Insulation 101, Cellulose Insulation / 06.07.22 Soundproof Your SANCTUARY Home

In the midst of life’s noise, your home should be the place where you can unplug and unwind. To understand how to make your home your sanctuary, we need to dive deeper into sustainable insulation solutions that will benefit your spaces for years to come. But first, let’s start with the basics.

How Sound Travels

There are two forms of sound: airborne and impact. Both forms of sound travel in waves away from the source and can easily spread throughout different rooms in a home.

  1. Airborne sound: Transmitted through the air, this includes every sound your ears pick up, from noisy traffic outside to TV or music volume inside.
  2. Impact sound: This is a noise that occurs when one object makes contact with another, including footsteps or vibrations from large appliances such as your washer and dryer.

To stop sound waves from spreading from one room to the next, they need to be absorbed by another material. Some of the best sound absorbers are fibrous insulations. For example, cellulose can help reduce reverberation where hard, flat surfaces reflect sound in your walls. Dense in nature, cellulose can help reduce noise by absorbing sound waves and converting them into small amounts of friction energy.1 This makes it the ideal material to keep the noise of the outside world out.

Choosing the Best Insulation for Sound Control

Since sound can be transmitted through small openings and cracks, materials are an important part of the solution. Installed in attics, walls, floors and ceilings, SANCTUARY® by Greenfiber is designed to bring peace, quiet and comfort to your home.

Proven to reduce the power of sound by 60% when installed in exterior and interior walls, SANCTUARY Homes are exceptional at controlling airflow and reducing pathways — not only for sound but also outdoor allergens, odors and pollutants.2

Want to learn how it works? Check out this demonstration on how to dense-pack an open wall cavity behind netting. Then, discover how to insulate the exterior walls of an existing home.

Limiting sound in rooms where privacy is desired, such as bedrooms, bathrooms and media rooms, is an important benefit to any homeowner. A well-insulated home not only minimizes noisy annoyances but also may have a positive impact on well-being. According to Harvard  Medicine, noise can contribute to issues such as sleep disturbance and increased stress levels. Today, with a variety of insulation options available on the market, you may find it difficult to narrow down which choice is best for you and your home. Before you make a decision, consider the following key differences.

Cellulose vs. Batts and Spray-Foam Insulation

An insulation product’s ability to isolate noise is measured in Sound Transmission Class ratings. To block loud speech, for example, a wall needs an STC rating of at least 40. For excellent noise blocking, you’ll need an STC rating above 50.


  • When it comes to soundproofing, cellulose outperforms spray foams such as polyurethane: The hardened foam of polyurethane forms a rigid material that weakens its sound absorption. It also creates a resonating chamber that appears to enhance midrange frequencies, adding to sound disruption. Allowing sound vibrations to travel through with ease, dense substances such as cellulose can help reduce this resonance, contributing to a less noisy, more relaxing home environment.
  • Batt insulation is not best for the job: Opting for batt insulation, where sound can escape between gaps, can result in a higher margin of error. According to the Wall and Ceiling Bureau, batt insulation must fit tight without gaps in order for soundproofing to be effective. Here to give you peace of mind, cellulose fills all nooks and crannies, which in turn blocks sound that can pass through air gaps in batt-insulated walls. Our product can go beyond your walls, too, as it is also ideal for filling spaces between floors and can be used in open attics.

Achieve Superior Sound Control with Cellulose Insulation

Noise reduction is more important than ever. While you can’t avoid all noise pollution, these simple steps can help you reduce the amount of unwanted sound in your home. With SANCTUARY®by Greenfiber blow-in or spray-applied insulation, you can reduce disruptions from sound and experience immediate and long-term benefits for you and your family.

Need peace and quiet? Find your closest Greenfiber retailer or contact a sales representative today. 

1 Fast, Doug. “Reduce Noise with Sound-Proofing Insulation.” Insulation Outlook Magazine, 2016.

2 In field testing on identical 2x4 exterior wall types, Greenfiber® R-13 stabilized spray-applied insulation outperforms R-15 unfaced fiberglass batts by 4 NIC rating points, which equates to a 60% reduction in sound power. The weak point in the assembly such as flanking through windows and doors will diminish the value of the reduction in sound power. Reduction in sound power is achieved through retrofitting, dense packing or spray applying Greenfiber into exterior walls (contractor installation is recommended for these applications). See manufacturer’s installation guide for full details on how to install to meet specifications.