Author Topic: Impact Noise from Ceiling and Construction Issues  (Read 13385 times)

Bryan

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Impact Noise from Ceiling and Construction Issues
« on: January 02, 2014, 09:19:17 AM »
Hello:

First time post, lot's of good reading. Would be grateful for any suggestions for the issue I am having. A 25 year old condo that is concrete construction. I don't hear a lot of ambient noise from neighbors, unless they have a stereo really cranked up or using a shop vac. What is bothersome is the "impact" noises such as footsteps and cupboard slamming, things dropped on the floor. It is not significant, but more of a nuisance that is really starting to get on my nerves over the years.

I had to open up the bathroom ceiling to replace a fan and took some pictures of the construction. There is steel I frames spaced every 4 feet apart and 12" in height from the ceiling. I see a lot of things that I think are not very good for noise reduction.

-The furring channel is attached directly to the I beams with bailing wire?
-1/2" drywall was used throughout.
-The ventilation ducting runs through the I beams and makes contact with the furring channel as well direct contact with the I-Beams. (This may explain why I can hear the neighbors banging around   in their kitchen from my  bedroom. I suspect the vibrations are transferred through the I-beam to the ducting and amplified along the duct work where it passes over bedroom ceiling).
-The interior walls are not insulated.
-The interior walls are decoupled from the ceiling but are "shorted out by the furring channels,as well as from cross members of channeling to support electrical boxes.
-There is no caulking used to seal any holes where electrical is run through.

I am thinking of the following and would appreciate any comments on how much of a improvement I would gain.

-Use Genie or Whisper clips with the proper 25 gauge furring channel
-Insulate the interior walls
-Remove any short circuits from the furring channels contacting any of the interior walls
-Isolate the electrical boxes from the drywall.The cross members should connect to the I-beams not the furring channels
-Caulk all holes where electrical wires enters the walls
-Wrap the ducting with insulation and place some type of insulating material between the ducting and the I-beam members so there is no direct contact.
-Replace the 1/2" with 5/8". Perhaps use 2 sheets with green glue.

Thanks in advance

Randy S

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Re: Impact Noise from Ceiling and Construction Issues
« Reply #1 on: January 02, 2014, 11:33:59 PM »
From the photo's you posted you are on the right track, I would use our neoprene clip IS-1 instead of the ones you mention they will perform better.
isolate the channel from the side walls, use the 5/8" sheet rock with green glue.
any electrical boxes in the ceiling should be wrapped with putty pads..
and absolutely insulate the ceiling.

Remember, because you are doing the soundproofing from the receiving side you will still get some flanking noise down the walls.
 
Randy Sieg

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Bryan

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Re: Impact Noise from Ceiling and Construction Issues
« Reply #2 on: January 03, 2014, 03:03:06 AM »
Thanks Randy for your reply:

I am a little concerned about the differing views on insulating the ceiling cavity. Some say yes, some say no. What is the advantage of insulating for impact noise. I ahev 5" of concrete so can't see any advantage to added mass.

Where would i apply the insulation. Can it be laid on top of the drywall, but then won't this provide a short circuit if the insulation touches the cross members?

I did read some information that insulation would reduce the cavity space and thus change the resonance?. No whether that would be for the better or for worse i don't know.

Randy S

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Re: Impact Noise from Ceiling and Construction Issues
« Reply #3 on: January 03, 2014, 04:12:31 PM »
ok, so the remittance of impact is airborne sound therefore you are trying to trap and absorb what is coming through the concrete. I agree you dont need more mass for airborne sound from above the concrete but what will stop the remittance of impact?

The Batt insulation will Not short circuit the floated system that is only if you use expansion foam which is also minimal.

every soundproof system will have a resonance factor, this is because you are working across a large range of frequencies. In your case the flanking issue will be more noticeable than a resonance factor. Those type of problems are normally in recording studios and such that pick it up on microphones or if you are trying to stop a specific frequency only.
 

Randy Sieg

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888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

Bryan

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Re: Impact Noise from Ceiling and Construction Issues
« Reply #4 on: January 03, 2014, 09:17:36 PM »
Thanks very much Randy. Did some googling last night and there was a few sites that mention insulation can actually be considered part of the air cavity because of it's minimal density. However one recommendation was not to compress it in a fashion that a air space is created below, before the drywall  or the triple leaf effect could come into play.

