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For room-in-a-room, should I attempt some isolation between walls and slab?
Old 5 days ago
  #1
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For room-in-a-room, should I attempt some isolation between walls and slab?

I'm building a room in a room on top of a concrete slab. My concern is with keeping sound from leaving the building (other areas on the same slab are not of particular concern). Should I build the interior room directly mounted to the slab, or attempt to isolate it a little with flexible material? We're considering this stuff:

https://kineticsnoise.com/arch/wallmat.html
Old 5 days ago
  #2
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Kyle P. Gushue's Avatar
No. Earth dampened concrete will not transmit sound nearly as easily as the walls and ceiling, unless they are also earth dampened concrete of the same mass as the slab. So the slab is not the weak point, sound will exit the walls easiest floated or not.
Old 5 days ago
  #3
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Thanks for the reply. I'm getting mixed messages on this. John Sayer said recommended 1/2" rubber, not just for isolation, but also due to possible unevenness in the floor to all mating. I haven't quite figured out how to think about it acoustically.
Old 5 days ago
  #4
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Starlight's Avatar
 

I know we are told it is not necessary but I happened to notice a certain studio in Joao B.'s Arda Recording Company - New Studios in Porto, Portugal that they put a Sylomer base to each of the studio walls - see the photos in post 56.
Old 4 days ago
  #5
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Kyle P. Gushue's Avatar
Quote:
Originally Posted by Mastiff View Post
Thanks for the reply. I'm getting mixed messages on this. John Sayer said recommended 1/2" rubber, not just for isolation, but also due to possible unevenness in the floor to all mating. I haven't quite figured out how to think about it acoustically.
Ive used shims to support the pressure treated footers on a slab that had a dip on one area. The booth is freestanding with ceiling resting on the inner walls. 10 years+ no issues.

You can level the concrete or fill voids with concrete and a trowel, or self leveling concrete. Ive chipped high spots down with a hammer and/or chisel.

Since your not gaining any isolation worth noting, there is no reason i know of to use a relatively expensive "acoustical" branded product for "possible uneveness".

First step would be to verify the slab is level and void of protrusions.

Rods book simply illustrates the footers pinned to the ground with spikes shot in by a powder accuated nail gun (like a hilti gun or ramset).

Last edited by Kyle P. Gushue; 4 days ago at 03:05 AM..
Old 4 days ago
  #6
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The product that you linked there isn't for a true room in a room construction. If you look at the assembly diagrams, the wall isn't individual framing.

You're planning individual framing for both walls and ceiling of the inner leaf right?

I did use this product-

http://www.acoustiguard.com/products...isolation.html

But my thinking was it's pretty cheap, and provides more of a continuous seal against the floor...
Old 4 days ago
  #7
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I think it's for under the wall. Here's the actual drawing:

For room-in-a-room, should I attempt some isolation between walls and slab?-wallmat.png

But maybe I misunderstand your comment. Yes, the interior room is not touching the surrounding structure anywhere, except via the concrete slab floor. That is where this stuff is planned. So with respect to the picture, remove one piece of drywall (and put it on the other side to double up) and that's what we're doing.
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For room-in-a-room, should I attempt some isolation between walls and slab?-wallmat.png  
Old 4 days ago
  #8
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Kyle P. Gushue's Avatar
Quote:
Originally Posted by RyanC View Post
The product that you linked there isn't for a true room in a room construction. If you look at the assembly diagrams, the wall isn't individual framing.

You're planning individual framing for both walls and ceiling of the inner leaf right?

I did use this product-

http://www.acoustiguard.com/products...isolation.html

But my thinking was it's pretty cheap, and provides more of a continuous seal against the floor...
The technical data sheet on the website doesn't seem to provide any data showing how effective it is at reducing sound transmission. Did you get any numbers from them before using it?

Using backer rod and caulking around the perimeter of the drywall (including the bottom) is an effective seal, as described in rods book and the usg construction manual.

