What’s The Best Insulation For Soundproofing Ceilings And Walls?

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Homes with multiple stories are often plagued with creaks and moans, especially if it is an older house, and you may be wondering how you could prevent or fix this problem with insulation. Of the many options out there, which material would be best for this project? We've done the research to give you an answer.

The best insulation for soundproofing the ceiling and walls is fiberglass. This material effectively reduces noise transmission while also being versatile and easy to install. 

So now you have your answer, but maybe you'd like to learn more about fiberglass insulation. Is it suitable for your specific needs? Keep reading to learn more.

Worker using a power drill for screwing nails, What's The Best Insulation For Soundproofing Ceilings And Walls?

Fiberglass Insulation

Knowing a bit more about how fiberglass is produced will give you a better idea as to why this material works well as a soundproofing agent.

How It's Made

An insulation contractor taking away fiberglass strips

Fiberglass is made of fibers created from molten glass. To begin the process, manufacturers bring in molten glass. This molten glass contains raw materials, such as silica glass, lime, or soda ash.

The molten glass is moved past air jets, and the high pressure that the air jets create blows the material into fibers. At the same time that this is happening, the fibers are being coated with a liquid binder and cut. When the fibers have cooled, they are piled together.

This "blanket" of fibers is then moved to a curing oven. This is when the fibers are bonded together. A vapor barrier may be added in this step of the process, but this depends on the product. After the blanket has been removed from the curing oven, it is cut to the desired length and width.

Take a look at this fiberglass insulation roll on Amazon.

How It Works

There are a few ways fiberglass works to create a more comfortable home for its users. One of these is preventing the movement of air. This is specific to keeping the house warm or cool.

The fiberglass creates pockets of air, preventing the air from moving freely from room to room or from inside to outside. This ensures that the air that has been provided through the ventilation system to the room, whether warm or cool, stays in that room.

More specific to soundproofing, fiberglass works by absorbing and blocking noise. Fiberglass is a porous material, and because of this, you are less likely to have a room that echoes. It will absorb much of the soundwaves that are released.

However, fiberglass also works by blocking noise or reflecting it. While this will not cause the room to echo, one may find that the acoustics are better than rooms that are insulated using other methods.

Choosing A Fiberglass Product

Fiberglass is undoubtedly the most effective, versatile insulation for soundproofing. Between fiberglass, mineral wool, and cellulose insulation, fiberglass consistently has the highest STL, Sound Transmission Class rating.

When choosing between fiberglass products, you can pay attention to the R-value, the STL rating, and the NRC, Noise Reduction Coefficient rating. The higher the number in all of these areas translates to better soundproofing.

Does A Higher R-Value Mean Better Soundproofing?

Yes, the R-value in an insulation material does affect soundproofing, and the higher the R-value, the more soundproof the space will be. However, you don't want to go too high with the R-value. It's still desirable to have some air and sound movement between rooms. Otherwise, the home will feel "stuffy."

What R-Value Is Best For Soundproofing?

To soundproof an area, it is recommended to use R-13 insulation in the walls while using R-19 insulation in the ceilings.

Check out this R-13 fiberglass insulation on Amazon.

We want to allow for some air and noise to move between rooms on the same floor, but a higher R-value should be used in the ceilings to prevent the noise of people walking and children playing being heard between floors.

How Thick Should Soundproof Insulation Be?

In ceilings, insulation should at least be 100mm thick. This is to correctly prevent the transmission of sound between floors.

In walls, the thickness of the insulation needed will depend on the R-value. The correct thickness will range between 3.5 inches to 6.25 inches, moving higher as the R-value increases.

Can Thermal Insulation Be Used For Soundproofing?

Yes, fiberglass is categorized as thermal insulation and can be used for soundproofing. However, this may nfshut be the case for all thermal insulation products. For example, cellulose is very effective at keeping a home warm, but it is ineffective at soundproofing a home.

Installing Fiberglass For Soundproofing

A construction worker checking the attic for insulation

When you have chosen the fiberglass insulation product for you, it's time for you to begin planning to install this insulation, but how do you do this? Should you hire a professional, or can you complete this project yourself? We will give you some instructions.

Safety Precautions

When working with fiberglass insulation, you must take measures to protect yourself. These are essentially tiny fibers of glass that you will be working with, and they can cause great irritation to the skin, eyes, nose, and throat if mishandled.

Because of this, you must first think of protecting your skin. The insulation will inevitably touch your arms and torso as you work with it, so wear loose clothing and gloves that will move the dust and fibers away from your skin. If you feel that the insulation has come into direct contact with your skin, rinse with warm water and soap.

You must also protect your eyes. The way of doing this is pretty straightforward. Wear safety glasses with side shields.

Inhaling the fiberglass dust can also be harmful to your nose and throat. In cases of prolonged exposure, it can affect your lungs. You will need a dust mask at the least and, at the most, a respirator.

It's also best to eat, drink and smoke before and after you have completed the project, and never during. If you stop mid-project to eat or smoke, you could ingest or breathe in fiberglass material.

Installing In Walls

A worker placing a tile on the wall

When installing fiberglass insulation in the walls, it's best to use faced batt insulation or faced roll insulation. Both are pretty similar in their installation; besides, the roll will have to be cut to fit the spaces between studs.

Typically, batt insulation is already cut to fit standard 8-foot tall walls. Still, if you need to cut either batt or roll insulation, you can do so by laying the insulation on a piece of plywood with the vapor barrier facing down. Then cut with a utility knife, adding an extra inch to the width to ensure a tight fit.

Fastening the insulation will be done with a staple gun. Lay the batt insulation between the studs with the vapor barrier facing outward. You will see mounting tabs [or, in some cases, paper] on either side of the insulation.

Take a look at this staple gun on Amazon.

Unfold these tabs and press them either against the front sides or the inner sides of the surrounding studs. Staple the tabs into the studs, ensuring that the staples are not protruding.

It's important to note that the building codes require the tabs to be stapled to the inner sides of the studs in some areas. Check your local building codes to be sure.

When you come to obstacles such as wires or pipes, you should always push the insulation behind the obstacle. As for electrical boxes, you should cut the insulation to move around them.

Installing In Ceiling

Worker screwing a smartboard to the ceiling

The process of installing fiberglass insulation into a ceiling is similar to doing so in walls. Either faced batt insulation or faced rolled insulation is suitable.

If you've chosen faced batt insulation, you will want to be sure that you purchase the correct width for the space between the ceiling joists. If you've chosen faced rolled insulation, you will have to cut the insulation to width and length before beginning.

You will begin by placing the insulation between the joists with the vapor barrier facing outward. You will see mounting tabs or paper on the outside edges of the insulation. For ceilings, you will want to always staple this mounting material to the inside of the joists.

Once you have completed this throughout the room, you will have an insulated ceiling.

Will Insulation Between Floors Help With Sound?

Yes, and this is the greatest reason a homeowner may choose to insulate ceilings and under floors. It will prevent noise transfer, such as stomping, running, and children playing.

In Conclusion

Worker using a power drill for screwing nails

Fiberglass is the best insulation for soundproofing a home, evidenced by its high STL rating, long-lasting effectiveness, and ease of installation. We have detailed how fiberglass is created and how it works to keep a home warm or cool and prevent sound from traveling. If keeping your home quiet is your goal, this is the product for you!

Want to learn more about insulation materials? Visit these related posts:

How Long Does Mineral Wool Insulation Last?

Does Cellulose Insulation Settle? How Much?

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