Acoustical Insulation Properties

Sound Control

Insulation provides more effective sound control than drywall alone. If you’ve ever been in a building that had little or no insulation, you probably noticed that you heard a lot more noise from outside than in a well-insulated building. This is because the sound transmission coefficient (STC) of an insulated building is lower. The STC is a calculation of the acoustic performance of a wall or ceiling, and a higher number is better than a lower number. It is widely used to rate interior partitions, ceilings/floors, doors, windows and exterior wall configurations.


Sound waves, like heat, always follows the path of least resistance. If there are leaks in the acoustical insulation, then the wall assembly will not provide a good sound barrier. ThermoShield™/ProCell™ because of its dense fibers and ability to fill irregular cavities has excellent sound attenuation properties.

The ability of an insulation for sound proofing is measured by the Sound Transmission Coefficient (STC). ThermoShield™/ProCell™ can be used to obtain rating in excess of STC 65 depending on assembly and application.

Noise reduction is achieved in three ways with cellulose.

  • The first is that cellulose completely fills cavities leaving few air pockets for sound to travel in.
  • The second is the cellulose material’s ability to trap air.
  • The significant difference between noise reduction with cellulose and fiberglass is its density. Cellulose is approximately three times denser then fiberglass. This helps deaden the sound through walls and between floor levels.

More information on acoustical properties and some STC wall and floor configurations using cellulose insulation is available on our site.  If you require some additional information on sound and fire ratings using our products, please email our technical representative at