Can You Use Polystyrene For Soundproofing?

Can polystyrene be used for soundproofing? 

Polystyrene can be used for soundproofing. It is a very unique and versatile material that can be molded into virtually any shape. It is also a very powerful tool for soundproofing your house, studios, conference rooms, etc.  

Whether you want to sing out loud in the shower or prevent your neighbors from eavesdropping, soundproofing is desired not just for eliminating unnecessary noise pollution but also for much-needed privacy.

Polystyrene like Styrofoam has been getting a lot of recognition for its powerful soundproofing utility. 

Here is everything you need to know about the soundproofing qualities of polystyrene so that you can make an informed decision. 

What is soundproofing? 

• Stopping the travel of sound with a barrier material able to deflect or absorb the sound

Sound can penetrate through solids, but you should know there is a way to prevent this and it is called soundproofing. The goal is to minimize unnecessary noise from your room, house, or general environment.  

There are several methods through which proper soundproofing can be implemented, and it all comes down to how much you wish to block out.

There are also many high-quality soundproofing materials available in the market like  egg crate foam tiles, for example.

However, it must be understood that different products come with its share of advantages and disadvantages.  

Quieter noises can be adequately controlled through sound absorbers, whereas noises of higher levels will require more drastic measures. Soundproofing can not only be beneficial for your walls, but also for your ceilings and floors as well. Besides, you will be making your own contribution to making the planet a quieter place.  

Soundproofing Vs. absorption 

Soundproofing means obstructing sound from going in or out from space with the help of absorption and noise reduction.

Read more about double pane and triple pane window in my previous article here (add your link).

It often includes layering materials to absorb or reflect soundwaves and minimize its transmission. The materials used absorb sound and convert it to heat which lessens the amount of noise that passes through, adequately reducing the amount of noise. 

Soundwaves advance through the air until they are absorbed or reflected by a barrier. The features of the material you use will determine how it interacts with the noise.  

Extruded Polystyrene Insulation (XPS) 

The pink or blue Extruded Polystyrene foam (XPS) that we commonly see are used in the construction industry. These insulators are strong and impact resistant. It has a smooth surface and stays impenetrable to moisture.  

XPS is produced using polystyrene beads which is heated and mixed and then pushed out to manifest an uninterrupted stream of foam that solidifies as it comes in contact with air. This is followed by trimming of the stream and then cutting into smooth-surfaced thermal panels that are rigid and durable.  

Expanded Polystyrene Insulation (EPS) 

Expanded Polystyrene (EPS) works as an adequate thermal barrier, but if used solely, it is not an appropriate sound barrier. Even though it possesses sound absorbing properties, it doesn’t have adequate mass so it won’t be appropriate as an adequate acoustic panel for you to hang on your wall. 

However, if you use it in conjunction with other materials, EPS can serve as a very powerful sound barrier. It possesses different characteristics that are effective when used in wall construction to prevent the transmission of sound. 

Is Polystyrene a Good Choice for Soundproofing? 

• Only if you add other soundproofing material with it

You will find many written content on the internet that claims polystyrene is not a good choice for soundproofing. Some reviews even say it sucks. 

They try to hang it on their walls as it is lightweight and expect it to diffuse or absorb sound.

This, however, indicates that they are not properly implementing the principles of soundproofing.  

Soundproofing has four elements to it. They are namely absorbing, adding mass, damping sound, and decoupling.

There are characteristics of polystyrene that make it an excellent thermal insulator like stone wool and fiberglass. However, it does not have enough mass to be able to absorb sound.  

EPS, on the other hand, has commendable absorbing and decoupling characteristics that make it a good choice for soundproofing.  

When you use polystyrene on wall constructions, it will help to muffle and even reduce the transfer of sound through the walls. The material works to decouple the layers on the wall while reflecting and absorbing the sound waves.  

Overall, it decreases the degree of transmission through the barrier. It works better in minimizing sounds that have mid to high-frequency range because of the simple fact that it lacks the mass to absorb the lower frequencies.  

