Condo Living: Noise Reduction Techniques for Highway Dwellers

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In my recent Dallas High-Rise Buyer’s Guide series, I noted that there are a lot of buildings too close to highways for comfort.  If I added in all the recent highway-adjacent apartments, none of us would be separated by the requisite six degrees from someone who has a noise problem.  What can you do?

Technology

High-tech and smart folks are of more use than making battery-operated gadgets that fit on your pocket.  Turns out there’s a whole science to minimizing road noise intrusion not only inside our homes, but shaving a few decibels when we’re outside. The place to start is the Acoustical Society of America, which was founded in 1928 by some smart folks at Bell Laboratories (yes, the phone people).  By the time of their first meeting in 1929, there were 450 members. By 1931 they’d joined with three other groups to form the American Institute of Physics.  Don’t let the “American” fool you — this is an international body that develops and sets standards in a variety of sound-related disciplines from musical acoustics to architecture.  Nifty, eh?

I’m pretty sure we all know that sound travels in waves caused by vibrations of some sort.  For example, in a speaker, we’re hearing the vibrations generated by the speaker’s flexible diaphragm. Those vibrations are pushed out into the air forming the sound waves we hear. That car roaring past your window?  The same thing without the melody.

In our homes we hang pictures and curtains … lay rugs and place furniture … all having the effect of absorbing sounds and quieting echo (sound bouncing). Deadening sound is literally the process of flattening vibrations.

Flattening sound-creating vibration is accomplished when sound encounters uneven surfaces that don’t allow it to bounce with the same intensity (think shag rug versus tile floors). Sound can also be deadened by generating an opposing wave.  Think of two people crashing into each other — both fall backwards as momentum is abruptly halted (sorta how noise cancelling headphones work … yes, there are little people in there).

Traffic Noise

Traffic noise adds complexity as its sound isn’t constant, but instead generated by different types of vehicles moving at differing speeds and generating slightly differing sounds.  This soup of noise ricochets off solid surfaces, which can also amplify and focus the sounds.  Think of that church where you can hear people whispering clear across the room.

Inside homes, the most used sound deadeners are insulation and multi-pane windows.  Solid surfaces like brick and concrete use their thickness to deaden sound very well for those on the other side.  But for those on the sound-generating side, these flat, solid surfaces can amplify sound.  Think about walking down streets with and without trees. The treed street is more pleasant because the irregular surfaces of the leaves scatter sound waves.  Multi-pane windows utilize the vacuum gap between panes to remove vibration energy from the sound waves. This calming of the wave reduces sound transmission.

Starting from Scratch

Outside your home there are a variety of techniques that can be used to reduce sound.  Now I’ll be honest, you’re never going to forget you live on a highway, but it can be made better.

First, sound reduction begins with architectural design.  Sound bounces off flat, hard, uniform surfaces.  Exterior building cladding that has an irregular texture will break-up sound waves, reducing echo. There are any number of scientific papers identifying the varying angles that produce the highest deadening based on the source of the sound.

In addition to deadening, the exterior should be constructed to deflect sound in the most beneficial manner. For example, using design, noise can be deflected up and away to make ground level quieter. In a multi-story building, balcony shapes can interrupt sound waves and navigate sound away.

I’d hazard a guess that of all these multi-story condos and apartments being built around town, none of them bothered consulting with an acoustics specialist. It’s a pity, as small changes would have reaped benefits for residents’ happiness. Experiments I’ve read on the subject say certain techniques can reduce exterior balcony noise by 23 decibles … the equivalent of cutting light traffic noise in half and heavy traffic by a third. No small potatoes.

Architects who understand acoustics are worth their weight in gold, especially in multi-story construction in noisy locations.

A balcony-sized Bedouin tent could be the answer

Building is Built, Now What?

Remember that a critical part of sound audibility is transmission. Let’s say you live in an apartment near a major noise source. You’d like to use your balcony but the noise is bothersome.  You also can’t make permanent changes to the building.

Fabrics and plants.  Remember, the goal is to interrupt sound vibrations using irregular surfaces.  If you do not have a chunky rug on the patio, get one.  If your balcony has side walls, explore hanging inexpensive fabric panels … the thicker and more textured the better. Hang them floor to ceiling and angle them slightly outwards to absorb, but also reflect sound outwards, away from your space.  Ditto if you have a ceiling.  Note: If installing ceiling absorption, do not have a front lip. It will trap noise rather than bouncing it outwards. The highest point must be the outer edge.

Along the railing, install plants, but not petunias.  Think bushes.  The thicker the plant, the more sound it is capable of absorbing.  Have a skinny balcony or lack a green thumb? Try weaving a lush carpet of fake grass between the spindles.  Combined, these tricks will help deaden sound and ensure you’re not simply funneling it into your home.

Remember, if using fabric panels, make sure they’re machine washable.  It’s dirty out there and you’ll want to keep them clean.  Pick darker fabrics, only using light colors if you’re a maniac about cleaning. Caveat: If your building has rules about stuff on your balcony, you’ll want to use fabric that matches the building’s exterior … no lime and fuchsia polka dots.

Good luck and here’s to getting more use out of your balcony.

Remember:  High-rises, HOAs and renovation are my beat. But I also appreciate modern and historical architecture balanced against the YIMBY movement.  If you’re interested in hosting a Candysdirt.com Staff Meeting event, I’m your guy. In 2016, my writing was recognized with Bronze and Silver awards from the National Association of Real Estate Editors.  Have a story to tell or a marriage proposal to make?  Shoot me an email [email protected].

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Jon Anderson is CandysDirt.com's condo/HOA and developer columnist, but also covers second home trends on SecondShelters.com. An award-winning columnist, Jon has earned silver and bronze awards for his columns from the National Association of Real Estate Editors in both 2016, 2017 and 2018. When he isn't in Hawaii, Jon enjoys life in the sky in Dallas.

1 Comment

  1. JoanneCarter on July 17, 2022 at 9:18 pm

    4th floor of 4 storey senior complex. City freeway system adjacent to building. Relocating here from peaceful lake property the freeway noise is extremely annoying. Can’t sleep with bedroom window open, impossible. Can’t even sit on balcony to enjoy a hot day. The only people it doesn’t bother are the hard of hearing. Everyone says oh you’ll get used to it. I’ve tried, but am noise sensitive but not crazy! I’ve put a lot of effort into making this my final home, besides the noise I’m content. Any suggestions. I realize there must be rules for the complex. I’m hoping when construction is finished on a “sister” development right across from my suite, the noise level will be reduced. Any suggestions?

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