Author Topic: Sound reduction in common wall  (Read 3241 times)


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Sound reduction in common wall
« on: May 10, 2016, 03:30:55 PM »
Hi My name is Andrew! I am a small builder and remodeling contractor. I have done some research on various soundproofing methods and products. We have done a home theater room in a basement with Resilmount clips, hat channel, double 5/8" TypeX with GG between the layers.
I understand decoupling is the best way to go if you can.

Now my question...I was asked to look at a common wall. There is an office on one side and an apartment on the other. The existing wall is a firewall. It has 2 layers of 5/8" on each side of a metal framed wall. It is a concrete floor. The office side has a drop ceiling. The firewall extends all the way to the framing/drywall above the drop ceiling. They each complain of noise through the wall.

Can I mount A237r clips over the existing double 5/8" and add the furring and one layer of 5/8"? I would cut the suspended ceiling back so that the new assembly could go to the ceiling above. All corners would be held back and sealed with acoustical sealant. I also would try and seal up the outlets and use some sound pads behind the covers. Any reason this won't work? All HVAC is completely separate between the 2 units. Being that it is a firewall I would prefer not to have to demo it down to the framing.


  • Guest
Re: Sound reduction in common wall
« Reply #1 on: May 10, 2016, 04:38:50 PM »
Or would I be better just adding another layer of 5/8 with GG? I could cut back the drop ceiling and run the 3rd layer up to the existing ceiling and caulk the perimeter with acoustical sealant.


  • Guest
Re: Sound reduction in common wall
« Reply #2 on: May 10, 2016, 08:33:30 PM »
Ok So I spoke with someone with GG and they say I could expect an approx gain in the STC rating of 8-9 if I added a third layer of 5/8" on each side of the assembly with GG in between and caulked the perimeter with sealant. My assembly right now has an approx STC of 44 +/-.

I could probably expect closer to 60 if I removed one side of drywall to the studs and did the clips, channel, and double 5/8" with GG.

Certainly open to other ideas...

Randy S

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Re: Sound reduction in common wall
« Reply #3 on: May 10, 2016, 09:46:18 PM »
You would create a triple leaf system...if it is just for human speech fine, not for low frequency.
If you found your system for the theater met your expectations then do it for the shared wall.

always run walls to deck with soundproofing. never cut a soundproof wall at the grid ceiling system.

Randy S.
Randy Sieg

Super Soundproofing Co
Ph. 760-752-3030


  • Guest
Re: Sound reduction in common wall
« Reply #4 on: May 11, 2016, 12:30:17 AM »
Thanks for the reply Randy! The more I am looking at things I am leaning that direction. Plus with the wall open I can address any outlet boxes that are possibly leaking noise.

I definitely will cut back the drop ceiling either way to further isolate it.