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Green Glue does not work..? Effects Pedals, Units & Accessories
Old 5th September 2011
  #1
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Green Glue does not work..?

Don't know, maybe this story is not fit for the forum, but I still would like to share it as I think somebody else might be having similar problem and they should not waste time with the solution I tried.

I live in a poorly consructed building and can hear my downstairs neighbors through the floor as if there is no floor - loud and clear.

This is what I used to have:
~~~~~~~~~~~~~~ old hardwood from 70s, 3/4 inch
________________ paper (yes!)
=========== old plywood
|| || || || beams with no insulation
------------- their ceiling

After reading on the web, I found out about magical Green Glue and believed it would help me. I have confirmed with the Green Glue company that usage of Green Glue is apropriate for the floor and did the following change for the entire apartment:

-------------- new 1/2 inch plywood screwed to the beams
^^^^^^^^^^^^^^ Green Glue at 1.5 - 2 tubes / sheet
=========== new 3/4 inch plywood screwed to the beams
^^^^^^^^^^^^^^ green glue at 2 tubes / sheet
=========== old plywood
|| || || || beams with no insulation
------------- their ceiling

25 days has passed and there is absolutely no difference compared to what it was before. And the sound does go through the floor, it is not flanking - I can hear it and the difference between sound from the wall and sound from the floor is obvious to me.

Can someone comment or suggest what else can I do to stop the sound? Or at least to reduce it? I am planning to put a carpet with padding on top, but f the sound is so strong that can pass 3 layers of plywood, I don't believe carpet would do any difference.
Old 5th September 2011
  #2
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Rod Gervais's Avatar
 

Sorry, but your problem is still flanking....... regardless of the fact that you believe it to be otherwise.

Green glue is good for what it does - which is dampen a panel - however it does not somehow magically decouple you from the structure below when you have a ton of direct connections in the form of the fasteners penetrating the assembly that give you a flanking path tied to that structure below.......

I'm sorry that you went to all this expense - added mass and green glue will help to some extent - however the lack of insulation and the fact that the ceiling below is not decoupled from the structure makes it very difficult to achieve any real level of isolation without then decoupling your floor from that structure....

An isolation mat with your wood floor floating on it would probably provide you with the best your going to get - although you must remember that your floor is also directly tied into the wall construction - which crates a whole different flanking path into your flooring below - it isn't just the flanking into the floor directly through the joists themselves......

This is a company who provides products to place between your new deck and the flooring above to decouple the 2........

Floor Underlayment, Underlayment, Acoustic Flooring

Good luck,

Rod
Old 5th September 2011
  #3
Gear Maniac
 

+1 to rod. If you dont believe its flanking you can test your walls. :D
Old 5th September 2011
  #4
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Thanks for replying... But what really surprises me is that there is absolutely no difference with the old assembly. Is that, hm, correct, expected, possible?

As per the floor - building rules require me to have carpet. The only carpet underlayment from your link says it is designed to reduce impact foot noise, helping my neighbors. How about something that would protect me? What if I add cork padding together with carpet pad - would that help me?
Old 5th September 2011
  #5
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Rod Gervais's Avatar
 

Quote:
Originally Posted by klotin View Post
Thanks for replying... But what really surprises me is that there is absolutely no difference with the old assembly. Is that, hm, correct, expected, possible?

As per the floor - building rules require me to have carpet. The only carpet underlayment from your link says it is designed to reduce impact foot noise, helping my neighbors. How about something that would protect me? What if I add cork padding together with carpet pad - would that help me?
It won't help to any really appreciable degree - except for your neighbors - who will not then hear you walk across the floor when you have shoes on. Carpet and pad are great to make direct impact sound go away. You really need decoupling for any appreciable difference here - by the way - what is it that you're actually hearing?

Rod
Old 5th September 2011
  #6
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Voice, music - that is what I hear.

But how can I decouple a carpet?
Old 5th September 2011
  #7
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Rod Gervais's Avatar
 

Quote:
Originally Posted by klotin View Post
Voice, music - that is what I hear.

But how can I decouple a carpet?
You can't decouple a carpet - carpet is already decoupled - you need to decouple what is beneath the carpet....... that's where the transmissions are coming from - and I am still not convinced your primary source of noise is the floor - your ears not withstanding.

If the source is the floor the frequency levels of speech should have definitely shown a marked increase in isolation.

