Soundproofing Spray Foam Insulation: Does it Reduce Noise? [2023]

When you’re in the lookout for the best ways to soundproof your home, sooner or later you’ll come across soundproofing spray foam insulation. 

When considered as a sound dampening alternative, this method usually raises several questions, out of which the main one always is ‘does it actually work?’.

The main thing you should know is that the principal use for spray foam is creating insulation. 

There are several types of insulation foam that you may use to create a thicker barrier between rooms and floors to reduce noise, but know that sound deadening is not the main goal when it comes to using this type of foam. 

However, to help you find the best way to soundproof your home, we’ve compiled all the information you need on sound deadening spray foam. 

You’ll learn everything from what it is and what it is used for, to if it actually works in reducing noise, so stick around for more.

What is soundproofing spray foam insulation?

Spray foam is a construction material used in the building of homes with the objective of thermally insulating walls. It is one of the most used materials nowadays to insulate rooms and ceilings, and it is super accessible and relatively easy to use by anyone.

However, even if the main goal of insulation spray foam is keeping homes warm, it has been used more and more as sound deadening material. The reason for this is that it creates an additional barrier between connecting walls, making them thicker and more sound resistant.

When used for soundproofing processes, insulation foam is called acoustic spray foam. 

Along with sound dampening paint and sound deadening panels, it can be used to reduce sound and absorb noises hitting your walls. 

Noise insulation foam is made out of polyurethane, which can be close or open-celled, and is used in home construction and renovation to add more build to walls and ceilings. It has thermal benefits and is used mainly for insulation and support.

When it comes to soundproofing your home, the benefits of insulation spray foam can be a bonus to your efforts. However, soundproofing and sound dampening are not sprayed foam’s main purposes, so in all actuality, they shouldn’t be your main focus point if you want to reduce noise in your home. 

Nevertheless, a point that could make soundproofing spray work is that is used to seal cracks and crevices along walls and window frames. 

These cracks and crevices no matter how small, are a freeway for sound and exterior noises to get into your room, and using spray foam to seal them is a great way to keep unwanted noise outside. 

As we mentioned, soundproof spray foam comes in two variations:

Closed-cell spray foam

This type of foam is made out polyurethane with closed cells, which make the foam much more rigid, dense, and heavy. Closed cells are compact and let very little air and heat flow through.

Closed-cell foam is water-resistant, keeping water and humidity outside your spaces. It is also much firmer and compact than an open-celled foam.

This kind of foam also expands relatively little compared to open-celled foam, since the closed cells only allow it to expand 1 inch. 

This contributes to making it denser and firmer, so it gives a more solid structure to constructions. 

Open-celled spray foam

When closed-cell spray foam is dense, hard, and doesn’t expand much, open-celled is the complete opposite. 

This type of spray foam is very light thanks to the open cells in the polyurethane, which make it expand up to 3 inches, three times more than closed-cell foams.

Opened-cell foam is very flexible and is great for sealing little creaks and crevices in walls and along windowpanes. 

It is also very good for insulation since it traps air and heat, but it doesn’t completely repel water and vapor.

Since open-celled insulation foam is so thick, it is much more preferable to use it with soundproofing purposes compared to closed cells. 

This type of foam is also much more affordable, so all in all, open-celled foam is the best option depending on your needs.

No matter which you choose, keep in mind that insulation is a great factor for applying spray foam to your walls, so you’ll want to make sure the foam you choose is great for both sound dampening and thermal protection.

What do acoustic spray foam sound ratings mean?

When it comes to measuring sound intensity, there are is a series of values and metrics to follow. These are very important to know if want to get proper soundproofing for our home.

The most important measurements when dealing with sound are Hertz and decibels. 

Hertz measures the frequencies of the sounds, while the decibels measure the intensity or the loudness of the sounds we hear.

When we want to dampen sound and prevent noises from reaching into our rooms, it’s important that we know these measurements in order to get the best results. 

Naturally, some materials work better than others at soundproofing. For example, fiberglass blocks the most amount of noise and reverberations, while closed-cell spray foam does very little in the way of keeping noise outside.

Open-celled spray foam, on the other hand, does a better job at dampening sounds since it gives better results within the sound metrics. 

The most important sound measurements when soundproofing your home are STC and NRC. 

STC stands for Sound Transmission Class, and it measures how effective different materials are at reducing sound transmission. 

The higher the STC number, the less sound is getting measured, with means that less noise is reaching inside. This means that the sound dampening method works.  

NRC stands for Noise Reduction Coefficient, and this rates how well a material reflects or absorbs the soundwaves hitting it. It works in Hertz, and the greater the final value means better the material is at absorbing sounds.

Let’s take a look at the NRC and STC of both open-celled and closed-celled foam. 

Open-celled foam, which expands 3 inches when applied, has an STC of 37 to 39, and an NRC of 0.70.

