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Sound Proofing Wall
Old 23rd July 2013
  #1
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fasttraxx's Avatar
 

Sound Proofing Wall

Need help sound proofing a wall. It's for a school wall that's adjacent to the band room. The room is going to be a studio control room of sorts. We are not allowed to do any construction (sheet rock, build anything) other than applying something to the wall itself in the form of staples, velcro, etc... And we can only apply sound proofing to the the inside of the control room. Our goal is to stop as much sound from the adjacent room as possible. I know this isn't a good situation as we cannot really sound proof they we really need to, but we are going to do our best with the given situation.
Our goal is to try to stop as much sound from the adjacent band room as possible.
So far our thoughts have been to apply MLV (mass loaded vinyl) or DB3 to the wall and then apply acoustic wedge foam for the control room reflections and cosmetics, and hopefully it will stop some of the sound transmitting from the band room. I have never used MVL, and not sure if it works good or not.

Any thoughts would be appreciated...
Old 23rd July 2013
  #2
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sheggs's Avatar
Unfortunately it isn't going to create the sound isolation you require. The only way to do that is via construction
Old 23rd July 2013
  #3
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A few points:
  1. Being commercial construction you may have utilize some different approaches and materials than for residential construction.
  2. It usually makes sense to first try to get the most from what you already have. Sometimes simple, easy treatments like sealing gaps and joints can make a significant difference.
  3. While the intervening wall is an obvious sound path don't forget 'flanking' paths such as shared ductwork, back-to-back power receptacles and so on.
  4. How much improvement you may be able to achieve can depend greatly on what is already there. With the limitations noted the improvements that may be possible with a simple framed wall that stops at the ceiling could be much different than if you already have a sealed and grout filled CMU wall that runs all the way to, and is sealed to, the structure above.
Old 24th July 2013
  #4
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Thanks for the thoughts guys. I agree with what you guys are saying as this is my obstacle. Not sure if the investment for MLV (mass loaded vinyl) is worth it or not.
I know we are getting a lot of sound around the door and we are sealing around it and under neath it. I believe this is much of the sound problem. As for the ceiling, the walls are so suppose solid and separate I'm told, meaning they go all the way to the roof making a barrier between the two rooms.

Anyone try roxul for sound proofing instead of MLV?
Old 24th July 2013
  #5
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MuseAV gave great advice.

Mass not firmly attached to the walls will do nothing. Beyond that MLV is overpriced for what it does in studio applications. Roxul material etc. on walls does nothing for isolation.

Andre
Old 24th July 2013
  #6
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If you can't add mass to the walls - then seal up the doors and you are pretty much done with whatever level of isolation that brings you..... this because your hands are (effectively) tied......

Unless your school was constructed pre 1970 the odds are that you do not have back to back outlets (this due to the fire safety codes) pre 1970 you might - and if you do sealing them effectively is problematic.....

If you can remove whatever baseboard you have you could check the bottom of the wall for caulking - and add if it doesn't exist........

But without adding mass to the face of walls - you are not going to make it very far.....

Rod
Old 25th July 2013
  #7
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Quote:
Originally Posted by avare View Post
MuseAV gave great advice.

Mass not firmly attached to the walls will do nothing. Beyond that MLV is overpriced for what it does in studio applications. Roxul material etc. on walls does nothing for isolation.

Andre
I can apply MLV to the walls via staples, so not sure how firmly I can acheive by this. Are you saying this is really not a good choice as a sound barries for this particular sitiuation?
Old 25th July 2013
  #8
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MLV is VERY expensive mass...... it can help - however you are locked into certain things that put you in a position where it simply (most probably) will not make sense.........

For example - you cannot seal the edges of that to anything - and a great amount of sound can escape the edges of isolation systems (for example - a 1/16" crack along the bottom of an 8' wall is the equivalent of punching a hole through the wall 2" x 2" in size.

In fact - the single greatest loss of isolation between rooms located on either side of a wall assembly is inadequate attention to detail when assembling the walls.......

I have field tested walls that were a fully 30dB (weighted average) below their lab tests - and 10dB variances are expected - all due (in either case) to conditions in the field related to flanking and application.......

To expect any meaningful results simply through stapling some mass to the inside face of the wall is grasping at straws (at best) and may well be (for all intent and purpose) meaningless when all is said and done.......

If you want to give it a shot - go for it - but don't expect much of an improvement.....

