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          Mark Saville 2012    

Mark: I am trying to make effective use of a basement space below a
 residential space in an industrial building. I am concerned that noises
 from the basement uses will interfere with the resi tenants living above.
 I am thinking of using resilient channels for the ceilings. The space is
 about 28 ft by 28 ft and the ceiling joists are about 16" on center.




 Will insulation help with sound transmission or is dead space better?
Will furring strips attached to the joists with sound suppressing tape on
 the resilient channels help with sound transmission?
Have you any video of a sound suppressed ceiling installation??

 Thanks in advance,   Harry

resilient barHi Harry,
Thanks for you questions and interest in the site.
Resilient channel is perfect for your application as it will stop the sound vibration through the joists.
 You only screw one side of the channel to let it float. Make sure you don't screw through the channel and into the
 joists when installing your drywall.
 Also fill the joist space with insulation to help deaden the sound.
 You can also use the tape or acoustical caulking which gives better

 I don't have a video on this application yet, I have some videos up my
 marksavillechannel  on youtube.

 If you have more queations, just ask.




 Hi Mark 

Do you know what is the STC rating for a hardwood floor with 10" joists?

To that number I suppose the resilient channel will add 10 STC points.
The Quiet Rock adds 10 more
The cavity with insulation adds just 3 Sheet rock 5/8  adds just 3.

Since the Quiet rock is a finished product I don't intend to add sheetrock.

Can you think of other stuff I can add to enhance the STC ratings?  Is
there a tape I can add to the joist before I screw in the resilient

Thanks for your advice.




resilient channel
                      An example of resilient channel. Photo Mark Saville.

 Hi Harry,

I haven't actually used the Quiet Rock but have read that it is
 a good product.
 Roxul Safe'n'Sound Insulation is also a good bet for the cavity.
 I know some are going with R channel, 5/8" then another R channel
 and another 5/8" making a very good structure, all depends on
 how much a person wants to spend and what number you're looking for.
 You can actually attain around 60 total with that system.
 As far as the building code is concerned a minium of 50 total is required.
 I would guess the flooring and joists would be some where around 25-30.
 There is also the accoustical caulking Green Glue you put between layers
 of sheetrock which can be used between the R channel and sheetrock.
  Hope this helps?


Hi Harry,

The channel needs to flex away from the joists to
be effective but you can put an accoustical caulk
in between the fastening flange and the joist.

I think if you fill the space with insulation,
use the channel and a layer of quiet rock you
should get 50 or more.
The hardwood may not be as good as subfloor depending on the joints.
I figure your existing floor should be around 30
compared to a 2x4 wall with 1/2" sheetrock both sides, no insulation is around 33.


Mark: Thanks.

My architect told me that the 1" hardwood floor and the joist together
gives a rating of 37.  I thought that seemed too high as we can hear
conversations between the two spaces as if they were in the same space!!

But the Quiet Rock and resilient channel adds 20 so whatever the number for the
floor this should augment it.

Is there something that can be attached to the noise between it and the
resilient channel ?  Or is that unnecessary given the flexing of the
channel itself?

And I think I shall skip the sheetrock since it only added 3 to the score
and is heavy
Mark: Thanks for the advice. I did do a resilient ceiling under the joists
as suggested and used 6" of insulation in the joist spaces and Quiet Rock.
I will now apply compound and test for sound.

1.   Do you know a simple and not too expensive way of checking the sound
suppression characteristics?

Hi Harry,

Glad I could help.

If you can find a db meter you could test it that
Low frequency seems louder to the human ear than high so if you play a stereo with the bass really loud on one side,
test the db level with the meter, then test on the quiet side,
if the sound is 100 db on the loud side and 50 on the quiet side,
you've attained a STC of 50.

If you have a smart phone with a recording feature, you can probably
get an application that tests sound levels. 









Mark Saville 2011 Reprint with Permission only.

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