Insulation | Does it Help With Sound?

When you think of insulating your home, the first thing that often comes to mind is keeping the heat in and the cold out. However, insulation also provides the added benefit of reducing the noise levels within your home.

Insulation acts as a barrier between the inside and outside of a house, which allows you to escape the hustle and bustle of the busy roads outside, as well as keep on good terms with your neighbors when you have a crowd over for celebrations.

Insulation can help to reduce the transfer of sound through walls, ceilings, and floors by absorbing the sound waves and reducing resonance and amplification. The best insulations for this are open-cell mineral wool or fiberglass, which reduce sounds by 45 dB and 39dB, respectively.

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Insulation Provides Noise Absorption

I stayed in a B&B for a stretch when I was in university. It was a converted home, and I found out the hard way that they had put up walls as room divisions only; there was no insulation to speak of.

The man next door snored so loudly, and the wall was so thin that I had to pull my bed away from the shared wall because it was vibrating with the sound waves. A little bit of insulation would have helped because it acts as a noise absorber.

For the most part, insulation is fluffy or foamy, absorbing the sound wave energy instead of passing it on.

The fluffy or foamy nature of insulation material means that it absorbs the sound wave energy that it receives from the noise or vibrations around it, discontinuing the reflection and transferal of the sound waves to the next room.

Resonance and Amplification Reduced by Insulation

In addition to absorption, insulation reduces the resonance and amplification of the sound waves.

This means that not only will fewer sound waves pass through the material, but those that do pass through will also be smaller, which means that the noise is softer and less high-pitched.

The thickness of the insulation as well as the density will affect this due to the ability of the insulation material to dampen the sound and absorb the frequencies and vibrations.

Girl sleeping well in the left room due to the insulation in the wall while the guy in the right room is playing a guitar loudly

What Affects Insulation-Related Sound Reduction

R-Value

The R-value informs a person of the efficiency with which a type of insulation retains heat within your home or prevents it from entering your home.

The inherent values differ according to the type of insulation, and the greater the R-value, the less heat is able to pass through.

The same is also true for sound, although this is a secondary function of insulation. A higher R-value means that less sound can be transferred through the walls.

Thickness

Another factor that influences how well your insulation can reduce sound is the thickness of the insulation material itself.

The thicker the insulation, the more material there is to absorb the sound energy before it reaches the other side, and the less likely it will travel out of the room.

Experts suggest that your insulation should be around 1/2″ thick for maximum effects.

Age of the Insulation

The great thing about insulation is that, when installed correctly by a professional, you really should never have to re-install the insulation at all while you stay in the home.

However, with age, it can still start to naturally compress down or wear down or move to expose certain areas. In addition, water and mechanical damage will make it less effective.

As the effectivity of the insulation material decreases, so too does its ability to reduce sound transfer because the density, thickness, composition, and coverage are compromised.

Type of Insulation

Not every kind of insulation can reduce noise levels to the same extent. In reality, some insulation methods simply reflect heat (radiant insulation) and do little to reduce sound.

If you want to limit noise transfer, then a good option is spray foam insulation, which can reduce the sound by approximately 30 dB.

Man-in-PPE-spraying-foam-insulation-on-roof-frame

Cellulose insulation can reduce noise by 44 dB, and mineral wool can reduce sound by 45 dB.

Often, batt insulation (especially fiberglass) is used when wanting to reduce noise, as it is the appropriate thickness and density to absorb the sound waves and vibrations of the noise. You can expect fiberglass to reduce the rate of noise by 39 dB.

What Insulation Is Best at Reducing Sound Transfer?

If you want to get the best possible option for reducing the transfer or sound within your home or building, then it is better to opt for open-cell cavity insulation, such as insulation made from mineral wool or fiberglass.

This type of insulation is created to fit tightly between wall studs, ceilings, and floors and makes use of absorption principles to reduce sound transfer. The insulation will fill the airspaces in these areas, and so the transmission of sounds can be reduced significantly.

Not Truly Soundproof

While insulation can definitely help with reducing the noise that travels throughout your home, it is not truly soundproof. Soundproof materials have to be competent in reducing the sound pressure of a medium. Proper soundproofing leads to a reduction of decibels (dB) or absorption of sound.

Insulation may not be completely soundproof as the total number of decibels does not reduce by much. It is perfect for preventing private conversations from being heard through walls.

However, if you are a musician or work in video and have a home recording studio, it is unlikely that the insulation will provide enough soundproofing to get your work done. If you are in this situation, you may have to invest in official soundproofing methods, installed by professionals.