NRC. (Noise Reduction Coefficient) represents the amount of sound absorbed by a particular surface.

Build up noise is a result of low nrcabsorptive material that does not reduce reverberation or limit reflections of sound. A material with an NRC of .80 will absorb 80% of the sound that it comes into contact with and reflect 20% back into the room.

High NRC does not address the barrier or STC effect.

STC. (Sound Transmission Class) represents how well a surface reduces the amount of sound between partitions. Partitions can be walls, ceilings/floors, doors, windows and exterior walls.

The most common concerns include noise transferring from two rooms with little to no interruption.

Spray polyurethane foam (SPF) can provide solutions for each of these through open cell application:

Low density foam absorbs 70-75 percent of NRC sound.

If installed correctly, SPF can reduce sound transmission by up to 50db (average is 30-34). stc

50+ is standard for SPF application: it provides a barrier that best controls weak points and seals joints and penetrations. According to this article, 50 STC = very loud sounds such as musical instruments or a stereo can faintly be heard; 99% of the population is not annoyed by this.


Spray foam installation for sound attenuation is ideal for:

  • Schools
  • Hospitals
  • Churches
  • Music/Event Spaces
  • Apartment Buildings
  • Theaters
  • Commercial Buildings