NYC Renovation Chronicles

NYC Renovation Chronicles: The sound and the fury

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Noise-wise, most New Yorkers have learned to tolerate trash trucks, sirens and the sermons of subway preachers, but in the sanctity of one’s apartment, the sound of a neighbor’s muffled conversation can be as disruptive as a root canal.

Worse, perhaps, is the golden rule of sound transmission: If you can hear your neighbor in their space, they can hear you in yours.

There are several things you can do during a gut renovation to sound-proof your home; even if you’re not renovating, there are some simple procedures that can help. To determine the right solution for your circumstances, you must first identify the type of noise causing the problem.

Acoustics 101 

Sound is transmitted through vibrations in any medium. With regard to urban residential spaces, we are typically concerned (1) with sound that is transmitted through the air, a.k.a. airborne sound, and (2) sound that travels through the building structure, a.k.a. structure-borne sound.

The sound of someone arguing next door or the sound of loud traffic are examples of airborne sound transmission problems. Structure-borne sound is also known as impact noise. The sound of a tennis ball bouncing, or footsteps above you would be examples of structure borne sound transmission problems. These problems often occur together, as when you hear both the loud sound and the rumbling of a demolition crew chopping concrete.

A third type of noise problem is sound reflection, which occurs when the sound from within a space bounces around and creates internal noise. Examples of sound reflection problems would be reverberation (where sound reflects off hard surfaces after its source has stopped) or resonance (such as the buzzing sound of materials vibrating in response to loud sound).

Each of these problem types is handled with a different solution.

1. Airborne noise solutions

If your neighbor’s lively nocturnal discussions are keeping you awake, you might consider installing an additional layer or two of gypsum board over your shared wall or ceiling.  If that doesn’t help, you can try a heavier material such as cement board or sheet lead. The additional mass will prevent the sound from leaking through the walls.

Just keep in mind that any sound-proofing is only as strong as its weakest link. If you cover your wall, holes around electrical outlets need to be filled with acoustic sealant as should any space at the baseboard. The same is true for the ceiling where, no matter how many layers of gypsum board you employ, recessed lights will serve as megaphones if left uninsulated.

I was told once that the floors of The Dakota were filled with sand. Whether or not true, I don’t know, but given its weight and ability to absorb vibration, sand does wonders as sound-proofing. I just wouldn’t try this at home as your building structure probably wouldn’t be able to support the weight – and your downstairs neighbor might not appreciate the retrofit.

2. Structure borne noise solutions 

Structure borne noise, such as that of someone jumping or moving furniture, travels through all components of the building that are rigidly connected. Noise of this type is best addressed by physically isolating adjacent spaces from one another on springs or some other elastic component to disrupt sound from bridging between spaces. This is referred to as discontinuous construction.

Carpet, the simplest solution of this type, is normally required by your board over 80 percent of your floor area for this very reason. Other effective solutions require a lot more than a trip to ABC Carpet.

To sound isolate a ceiling, for example, the finished gypsum board surface is suspended from the slab and beams above either on rubberized pads or more effectively, on springs. In both cases, the ceiling should not be tied rigidly to the side walls or it will defeat the purpose of isolating it. Similarly, the interior walls should not be rigidly tied to the structure—it should be isolated on elastic strips if possible. In extreme cases, where space is not an issue (hah!), you can build a completely independent wall separate from the apartment’s perimeter wall.

Seeking new office space recently, I checked out a space with spectacular views – next to a drummer’s studio. The place wasn’t right for me, but not because of the acoustics. The drummer had sound isolated his studio by creating secondary interior walls that were extraordinarily effective at keeping the melodic banging inside his space.

 3. Sound reflection noise solutions

Anyone who has dined in a restaurant devoid of soft surfaces understands the frustration of sound reflection noise. An abundance of hard surfaces can be problematic, particularly where clarity of sound is important, such as in a home theater, or in a room used for entertaining. Solutions in such circumstances involve the addition of soft materials such as carpet, drapery, or upholstery.

There are also sound absorption panels made specifically for this purpose, as well as a spray on acoustic plaster.  (Note: The latter leaves a rough texture a lot of people don’t like so you might want to run it by your decorator before committing.)

Other helpful hints...

Single pane windows are not only terrible heat insulators, they also do little to prevent sound infiltration. A double pane window will do wonders to achieve greater sound privacy. Short of a full-blown window replacement, some companies make interior windows that can be installed in front of yours at the interior to similar effect. 

For doors, the heavier the better. A hollow core door is little better than an open window in terms of soundproofing. Likewise, installing rubber gaskets around the doorframe will prevent sound from seeping through the edges. And if sound is a big issue for you, stay away from sliding doors. It is impossible to insulate them.

Lastly, it is important to isolate any machinery that vibrates. Washers and dryers should be placed on rubber blocks. And mechanical equipment should be hung from the structure on isolation springs.

At the end of the day, though, it comes down to what you can live with – or what you can afford to change. Some people can tolerate a lot more noise than others, and if you find yourself searching for silence in this city, you're probably in the wrong place.

 


David Katz (www.KATZarch.com) has been practicing architecture in New York City for the last 20 years. Detail oriented, nervous and a little neurotic,  he specializes in co-op and condo renovations.

Disclaimer: Information provided herein is not to be construed as professional advice. Readers are urged to consult with a licensed architect regarding their specific circumstances prior to undertaking any renovation work. (We do not want any buildings falling down!)

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