Best Insulation for Soundproofing Walls [2024]

With so many soundproofing materials available today, you may be wondering which one offers the best insulation for soundproofing your walls

Well, look no further as we lay it all out in this guide. 

Think about why you are soundproofing. Is it because you want to drown out noises from outside or are you trying to amplify sound within your rooms such as a home theatre?

Only when you answer this question will you be able to choose the correct material that will meet your demands. 

The difference here is that some of the materials are thick and heavy for better soundproofing to drown out noise while others are soft and porous for improving sound quality in a room.




The best insulation for soundproofing walls

The Owens Corning 703 is the most commonly used panel and consists of inorganic glass fibers.

This is due to its affordability, weight, resilience and easy to handle nature.

They are the most eco-friendly option since they reduce heat transfer which leads to lower operating costs.

Aside from that, they improve the acoustics of a room when installed properly.

The 703 features a polymer film which improves its fire and moisture resistance.

You get them in packs of 6 measuring 24×48 and are 2-inch thick which covers a total area of 48 square feet.

Boasted as the best insulation for soundproofing walls, Rockwool mineral wool comes in 48 x 24” no matter which density you choose.

With a high NRC rate of 0.8, this acoustic insulation product was created to block out additional sounds. 

That means it can block out up to 80% of airborne frequencies.

It is excellent for blocking out high-frequency noises rather than low ones.

Apart from its fantastic soundproofing properties, the Rockwool is hydrophobic and has a Class A fire rating.

In other words, it repels water and protects homes in the event of a fire.

The insulation panels have an NRC of 1 to block out 100 percent of sounds in the air for sound deadening insulation.

With increased mass and decreased structural vibrations, The Auralex insulator was designed for acoustical usage.

Mineral fibers are fire-resistant so this particular insulator has Grade A flame retardancy rating. 

Measuring at 48×24”, they come in packs of six at 2 inches thick or packs of 3 for the thicker panels.

The 2-inch panels cover a total area of 48 square feet and the thicker panels cover 24 square feet.

The main advantage of using cellulose is that it is usually made from renewable, recyclable or recycled material.

This is perfect if you are someone who loves to protect the environment and at the same time, insulate your room.

You will find cellulose insulation products that they are easier to work with.

They are easier to cut because of the fabric material used in production which does not contaminate the air when being handled. 

The NRC rating for this product is 1.06-1.18 against frequency racing between 500 to 4000 Hz with a class A fire rating.

If you are looking for a faster and more convenient way to soundproof your room, look no further than the Foam It Spray Foam.

This foam spray is a closed-cell sprayer that insulates in just seconds.

The insulation kit comes with everything you need including the pressurized spray canisters to a Tyvek suit. 

The entire contents of the kit weigh a whopping 120 pounds. 

The green foam is derived when you mix the blue and yellow components. 

Once you have a light green hue, that means that you did it right and the foam is ready to be installed.

The mold is anti-microbial and is considered a Class I E- 84 fire retardant.

Types of soundproof insulation

Now you are probably wondering how you will know what type of insulation is best for soundproofing. 

Stay with me as I explain the selection criteria and how each soundproof insulation works. 

Let’s take a look at the selection criteria first. 

Here is a list of some things to take into consideration to choose the right soundproofing material.

Sound Transmission Class

STC is a number given to a material to measure its ability to block sound waves. 

The higher the STC rating the higher the chances of blocking out or reducing sounds are.

Noise Reduction Coefficient (NRC)

In addition to a high STC rated material, you will also need better sound-absorbing materials.

These sound-absorbing materials reduce the echoes generated in the house. 

NRC measures the amount of sound the material absorbs to absorb or minimize noise reflection.

R-Value of Insulation 

The R here stands for the resistance of heat and sound waves.

A high R-value means less heat and sound will flow through the wall.

Let us now move on to the types of soundproof installation. They are all listed below.

Batt Insulation

Batt insulation comes in rolls or panels wide enough to fit in the space between wooden studs in your walls, ceilings and floors. 

Don’t worry if you have narrow spaces between the walls. You will be able to find ones that fit.

Batt insulation offers a blanket type insulation and is commonly made from fiberglass.

 Fiberglass is pretty stiff, durable and fire-resistant. 

If for any reason you need to cut the fiberglass, wear protective gear to protect your face and use a saw or serrated edge knife.

This type of insulation material can also be made from different materials like natural and synthetic fibers.

One such is cotton batts which are derived from recycled clothing scrap for an eco- friendly option. Though not as fire-resistant as fiberglass and cellulose, they trap sound better. 

Foam Spray Insulation

Foam spray insulation is the perfect match for any spaces around and between obstructions on your wall. 

Since it will be hard to cut material to fit an odd space, the polyurethane foam gets the job done without fuss. 

It will provide a great option to fill cracks and crevices in your wall without taking it apart.

