What Type Of Insulation Is Best For Soundproofing?

DISCLOSURE: This post may contain affiliate links, so if you buy any products featured on this site I may earn an affiliate commission. As an Amazon Associate I earn from qualifying purchases.

To achieve the best soundproofing results, you need the right materials. You may mistake soundproofing as sound absorption and, yes, while this is a key element, there are other ways to soundproof different spaces.

You can add layers of soundproofing materials to new or existing walls to block sound entering or leaving. However, some materials are more efficient than others. 

What Type Of Insulation Is Best For Soundproofing

To effectively soundproof something, you must trap the sound, not stop it from existing. Proper soundproofing involves trapping sound outside a certain area and keeping sounds inside an area, you guessed it, inside.

When looking to soundproof any space, you must consider the best material available to achieve the best sound-dampening results.

The good news is that there are many different materials available on the market and today and we are going to discuss the best for you to use.

If you’re in a hurry, the best materials on our list today are:

  • Fiberglass
  • Mineral wool
  • Spray foam insulation
  • Foam board
  • Blown-in cellulose

Let’s take a closer look at each material to see what they offer and if they are right for what you need.

Best insulation materials for soundproofing


Fiberglass is a popular choice when it comes to soundproofing in different areas. This material is made from melted plastic that is spun into wool. It is then reinforced with very small fibers of glass.

This porous material traps air to help keep a room warm or cool. This depends on the season and the temperatures of the space. As well as keeping you cozy or cool, fiberglass absorbs airborne sound similar to our next material, mineral wool. 

Mineral wool

Mineral wool is another spun fiber but this time it is made from molten igneous stone or, on occasions, slag. This material is completely incombustible meaning it is fireproof and can not be burned.

It also doesn’t absorb any water making it a safe option for soundproofing rooms around your home.

Mineral wool is a porous and dense material that is very effective at slowing down the rate of temperatures through walls, ceilings, and floors. As with fiberglass, mineral wool can also absorb airborne and impact sounds and vibrations.

Spray foam insulation 

Next up is spray foam, a polyurethane foam spray that works as a thermal barrier and is effective at minimizing air movement. Spray foam is excellent at keeping the heat or cold temperatures in or outside of a room.

Internal wall insulation

However, it is not as good when acting as a sound absorber.

Nonetheless, sound control spray foam is available to block different sounds. This can be applied to post-construction walls.

Foam board

Made from extruded polystyrene, foam boards are available in blue or pink colors. Why these colors? Well, they are simply there to represent the different manufacturers.

These are board rigid and have an insulating factor of R5 per inch of thickness. This “R-value” is a measure of how well a two-dimensional barrier like insulation resists certain levels of heat.

Polystyrene boards can be very effective in reducing the transfer of sound. They work best by muffling sounds inside and outside of spaces by decoupling the layers of the boards. 

However, expanded polystyrene foam panels are not so good at insulating rooms. They tend to be more fragile making them a less popular choice in construction. Polyisocyanurate or ISO panels are better insulators than these blue or pink panels but, in general, are more expensive.

Blown-in cellulose

This cellulose insulation is typically made up of 75% to 85% recycled fiber from paper. The remaining 15% to 25% is then constructed from a fire retardant material. 

Blown in cellulose

If the fibers are loosely packed, they become better at dampening and absorbing sounds. Most of the time, blown-in cellulose is added to post-construction partition walls and is deemed to be much easier to install as well as more cost-effective than other materials. 

Different types of soundproofing

Although there is one goal with soundproofing (to block or dampen sounds from entering or leaving a space), there are different methods to achieve such results.

To improve the sound rating of your home during the construction stage, you can use the following methods individually but the best results are when they are combined:

  • Sound absorbing – This is when materials are used to absorb sound. They reduce or prevent noises from bouncing off walls and entering another room or traveling through barriers. These are generally lightweight and porous materials that effectively trap soundwaves.
  • Sound dampening – This reduces or prevents vibrations from carrying through walls, floors, or ceilings.
  • Sound blocking – Using thick, hard, or heavy sound blockers, these materials can prevent or reduce the transmission of noise through walls, floors, and ceilings. Their sheer mass manages to reflect sound and prevents it from entering or leaving a space.
  • Sound decoupling – This construction method decouples or separates one side of a wall from the other. Using double or staggered stud framing and isolation clips or channels are effective ways of preventing the transference of sound from one room to another.