Closed-cell spray foam, on the other hand, expands only 1 inch when applied, and has an STC of 36 and an NRC of 0.70.

While the NRC level of both types of foams is the same, the STC level of closed-cell foam does not achieve much when it comes to reducing the amount of noise coming from the other side of the wall. 

This leaves open-celled foam as the best option if you want to use soundproofing spray foam for existing walls in your home.

Does spray foam insulation reduce noise?

Before getting our hands on the first can of soundproofing spray foam we can use, let’s answer one vital question: does insulation spray foam actually reduce noise?

To determine this, let’s first understand the types of noises we deal with on a daily basis.

The most common types of noises we hear – and want to keep out of our spaces – are airborne and impact sounds. 

These travel in different frequencies which determine the way in which they encounter obstacles like walls and other objects.

Sounds are made up of vibrations, and these vibrations travel through the air find their way through the walls of our homes. 

When we want to soundproof walls, we want to find a way so those vibrations are properly dampened and absorbed so they don’t bother us as much.  

The hardness of surfaces like walls makes sounds and vibrations travel easily through them. This is why soft, spongy materials are the best way to soundproof a room.

Take a look at sound dampening panels, for example. They’re made out of spongy polyurethane that absorbs sounds and vibrations in a unique way, reducing interference and echo.

This is why insulation foam may seem like a good soundproofing material. After all, panels and spray foam are made out of the same stuff, right?

Well, the truth is that even open-celled spray foam, which does a better job at blocking sounds than closed-cell foam, does not reduce enough noise to make a significant difference to our ears. 

While the flexibility and expandability of open-celled foam do reduce a little bit of sound coming in from the outside, it really doesn’t do much in the way of reducing a big amount of noise.

However, let’s not cast out soundproofing spray foam just yet.

While it doesn’t really perform in the best way when it comes to reducing vibrations and sounds, it can work as an important foundation when using more effective soundproofing methods.

For example, you can apply your insulation foam to all the crevices you find in your walls, to make sure sound is not coming in through any fissures. 

Then you can apply up to three layers on sound dampening paint, which is the amount needed to actually begin to reduce sound from the other side of the wall.

Soundproofing paint is very thick, so several layers of this specially made material can actually make a small difference in noise perception.

Then, when the paint is dry, you can install a number of acoustic panels right where your wall receives the most of the noise. 

These panels are the definitive touch to soundproof your rooms and will make your acoustic insulation spray foam actually work. 

Sound deadening spray foam alternatives

Now that you know how to make insulation spray foam work as a soundproofing method, let’s take a look at the best alternatives that will complete the job and actually give a nice and quiet space to work and live in.

Acoustic sound-absorbing panels

These panels are by far the best way to improve the sound quality of any room you install them in. 

They’re made of polyurethane foam and come in the shape of squares that you can hang n your walls to reduce echo and significantly improve sound and reduce noise. 

They usually come with wedged or pyramidal textures that can contribute to the quality of the sound, but what makes them work so well is its 1 inch of foam dissipates sound waves.

Not only are acoustic panels super effective when it comes to reducing noise, but they are actually rather safe since they are also fire retardant.

Sound reducing curtains

Noise-reducing curtains are one of the best choices for your home, since not only are they thick and soft enough to absorb sound vibrations, but they are also completely blackout.

Thick fabrics like these are great for your home because they can improve the acoustics of your rooms while also serving as stylish curtains.

If you want to keep adding sound improving fabrics to your home, you can also acquire some sound reducing moving blankets. 

You can hang these anywhere in your room for a more quiet experience, and serve as a good alternative if you’re working towards soundproofing your home step by step. 

Soundproofing paint

Soundproofing paint can go a long way in reducing the noises that come into your spaces by providing a thick layer of specially designed materials that are absent in traditional paint. 

It can prove taxing to apply – it is a very thick, very heavy paint that requires up to three layers for the sound dampening to take effect. 

However, when combined with other methods like acoustic panels and soundproofing foam, it can be very effective. 

Fiberglass paneling

Fiberglass as a soundproofing method is mostly used in house and building construction since it is a very good insulator for both temperature and noise. 

For soundproofing your home, you can use fiberglass in the form of wood panels or in the shape of square wall paneling similar to polyurethane foam acoustic panels. 

Fiberglass is a little bit pricier than other methods, but it is highly effective when it comes to reducing both high and low frequencies. 

Mass loaded vinyl

What mass loaded vinyl does is absorb sound and reduce external noises by significantly diminishing the incoming vibrations. 

This material can be applied to walls and machinery alike, making a great choice for quieting down your car. 

It’s a great option for home theaters, music studios, and offices that need to improve the acoustics of the space. 

What we can take from this is that while insulation spray foam is no the best soundproofing material out there for your needs, it can perform well when accompanied by more effective methods.

If you want to properly soundproof your home or your workspace, don’t worry. There is a large number of options to choose from when it comes to getting the peace and quiet you need.