Rod
Old 26th July 2013
  #9
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Quote:
Originally Posted by Rod Gervais View Post
MLV is VERY expensive mass...... it can help - however you are locked into certain things that put you in a position where it simply (most probably) will not make sense.........

For example - you cannot seal the edges of that to anything - and a great amount of sound can escape the edges of isolation systems (for example - a 1/16" crack along the bottom of an 8' wall is the equivalent of punching a hole through the wall 2" x 2" in size.

In fact - the single greatest loss of isolation between rooms located on either side of a wall assembly is inadequate attention to detail when assembling the walls.......

I have field tested walls that were a fully 30dB (weighted average) below their lab tests - and 10dB variances are expected - all due (in either case) to conditions in the field related to flanking and application.......

To expect any meaningful results simply through stapling some mass to the inside face of the wall is grasping at straws (at best) and may well be (for all intent and purpose) meaningless when all is said and done.......

If you want to give it a shot - go for it - but don't expect much of an improvement.....

Rod
I appreciate your comments and honesty. I was thinking MLV might be a waste, and this is why I am here to ask you guys that really know this stuff.
Thanks, I will save the money and do the obvious stuff first (like door gaps, etc...) and see what we get and go from there.
Old 26th July 2013
  #10
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Not sure if the investment for MLV (mass loaded vinyl) is worth it or not.thank you
Old 26th July 2013
  #11
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Quote:
Originally Posted by fasttraxx View Post
Thanks, I will save the money and do the obvious stuff first (like door gaps, etc...) and see what we get and go from there.
Yes, look into the possibility of adding another layer of 5/8" drywall once you go over all the seams with acoustic caulk. Also, replacing hollow doors with solid core, weatherstripping, and threshold installing are little details that will help a lot. Good luck!
Old 26th July 2013
  #12
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Herman,

I would be pretty surprised to find hollow core doors in a schools setting........ I've worked in a lot of schools over the years - and can't think of one where that was the case...

To the OP.... If you are the one willing to fund (or otherwise raise money for this outside of the school budget) this I cannot (for the life of me) understand why the school would not allow you to add mass to those walls........ you would be improving the infrastructure of the school - as such the "gift" to them should be happily received.

Speak to them about this again and explain how it will enhance the learning experience of the students involved......

Rod
Old 26th July 2013
  #13
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Quote:
Originally Posted by fasttraxx View Post
As for the ceiling, the walls are so suppose solid and separate I'm told, meaning they go all the way to the roof making a barrier between the two rooms.
They're supposed to be, but are they? Too often someone decides that close to the bottom of the deck was good enough or someone comes in after construction and punches holes to run cables, etc. Unsealed penetrations and gaps are usually much more likely if the walls are not fire rated but it would be far from the first time I had seen a supposedly rated wall with unsealed penetrations.

The effects of adding mass are relative. If you have something like a single layer of 1/2" gypsum board then adding another layer of 1/2" or 5/8" sheetrock may make a noticeable difference, but if you already have a couple of layers of 5/8" gypsum or CMU block or something more massive then that same change will have less, and possibly negligible, effect.

Due to policies and liability issues, and especially if this is a public institution, I can see there being factors involved such as any modifications of walls having to be reviewed by certainb parties and performed by an approved, licensed contractor.
Old 26th July 2013
  #14
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Quote:
Originally Posted by Rod Gervais View Post
Herman,

I would be pretty surprised to find hollow core doors in a schools setting........ I've worked in a lot of schools over the years - and can't think of one where that was the case...

Rod
Ah yes, they are supposed to be fire doors
What if they are not though? You never know.

I would work things out with the school. They may have to get an inspection and somebody licensed to do the work.
Old 27th July 2013
  #15
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It's a pretty solid metal door. The school is 13 years old. And like I said before we cannot put up any sheet rock, etc...
Old 27th July 2013
  #16
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Rod Gervais's Avatar
 

Quote:
Originally Posted by fasttraxx View Post
like I said before we cannot put up any sheet rock, etc...
Then you have your answers - which are

1) Check to see if anything that you can touch needs to be sealed"

and

2) Other than that - you really can't do anything meaningful.........

Rod
Old 27th July 2013
  #17
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Quote:
Originally Posted by HermanV View Post
Ah yes, they are supposed to be fire doors
What if they are not though? You never know.

I would work things out with the school. They may have to get an inspection and somebody licensed to do the work.
That sounds like the answer. Good luck with your endeavor.
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