When improving your home, kitchen remodeling and living room design tend to get most of the attention; room soundproofing, not so much.
You can soundproof a room in a couple of ways. You can replace the existing drywall with special soundproofing drywall. Sound-dampening drywall is effective at soundproofing walls where it is not practical to reframe or use other structural methods. Another way that has been used for years is to double- or even triple-up the existing drywall with additional sheets of drywall.
Traditional drywall panels consist of a layer of rigid mineral gypsum sandwiched between layers of paper.
This tight, dense layer is actually quite a good conductor of sound, and soundproofing a wall constructed with standard drywall requires other framing adaptations, such as building extra-thick walls and filling the cavities with insulation, or installing sound-dampening sheets behind the standard drywall.
Soundproof drywall panels use an inner layer consisting of gypsum, viscoelastic, and ceramics, which makes them much more resilient and less able to transmit sound waves.
PABCO's QuietRock, CertainTeed's SilentFX, and National Gypsum's SoundBreak are prominent brands of sound-proofing drywall. Some brands claim that their product achieves sound-dampening levels equal to eight layers of standard drywall.
Introduced in 2003, QuietRock was one of the first sound-dampening panels to reach the market.
PABCO's current entry-level product most suitable for do-it-yourself installation is QuietRock 510. This product comes in 8-, 9-, 10-, and 12-foot-long panels, and is cut and installed in exactly the same way as traditional drywall.
Additional QuietRock products:
- QuietRock EZSnap: Designed with a special paper that easily scores and snaps.
- QuietRock EZSnap Mold Resistant: This product uses a mold resistant treatment of the paper and core to contribute to a healthier indoor environment.
- QuietRock 530: This product is a 5/8-inch thick version, used where fire resistance is required.
- QuietRock 530 RF: This product is a radio-frequency (RF) shielding version of drywall, 5/8-inch thick.
- QuietRock 545: PABCO's top-end product, used in commercial settings such as theaters and recording studios is QuietRock 545.
QuietRock products use a three-layer design: two layers of gypsum drywall about 1/4-inch thick, sandwiched around viscoelastic sound-absorbing polymers in the middle.
Basically, this middle layer can be thought of as rubber, though it is more accurately defined as a viscoelastic material that dissipates energy and sound waves much better than any synthetic rubber or polymer. It is a special material that combines the elasticity of rubber with a viscous (sticky and thick) quality.
Evaluating Drywall STC Levels
Drywall panels, both sound-dampening and conventional, are rated for Sound Transmission Class (STC).
Higher STC numbers mean better soundproofing. But it is important to note that STC ratings are not for single panels, but rather a rating for an entire wall construction system including the surface panels.
This means two layers of soundproofing wallboard, framing studs, and insulation. While soundproofing drywall panels are all inherently better than standard drywall at resisting sound transmission, it is not until these panels are integrated into a complete wall system that the true benefit is enjoyed.
Soundproof Drywall vs. Soundproofing With Drywall
|Wall Assembly||1/2-inch QuietRock 510 gypsum panel applied vertically on each side of 2 x 4 wood studs. Glass fiber insulation (3 1/2-inch thick) installed in the stud space.||1/2-inch CertainTeed drywall on each side of 2 x 4 wood studs. Mineral wool insulation (3 1 /2-inch thick) installed within the cavity.|
|1 Layer||STC 52||STC 34|
|2 Layers||STC 104||STC 68|
You can either use soundproofing drywall or you can soundproof with conventional drywall. The advantage of soundproofing drywall is that it offers more soundproofing, with less thickness.
When using conventional drywall, you can double up the layers to achieve an STC level of 68: two layers on each side. But if you use a single layer of QuietRock on each side, you can have almost as much soundproofing: STC 52.
With the soundproofing drywall, costs will be higher. But you'll have fewer hassles with trying to make double layers of drywall work on your walls.
Multiple Layers of Drywall as Soundproofing
QuietRock and other soundproofing drywall products state that a single layer offers a sound-transmission barrier equal to as many as eight layers of standard drywall.
So, it's possible to achieve good soundproofing with multiple layers of standard drywall. However, eight layers of wallboard would be roughly 4 inches thick, leading to a host of issues:
- Increased weight on your walls and ceiling
- Added cost
- Receptacles need to be bumped out
- Floor space is lost
- Higher labor costs
- Higher ancillary materials cost with joint compound, drywall tape, and more.
Costs and Bottom Line
Currently, the cost of QuietRock 510 is about $54 per sheet of 1/2-inch-thick, 4 x 8-foot panel. This compares to a sheet of conventional 1/2-inch-thick drywall selling for about $10 per panel.
This means that you can purchase roughly five sheets of standard drywall for the cost of one QuietRock panel. If sound transmission is a serious issue for you, the extra expense might well be worth the investment, especially if quiet is very important to you. Installing QuietRock or another form of soundproofing drywall might well be an excellent choice for bedrooms, for example.
Special Design Considerations. U.S. General Services Administration.