Soundproofing your home? We look at the acoustic properties for common insulation products.

Soundproofing your home

What insulation is right for soundproofing your home?

If you’re looking at soundproofing your home then insulating your walls is a great starting point. The main reason you get a lot of noise transfer through your home is that for most New Zealand homes, there’s little to no insulation in the walls. This means that all you have separating one room from another is a thin sheet of plasterboard on either side of the wall.

Insulating your walls helps fill the air gap and reduces noise transfer inside the home. Not all insulation products are created equal however and choosing the right product for your walls will make a big impact on the level of noise reduction.

In this article we look at several types of insulation products available in New Zealand and discuss the advantages and disadvantages when it comes to soundproofing your home.


Batts are usually made of glass wool (also known as fiberglass) insulation. This type of insulation has been used in the New Zealand market for over 50 years and is generally known as an effective insulation product. It’s made from recycled glass and comes in a variety of thicknesses and sizes.

Batts typically comes in a roll that has a fixed width and you cut segments from this into the sizes you need for your walls or roof cavity. These segments are then placed in-between your timber framing.

Soundproofing with a batts style product can be a little challenging. Even with the best installation, there are often small gaps left around the corners and edges of the batts. This means that air and noise penetrate the walls. Soundproofing a house requires no gaps in your insulation barrier to be effective at eliminating noise transfer. For this reason, batts are not our preferred solution for soundproofing your home.

Foam Insulation

Sprayed polyurethane foam insulation has been widely used over the last few decades in New Zealand homes. It’s effective at completely filling your wall and helps to curb sound resonance however it’s not as effective as other insulation products that are denser.

While foam insulation will help seal a cavity and provides an effective thermal barrier, the compound is not effective at absorbing sound and therefore not a good choice for soundproofing your home.

The recent decline in popularity of foam insulation has also been driven by recent studies which show that spray foam can lead to damage of your timber framing, the material may actually shrink overview and there are several potential health issues caused through the chemicals used in the insulation.

Loose Fill Insulation

Many insulation companies these days are using a loose-fill glass wool product. CosyWall Insulation is a good example of common loose-fill insulation and has been widely used throughout New Zealand homes for the past 20 years. Insulation is blown into your wall cavities and doesn’t require the removal of the wall linings. The process is fairly simple and can be done from either the inside or the outside of your walls.

The materials in loose-fill insulation are similar to those found in batts.  It’s blown at such a high density that it fills up all the space in your walls. This doesn’t leave any gaps for air or noise to penetrate. Blown Insulation is a great product that provides both thermal and acoustic insulation properties. It’s our preferred choice when soundproofing your home.

Do you need some more help?

If you’re wanting to fully soundproof your home, insulation is only one part of the puzzle. Insulation will help in soundproofing but should be used in combination with other products and materials for the best results.

The team at CosyWall Insulation would love to chat to you about insulating your home. If you have questions about acoustic insulation or soundproofing your home contact us and we’d be happy to help you further.

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