block it, according to soundproofing service provider Sound Service. It says that you can block sound by using a high-density sound blocker, like the high-density acoustic plasterboard. The thicker the sound blocking material is, the more effective it will be in blocking noise.

However, you can also use a combination of sound blocker and sound absorber to give your wall a good level of sound reduction. Acoustic mineral wool is one example of a sound absorber. If used in the correct density and thickness, it is very efficient at absorbing sound.

The FHWA likewise recommends that you can insert acoustical or isolation blankets in the airspace to increase sound attenuation. Acoustical blankets are made from materials that absorb sounds, such as mineral, rock wool, wood fibers, hair felt, and fiberglass. These materials, it says, can reduce noise by as much as 10 decibels.

It is also important to make sure you seal your wall’s perimeters or edges. You also need to make sure there are absolutely no cracks and holes on the wall as it could make your insulation efforts futile.

Soundproofing and Insulating Your Cavity Wall: A Few Tips

It is not recommended that you install cavity wall insulation yourself. It is not suitable for a DIY project. It is a job that has to be carried out by a professional. Insulation work may also not be recommended if your home suffers from damp problems. You will have to get your house assessed by a professional surveyor first.

You should also keep in mind that soundproofing and insulating your cavity wall is not a one-stop solution for completely getting rid of noise pollution. Noise from the outside can still get in through your windows and your doors. Your doors and windows let in the most noise, followed by lofts and roofs. As such, you can further soundproof your home by also providing adequate loft insulation.