• Airborne Sound
  Airborne sounds are noises that move through the air. Vehicles honking, radios, conversations, or dogs barking are examples of airborne noises.

• Impact Sound
  Impact sounds are noises caused by something striking something else. For example, a toy or glass falling on the floor or people walking on a hardwood floor are impact sounds.

• Flanking Noise
  Flanking noises are sounds that travel through, under or over a sound barrier. They are the most difficult to control as they take an indirect path. Sound waves can travel through ductwork, over or under the best soundproof wall, and through hollow core doors. Sound can even transfer through back to back electrical boxes!

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Understanding STC and STC Ratings

STC (Sound Transmission Class) is a method of comparing how well windows, doors, floors, walls and ceilings are at reducing sound transmission. It measures the decibel (dB) decrease as sound passes through or is absorbed or blocked by material or wall.

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Recommended STCs for Your Home

A quiet home has an STC 40 rating. The International Building Code (IBC) recommends a rating of STC 50 for walls, ceilings, and floors as a minimum requirement. An increase to STC 55 or STC 60 would be better.

For residential locations, an STC 52 for bedrooms and STC 56 for bathrooms, living rooms and kitchens, are recommended minimums. A 2×4 wall with ½” of drywall on both sides, but no insulation, has an STC 33 rating.

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NRC (Noise Reduction Coefficient)

The Noise Reduction Coefficient (NRC) measures the amount of sound a material absorbs or reflects on a scale of 0 to 1. No sound is being absorbed or reflected at 0, and all sound is absorbed or reflected at 1.

• A typical interior 2×4 wall with 1/2” of drywall on both sides has a rating of STC 34.

• Adding standard fiberglass insulation improves the rating to STC 39.

• Adding sound rated insulation can improve that to STC 45.

• Building the same wall using 2-1/2” metal studs with 1/2” drywall on each side you get an STC of 34; add same sound rated insulation can bring the rating to STC 47.

• Using 5/8” drywall instead of 1/2” on the steel studs brings the sound insulated wall up to STC 49.

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High Performance StoneWool

High performance AIB stonewool is lightweight insulation with improved thermal and acoustic properties. It is manufactured from a mix of stonewool from molten rock and slag. It has improved sound damping and absorption properties. The fibers make it more fire, moisture, water, and rot resistant.

With sound absorbing ratings of 95% and NRC of 1.05, high performance stonewool provides improved sound reducing values. Much lighter in weight provides equitably with twice the density of multi-purpose mineral wool.

ACOUSTIC INSULATION BOARD is rigid board made for use in ceilings and floors, as well as walls. It not only provides a thermal barrier, but also improves sound absorption, and impact vibration and noise.

It is made from STONEWOOL spun from molten basaltic and igneous rock. They can be easily cut and even shaped.

• AIB 1050

• AIB 1350

• AIB 7050