Rod
Old 5th September 2011
  #8
Gear Maniac
 

voices from below are clearly heard? If so.. you got really poor STC
Old 5th September 2011
  #9
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Well, I can definitely be wrong, but that is what I hear... If they are talking downstairs - I hear the speech. Quite loudly. If I put my ear to the wall (either of them) I can hear same speech from the wall but far less loud than if lie down in the middle of the room and put my ear to the floor...

As I still have not covered the third plywood layer, I can remove part of the screws. Will it help decouple it somewhat, letting green glue work better? Or will it become squeaky instead?
Old 5th September 2011
  #10
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I think I have 24-32 screws per 2x4 plywood sheet. Is that too much?
Old 6th September 2011
  #11
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Rod Gervais's Avatar
 

Quote:
Originally Posted by klotin View Post
I think I have 24-32 screws per 2x4 plywood sheet. Is that too much?
Loosening screws will not help (but will make for a squeaky floor) and you need enough screws to make the floor work - I have told you what you need to do next - and have provided you with a link........... and still doubt that you will get what you need.....

The fact that you can hear a greater level when listening with your ear pressed to the floor is only due to the fact that it is a direct transmission source...... if you can hear it through the walls - even though at a lesser level - factor into this the fact that you have 4 walls transmitting the sounds to you - and only one floor.....
Old 6th September 2011
  #12
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mlange's Avatar
 

The Green Glue installed within the double-layered 5/8" drywall on my free-standing (decoupled) basement framing is definitely working

Thanks for the great product, Rod!
Old 6th September 2011
  #13
Gear Addict
 

I am curious to know if your neighbour has experienced any change in perceived airborne sound insulation.

You have not really increased the mass of the floor - the new 3/4-inch plywood may actually be lighter than the 3/4-inch hardwood it replaced and then you have only added added 1/2-inch of plywood on top. Based on the manufacturer's published test results, I wouldn't be surprised if the Green Glue is providing some improvement in your situation for your neighbour.

As others have said, there is very likely to be flanking transmission via the perimeter construction and this will limit what can be achieved by upgrading the floor only. We don't really know what the level of flanking is. If you are keen to proceed further, then flanking may be able to be reduced by installing new 16mm plasterboard to all the walls, using Green Glue as a damping layer. You could do this to one room only and see if it makes a difference.

Otherwise, what would have been better for you - if flanking is not an issue - would have been to have floated the new 3/4-inch + 1/2-inch plywood layers on a bed of load-bearing Rockwool. Obviously this has implications for ceiling height and door-head height in your apartment, as Rockwool at least 25mm and preferably at least 50mm thick would be recommended. It is not an ideal construction but it would significantly reduce the transmission of speech sounds and TV (again, if flanking is not an issue).
Old 6th September 2011
  #14
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Raj Smoove's Avatar
I have green glue in between 3 different layers of drywall and they provide a substantial amount of sound absorption. we can be cranked way up inside and by the time you get to the sidewalk outside it sounds like a tv is on at a moderate level.
Old 6th September 2011
  #15
Gear Addict
 

As Rod and others have said, the flanking is the problem. If you can clearly hear voices, you have flanking. Might you have baloon framing in the walls?
Old 7th September 2011
  #16
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I don't know what baloon framing is... I am tired and exhausted together with my wallet to do any additional experiments...

As per the weight of plywood vs hardwood - both are heavy. But I think that my hardwood was a little bit lighter than 3/4 plywood.

What depresses me the most is that the web is full with success stories and I have even reached out to support of the green glue website to see if I am doing a right thing and they confirmed it is a correct application scenario.

It might be flanking sound, it might be something else, but I want to stop it. Will just cover it with the carpet and forget about it.

If somebody is interested - in addition to the floor I did a change to the ceiling as well. My neighbor from above has very squeaky floor with old hardwood. Same hardwood as I had, but she has it covered it with the carpet.

I covered my entire ceiling with a quietrock 500 from lowees. With green glue between it and current ceiling. Also 20-25 days ago. The difference is very minor if any at all (can throw a number of 20% based on my feelings).

I can hear her every step and can track her movement based on the sound source position change. With my ears. Is that flanking? It is not coming from the walls, otherwise I would not be able to locate the source as she moves... no?
