subject: Soundproofing [print this page] There is so much misleading information on the Internet regarding Soundproofing. I am going to try to clear up the myths and the misconceptions that are out there.
As a general rule, adding mass to any structure such as a wall or a ceiling will add greatly to the soundproofing and blocking ability of these assemblies.
One of the state of the art materials for blocking noise through a wall for example is a product called Mass Loaded Vinyl, or (MLV) for short.
MLV is a high grade vinyl material the is impregnated with barium salts and silica (sand) to give it mass similar to the mass of lead sheeting.
The MLV avoids all of the hazards that are attributed to lead sheets and is much easier to apply to walls and ceilings.
Mass Loaded Vinyl comes in rolls that are generally 4' wide X 25' long and has an STC value of the 27 STC. STC stands for Sound Transmission Class and is a rating system for the effectiveness of sound blocking materials. In essence a 27 STC equates to a decibel reduction of 27 dB. This is quite signifigant considering what is in a standard drywall assembly.
It is best to attach the MLV directly to the stud structure of a wall. If the studs are wood studs the MLV can be stapled up using a standard air drive stapler or even a plastic cap stapler. You can also use a nail gun the shoots the roofing nails with the large plastic heads, keep in mind that as a grneral rule, MLV is not a re-inforced product so by it's sheer weight it could rip through a common nail.
Now if you are attaching the MLV to steel studs, it will be necessary to use self tapping drywall screws with large washers on them.
You want the MLV to be stretched across the stud assembly much like a soundproof membrane. Once the MLV is attached to your studs, you would then caulk all of the seams as wells as around the entire perimeter using and acoustical caulking compound. The better you seal this product, the better it will block the unwanted migrating sounds that would usually pass through and common drywall wall assembly.
MLV can also be weaved through a stud assembly, but weaving makes it more difficult to seal the seams. weaving however does change the resonant frequency of the MLV and therefore does help with the soundproofing effort.
Here at soundproofing America, Inc, we have had great luck both weaving and also attaching the MLV directly to the stud structure itself like a membrane.
Once the MLV membrane is attached to the studs and sealed properly with acoustical caulk and seam sealer tape, it is time for the drywall. We always recommend using the best quality 5/8" thick drywall you can find. You would simply screw up a new layer of 5/8" drywall directly over top of the MLV. Always try to hit the studs with the screws to prevent puncturing the MLV product.
That's it in a nutshell. This wall assembly with the 1# MLV and the 5/8" drywall will add nearly 40 STC points to cany common wall.
For more information on soundproofing with mass Loaded Vinyl or for any soundproofing project, please contact the professionals at Soundproofing America, Inc. They will be happy to help you with all of your soundproofing needs. Thanks for reading, Bob O.
