Does Cavity Wall Insulation Reduce Noise?

cavity wall insulation noise

Last updated: March 1, 2023 at 16:26 pm

Most houses these days have some sort of cavity wall insulation. It’s main purpose it energy efficiency to heating retention, but does it help top reduce noise?

In this article:

We’ll explain what cavity insulation is, if it helps to reduce noise, and what alternatives you could use.

What is Cavity Wall Insulation?

You may be wondering what cavity wall insulation is. Well, it’s an insulating material found in the inner walls of your house. You’ll find it in between the interior and exterior brickwork of your home. So, you can’t see it unless you drill a hole through the wall.

The main function of cavity wall insulation is to insulate your home. It’s an eco-friendly solution to cold weather and aims to reduce the amount that homeowners use their central heating. Not only does this save on fossil fuel usage, but also boiler wear and tear.

Does Cavity Wall Insulation Reduce Noise?

Even though it’s not designed to reduce noise, cavity wall insulation is a great soundproofing material. It helps to bounce sound waves back away from your home, which will reduce noise noticeably. The way it reduces sound is very similar to how it insulates your home. The sound waves bounce off of the wall, much like the heat bounces into your home.

However, because cavity wall insulation is designed to insulate your home (not to reduce noise) it’s not the best solution for noise reduction. This is because sound travels differently to heat, and cavity wall insulation isn’t the best material to absorb sound. There are better soundproofing materials to use, but if you already have cavity wall insulation within your walls, it certainly won’t do any harm.

How Do I Install Cavity Wall Insulation?

Cavity wall insulation can be tricky to install. This is because it needs to be installed in between the brick layers of your house. And you can’t just tear the walls down, as this would be extremely impractical and expensive. Instead, there’s an elegant solution.

If you’re thinking about installing cavity walls into your home, you’ll first need to establish whether your home has it installed already.

A good indicator is the date when your home was built. If it was built before 1920, then you probably don’t have cavity wall insulation in your home. This is because cavity wall insulation was seen as a waste of money, and there was much less knowledge on insulation and energy saving.
However, if your home was built after 1920, you probably already have cavity wall insulation. Cavity wall insulation became extremely popular in the 1920s and 1930s, so most new homes were built with it.

If built after 1990, then your home is guaranteed to have cavity wall insulation, as building regulations were altered, and all homes were required to have cavity wall insulation fitted.
You can also tell if you have cavity wall insulation by looking at the brickwork outside your home. If your bricks have a stretcher bond (all bricks are laid next to each other) then you probably have cavity wall insulation installed.

Flemish brickwork
Flemish brickwork

Whereas if your bricks have a Flemish bond (bricks laid in an alternating fashion) you probably don’t have cavity wall insulation.

Installing in Already Built Walls

Drill a hole into several holes into the wall of the building. Then, use a pump to reach inside the wall, and use a poly-bead insulation to fill the cavity in the wall. Do this all around the walls, and you’ll have filled the cavities in your walls.

This may sound easy, but it’s not. Your best bet is to call a professional to do this for you. They’ll know where to drill the holes and how much insulation to use. If you try this yourself, you could end up damaging your walls, and probably won’t fill the cavity evenly.


Cost effective – cavity wall insulation will help to reduce both noise and heating costs within your home. It’s one of the cheapest ways to do this, as well as one of the most effective.
Save on energy bills – Homeowners will cavity wall insulation save up to £300 more on energy bills than those who don’t have it installed.


One of the least effective ways to reduce noise – although cavity wall insulation will reduce noise in your home by a good amount, it’s not the best way to reduce noise in your home. This is because the primary purpose of cavity wall insulation is insulation and heat retention, not soundproofing.
A hassle to have installed – If you don’t have cavity wall insulation installed, it’s going to be a pain to get it finished. The combined drilling and pumping will be extremely loud whilst it’s being installed, and it can take over a week to finish.

Alternative Methods to Reduce Noise

If you already have cavity insulation, you don’t need to do anything. It will work in your favour and along with other soundproofing materials can work out great. If you don’t have it, try other solutions before installing (purely for soundproofing) as installing it can be noisy and expensive.

Soundproofing panels: Putting soundproof panels on your walls is a great way to reduce noise. The panels absorb noise and stop it from bouncing around your home. This is also a great idea if you play an instrument or have a home office and require a very quiet environment.

Mass loaded vinyl: MLV is a great soundproofing material, and can be used in various situations.

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Last update on 2023-11-20 at 13:17 / Images from Amazon Product Advertising API

Double glazed windows: Windows are one of the weak spots in your home and can let in a lot of outside noise. But, if you invest in double glazing, the noise coming into your home can be significantly reduced.

Check out our in-depth article for more info on soundproofing a wall.


From a purely soundproofing perspective, cavity wall insulation wouldn’t be the first thing we’d recommend. It helps a little if you already have it, but it’s build to retain heat, not to absorb sound. You’d be better of experimenting with mass loaded vinyl, soundproof panels or even handing soundproof curtains initially and see what difference that makes.

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About the Author: AJ

AJ is a self-confessed soundproofing nut. He has written full-time on Quiet Living for the past 4 years, and has a wealth of knowledge about living a quieter life, soundproofing and fixing loud noises.

1 Comment

  1. Hello, would you know if having EPS beads blown in underneath floor boards would work as sound insulation? We are having a top up of existing cavity wall insulation but also wish to sound insulate the floors of two rooms. Is this a crazy or a workable idea?

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