What's in Your Walls? How to Soundproof a Room

The last place you need noise pollution is your own home. If sirens, car chases on TV and drum practice are making you tense, there’s a remedy. Rooms can be made soundproof from floor to ceiling. 

An Important Distinction

First, it’s important to distinguish between soundproofing and sound absorption.

Absorption panels, also called acoustic panels, are large, wood-framed panels filled with fiberglass or foam and covered in special fabric. They soak up sound to keep it from bouncing against surfaces in a room. The panels are affixed to walls or ceilings to reduce echo and improve clarity.

They are not designed to reduce noise transmission between rooms; they’re meant to enhance the sound quality in the room in which they’re installed. If you just want to improve the sound of your piano playing or favorite TV shows, acoustic panels are an easy fix. You can save money by constructing your own.

Along similar lines, consider acoustic ceiling tiles, hanging baffles or soundproof curtains.

Acoustic tiles come in a wide range of styles and materials. Like anything, a dropped ceiling — that is, a secondary ceiling that's constructed beneath the existing one — can be affordable or costly depending on the materials you choose. Some cost-effective choices are up to 70 percent effective in blocking sound and while very functional, you may not like their commercial-looking appearance.

Specially designed hanging baffles cut down on echo and reverberation. Quality products have been rigorously tested and proven effective. However, baffles are expensive, especially since interior designers are now in on the act. If you’re not that interested in making a statement, there are better ways to go.

Again, you shouldn’t expect absorption products to soundproof the room. If soundproofing is your goal, then read on.

The Sound of Silence

To make a room completely soundproof means physically blocking sound with dense, heavy insulating materials. Ordinary drywall just doesn’t get the job done.

Complete soundproofing is a good choice if loud conversations distract you in your home office, or the blaring TV in your media room creates irritation for family members. As a do-it-yourself project, it isn’t especially difficult. You don’t need crazy, expensive tools or exceptional construction skills, but you should be somewhat familiar with hanging wallboard.

Going soundproof from the inside out is best done when you’re completing new construction or a renovation underway, but it really can be done at any time. Here are the basic steps:

• Ripping away the existing wallboard

• Filling the walls with a thick layer of insulation

• Attaching a resilient channel to the studs

• Affixing the new, soundproof drywall to the channel

• Insulating the floors, ceiling, windows and doors from sound

A resilient channel (or r-channel) is made of thin metal rails. They act to isolate the wallboard from the studwork, so sound wave transmission is significantly weakened.

Here are some of the most effective sound-blocking materials:

Rockwool insulation

This sturdy, sustainable insulator, also called mineral wool, is mineral in composition, rather than glass fibers. In addition to its sound-blocking properties, it repels water and deters mold and mildew. It's fire-resistant to 1,400 F, and it won’t degrade over time.

You can use Rockwool anywhere that you’d use fiberglass, but it’s especially effective in the walls and ceilings of interior rooms that generate noise. It’s widely available and sold in batts for ease of installation.

Rockwool costs more than fiberglass, but it pays off in significant energy savings and durability. If you work with it, wear a safety mask to prevent deep inhalation.

Mass-loaded vinyl

Mass loaded vinyl are heavy sheets that hang somewhat loosely behind your drywall to help absorb sound. It is important when hanging mass loaded vinyl to follow the manufacturer's installation instructions. Many people end up pulling the material taut behind their drywall, which lessens the effectiveness of the sound barrier. Think of the head of a drum. When pulled completely tight over the shell of the drum it can create a very loud percussion type noise when struck. However, if you were to loosen up the material and try to hit it, it would make very little noise as the material is able to absorb more of the impact and sound.

Noise-deadening compounds

These may be sold as glue, gel, putty or sealant. Many come in dispensers that resemble caulking tubes. When you apply one between layers of drywall, it deadens sound. You can also use the products to fill in holes or thin seams in your walls, floors or ceiling. You can even seal spaces around fixtures and outlets to prevent sound from seeping in or out.

Similarly, there are spray-on polymers for nonporous surfaces.

These products are not terribly expensive, but you’ll need them in large quantities. They are most effective when used between at least two layers of five-eighths-inch drywall. The compounds take between 30 and 90 days to reach maximum effectiveness.

Soundproof drywall

Rather than purchasing the poymers or specialty products and applying them yourself, you can certainly spring for drywall that’s already soundproof. You’ll spend a lot more for a single sheet, but experts say that you’d have to use eight layers of ordinary drywall for the same results. Soundproof drywall is made of gypsum, ceramics and viscoelastic. Noise can’t permeate it.

Many homeowners compromise by using regular drywall where they can get by with it and soundproof drywall in walls and ceilings where noise is a problem.

Soundproof flooring materials

Thick, heavily padded carpet is an excellent noise-reducer, but there are also options for wood and tile floors.

If you’re replacing a floor or laying a new one, you can either insulate with Rockwool or install underlayment made of cork, vinyl, rubber, felt or foam. Underlayment is sold in rolls for easy installation. You may even choose vinyl, interlocking foam tiles or cork tiles for the flooring itself.

Unless you're highly skilled, it hardly makes sense to rip up beautiful wood flooring that’s in good shape to install insulation or underlayment. Find a good-looking rug and use it with a soundproof pad made of dense felt fiber.

Noise-reducers for doors and windows

For doors, regularly replace gaskets and install soundproof door sweeps.

Be sure to seal all cracks around doors and windows with noise-blocking sealant or putty. Close air gaps with high-density, adhesive foam tape.

Alternatively, custom soundproof windows are a significant investment, but they're energy-efficient for savings over time.

What’s making all the racket at your house? Mind you, soundproofing won't actually make the furnace stop rumbling, or the drummer in your house take up journaling instead, but it sure will help it seem that way.