Home Soundproofing Tips

Every home has a certain level of noise, and every occupant has their own comfort level of how much noise they can tolerate. Total silence can be disturbing for many people, so we don’t want to get rid of all noise, nor is it possible in most cases, but there are steps you can take to keep household noise to a reasonable level.

Tactics for noise control fall into two categories; stopping noise at its source, or stopping sound from being transmitted in your house from one location to another. We look first at stopping noise at the source.

Noise Sources

Reducing or eliminating noises at their source can be done relatively easy, but you are limited to sources within the home. This includes appliances such as dishwashers, clothes washer and dryers, refrigerators and central vacuum systems, plus heating, ventilating and air conditioning equipment. You can also eliminate some plumbing noises, depending on the construction and type of pipes in your home.

Appliances should be placed so that they will not make direct contact with walls or surfaces of cabinetry or other furnishings which tend to amplify lower level noises into more annoying sounds. Any time you hear a rattle or vibration you never heard before coming from an appliance, check it for loose fasteners; chances are there is a loose bolt or nut somewhere that you can tighten and get rid of the problem.

If you are shopping for new appliances, look for models that are rated low noise; they could have extra quiet motors, extra insulation or a special sound-damping design. You can also purchase sound deadening kits for some appliances. These kits typically have rubber padded mounting plates or brackets that acoustically isolate the appliance from walls or floors.

In rooms that noisy appliances are in, sound can be further reduced by adding insulating materials. Thick carpeting and carpeting pads, acoustic ceiling tiles, a suspended ceiling with fiberglass insulation above it, thick drapes and wall hangings all help absorb sound and contain noise within the room. When adding a drop ceiling, look for ceiling tiles with a Noise Reduction Coefficient of at least .65.

Additional benefit can be gained by adding hollow, tubular weatherstripping gaskets around the door opening molding, a doorsweep strip below the door, and replacing hollow doors with solid ones made of wood. This will, of course, only reduce noise from being transmitted to other areas of the house; when inside the appliance room, there will still be noises heard coming from outside the room.

Insulating Walls for Sound

Another way of stopping noise from getting out of one room into the rest of the house is by adding extra thickness to walls. Putting up a layer of 5/8 inch thick drywall on one side or both sides of a wall should be enough to reduce loud noises to a low level.

Attach the drywall with adhesive rather than drywall screws or nails for best soundproofing results. You will need to use drywall screws temporarily to hold the sheets on place while the adhesive dries. Bottoms and top edges of the new surface should be sealed with paintable caulk, or unpaintable caulk if you will be installing base and crown molding.

In new home construction, or when doing extensive remodeling, you can take advantage of the principal of structural discontinuity, the separating of structural elements in order to prevent sound transfer. This involves building a second wall parallel to a dividing wall between two rooms, providing a gap between the two walls of at least one inch, and preferable two to five inches. The air in the gap acts as a sound absorbing insulator, and the wider the gap, the better the soundproofing effect.

The second wall’s construction can be either standard two by four framing or steel framing of sixteen gauge two by four members. The steel framing provides the superior soundproofing of the two. To isolate the wall from the floor and ceiling, install acoustical cork pads beneath the frame at the bottom and above it at the top.

Further sound absorption is provided by filling the space between wall studs with fiberglass insulation. Finish the wall with a layer of half inch thickness sound insulation fiberboard, fastened to the framing with nails, over which is fastened a layer of 5/8 inch thick drywall with adhesive. Avoid installing electrical outlet boxes on the wall as this will compromise it’s soundproofing capability.

Flooring Soundproofing

Sound can also travel through the house via floors and ceilings; of the two, soundproofing floors is the most effective means of stopping sound transmission, although more expensive. The easiest remodel to do on your floor is to remove the finishing surface, then add a layer of sound insulating fiberboard over the subflooring and install new finish flooring; the ease of this method is dependent on the type of flooring finish, with hardwood planks and heavy stone being the most labor intensive.

The best new finish flooring in terms of sound transmission is to use a resilient flooring material such as carpeting or vinyl sheet. One option for hard to remove finish flooring is to simply leave it in place and cover it with layers of new sound insulating fiberboard and finish flooring; take into consideration, however, the fact that this will raise the floor level.

For renovation where high noise levels are a problem, another alternative is to install a floating floor, a framed floor which incorporates sound absorbent insulating materials, built above the existing floor. This will reduce the room’s effective ceiling height so be sure your room has adequate clearance.

The floating floor is installed by putting down a layer of vibration isolator rubber strips or sound insulating fiberboard on the subflooring or existing finished floor. Floor joists of two by ten inch lumber or composite engineered wood are installed onto that layer, using construction adhesive. Unfaced fiberglass insulation is placed in the spaces between the joists. A second layer of sound insulating fiberboard is installed onto the top of the joists, and the finish flooring is installed over that. For maximum effect, use hardwood finish flooring and cover it with a carpet pad and thick carpeting.

Sound Proofing Materials

- Armstrong World Industries: manufacturer of soundproof floor and wall covering and soundproof partitions
- CetainTeed: supplier of soundproofing insulation
- Homasote Company: manufactures sound insulating fiberboard as well as other sound insulating materials
- Manville-Schuller Inc.: manufactures sound insulating materials
- Owens-Corning Fiberglass Corp.: manufactures sound insulating materials
- United States Gypsum Co.: their Gypsum Construction Handbook has a good chapter on noise resistant drywall construction methods.