On the reasonance, I thought the idea was to try and design, use materials to keep it the frequency as low as possible  for example 20hz reasonance is better than 40hz etc, but I suppose to do that one is getting into the realm of having sound engineers assess all the parameters.

So to sum up I can go ahead and add a layer of insulation rfinerglass or rockwool bats on top of the drywall and not worry about crossing over the furring channels etc.

Any suggestions on how to attach the resilient clips to the steel iframes.??. I see no option but to drill and use bolts. I do have another thought on it that may make my work easier and I will do up a drawing. Basically adding members across the steel ibeams and have the furring channels running parallel with the Ibeams. Gives me more control of where I can place the resilient clips. Easier if I post a drawing

Randy S

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Re: Impact Noise from Ceiling and Construction Issues
« Reply #5 on: January 04, 2014, 05:27:26 PM »
The insulation will not and can not create a triple leaf effect, that is only created when you have rigid material in play, insulation is an absorption product not reflective. So your ok on the insulation.

You are correct when you approach this project based on resonance...I have had similar projects in the past which people attempted this and the difficulty level is high and your only changing it from one frequency to another..either way you will still have one in the end...and to top it off your flanking value will still most likely be more noticeable anyway because your are not addressing the problem at the source side.

For the clip installation, if you have the room you could do furring strips and then add clips and channel. There are other methods as well but they do get more expensive.
Here is a link that you can review different mounting methods.

http://www.kineticsnoise.com/arch/isolated_ceilings.html


Randy S.

Randy Sieg

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888-942-7723
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Fax.760-752-3040

Bryan

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Re: Impact Noise from Ceiling and Construction Issues
« Reply #6 on: January 05, 2014, 11:07:18 AM »
Thanks Randy.

I will insulate then. Just going back to the issue with"flanking". Yes unless I completely decouple the exterior walls, and the flooring it is something I am going to have to live with. Ffor example this morning I could hear someone slam a cabinet. i know the neighbors above me are away and the unit next to me is vacant awaiting sale. So the sound had to come from somewhere in the building. Concrete is great for the mass and stopping ambient noise, but from what I read the transmission of sound waves through concrete something is something like 10,000 FPS and "impact" noise can travel easily unimpeded through concrete.

I am pretty confident that with the deficiencies I have identified earlier after opening up the ceiling I can certainly make a great improvement

Thanks for the link on the methods of clips and furring. I am going to post another post on a possible solution if you don't mind for furring and channeling, need to take some pics.

P.S. Going from the pic attached, any other recommendations for isolating any sound transfer through the ducting. I am positive that sound vibrations from the concrete ceiling is being transmitted through the steel  I-Beams and into the ducting which it contacts. I was as going to line the outside of the ducting with insulation such as this. But wonder what material you would recommend to "stick" between the ducting and the steel I-Frame. 

http://www.homedepot.ca/product/duct-insulation-sleeve-4-inchx10-foot/964004







Randy S

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Re: Impact Noise from Ceiling and Construction Issues
« Reply #7 on: January 06, 2014, 04:59:55 PM »
Your right on the money and yes isn't the concrete amazing(10,600 fps :) ) when it comes to impact noise...glad to see you have done your research.
since you have hard ducting and not flex duct, I would use a btter material geared for sound.
Here is the link to review.
http://www.supersoundproofingsales.com/SSP-Foam-Mat-1_2-thick-by-48-wide-with_PSA-per-foot/productinfo/09-42725-PSA/
Randy Sieg

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888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

Bryan

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Re: Impact Noise from Ceiling and Construction Issues
« Reply #8 on: January 07, 2014, 09:02:21 AM »
 Hi Randy:

I could swap out the ventilation duct for the bathroom with insulated flex, but probably just going to gain the same efficiency by lining the exterior with the insulation tubing. Have to use hard ducting for the kitchen exhaust. Code will not allow flex.

Does the foam mat you referenced compress at all. the ducting fits pretty tight between the I-Frame in places so may have to bang in some dents to slip in the matting.

Randy S

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Re: Impact Noise from Ceiling and Construction Issues
« Reply #9 on: January 08, 2014, 06:33:42 PM »
yes the foam mat will compress to a degree. you definitely want to break any connections from the duct to any ceiling channels or I-frames.
 
Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

 

anything