How to Soundproof Walls
There are lots of reasons to soundproof a room. Whatever your reason, take a look at our tips to see how.
If you want to limit the amount of sound that escapes from a room, incorporate one or all of these five strategies into wall and ceiling construction.
- Add sound-absorbing material into the stud or joist bays (Step 1).
- Separate the two sides of the wall from each other. One way to do this is by screwing resilient steel channel to the wall or ceiling, then screwing the drywall to the channel. Other methods include staggering 2x4 studs on a 2x6 soleplate, or even framing two walls, then separating them with a 1-inch dead-air space. You'll gain additional isolation by gluing and screwing the second layer of drywall to the first, not to the framing (Step 2).
- Increase the mass of the wall or ceiling by using thicker panels and/or installing multiple layers (Steps 3 and 4).
- Install a sound-reduction board as the first layer and top it with drywall.
- Seal sound pathways by caulking, gasketing electrical outlets, and weather-stripping doors (Step 5).
Successfully decreasing sound transmission makes a room more acoustically reflective. You'll probably need to consider adding sound-absorbing materials such as carpeting and drapes.
Install a Sound-Reduction Board
A special type of wall panel is engineered to serve as the base layer instead of drywall in a two-layer sound-reduction installation. (One brand is Homasote 440 Sound Barrier Panel.) Following the manufacturer's instructions, install the panels vertically to wood or metal studs, using adhesive and screws. Top it with a layer of 5/8-inch drywall, secured with adhesive and No. 10x1-1/2-inch type G screws driven into the base panel, not the studs.
Step 1: Install Insulation
Install insulation in the stud cavities to dampen sound transmission. For this purpose, sound attenuation fire blankets (SAFB) are superior to fiberglass. The mineral fiber blankets stand up in stud bays without mechanical fastening. For ceiling applications, installing resilient channel first is a good plan.
Step 2: Attach Steel Channels
Screw resilient steel channels to the walls, spacing them 16 inches on center. The channel's design minimizes the amount of direct contact between the studs and the wallboard.
Step 3: Install First Drywall
Install the first layer of drywall vertically, screwing it to the channels. To achieve the best sound control, make each layer of drywall as thick as possible; two applications of 5/8-inch panels produces excellent results. In high-end projects where even greater sound control is needed, you can use a third or even fourth layer.
Step 4: Second Drywall Layer
Apply adhesive to the back of the second layer and install it horizontally. Drive type G screws into the first drywall layer, avoiding both the studs and resilient channels.
Step 5: Fill Gaps
Using a caulking gun and a special acoustical sealant, fill all cracks around the wall's perimeter, especially at the bottom of the wall. Also caulk any gaps between the drywall and electrical boxes and heat ducts.
Batten Down the Outlets
After you've finished the wall, install closed-cell foam gaskets around electrical outlets and switches. The precut sheets are inexpensive and easy to install before you add the cover plates.