Author Topic: Condominium Ceiling Cost/Benefit  (Read 4749 times)

Ken Johnson

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Condominium Ceiling Cost/Benefit
« on: February 20, 2001, 01:53:55 AM »
I live in a very nice condominium with a rather poor ceiling separation between the upper and lower floor.  Our upstairs neighbor is not cooperative, so soundproofing his floor is not an option.  I have extensively reviewed your site and reviewed the EPA reprint and found it very helpful.  At this point, I need to know what will provide the most benefit and then balance that with the cost that I will pay to decide how much of the retrofit to do.
The current floor ceiling costs of layers as follows:
1) carpet 2) 1/2" carpet pad 3) 3/4" plywood 4) open web trusses spaced 24" on center (the floor/ceiling nailing surface is essentially a 3-1/2" wide surface) 5) 5/8" drywall on the underside of the truss.  
There is no insulation between the drywall and the plywood.  This airspace is approximately 14" deep.  I can hear my neighbors shouting quite easily, and his footsteps (he is a loud walker) and music/tv are also quite noticeable.  Based on this, I believe my STC is about 35.  
Based on what I have read, I believe the following actions will improve the STC and IIC:
1) Add 5-6" layer of dense, blown-in cellulose insulation to the existing ceiling cavity via ceiling cutouts that are plugged after the insulation is blown-in.
2) Prepare the ceiling according to the EPA recommendation with 1" furring strips fastened along the existing joists, the resilient channel perpendicular to the furring strips.
3) Add a layer of 1" fiberglass insulation between the furring strips
4) Attach 5/8" drywall to the resilient channel, taped and edge-detailed as described in the EPA reprint.  
Questions are as follows:
1) Is the extra 1" of insulation between the furring strips going to do a whole lot if I also put the blown-in cellulose in?
2) Is the blown-in cellulose going to do much?
3) Will reducing the thickness of the furring strips from 1" to 1/2" affect the sound reduction?
4) Wouldn't running the furring strips perpendicular to the joists, then the resilient channel perpendicular to the furring strips be even better, provided that the furring strips were thick enough to support the drywall weight?
I am hoping to achieve an STC in the range of 55, and a corresponding increase in the IIC also.  Will what I do achieve that?
Last question - would I be better to forego the blown-in insulation, instead rip out the old ceiling, put in 5-1/2" thick fiberglass batts, attach resilient channels to the bottom of the exposed joists, then new 5/8" drywall to the channel?  
Any help would be much appreciated.  I am looking for some good, practical help.  Thanks in advance.

Randy - Super Soundproofing CO

  • Guest
Re: Condominium Ceiling Cost/Benefit
« Reply #1 on: February 21, 2001, 03:55:14 AM »
: I live in a very nice condominium with a rather poor ceiling separation between the upper and lower floor.  Our upstairs neighbor is not cooperative, so soundproofing his floor is not an option.  I have extensively reviewed your site and reviewed the EPA reprint and found it very helpful.  At this point, I need to know what will provide the most benefit and then balance that with the cost that I will pay to decide how much of the retrofit to do.
: The current floor ceiling costs of layers as follows:
: 1) carpet 2) 1/2" carpet pad 3) 3/4" plywood 4) open web trusses spaced 24" on center (the floor/ceiling nailing surface is essentially a 3-1/2" wide surface) 5) 5/8" drywall on the underside of the truss.  
: There is no insulation between the drywall and the plywood.  This airspace is approximately 14" deep.  I can hear my neighbors shouting quite easily, and his footsteps (he is a loud walker) and music/tv are also quite noticeable.  Based on this, I believe my STC is about 35.  
: Based on what I have read, I believe the following actions will improve the STC and IIC:
: 1) Add 5-6" layer of dense, blown-in cellulose insulation to the existing ceiling cavity via ceiling cutouts that are plugged after the insulation is blown-in.
: 2) Prepare the ceiling according to the EPA recommendation with 1" furring strips fastened along the existing joists, the resilient channel perpendicular to the furring strips.
: 3) Add a layer of 1" fiberglass insulation between the furring strips
: 4) Attach 5/8" drywall to the resilient channel, taped and edge-detailed as described in the EPA reprint.  
: Questions are as follows:
: 1) Is the extra 1" of insulation between the furring strips going to do a whole lot if I also put the blown-in cellulose in?
NO
: 2) Is the blown-in cellulose going to do much?
NO
: 3) Will reducing the thickness of the furring strips from 1" to 1/2" affect the sound reduction?
NO
: 4) Wouldn't running the furring strips perpendicular to the joists, then the resilient channel perpendicular to the furring strips be even better, provided that the furring strips were thick enough to support the drywall weight?
yes
: I am hoping to achieve an STC in the range of 55, and a corresponding increase in the IIC also.  Will what I do achieve that?
NO
: Last question - would I be better to forego the blown-in insulation, instead rip out the old ceiling, put in 5-1/2" thick fiberglass batts, attach resilient channels to the bottom of the exposed joists, then new 5/8" drywall to the channel?  
Fiberglass will do little or nothing in practice, neither will the cellulose.  You must have missed the addendum we put in the back of the EPA manual on how to do this right.  Never mind, another copy is on the web site!
: Any help would be much appreciated.  I am looking for some good, practical help.  Thanks in advance.


 

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