Soundproofing Spray Foam: Does Spray Foam Insulation Reduce Noise?

Soundproofing Spray foam, also known as spray foam insulation or polyurethane foam, is a type of expanding foam that’s mainly used for insulation with soundproofing as a secondary advantage.

In this guide, we shall be looking at the different types of spray foam, how they work, as well as their effectiveness regarding noise reduction.

Let’s get started:

What is Soundproofing Spray Foam?

There are two types of spray foam insulation- closed and open-cell polyurethane.

The two materials are made of two components that mix when sprayed to walls or cavities and expand before hardening.

The two materials that foam spray foam are polyol resin and isocyanate resin that react when mixed together and expand up to 30-60 times when sprayed in place. (Source)

Spray foam gives a high thermal insulation value and virtually no air infiltration- a characteristic that facilitates its noise reduction properties.

Besides thermal insulation, soundproofing spray foam insulation is also used to reduce noise.

It acts as a barrier to airborne noise and significantly reduces airborne noise transfer through a building’s floor, walls, rooms compared to an uninsulated building.

Spray foam insulation is of two types:

  • Open-cell spray foam insulation
  • Closed-cell spray foam insulation

Open-cell spray foam is brittle and can be easily crushed in your hand. This product also has a lower insulation value.

On the other hand, closed-cell insulation is quite rigid to the touch since every single air cell is completely sealed.

It has a high R-value and also more expensive than open-cell spray foam.

Open Cell Spray Foam

It’s also known as half-pound foam.

It’s semi-rigid with a sponge-like appearance and expands during application to create small open cells filled with carbon dioxide.

The material is perfect for filling cracks, voids, crevices and adheres to substrates and irregular surfaces to form airtight sealing insulation.

It has a thermal resistance value (R) of 3.8 per inch, and when installed at 5.5 inches or more, it acts as an air barrier.

It’s not a vapor barrier and hence only recommended for indoor applications.

Closed-cell Spray Foam

Also known as 2lb foam, this is a rigid insulating material with a higher thermal resistance ranging between 5.1-6 per inch.

With a minimum of 50mm installed, this product acts as both an air barrier and vapor barrier.

Does Spray Foam Work for Soundproofing?

Yes!

Spray foam does work for soundproofing.

The product not only help in noise reduction, but it also helps cut energy bills by significantly improving your home’s energy efficiency.

We’ve seen that upon application, spray foam expands to fill even the smallest of the gaps before setting down to form a protective seal around your house.

Soundproofing Spray Foam: Does Spray Foam Insulation Reduce Noise?

Below is a simple illustration of how foam insulation improves the Standard Transmission Class (STC) of a 2”by4” wall with ½ “ gypsum/drywall on both sides.

Insulation Thickness NRC STC
Open Cell Polyurethane 3” 0.70 37-39
Closed Cell Polyurethane 2.75” 0.70 36

 

This hardened protective structure locks in heat while at the same time it’s sound deadening abilities block outside noise from entering your home too.

You can use it to soundproof the ceiling, walls floors, and it’s a good solution for anyone negatively affected by noise pollution.

What Are the Benefits of Soundproofing Spray Foam?

Spray foam fills walls, voids, and cracks; this helps curb resonance, keeping sounds from leaking in or outside the room/space.

It also helps reduce noise generated inside wall spaces caused by clanging pipes, flushing toilets, and other miscellaneous utilities.

Other benefits include:

  • Promotes a peaceful and restful quiet home environment
  • It can be applied on walls, ceilings, floorboards, and lofts
  • Reduces energy bills by locking warmth inside the home

Soundproofing Spray Foam for Existing Walls/ Ceiling?

Spray foam insulation is quite effective in soundproofing existing walls.

But here’s the catch.

You have to get rid of the existing drywall before you can apply the foam.

This is because spray foam expands 30-60 times when applied to the inside of walls.

Adding the insulation without removing the drywall could overfill the panel, exerting immense pressure to the plasterboard.

As a result, drywall can break or crack.

You can remove the drywall yourself, but this is a time-consuming and messy activity; hence, I recommend hiring a professional to do it for you.

If that sounds like a time-consuming DIY activity for you, then I would recommend you read this guide on soundproofing walls without removing drywall.

Spray foam is also great for ceiling soundproofing.

However, just like in the case with walls, you will need to remove the drywall before adding the foam.

Soundproofing Spray Foam Alternatives

Even though spray polyurethane foam has become a popular form of home insulation in the USA, it still poses an adverse health risk when poorly installed.

According to an article published on National Library of Medicine, faulty application of spray foam insulation in residential homes saw people experience chest tightness, throat irritation, skin rashes, insomnia, etc. (Source)

If you’re worried that anyone in your home with an allergy condition or existing health problem could be affected by SPF, then I would recommend you to try these alternatives.

Fiberglass Insulation

Fiberglass is an excellent thermal insulator as well as a sound absorber.

It’s important to note that fiberglass doesn’t block sound but instead absorbs it.

By sound absorption, I mean that you won’t get echoes or reverbs in a room where it’s installed- you get better audio quality.

For this reason, I would recommend adding fiberglass insulation in rooms where you need thermal insulation coupled with acoustic treatment, such as home theater, TV room, or your drum room.

Blow-In Insulation

Blow-in insulation is another great alternative to soundproofing spray foam.

And just like the fiberglass above, this material doesn’t block noise like mass-loaded vinyl soundproofing, but instead, it absorbs sound.

It requires a specialized blowing machine that can be rented from the dealers who sell this type of insulation.

One of the most recommended blow-in insulation is U.S. GREENFIBER LLC INS541LD Fiber Insul.

Stone Wool

This product is available in battens and insulating boards, and it’s ideal for noise reduction compared to spray foams.

A perfect example is Rockwool Acoustic Mineral Wool Insulation, which is used as a soundproofing material and water-repelling and fireproofing material.

On Soundproofing Spray Foam

Soundproofing Spray foam kills two birds with one stone.

It thermally insulates a house while at the same time acoustically treat it.

While spray foam’s main focus is thermal insulation, you may need to consider complementing it with other soundproofing techniques.

For example, adding a layer of Quietrock drywall after spraying the foam could significantly improve the acoustics of your home.

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