Soundproofing insulation is a special type of insulation product, designed to be an acoustic barrier. The insulation barrier absorbs sound and can greatly reduce noise leakage from one room to another.

The result of installing soundproofing will be a peaceful and private home for all to enjoy. Soundproofing insulation is typically made of mineral wool (also known as rockwool), fiberglass, and sometimes cotton or cellulose materials.

In the application of soundproofing a room, we highly recommend using the rigid panel style mineral wool/rockwool products. These insulation products are usually sold in the form of rigid panels and softer batts. They are sized for use within residential interior walls, floors, and ceilings.

Soundproofing Insulation in Walls

Typical Insulation Sizes

Soundproofing insulation panels can be purchased for wood or steel stud walls and ceilings.

  • Wood Stud Panels: 15.25” x 47” x 2” or 3” Thick
  • Steel Stud Panels: 16.25” x 48” x 2” or 3” Thick

Installation Tips

Mineral wool and fiberglass soundproofing insulation can be purchased in packages of multiple panels. They are manufactured with good tolerances, and fits snugly in between wall studs and ceiling joists. They will fit into the cavities with a friction press fit, ensuring there is no air gap for sound to leak into adjoining rooms. The insulation panels are 2”-3” thick and are rigid enough to be easily cut to shape around electrical outlets and studs. You can use a drywall saw to precisely cut out the notches to make each panel fit into place. Wall and ceilings can be finished off with standard or soundproof grade drywall, no vapor barriers are required.

Comparing the Top Products – Acoustic Performance

ProductNRC125Hz500Hz1000Hz4000HzDensity
Mineral Wool – High Performance
Safe'N'Sound by Roxul1.050.521.181.071.052.5 lb/ft^3
Mineral Wool – Multi Purpose
Roxul Acoustic Fire Batts (AFB)0.950.281.091.091.072.5 lb/ft^3
Roxul Rockboard 60 (2")0.950.321.061.021.046.0 lb/ft^3
Roxul Rockboard 80 (2")1.000.430.900.971.008.0 lb/ft^3
Fiberglass – Multi Purpose
ATS Acoustics Rigid Fiberglass (2")1.000.291.111.131.033.0 lb/ft^3
Owens Corning 703 (1")0.700.110.680.900.963.0 lb/ft^3
Owens Corning 703 (2")1.000.171.141.070.983.0 lb/ft^3
Owens Corning 705 (1")0.650.020.630.850.956.0 lb/ft^3
Owens Corning 705 (2")0.950.161.021.010.996.0 lb/ft^3
Other Materials
Applegate Cotton Batts1.050.271.171.151.062.5 lb/ft^3

High Performance Mineral Wool

Roxul Soundproofing InsulationThe Roxul Safe’N’Sound product has some of the best low and high frequency ratings, and is very cost effective. It is designed specifically for soundproofing, and thus should be used only on interior ceilings, floor, and walls.

All of the Roxul mineral wool products are made from natural stone fibers, making them fire, water, and moisture resistant. The major downside is that for some reason it is VERY difficult to find online or in stores.  The good news is the other Roxul products are almost as good, and much easier to find in stock.

Multi Purpose Mineral Wool

The Rockboard 60 and 80 mineral wool products are more of a multi-purpose insulation.  While they have slightly lower sound absorbing performance, they have improved thermal insulating capabilities.  These products could be used on the inside to soundproof exterior walls on top of standard thermal insulation.

Rockboard 60 is better at absorbing high frequency sound, while the 80 is better at low frequencies. AFB is a low cost, soft and flexible insulation product, best suited for framed, or covered panels.

Roxul Acoustic Fire Batts (AFB)

Roxul Rockboard 60

Roxul Rockboard 80

Fiberglass Soundproofing

Fiberglass has similar sound absorbing performance as mineral wool in the same thickness, but at a higher price.  Fiberglass is a good alternative to the mineral wool if you need thermal insulation on top of the soundproofing.

ATS Rigid Fiberglass

Owens Corning 703

Owens Corning 703FRK

Cotton Soundproofing

Cotton soundproofing is very affordable and provides very good sound absorption performance.  The cotton is soft like a batt, and needs the support of a frame or covering.  Cotton is a good choice for small projects like building your own acoustic panels.

Difference Between Soundproofing and Sound Absorption

Continue on to: Soundproofing a Room