Cohousing-L Mailing List: Re: Soundproofing between stacked units in cohousing

[Bryan Bowen (bryan]

Hi - thought I'd add a little technical info.

There are two types of sound transmission between units like these:  impact
transmitted sound and airborne sound.  

Usually airborne sound (voices) is less of a problem.  I know at Wild Sage
we can't hear a chop-saw from unit to unit.  To fix airborne sound requires
different strategies from impact sound transmission.  Our only airborne
sound issues were due to window being open and having homes in close
proximity.  

Impact sound is the more common issue (footsteps, dragging furniture, bass
notes in music, etc as Sharon said).  To rectify this you have two choices:
absorb the impact or prevent it from transmitting.  

Absorption:  Soft surfaces like carpet over high density padding will make
the most impact. User behavior is also a big one.  

Isolation:  If you want a hard surface, you can float it over a soft
substrate: cork planks over foam (not homosote) for example.  This approach
won't work for tile, fyi.  Direct applied floor materials like marmoleum
also help, but aren't as effective.  You can also disconnect layers
throughout the floor-ceiling system.  In a rehab scenario, you can add a
layer of drywall to the ceiling for some improvement, or add a layer of
resilient channels (google it to see what they look like) and then a layer
of dryall.  It's a hassle, but there's an improvement.  Adding ceiling
insulation will also help to some extent.  

There's a ton of good information on the web.  Just look at manufacturers
sites.  Acoustimat, AccuQuiet, Maxxon...

The other thing we do in some commercial projects is to use sound masking.
Fountains or low music help prevent you from being distracted by noise.

If you ever have a technical question about a fix for something like this,
feel free to email me directly.  


b

bryan bowen architects, p.c.
1510 ZAMIA AVENUE #103   -  BOULDER, CO  80304  -   (303)443-3629
www.bryanbowenarchitects.com


-----Original Message-----
From: cohousing-l-bounces+bryan=bryanbowenarchitects.com [at] cohousing.org
[mailto:cohousing-l-bounces+bryan=bryanbowenarchitects.com [at] cohousing.org] 
On
Behalf Of Sharon Villines
Sent: Saturday, February 25, 2012 9:33 AM
To: Cohousing-L
Subject: Re: [C-L]_ Soundproofing between stacked units in cohousing



On 25 Feb 2012, at 11:06 AM, rhmorrison [at] aol.com wrote:

> Sharon V wrote recently that there is a similar issue with soundproofing
between their stacked units (at Takoma Village).

I'll add one thing. Most of the sounds we are aware of dampening are
dampened by soft surfaces. But in my limited study of acoustics I learned
that hard surfaces transmit sound and that it is the beams between the
stacked units that need attention too. If I put insulation between my
ceiling and the floor above, some noises would be dampened but other noises
would not.

What helped a lot was people purchasing furniture, which was done over the
year or two years after move-in. The noise at first was incredible.

Rugs help because sound is most easily stopped at the source. The heavy
furniture helped stop the vibrations moving through the beams. 

The solution I found would have meant tearing out the ceiling and putting
what I can only describe as braces between the beams. It's a manufactured
system - not just installed by a carpenter - but I've forgotten the name. 

The more you can do before you move-in the happier everyone will be. The
average construction grade, and we supposedly had better than average,
means:

1. Heavy walkers will be heard every time they walk and you will know when
they have had a bad day.
2. Running children, even babies, will sound like heavy walkers running
fast.
3. Two running children will be like a percussion orchestra.
4. Dropped cans, dishes, containers of silverware in the kitchen will be
sharp whaps.
5. Active lovemaking in the middle of the night will embarrass someone.
6. Sliding closet doors will be like chalk on a blackboard.
7. If you like to fight in the bathroom, don't. The hard surfaces, like
porcelain, reflect more sound.
8. Don't lift weights or run laps at home.

This sounds horrible which it isn't. No one does all these things at the
same time nor is everyone home to hear them at the same time. But I do live
in fear that a child will move in upstairs and that my downstairs neighbor
suffers when children visit me, as they often do.

Sharon
----
Sharon Villines
Takoma Village Cohousing, Washington DC
http://www.takomavillage.org




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