What’s the Best Way to Add Sound Insulation to an Existing Wall?

By Jamie Orr
Date 09/12/2021
what’s the best way to add sound insulation to an existing wall?

Noisy neighbours. Street noise and traffic. Or just your own pride and joy listening to their music in the next bedroom. There are several reasons why you would want to add sound insulation to existing walls – either between rooms or as a barrier to the outside world.

In this post, we’ll list some of the options available for wall sound insulation and discuss the best way to sound insulate a wall.

Foam panels

One of the most commonly used solutions for insulating existing interior walls for sound are foam panels. Also known as insulation boards, they are typically made from polyurethane – a plastic material which is made into a sound-absorbing foam.

They’re relatively effective, with some of the best options offering noise reduction of up to 12 decibels. However, at 30-40mm in thickness, they do eat away at the size of a room, especially when you factor in plasterboards on top of the panels.

Insulation roll

Another option is wall sound insulation roll, which is generally marketed for its thermal insulation qualities. Some rolls are around 4-6mm thick, making them much thinner than panels or boards. Unfortunately, that comes with subpar performance, where you might not even notice the difference in sound.

On the other hand, you can find more substantial rolls made from glass mineral wool. While they’re more effective acoustically, these products have the same problem with bulkiness – measuring up to 50mm in thickness.

Cavity slabs

If you’re looking for the best way to sound insulate a wall without compromising on the size of a room, it makes sense to consider the wall cavity. While load bearing walls are typically solid, stud walls have space inside that can be filled with insulation.

Insulating cavity slabs are a good way to add insulation to the hollow part of a stud wall. That said, they’re more suited to walls which are being newly constructed or replaced. If you’re insulating existing interior walls for sound, it will be quite messy, time consuming and costly to rip away the existing plaster, fill the cavity and then cover it back over.


When you’re searching for the best sound insulation for internal walls, it’s hard to see past SprayCork. The internal coating provides the same sound insulation qualities as panels or boards – up to 12 decibels – but without the same bulk and hassle.

As an insulating internal wall coating, SprayCork is applied in two coats of 3mm each and finished with a 2mm skim of plaster. That’s a thickness of just 8mm, while still significantly reducing the amount of sound coming into a room or building.

What’s the best way to sound insulate a wall?

Ultimately, it’s up to you to decide which wall sound insulation is best for your property. Our verdict is that foam panels are effective but bulky, rolls are practically the opposite, and slabs are pretty unsuitable for existing walls.

At CorkSol, we believe SprayCork provides the best of both worlds when it comes to insulating existing interior walls for sound. That’s topped off with great thermal insulation, breathability and damp-resistance.

If you would like to find out more or arrange a quote, please contact our team.

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