soundproofing floor

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Old 10-06-05, 05:57 AM
jaseweil
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soundproofing floor

I am adding a second floor above part of my house. I want to eliminate sound travelling through the floor. I was thinking that I could put a layer of 1" rigid foam insulation between the floor joists and the plywood floor sheathing. This seems like it would do the trick as far as minimizing sound travel, but will this compromise the structure of the addition if the 2nd floor walls are sitting above the rigid insulation? Would it be better to put the rigid insulation between the floor sheathing and the finish floor? Is there a better system for soundproofing?
Thanks.
 
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Old 10-06-05, 06:16 AM
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Rigid foam insulation is not an ideal sound proofing material as it is too dense. You need something a little softer like batt insulation which can be stuffed between the joists.

I did this in my basement ceiling prior to drywall and it works perfectly.
 
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Old 10-06-05, 06:16 AM
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em69, she's referring to putting the rigid foam on top of the floor joists, and sandwiching it between the plywood. (Which is a bad idea) It'd be a great idea if there was no other weight on top of the plywood.

I think that you'd have better luck looking into rubber floor membranes (sound deadening pads) like the ones discussed at:
http://www.multi-housingnews.com/mul..._id=1000497133
 
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Old 10-06-05, 10:47 AM
jaseweil
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Thanks for the tip and the link. After looking at the link, Homosote seems like a good product to accomplish the soundproofing I need. Has anyone out there had any experience with Homosote in an application like this, and how well has it worked.
 
  #5  
Old 10-07-05, 05:45 AM
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Thanks XSleep...but I understood the post.

If your adding a second floor, then usually you will have access to the space between the joists before installing your plywood subfloor. From the extensive research I've done, I personnally think batt insulation is a superior method. In addition, if you can, I would add resilient channels to the underside of the joists. But in your situation, you may not be removing the ceiling of the 1st floor to be able to install the channels.

The rubber floor mats are fine for situations where you do not have access to the space between the joists. You can certainly get a better STC rating than just installing the mats.
 
  #6  
Old 10-30-05, 07:56 PM
twojciac
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Your best bet is to dampen the sound, and it's actually pretty easy to do. You can put down GreenGlue between your existing subfloor and a new layer. Ideally you'll want the thickest subfloor you can afford, but even 1/4" with the the viscoelastic sandwich you will realize sufficient dampening.

As others stated, foam insulation is not a good sound insulator. The dense closed cells are fairly efficient at transferring sound energy.

Talk to the guys at Audio Alloy, the mfg of GreenGlue. They're all extremely helpful and eager to help.

http://www.audioalloy.com
 
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