It is advisable to use the liquid foam insulation that comes in small spray canisters. 

A slow curling liquid foam is better since it catches all the little nooks and cranny before it hardens

However, if you need to cover a large area, you will need a pressure sprayer to cover the area effectively. 

Both these applications use a different foam formula so choose based on your needs.

Once sprayed on, they both expand to fill the crack and harden to insulate your wall fully.

The major drawback to using this type of insulation is that it does not have a thermal barrier. 

You may have to install a fire-resistant material on top of the hardened foam if you are required to.

Blown Insulation

Blown insulation looks like foam insulation when you first look at it. 

Upon closer inspection, you will see that the structure is a bit looser.

Similar to foam insulation, it works to fill any irregularly shaped spaces in pre-existing walls.

It falls somewhere in the middle of batt insulation and foam insulation.

Mimicking the foam insulation which is sprayed on, blown insulation as the name suggests is blown or poured into the area which you want to be covered.

On the other hand, it comes in chunks instead of rolls and panels but is made from the same materials as some batt insulation.

It can either be fiberglass, mineral rock or cellulose.

Insulation Boards and Panels

All the other types of insulation mentioned before focused on insulating an interior wall.

Let us now take a look at what can be used on the exterior of a wall.

Insulation boards and panels are meant to be used on exterior walls but can be used on interior walls as well.

These are primarily made from polystyrene commonly known as styrofoam, polyisocyanurate, polyurethane foam.

With a wide range of applications due to the sturdy nature of these materials, you can use them almost anywhere. 

Despite being light and thin, they offer some pretty decent insulation properties.

For fire safety, it is recommended to cover your foam board with some sort of fire-resistant material like a half-inch gypsum board.

If you are using an exterior wall then you would need a board or material that offers protection from the weather. 

Living room with sound deadening insulation

How to install soundproofing insulation

Given the different types of material and how to go about choosing which one is best, now you may want to know how to install it.

Follow me as I take you through to give you a better understanding to install soundproofing insulation.

1. Prep the room

If you are doing walls in a room that is already built and being used, you will need to remove everything from the room.

If you are doing one wall only, you may be able to move everything to the other corner of the room and cover it with a tarp.

Note that if you are insulating a newly built room, the easier things will be for you.

With the room now cleared, you can go ahead and remove the drywall.

In some instances, you may reach the wooden construction in the wall without removing the drywall.

 If that is the case, you can move on to the next step.

2. Measure 

Nothing is worse than purchasing something only to realize it is not the size you require.

Measure the wall that needs insulation before you rush out to buy any material.

One way to get precise measurements is to calculate the height of the wall, the width between the vertical studs and the number of hollow slots between the studs.

You will find that most batt insulation products should fit perfectly between the vertical studs.

Keep in mind that you need to make a note of where electrical boxes are located as well as wires and how much space they take up so you can customize your batt insulation to fit.

Using that calculation method will also tell you how much insulation material you need.

This method works for any type of batt insulation whether it’s fiberglass, cotton, mineral wool or cellulose.

3. Protect Yourself 

Handling and installing insulation can be a messy and sometimes risky task. 

Practice safety with these few steps to avoid accidents when insulating your walls.

First off you need to cover up your arms and legs fully to protect your skin in case it reacts to the materials you’re working with.

Wear clothing that you don’t need anymore and won’t mind getting dirty.

Secondly, you need some protective gear for your face and hands.  

Wear a face shield or goggles and gloves to protect your airways, eyes and hands.

Gear up when installing soundproofing insulation

4. Customizing the Insulation

Sometimes you may have to cut the insulation to fit since no 2 walls are alike. 

No much cutting should be required but if you have to, use a good utility knife to get the job done.

Only handle and cut your insulation products while you’re fully protected with all your protective gear.

5. Installing the Insulator

Now that we have followed all these steps to prep the room and protect ourselves, the time has come to actually install the insulation product. 

You may need some help with this part for faster and better installation.

If your insulation product has a  front and backside, push it with the face pointing towards you.

Push the batt insulation between the studs and use a staple gun to attach the insulation to the wooden studs.

Remember to move the material around, twisting and turning it to ensure it fills out the entire space. 

6. Cover It Back Up

After installing the insulator, you now have to put back the drywall.

At this point, you may use your old drywall or opt for some new ones.

You can choose to buy a new one especially if you are doing a kitchen wall, you can now place fire-resistant drywall for added fire protection.

If it is a bathroom wall, then moisture-resistant drywall will work best so no mold or mildew here.

To boost the sound blocking properties of your insulation, you can place a layer of Mass Loaded Vinyl over your insulation product. 

All you do is nail it to the wall stud and tape the separate pieces together. 

Or you can use resilient channels to lessen the transmission of noise. 

Resilient channels are metal rails that separate the inner structure of the wall from the outer structure, the drywall.

For another option, you can double up on the drywall as well to minimize the transmission of sounds.

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