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Sound bar under ceiling drywall?

ForceFed70

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I was talking to the inspector today about drywall requirements for the ceiling in my shop.

Since there will eventually be living space in the attic above the shop, I wanted to confirm that 2 layers of 5/8th drywall was required.

He said that 2x 5/8th would work but reccomended I use sound bar and a single layer of 5/8th instead. He said that the sound bar will give the same fire rating (why 2 layers of drywall would be required), will result in better sound proofing, and is cheaper.

What do you guys think? Anyone have experience using sound bar or a similar product?
 
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ForceFed70

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Thanks. I am aware of what it is. Was just looking for feedback as to whether it's a good idea or if I should just go with 2 layers of drywall.
 

Monkey Radio

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Normandy Park WA
I would go two layers of 5/8.Using RC Chanel is not going to give it a fire rating. the living space above requires two layers. I helped built a sound proof garage with RC Chanel sound insulation and drywall. And then furred out all the walls and did it again. It was still pretty loud
 

Zengineer

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Won't do ****** all for fire rating. For sound, put as much batt insulation as you can in the rafters, use the resilient channel, and the 5/8" over that. It's a pretty cost effective system that does a good job at reducing sound transmission.
 
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ForceFed70

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I will need to look at the specs but the inspector seemed to think it was good for the fire rating. He said that with drywall it's the heat transfer you need to worry about as the drywall itself doesn't burn. The sound bar keeps the drywall away from the wooden trusses and prevents the heat transfer like a 2nd sheet of drywall would.

I like to idea of better sound insulation and cheaper! But don't want to regret it in the end.
 
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RivennHewn

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Look up 2 hr. fire rated ceiling assemblies online.

You can't just cram the joist bays with insulation.

You have to follow the rated assembly exactly like it's described.

You should be able to find different assemblies for RC and double rock.
 

Stretch660

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Feb 13, 2008
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North Canton, OH
Those Iso clips are the bomb for eleminating sound transfer (nothing to do with fire rating). I just built a sound room in a basement for a guy who was in a band and now he and the 4 others in the band can practice in the room in his basement and up stairs it just sound like a person watchin TV with the volume turned up a bit. For sound transfer I highly recommend them. Granted we also did use the iso clips with 2 layers of 5/8 drywall and Green accoustical glue between the 2 sheets.

Customer was extremely happy. Now have a few more to do as a result.

Just my 2 cents
 

rlitman

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Long Island
Those Iso clips are the bomb for eleminating sound transfer (nothing to do with fire rating). I just built a sound room in a basement for a guy who was in a band and now he and the 4 others in the band can practice in the room in his basement and up stairs it just sound like a person watchin TV with the volume turned up a bit. For sound transfer I highly recommend them. Granted we also did use the iso clips with 2 layers of 5/8 drywall and Green accoustical glue between the 2 sheets.

Customer was extremely happy. Now have a few more to do as a result.

Just my 2 cents

Yup, that's how to do it.
It's also important to seal the gaps between sheets (in corners, around boxes, etc) for the most sound dampening. The green glue is very good for that.
 

K'ledgeBldr

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Aug 22, 2011
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Johns Creek, GA
Here's one of my previous posts that cover your concern-
http://www.garagejournal.com/forum/showpost.php?p=1701420&postcount=15

I don't know if it was implied or no one knew that the 5/8 needed would be 5/8 type "X".
That's the fire rated version. And a double layer is over-kill and not necessary unless, the convening authority has amended the code for their jurisdiction.
Resilient channel isn't exactly all it's cracked-up to be- though it does help lower the "transfer of sound waves". As far as heat transfer- instead of using regular f/glass batt insulation, use batt rockwool. Rockwool has a higher heat temp resistance and has a naturally better sound attenuation because it's heavier than stand f/glass batt. Rockwool has an R-value rating of approximately 3.5 per inch.
 
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