Noise not only annoying, it’s also a health issue that needs to be silenced

United feature syndicate inc.

WASHINGTON -- Noise can be an unwanted irritant, whether it comes from traffic roaring by outside, the kids' stereo blaring in the room above, or the washing machine spinning away down the hall.

Noise isn't just an annoyance, though. It's also a health issue, second only to air pollution, according to the World Health Organization.

Yet builders and their architects often overlook soundproofing. The lion's share of the Green Glue Co.'s business comes from builders, says Adam Burnett, a business-development manager with Saint-Gobain Performance Plastics, Green Glue's parent company. But only 5 percent or so of all builders address the issue before it becomes a problem.

It's not too late to noise-proof a room or two after you've moved in. But it's much simpler, potentially less expensive and far more effective, if your builder takes on the task while the house is under construction.

"Starting from a clean slate offers the greatest opportunity to address any noise issues," Burnett says.

Green Glue, a manufacturer of viscoelastic materials and a leading producer of sound-isolation products used in residential and commercial construction, says its customers tend to concentrate on deadening sound in four rooms -- the master bedroom, laundry room, home theater and home office.

But if you have teenagers, you may want to think about isolating their rooms, too. If you expect your teens and their friends to gather on a regular basis in the basement, also figure on soundproofing that area as well.

If Junior's garage band will be practicing at your house, keeping that noise at bay should be addressed. And if your lot is on a high-traffic street or backs up to a highway, your home's entire perimeter needs to be protected.

In a recent interview, Burnett, who is trained as a mechanical engineer, walked through the five basic principles of noise isolation:

• Mass. One of the most annoying noise issues that homeowners experience is simple footsteps from above, especially in multifamily structures. This is "impact noise," which is one of the hardest problems to solve.

The best way to treat impact noise is by adding a second layer of subflooring to the room or rooms over the area you are trying to protect. Another method is to apply noise-proofing tape, sticky-side down, between the floor joist and the subfloor to act as a buffer so the joists and subfloor don't rub together, creating annoying squeaks.

To isolate the noise even further, a good, thick carpet and pad forms a third layer of protection. And a combination of all three techniques is optimal.

If the floor above is tile, or you live in a multifamily structure and the floor above is not yours, the next best thing to treating the floor above is to treat the ceiling below.

• Absorption. Insulation in the form of fiberglass, mineral wool and blown-in cellulose has great noise-control benefits. Most builders don't use it between floors or interior walls, but they should, especially if you want to prevent noise from filtering from one room to another.

"Insulate, insulate, insulate," Burnett says. "It's a must-have."

Beware of sprayed-on insulation, though. While it creates a good thermal seal, it will have no absorbing benefits if it is one that dries hard.

• Damping. Sound is vibration. To stop the sound, stop the vibration by applying a layer of damping compound such as Green Glue or QuietGlue Pro between the two layers of any rigid surfaces -- drywall, plywood, oriented strand board -- that come in contact with another.

These compounds convert the vibration into small amounts of heat and reduce noise transfer -- even low-frequency sounds normally resistant to soundproofing -- by as much as 90 percent.

"It's the same principle as holding a cowbell in your hand to dissipate the sound," says Burnett. "It converts vibration energy into a small amount of heat energy."

• Decoupling. Here the idea is to separate the wall on one side of the interior stud from the wall on the other side. This "very important" technique creates a physical break between the wall surface and the interior frame.

"Mechanically separating two sides of a wall can improve sound transmission by allowing one side to vibrate independently from the other," Burnett says.

The most efficient (but most expensive) way to accomplish this is to use two rows of studs, known as a double stud wall. Another method is to use a staggered stud wall so that the drywall in one room is screwed to one set of studs while the drywall in the adjoining room is screwed to the second set of studs.

A second decoupling method, which the Green Glue representative says is "less efficient, though still very good," involves sound clips with resilient "hat" channels, so called because they resemble a hat. Here, clips are screwed into the stud, and a metal channel is snapped on to them. Then the drywall is screwed into the channel.

A third way -- this one even less expensive and less efficient, but still an improvement -- eliminates the sound clip. Instead, the channel is screwed into the stud, and the drywall is attached to the channel. Be aware, though, that walls built with resilient channel are frequently installed incorrectly. If the screws attaching the drywall into the channel penetrate the studs, the channel's flexibility is short-circuited.

• Seal. A tight house isn't only essential in cutting your heating and cooling bills; it also helps to cut down on unwanted noise transmission. And nine times out of 10, the problem with exterior noise isn't with the walls. Rather, it is with the doors and windows.

Two panes of glass and double doors, each set as heavy and as far apart as possible, will yield the best results. But windows, doors and walls also need to be properly sealed to make sure that no air gaps exist under the door or around the windows.

Your builder also must guard against large gaps between the drywall on the wall and the drywall on the ceiling. "No amount of soundproofing done to the wall will be able to stop sound from leaking through those cracks," Burnett says.

Be aware, though, that noise will travel between spaces at their weakest points, a phenomenon called "flanking." A proper seal will help prevent flanking, but sound also can travel over, under, and around a wall as well as through common ductwork, electrical outlets, plumbing or corridors.

Lew Sichelman has been covering real estate for more than 30 years. He is a regular contributor to numerous shelter magazines and housing and housing-finance-industry publications.