Soundproofing: Insulating for noise reduction

Noise from industrial environments and busy cities can make its way into your home and building structures, but it can be reduced with insulation. However, all insulation types do not help with noise reduction. For example, van insulation does a poor job at soundproofing because it is lightweight, and mass is needed for proper sound blocking and absorption. 

The sounds we hear are just vibrations (mechanical waves) that can travel through any medium (gas, liquids, or solids). Sound waves move equally in all directions from the source, just like water ripples. Sound can be described in two ways: level (what we interpret as loudness) and frequency. Level is measured in decibels (dB) and describes how loud something is (or how much sound there is). Frequency is the pitch of a sound and is measured in “Hertz” (Hz), also known as cycles per second. Noise can usually be differentiated by frequency into three categories, high frequency (usually described as a hissing sound, 1000Hz-8000Hz), mid-frequency (a roaring sound, 125Hz-500Hz) and low frequency (rumble, 31Hz-63Hz). In environments where ambient noise exceeds 85 dB, hearing protection is required to reduce potential long-term hearing loss.

In industrial environments, the two main types of sound control are sound absorption and sound transmission. Sound absorption is used to reduce echoing in environments where hard and flat surfaces reflect sound. The Noise Reduction Coefficient, or NRC, is a value of how much sound a material can absorb. Generally speaking, a product with an NRC value of 0.5 can absorb 50% of the sound that strikes its surface and will reflect the remaining 50%, while a product with an NRC value of 0.75 will absorb 75% of a sound and reflect the other 25%. The ability of a material to block sound is measured by the Sound Transmission Class (STC) rating. 


The best sound absorption and transmission materials are products made from open-cell materials like Prodex Total 10M or Prodex Total 5M plus. The structure in these materials dissipates sound by absorbing the sound waves and then transmitting them into small amounts of inaudible energy. When there is too much sound present in a wall or pipe, adding weight and thickness to it can help lessen the amount of sound that travels through that medium. That means the best solution for noise reduction is thick and heavy insulation.

Soundproofing insulation

Soundproofing insulation should be installed during construction or remodeling because it needs to be installed in the walls and around the wall framing. An effective and affordable way to soundproof a room is to put batt or blanket insulation between studs or joists. Fiberglass or rock wool batts are made specifically for this purpose because they are both excellent at absorbing sound that would otherwise travel through the air. If you want to insulate and soundproof your walls post-construction, you may opt for diy spray foam insulation. It is fairly easy to install and with the added benefit of open-cell spray foam, you will have better soundproofing as well. Most American homes and buildings have cavity walls that are hollow on the inside and are usually filled with insulation. In order to cut down on cost and speed up the building process, most American houses don't have two layers of brick with insulation in the middle but are prefab built. That means that they are made in factories to be constructed on-site.

Soundproof insulation for walls

When it comes to wall insulation, the main purpose is to make the inside of a room more thermally insulated. However, several insulations have the added benefit of providing soundproofing, some better than others. Some insulation is even made with soundproofing in mind. Some of the best soundproofing insulation are: acoustic insulation and Prodex Total 5M. Both of these are open-cell insulations, and as mentioned before, open-cell insulation is among the best for soundproofing.

How to Soundproof a ceiling and floor construction

The first thing you’ll have to do when preparing for wall, floor, ceiling, or even roof insulation and soundproofing is clear out the room. If you’ve ever painted a room, the process is exactly the same. Move as many pieces of furniture outside the room as you can. When soundproofing the ceiling or floor, it is best to remove all of the furniture. When you have cleared the room, you can start removing the drywall, assuming you are insulating an already built and decorated room. Once you reach the wooden construction in the walls, it’s time for the preparation process.

The next step is to measure the area you will be insulating. Calculate the width between the vertical status and the number of hollow slots between the vertical studs. Most batt insulation products come in standardized sizes that should fit perfectly between the wooden construction. When you have measured everything carefully, you will be able to calculate how much insulation you will need. The best types of insulation for the inside of a wall are batt insulations: fiberglass, cotton, mineral wool or cellulose. Adding a layer of MLV (Mass Loaded Vinyl) will greatly improve the soundproofing qualities of your ceiling or floor. Try to avoid any DIY solutions because once the floor and/or ceiling insulation is installed and covered up, it will be a long time until a replacement is needed. Watch out for any pipes, electrical wires, or electrical boxes, and take into consideration how much space they take up before ordering the amount of insulation you need.

Right before you start handling insulation, you should gear up accordingly. That means wearing old clothing that you don't mind getting dirty or even having to throw it away after. Be sure to completely cover your arms and legs to avoid any reaction that may occur because of the materials in the insulation. We recommend wearing a protective mask and goggles. Have a utility knife on hand for cutting the batt insulation so that it properly fits. A staple gun will be needed to attach the insulation to the wooden studs.

After measuring and preparing your gear, the next step is cutting the insulation. Be careful when handling Fiberglass in particular, if you aren’t planning on installing it as soon as you get it, don’t unpack it. Fiberglass releases tiny particles in the air and may irritate people with breathing problems.

The next step is installing the insulation. The batt face should be pointing toward you when placing it. When in place, use a staple gun to attach the paper lining to the wooden stud, about every 7 inches. Having someone to help at this step can make placing the insulation a lot easier.

The final step is covering up the ceiling or floor. If you have damaged your ceiling panels or floor wood when removing it, you may want to look into getting new ones. By now, you have improved the insulation and soundproofing quality of the room you are in.

Different types of insulation

Mineral wool is a spun fiber made from molten igneous stone or slag. It is impervious to moisture as it doesn’t absorb water at all. It is a dense and porous material, so it slows the movement of heat and can absorb airborne as well as impact sounds and vibrations.

Fiberglass is also a spun fiber, but it is made from melted plastic which is spun into wool and reinforced with fibers of glass. It is similar to mineral wool in terms of insulation but blocks airborne sounds better than impact sounds. Fiberglass, among its other strong points, is also great RV insulation.

Blown-in cellulose is made from about 75%-85% recycled fiber from paper, and the rest of the material is made from a fire retardant material. It’s great insulation, but not as good at absorbing sound as mineral wool or fiberglass.

Spray foam insulation is polyurethane foam spray. It creates an excellent thermal barrier and minimizes air movement. Spray foam works well as a sound blocker that can be easily installed in post-construction walls. Some spray foam is made to be a better sound absorber than others. 

Foam boards are made from extruded (or expanded) polystyrene. They come in a blue or pink color, the only difference being their manufacturer. Foam boards don’t insulate as well, but provide good muffling and help reduce sound transfer.

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