Insulating for Sound in Your Home
Today’s lifestyle is often a loud one. Modern appliances and amenities coupled with today’s high ceilings, hardwood floors, and air tight structures help create beautiful indoor environments, but also contribute to noise levels that impact a family’s quality of life. Improving your home’s acoustic comfort with acoustic—or sound—insulation can reduce stress and improve overall health and wellness.
Noise can affect family health
Throughout dozens of studies, noise has been clearly identified as an important cause of physical and psychological stress—and stress has been directly linked with many common health problems. That means that noise can be associated with many of these disabilities and diseases, which include heart disease, high blood pressure, headaches, fatigue, and irritability.[i]
What does insulation do for noise?
Sound insulation is one of the best ‘quieting’ technologies available. Insulation installed in the walls and floors between rooms absorbs the transfer of noise from one room to another, reducing the level of sound heard in one room from another. A good noise control insulation package not only increases the comfort of your home, but also adds to its value. In fact, one of the most economical ways to improve the acoustic comfort of your home is to install fiberglass, rock wool, or slag wool (collectively known as mineral fiber) acoustic insulation—at the time of construction, if possible.
Understanding sound transmission
The Sound Transmission Class (STC) is a single number rating used to indicate the effectiveness of an entire construction assembly (partition, wall, floor/ceiling) in resisting the passage of airborne sound. The higher the STC rating, the better the sound insulation performance of the construction. The 2015 National Building Code (NBC) requires a minimum ASTC 47 performance, which takes into account both direct and indirect noise transmission paths (flanking paths).
|STC||Speech Heard Through Wall or Floor|
|25||Normal speech understandable|
|30||Loud speech understandable|
|40||Loud speech audible as murmur, but intelligible|
|50||Loud speech barely audible|
|55+||Loud speech not heard|
How to achieve optimum acoustical performance in your home
Apply the three basic principles to minimise sound transmission:
- Block the vibration path (use multiple layers of thick gypsum board on either side of the wall assemblies)
- Break or isolate the vibration path (using resilient channels, double stud walls, or staggered stud walls)
- Absorb the sound energy by filling the cavity with acoustic insulation
All partition walls, floors, and ceilings should have a minimum STC rating of 50 (walls and floors) and a minimum impact insulation class (IIC) 50 (floors). Avoid rigid connections to adjacent walls and use insulation and resilient floor treatments (i.e., carpeting and padding) to minimise flanking transmission through floor and ceiling assemblies. The 2015 NBC lays out prescriptive solutions to meet the minimum ASTC 47 performance requirement.
Solutions for acoustic comfort
An easy and economical method for increasing the sound transmission loss of a wall is to install sound absorbing acoustic insulation in the wall cavity. Installing mineral fiber insulation batts between rooms such as bedrooms and adjoining bathrooms, or between a recreation room and a den or study, will keep the noise level down between rooms.
Where to insulate for acoustic control
Installing sound insulation in certain parts of your house can have a significant impact on acoustic comfort. Key areas for insulation include:
- Exterior walls
- Interior walls
- Floor Assemblies
Exterior walls should be constructed with resilient channels and mineral fiber insulation filling the stud activity. Ensuring a continuous airtight air barrier system will enhance occupant comfort, reduce energy consumption, and will also improve the acoustical performance of the assembly.
All interior walls and floor assemblies between living spaces should have an STC rating of at least 50. The basic guideline for installing insulation in wall and floor cavities is to fit the ends of the batts snugly against the top, sides, and bottom framing.
Duct design should be given special consideration when planning a home’s layout since ducts can easily transmit sound. Installation of sheet metal ducts, lined with sound-attenuating duct liner insulation, or using fiberglass duct board systems will reduce transmission of unwanted sound, including fan noise through the duct. Sealing the joints in the duct system will also improve the acoustic performance and energy savings.
Best practices for sound control
There are best practices for sound insulation that you and your insulation contractor or builder should follow for optimal results.
[i] U.S. EPA, Office of Noise Abatement and Control, “Noise: A Health Problem,” p.23