Old 7th September 2011
  #17
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Rod Gervais's Avatar
 

Quote:
Originally Posted by klotin View Post
If somebody is interested - in addition to the floor I did a change to the ceiling as well. My neighbor from above has very squeaky floor with old hardwood. Same hardwood as I had, but she has it covered it with the carpet.

I covered my entire ceiling with a quietrock 500 from lowees. With green glue between it and current ceiling. Also 20-25 days ago. The difference is very minor if any at all (can throw a number of 20% based on my feelings).

I can hear her every step and can track her movement based on the sound source position change. With my ears. Is that flanking? It is not coming from the walls, otherwise I would not be able to locate the source as she moves... no?
You're talking apples and oranges here.....

The sound from below is airborne - the sound from above is impact.......

In either case the answer to the problem is to decouple - you would have gotten better results from your ceiling if you had removed the existing drywall - insulated the cavity, properly installed RC2 and then installed 2 layers of 5/8" drywall - you didn't need to spend the money for the quietrock or the green glue.....

Coming to ask questions makes more sense before you spend a ton of money - not after......

Sorry,

Rod
Old 7th September 2011
  #18
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jhbrandt's Avatar
Quote:
Originally Posted by Rod Gervais View Post
....Coming to ask questions makes more sense before you spend a ton of money - not after......
+1 Rod.

that's what we're here for!

Cheers,
John

Last edited by jhbrandt; 7th September 2011 at 02:49 AM.. Reason: forgot quote
Old 7th September 2011
  #19
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Ok.. If I decide to go with the floatimg floor and need to have carpet on top - how do I attach plywood sheets to the underlayment so that the don't move and let me have carpet?
Old 7th September 2011
  #20
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Correction - how do I attache plywood sheets together so that they don't move and let me have carpet over it?
Old 10th November 2011
  #21
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Rod, what's RC2? I have a similar ceiling problem - Thank you.
Old 10th November 2011
  #22
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Rod Gervais's Avatar
 

Quote:
Originally Posted by Peegy Mik View Post
Rod, what's RC2? I have a similar ceiling problem - Thank you.
Peegy,

RC-2 is a resilient channel that has 2 legs to attach to structure - thus it is shaped like the track section used with RISC clips - however it has slots (or holes depending on the manufacturer) cut into both legs whereas standard track (sometimes called hat sections) has none.

Rod
Old 10th November 2011
  #23
Gear Addict
 

There is an RC-1 and an RC-2 and a 7/8" Drywall Furring Channel. The RC-2 is not Drywall Furring Channel, though they have the same shape. The DFC has a spec from the Steel Stud Manufacturer's association. RC-1 and RC-2 have no spec whatsoever.

Any company that bends steel products can produce RC-1 and RC-2 in any form they like. Might be 20, 22 or 25 gauge. Might have hemmed edges, might not. Might be solid, slotted perfed or otherwise modified. Since there is no construction standard for RC-1 and RC-2 you have no idea what you're getting.

If using resilient cips it's important to use a 25 gauge 7/8" DFC as spec'd by the SSMA.
Old 10th November 2011
  #24
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Rod Gervais's Avatar
 

Quote:
Originally Posted by Ted White View Post
There is an RC-1 and an RC-2 and a 7/8" Drywall Furring Channel. The RC-2 is not Drywall Furring Channel, though they have the same shape. The DFC has a spec from the Steel Stud Manufacturer's association. RC-1 and RC-2 have no spec whatsoever.
Phillips Channels has a good website that gives you a chance to see the differences between products -

Phillips Channels

Although Ted is correct that there is no standard for the RC series of products - good manufacturers do have their products tested - as noted on the Phillips' site - tests results are available upon request.

Rod
Old 10th November 2011
  #25
Gear Addict
 

Hey Rod. True enough most RC manufacturers say they have data, however while I haven't done a survey lately most RC manufacturers simply default to old USG test data for RC-1 and RC-2. I can only recall Dietrich having done any recent testing of RC products in recent history, and they sold out to Clark Western, so not sure what they are / will be doing. I don't personally track RC-1 or RC-2 testing because in even the best of circumstances they are fatally flawed products with a limit in terms of performance.

Actually, I believe the Phillips channel you linked references the old USG channel testing from a few decades ago, even though the product being referenced is different than what was originally manufactured and tested. I really am at a loss as to how they can even get away with that.
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