Soundproofing over existing Drywall

There are a lot of people out there who want to soundproof walls and ceilings, but do not want to demo (demolish) the existing drywall. There are many ways to get effective soundproofing without removing the existing sheetrock. I will discuss one very effective method in this article.
There is a misconception about mass loaded vinyl being sandwiched between 2 layers of drywall. Basically regular mass loaded vinyl needs to be able to move or resonate as the sound tries to pass. If the MLV is sandwiched between drywall, it is virtually impossible for it to move or resonate, so in essence you will only be experiencing a fraction of the vinyls full soundproofing potential.
That is why we recommend using the mass loaded vinyl with the standard or the premium foam backing. The foam backed MLV can be nailed or screwed directly to existing drywall, hitting the studs and joists as much as possible. The foam backing will face towards the existing drywall and all seams will be caulked liberally with an acoustical caulking. You will also need to caulk the entire perimeter of the newly installed vinyl. The next step is to tape the caulked seams, it is not necessary to tape the perimeter. Now for a few more STC points, it is advisable to have a 1/8" gap where the foam backed MLV does not touch the edges of the adjoining walls, ceiling or floor. This will give the MLV a way to flex or move from side to side as well as allowing it to resonate inwards towards the stud or joist cavities. Now it is time to install the drywall. I would recommend using 5/8" sheetrock or better yet 2 layers of 1/2" drywall with a bead of caulk between each layer. Once again, as you are installing the new drywall, leave your 1/8" gap where the drywall does not contact the adjoining wall, ceiling or floors. Now that the drywall is up, go ahead and caulk in the 1/8" gap around the perimeter of the drywall and that will become the resilient interface between the soundproofed wall or ceiling and the adjoining structures.
This system, according to the manufacturer, is as effective as a floated ceiling assembly using sound clips and furring channel. I know one thing, it is a lot less labor intensive than a full float using sound clips and f-channels.
Now you have the option of soundproofing a wall or an entire room and not demoing the existing drywall. Thanks for reading and learning, fo more information on soundproofing walls ceilings and floors, go to www.soundproofingamerica.com or call the pros at Soundproofing America at the number listed on the website.

As Always,

Bob O.
Senior Technical Director
e-mail: dr.bob@soundproofingamerica.com
Call Toll free (877) 530-0139

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