Features

When we were younger, we took it for granted that if one lived in an apartment, condo, town house or duplex — any multifamily dwelling, for that matter — sharing secrets with your neighbor was the norm. We later discovered that sound can be substantially deadened between homes — without spending a fortune. 

We once built an apartment on the top floor of a seven-story mini-skyscraper in San Francisco. We built it inside an existing metal-walled structure. The air-conditioning system for the entire building was enormous. When it ran it was incredibly noisy. We couldn’t figure out how a home could be built within 40 feet of such a large and noisy machine without it having major noise problems. 

We met with an acoustical engineer who suggested that we cover the interior surface of the party wall with three layers of 5/8-inch wallboard. He told us to use R-30 fiberglass batt insulation in the stud cavities. We could not believe that three layers of wallboard and a layer of R-30 insulation would effectively quiet the roar of the massive air conditioner. 

It took about nine months to complete the construction. Much to our surprise, the noise outside stayed there once the sound wall was complete. 

Granted, there were no windows or doors in the sound wall; there were only the studs, R-30 fiberglass insulation and the three layers of wallboard on the inside surface — and the texture and paint. 

One could go outside and hear the roar of the equipment, and then go inside and hear no trace of it. We couldn’t believe our ears. We then were convinced that multiple layers of wallboard and a layer of R-30 insulation could do the job. And, we discovered that killing noise doesn’t have to be costly. Wallboard is rather inexpensive, as is fiberglass insulation. 

In homes where families live on opposite sides of a common wall, it is best for the studs on one side to be separate from the studs on the other side. We think that two separate walls work best. One wall for one side; one wall for the other. This way when someone pounds on his wall, the vibration isn’t transferred to the other side. Also, wallboard should not be applied between the common walls. The layer of wallboard can defeat the sound-deadening properties of the insulation layers in each of the walls. Remember the configuration: three layers of 5/8-inch wallboard, a stud wall filled with fiberglass insulation, a space between, another stud wall filled with fiberglass insulation and three more layers of 5/8-inch wallboard. 

We think that the building code ought to be up scaled to include a full separation between multiple dwellings and that the party walls should each have several layers of wallboard within each dwelling. Wall cavities should be filled with as much fiberglass batt insulation as will fit without compression to add more sound-deadening quality. No portion of the wall cavities should be without insulation. 

You can’t do all of these fancy framing things unless you’re building from scratch. But if you have room, you can build a wall inside your place holding it a few inches away from the existing one and adding as many layers of wallboard and-or soundboard as you can afford. Also, you can simply add wallboard to an existing wall. If the studs in the wall travel all the way to the other side, some sound might come through even with several layers of wallboard. 

There are some types of soundboard that come with fabric or wallpaper applied to one surface. Screwing soundboard to a wall is easy, but be sure to properly extend the electrical boxes. 

If you live in a rental with noisy neighbors and the landlord doesn’t care, consider moving. Your landlord might not want to spend the money it takes to silence the noisemakers, but you might have grounds to cancel your lease if his inaction is causing you to lose sleep. 

We recently returned from a visit to the research and development labs of Johns Manville in Denver. Their acoustic testing facility is one of the best in the country. If you want more information on sound control, check out their Web site at www.jm.com/sound.