Building a Soundproofing Walls

During building or remodeling, an effective and affordable way to improve the soundproofing walls and ceilings is to put batt or blanket insulation between studs or joists. This absorbs the sound that would otherwise easily travel through the air pockets between wall framing. The result of soundproofing walls will be a peaceful and private home for all to enjoy. Soundproofing insulation is typically made of mineral wool or also known as rock wool, fiberglass, and sometimes cotton or cellulose materials. Soundproofing walls and sound blockers keep noise from traveling through walls and floors from one space to another. Sound blockers are typically hard, heavy, thick, or in some cases flexible materials that reflect noise. To keep noise from entering a room, they are typically installed in walls, ceilings, floors, and doors. Sound absorbing materials and methods keep noise from bouncing around inside a room, improving sound quality in a room. Sound absorbing materials are typically porous, lightweight, and soft to the touch which foam panels are a familiar form. Because they are often applied to surfaces as a finish material, they come in a variety of colors and styles.

Soundproofing Wall Construction:

Metal wall studs

Using metal wall studs helps; the same wall, built with 2 1/2-inch metal studs, yields an STC rating of 45.

Two layers of drywall

Another way to achieve better performance is to apply a second layer of 1/2-inch gypsum wallboard to one side of the wall. This gives the surface more mass, making it less prone to vibrate and transfer sound waves. Adding this layer to one side of an insulated wall increases the STC rating to 40; adding it to both sides pushes the STC to 45.

Sound isolation systems

An even more effective way to build an interior wall is to mount 1/2-inch gypsum wallboard on special resilient channels or clips that across the wall. These channels or clips absorb sound so it isn’t conducted through the wall studs, resulting in an STC rating of about 46. The drywall is screwed to a flange on the channels, not to the studs.

Staggered wall studs

In roughly the same category is a wall with staggered wall studs. Though this requires more labor and framing material, a wall of 2-by-4 studs, staggered along 2-by-6 bottom and top plates with two thicknesses of fiberglass insulation, produces an STC of about 50. Because the wall surfaces are each fastened to an independent set of studs, noise can’t travel through the studs from one surface to the other.

Fire blocking

Where codes and safety allow, consider eliminating fire blocking in interior walls; these short blocks, mounted horizontally between wall studs, transmit noise readily from one wall surface to the other. If you’re thinking about doing this, be sure to check with your local building department.

Mass Loaded Vinyl (MLV)

Barriers offer a serious step-up, with an STC addition of about 32. Made of high-density organic sands and salts, as well as minute metal particles, these 1/8 to 1/4-inch-thick products are sold in 4-by-8-foot sheets and 4.5-by-20-foot rolls. At about 2 pounds per square foot, they are heavier than they look.

In the application of soundproofing walls, experts highly recommend using the rigid panel style mineral wool or rock wool products. These insulation products are usually sold in the form of rigid panels and softer batts. They are sized for use within residential interior walls, floors, and ceilings.