Acoustic Insulation

The need to control sound depends on your tolerance for sound. On one end of the sound control spectrum is complete silence; on the other, sound flows freely through walls and floors. The best sound isolation systems are designed by sound engineers with state of the art materials, and can cost over $50 a square foot for the system. These high quality sound control systems can be achieved by understanding an expectation of sound control, paying attention to detail, and utilizing relatively inexpensive materials. 

Fiberglass batt insulation is the least expensive option for sound control protection in walls or floors. Most people have lived in a home without interior sound insulation and have a good idea of what hollow walls and floors sound like. Batt insulation will dampen sound, but will not stop sound transmission from room to room or floor to floor. Sound control can also be achieved by stopping or slowing air travel.

Treating sound walls with a sound caulk similar to an Ecoseal air barrier sealant is a cost effective way to control sound transmission. In this process, we wrap electrical receptacles behind the drywall with putty pads, pliable 1/8"-thick self stick pads. This process can also be used for airtight covers for recessed can lights. Walls require one side to have drywall installed prior to air seal, and substrate seams should be sealed and intersections with joists are sealed. A third option to increase sound control is to utilize higher density batt, board, blown, and roll materials.

The following chart represents the density of most common sound attenuation materials and approximate cost:

Material Density Approximate cost per square foot – material and labor
3.5" Fiberglass batt 1 pound $.40 per square foot
3.5" Fiberglass Blown-in-Blanket 2 pound $.95 per square foot
3" Rockwool Sound Attenuation Blanket 2 pound $1.40 per square foot
Fiberglass Black Acoustic liner 2.25 pound $3.25 per square foot
Fiberglass Black Acoustic Board Glass 3 pound $6.00 per square foot
3" SAFING Rockwool 4 pound $1.60 per square foot
Industrial Rockwool 4-8 pound $3.00-$5.00 per square foot
     
Interior wall air seal   $.70 per square foot
Interior wall putty pad   $7.00 each
1/8" Acoustiblok   $6.00 per square foot

If cavity insulation and air sealing are not good enough, the next step is to add resilient channel to the surface of the wall or ceiling prior to the installation of drywall.

Resilient Channel and Acoustical Underlayerments

Resilient channel adds airspace to the sound assembly at the face of stud or bottom of joist. The drywall is then hung directly to the resilient channel instead of to the wood stud or wood joist. It works by isolating the drywall from the framing which then slows direct sound transmission through the framing members to the interior surface. Consult your drywall contractor if you want resilient channel added to any wall or ceiling surfaces. The next step in sound control is to add an acoustic underlayment to the assembly, prior to resilient channel and drywall.

We use Acoustiblok when a project requires acoustical underlayments. Acoustiblok is the most widely tested and approved loaded vinyl on the market. If you are interested in Acoustiblok for your project, give us a call to consult one of our professionals, or visit acoustiblok.com for more information on this product, its intended uses, and performance record. 

When people ask me "What is the best thing I could do for sound control?" My answer is always "Pay attention to detail – you won't know how good you did until you move in." The best sound control system, if not properly installed, will only work as well as the installation, and never as well as it was designed to work.