Can Polystyrene Absorb Sound? 

• yes but only to a small degree (not enough to be used for soundproofing)

The same properties that make polystyrene an effective thermal insulator is the same reason why it is a good sound insulator.

However, EPS lacks the necessary mass that would have made it a good sound blocker.

That said, if you attach it to MDF, concrete, or drywall, it performs excellently well at blocking the transfer of sound. 

If you use it on regular interior wall construction and polystyrene will increase the rating of STC to over 40.

In case the construction of the wall has  Green Glue  or loaded vinyl, using EPS can dramatically improve the same wall to over 50 STC.

In short, polystyrene can absorb and decouple to prevent the movement of sound.  

Sound Absorption Coefficient 

If you want to identify how effective material can be at absorbing or blocking sound, you can refer to the Noise Reduction Coefficient (NRC) and Sound Transmission Class (STC) values. You can measure NRC between a scale of 0.0 to 1.0.

This measurement shows the average control of noise between the frequencies 125 Hz to 4,000 Hz.

Its ability to absorb or block sound is influenced by the density and thickness of the material.  

Polystyrene is basically a lightweight building material that is not very dense. At its best, polystyrene has a sound absorption rate of 0.20.  

EPS is most effective when you use it along with other materials and in itself performs better at attenuation of mid-upper sound frequency.

The NRC of polystyrene 25 is 0.59 at a sound frequency of 2500. It may be noted that its low-frequency performance is not very good.  

Practical Uses of Polystyrene 

You can improve the soundproofing capability of your home by attaching  polystyrene  soundproof materials on wall constructions.

If you want better performance out of it, you can combine it with other materials to increase the decoupling barrier capacity and become a better sound absorber. It performs better when you pair it with other materials.  

Door and Window Plugs 

If you want to soundproof a media room, office, or recording studio, you can make a plug.

This will help to increase the sound abatement of a door or window. Besides being an excellent material for decoupling doors and window plugs, polystyrene is also resistant to mildew and moisture as well as being lightweight.

If you want to effectively soundproof an interior space, you can attach it to MDF frames or panels.  

Structured Insulated Panels 

SIPs are actually made to be used in the building industry. These are made in highly controlled areas from panels of polystyrene that are sandwiched between two OSB layers.

ESP prevents the transfer of sound, decouples the layers of a wall while also providing thermal insulation. As for the OSB, it offers rigidity to the framework.  

Sound Diffusers 

Polystyrene is molded into different shaped acoustic sound diffusers. You can use them as wall panels, ceiling or even ceiling tiles in order to diffuse sound frequencies that range between 600 Hz to 5,000 Hz. 

These materials help to disperse and break up soundwaves in order to reduce reflection. One cool thing about this mechanism is that it absorbs the sounds waves and converts them into heat! 

Other alternatives for soundproofing 

Besides polystyrene, you can find other soundproofing alternatives that are denser and heavier and has more mass, thereby performing better when handling low-frequency sounds.  

Fiberglass Insulation

This is an insulation material meant for constructions.

It is available in rigid panels and batts. It has an NRC rating of 0.85 to 1.05 and can significantly improve a wall’s STC. 

You can use the batts on walls, but the materials are not as rigid as the other products in the market.

A more rigid option is the  Owens Cornings 700  which can be hung or wrapped as acoustic panels or can be directly attached to walls.  

Roxul

Stone Wool is used a lot in sound-absorbing panels. This popular construction insulation is available in  rigid panels  and battens.

Its NRC is between 0.85 – 1.05 and can improve the quality of sound when used on walls or hung as acoustic panels.

Using these stone wools a tremendously increase a wall’s STC to an impressive 52 or above.  

Bottom Line 

Polystyrene works as a great thermal insulator. However, it is too lightweight to be able to perform independently as an effective material for soundproofing.

It does perform really well when used in conjunction with other materials.

You can find a lot of options in the market that suits your requirement.  

I hope this article is able to provide the information that you were looking for.