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InsulPure insulation fully installed in wood stud walls

Soundproofing with Fiberglass


By Grace Henry on February 11th, 2022

An important yet easily overlooked consideration for new home construction and renovation is insulating for sound. Of course, it’s a given that insulation improves thermal performance, air tightness, and moisture control. However, another essential characteristic of fiberglass insulation is its ability to control sound.

The last two years have brought significant changes in how people live and work. One of the more notable developments has been the growing acceptance of remote work. In fact, it’s estimated that 25 to 30 percent of the U.S. workforce will be working-from-home one or more days a week this year.

As a result of this shift, a dedicated home office or workspace has become essential for a significant segment of the population. Optimizing a home office for function and comfort is critical, and building in sound control is an important construction characteristic that should be considered.

Understanding Noise 

When talking about sound control, there are two types of paths that sound uses to travel through a building: airborne and structure borne.

Airborne sound is transmitted directly from a source into the air. The source can be noise from within the home, like appliances, home theaters, video games, or voices from another room.. Airborne sound can also be external noise such as traffic, sirens, and low-flying airplanes.

Structure-borne sound travels through solid materials that are usually either in direct contact with the sound source or receive the impact of that source – for instance, vibrations from a loudspeaker, a humming refrigerator compressor, or footsteps on a hardwood floor.

As sound energy travels through a building, it changes from one type of transmission to the other and back, losing energy in each transition. Because of its rigidity, framing tends to be a very good transmitter of low-frequency sound, and hollow wall cavities and thin doors do little to reduce sound transmission. Using fiberglass insulation inside the interior walls can block sound transmission and provide the quiet environment that homeowners seek.

Sound Measurements 

The Sound Transmission Class (STC) is a single number rating used to indicate the effectiveness of a construction assembly (a partition, wall, floor, or ceiling) in resisting airborne sound transmission. The higher the STC rating, the better the acoustic insulation of the construction assembly.

STC RatingWhat can be Heard
25Normal speech can be understood
30Loud speech can be understood
40===35Loud speech audible but not intelligible
45Must strain to hear
48Barley audible

Managing Sound with Fiberglass Insulation 

The way in which a building’s walls and floors are constructed affects acoustical performance, which in turn has a significant impact on the well-being of occupants. We offer a number of insulation products designed to limit sound transmission through different types of wall and floor/ceiling assemblies.

InsulPure insulation being installed in exposed, metal stud walls.

Fiberglass insulation, such as InsulPure™ batt and roll and OPTIMA(r)  blown-in insulation, can mitigate noise by managing it from both outside and within the house. Fiberglass insulation helps to reduce exterior noise and is also great for soundproofing interior walls. In fact, on the authority of the Insulation Institute, fiberglass insulation in interior walls and floors/ceilings can improve sound reduction. Installing batt, roll or blown-in fiberglass insulation in a building will noticeably improve STC ratings.

Don’t forget the ducts. Uninsulated ductwork exhibits poor sound dampening and acoustic performance. Controlling the sound of airflow, conversations in other rooms and mechanical noise is crucial for multifamily dwellings and many commercial structures. InsulPure™ Duct Wrap and WideWrap are engineered to provide thermal efficiency. Duct wrap helps with air movement/operation noise within the duct. However, ToughGard(R) duct liner within a metal duct is the best solution for noise control within a sheet metal duct for heating, ventilating, and air conditioning ductwork.

Our InsulPure  fiberglass insulation products won’t settle, accumulate moisture, or lose their R-value over time. These products use a more efficient binder with improved mechanical properties for ease of installation, long-lasting thermal performance, and noise reduction qualities, and are GREENGUARD® Gold certified.

A Sound Decision

Insulation serves multiple and essential roles when it comes to the health of a building and its occupants. Selecting fiberglass insulation to help manage noise levels, while also improving efficiencies and moisture control, will always be a sound decision.