More About Sound

Sound is vibration that moves in waves

Those waves move through both the air as air-borne sound, and through solid construction as structure-borne sound.  Sound that begins as air-borne can become structure-borne as it travels through the air, collides with a building surface, and the vibration transfers to the assembly components.  Structure-borne sound is also created by mechanical contact with an assembly surface, such as footsteps on the floor above.

Did you know...
There are laws governing noise transmission in buildings just as there are for thermal insulation?
  

 

Noise regulation can be problematic for builders. Code enforcement officials tend to fail in review of acoustic performance of a building assembly largely because the science of noise control is not well understood.

HushFrame Raft Connectors can solve your noise regulation problem.​

There are 2 rating measures for interior sound transmission through building assemblies:

Sound Transmission Class (STC) is the rating measure of a wall or floor/ceiling assembly's ability to resist the movement of air-borne sound through it.

​Impact Insulation Class (IIC) is the rating measure of a floor/ceiling assembly's ability to resist the movement of structure-borne sound through it.

What do building codes require?

  • STC minimum of 50

  • And IIC minimum of 50 for walls and floor/ceiling assemblies separating dwelling units from each other, and from common and service areas.

The generally accepted scale of quality ratings of STC and IIC for building assemblies separating dwellings and between dwellings and common areas of buildings is as shown below.

The higher the STC or IIC rating of an assembly, the greater the ability of that assembly to resist the transmission of sound through it.

1/8

What is a typical construction STC rating?

 

  • A typical 2x4 insulated wall with 5/8" firecode drywall on each side achieves an STC 39.
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  • A typical 2x6 insulated wall with 5/8" firecode drywall on each side achieves an STC 42.
     

  • A typical 2x4 insulated staggered stud wall with 5/8" firecode drywall on each side achieves an STC 46.
     

  • A typical 2x4 insulated double stud wall with 5/8" firecode drywall on each side achieves an STC 56.


What happens when you add HushFrame Products?

  • Add HushFrame Raft connectors to one side of a 2x4 and its STC rating jumps from an STC 39 to STC 53.
     

  • Add HushFrame Raft connectors to one side of a 2x6 stud and the rating increases from STC 42 to STC 56.
     

  • Double the drywall and achieve an STC 63.

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Vibration Isolating Structural Connectors
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