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Does Styrofoam Absorb Sound?

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If you are looking for a way of soundproofing a room inside your home, you may be wondering whether styrofoam is a worthy option. Of course, any material that is used as a soundproofing solution must be effective in absorbing sound.


Although styrofoam possesses impressive soundproofing properties and will dampen noise when used with other, denser materials, when used alone, it will not completely absorb sound.

For this reason, you will likely find that attempting to soundproof an entire room with styrofoam will prove insufficient in catering to your needs. 

What is styrofoam?

Styrofoam is a type of closed-cell polystyrene foam that is often installed as insulation in walls, foundations, and roofs. It is a trademarked product that can be used for craft purposes. It’s lightweight, durable, and has thermal qualities, similar to fiberglass. 

Despite its initial uses as an insulating material, many people now use styrofoam as a way of muffling sounds that are a potential disturbance. It’s also pretty effective in absorbing shock.

What is sound absorption?

To determine whether a material can successfully absorb sound, you must have a clear understanding of what you are expecting it to do. Sound absorption essentially describes how well a material or object takes in and controls sound energy when it comes into contact with sound waves.

Some of this energy is then converted into heat. The fewer waves that pass through, the more effective the material is going to be in absorbing sound. 

The STC (sound transmission class) and the noise reduction coefficient (NRC) are used to identify the effectiveness of a material in absorbing sound. There are several factors that are going to influence how well a material absorbs or blocks sound.

For example, thickness and density are the most prominent factors. Styrofoam isn’t very dense and is quite lightweight. Because of this, it isn’t going to have a very strong shock-absorbing effect. 

We have listed the other factors that determine how good a material is at absorbing sound below. 

The mass of the material is perhaps one of the most important factors to consider when discussing sound absorbency.

Often, depending on the material that you use, you will need to thicken it up to enhance its effectiveness. There are also some materials that are rather soft but are good at muffling the intensity of the sound.  

The characteristics of styrofoam

As touched upon, styrofoam is lightweight and has a relatively low NRC and STC rating. Aside from this, styrofoam is also pretty tough which means that it lacks flexibility.

On the other hand, the toughness can be considered a favorable feature as it is going to be pretty easy to cut to the desired size and it is also going to be pretty resistant to damage.

It is also worth noting that styrofoam is a flammable material, so you will need to be cautious regarding where it is installed. 

What are the practical uses of styrofoam?

When installed behind concrete, MDF, or drywall, styrofoam is a very good sound absorber. In fact, when used in conjunction with certain materials you will notice that the STC rating increases quite dramatically. 

This type of insulation is typically added to inside walls and is available in several varieties.

For example, it can be purchased in a spray version which is handy for those who simply need it to fill in gaps that sound is prone to traveling through.

Of course, the spray varieties aren’t going to compare to styrofoam panels in terms of how well they help to block out the noise, but will most likely suffice on a small scale.

It can also be used for layering windows to block the noise from the outside. Furthermore, it can also come in shapes and diffusers which are ideal for those that need to muffle sound that travels through the ceiling. 

Are there alternatives to styrofoam?

As we have covered, styrofoam isn’t the best sound absorbing material available and is only really successful in its purpose when used alongside other materials. For this reason, you may be wondering whether there are other, possibly better, alternatives out there. 

There are certain panels available that are specifically designed to soundproof a room and absorb the sound. Another option is fiberglass. This type of insulation will absorb sound, ultimately helping to reduce the noise.

Although it will not be 100% effective in absorbing the sound, in comparison to many other material options, it is one of the best. Furthermore, it can also be used in ceilings, walls, and floors. 

If you do not feel that styrofoam is going to absorb the sound in the room to the level that you would like, you may wish to opt for one of these alternatives. Even when used alone they absorb and reduce noise levels very well.