Im not sure whats to be gained sealing the footer when 1.5" above the footer isnt sealed, its an open cavity filled with insulation.

And flanking isn't an issue because the resonant frequency of the wall is (generally) much higher than the resonant frequency of an earth dampened slab.
Old 4 days ago
  #9
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Kyle P. Gushue's Avatar
Quote:
Originally Posted by Mastiff View Post
I think it's for under the wall. Here's the actual drawing:



But maybe I misunderstand your comment. Yes, the interior room is not touching the surrounding structure anywhere, except via the concrete slab floor. That is where this stuff is planned. So with respect to the picture, remove one piece of drywall (and put it on the other side to double up) and that's what we're doing.
Kinetic doesn't provide test data either on their website. They claim "up to 10 stc points" but don't state on what type of assembly, or at what frequency. Stc is useful for voice frequency ranges not music.

Before buying a product its necessary to have the test data (full report not just the numbers) to verify its effective in your use case.

Good marketing is going to word things so it seems most appealing to the most people.

When you look up a product like Risc-1 clips for example, the website (pac international) shows the test data based around numerous different assemblies. The information is made readily available, they dont hide behind vague, suggestive language. They show how effective it is for each assembly.
Old 1 day ago
  #10
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Quote:
Originally Posted by Kyle P. Gushue View Post
The technical data sheet on the website doesn't seem to provide any data showing how effective it is at reducing sound transmission. Did you get any numbers from them before using it?

No and I'm sure they don't have any

We built a lot of the walls inside-out, so they had to be drywalled on the floor and stood up. To me the sill mat was relatively cheap and also (probably) helped make sure that a 2500lb wall segment wasn't going to slip on the floor.

But you're absolutely correct in that I really have no idea if it was 'worth it'. I also used 5" x 1/2" titen HD bolts (which can be found much cheaper on ebay), between each stud, so that the sill plates were sucked really tight against the floor.

But agreed in general that these products don't make a whole bunch of sense, even in the first place. If the concern is that vibrations from the wall will get transferred into the floor, then logically those same vibrations will get transferred into the floor in the room in the first place. Especially if the drums are sitting on the floor anyway...there is no way that the wall is going to add to the vibrations that are already there via flanking (to whatever extent that they don't get damped).

I did read some anecdotal stuff over at the Sayers forum, the one woman from Australia used a similar product in one room and not in another IIRC, and said something to the effect of she would have used it in the others if she had it to do again...I figured why not, considering that it isn't adding much in the way of cost. I still sealed it with tremco acoustic sealant (nasty stuff) too.
Old 1 day ago
  #11
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Kyle P. Gushue's Avatar
Quote:
Originally Posted by RyanC View Post
No and I'm sure they don't have any

We built a lot of the walls inside-out, so they had to be drywalled on the floor and stood up. To me the sill mat was relatively cheap and also (probably) helped make sure that a 2500lb wall segment wasn't going to slip on the floor.

But you're absolutely correct in that I really have no idea if it was 'worth it'. I also used 5" x 1/2" titen HD bolts (which can be found much cheaper on ebay), between each stud, so that the sill plates were sucked really tight against the floor.

But agreed in general that these products don't make a whole bunch of sense, even in the first place. If the concern is that vibrations from the wall will get transferred into the floor, then logically those same vibrations will get transferred into the floor in the room in the first place. Especially if the drums are sitting on the floor anyway...there is no way that the wall is going to add to the vibrations that are already there via flanking (to whatever extent that they don't get damped).

I did read some anecdotal stuff over at the Sayers forum, the one woman from Australia used a similar product in one room and not in another IIRC, and said something to the effect of she would have used it in the others if she had it to do again...I figured why not, considering that it isn't adding much in the way of cost. I still sealed it with tremco acoustic sealant (nasty stuff) too.
One thing i find interesting is ive not seen any accounts of floating walls making things worse acoustically, than they otherwise would be, it seems its a financial thing.
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