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alanrudy
06-25-2011, 06:07 AM
Need some advice on effective sound removal techniques for both pipes and floor. I recently bought a two story SFR that was converted to a duplex (2 garages on 1st floor). I plan to live on the first floor (220 sq ft of living space) and rent the top floor out to save money; however the major concern I have is from noise from the upstairs unit that is currently un-livable for me (the pipes from bathroom, them walking up the stairs which underneath is part of the closet for the bedroom downstairs, and from them walking around in general). I have researched several ideas that I am looking for the right contractor to do, but it would greatly help me if anyone could give me advice on what would be most effective: Cost is an issue, but a price difference of $1k total should be okay as long as the method is that much more effective.

1. Breaking ceiling drywall and adding cork or insulation and redrywall.

2. Using green glue and adding second 5/8th drywall to ceiling.

3. Wrapping the pipes with carpet pads.

4. Replacing the pipes with cast iron pipes.

5. Since there are higher than average ceilings on the first floor (except the stairs), adding insulation and then a second drywall in the existing first floor.

Or maybe someone has another idea that I am not aware of? What can I except from these different sound reduction techniques? If there was a sliding scale of effectiveness and cost that would be very helpful. For example something like you should do #3 and #5, 5 would reduce the noise from walking about 50%. The % noise reduction is probably subject to many things, but I'm just trying to get some idea which method would be most effective and a general idea of cost. Thanks so much in advance for any help.

jimbo
06-25-2011, 07:00 AM
I don't know any method to "glue" drywall to ceiling, but in general all the items you mention help some with noise reduction. You said $1 thousand, but I'm sure that was a typo, as you realize the work will be in the $10 thousand range

LLigetfa
06-25-2011, 07:17 AM
I don't know any method to "glue" drywall to ceiling...

Standard practice for soundproofing is to de-couple the drywall, not to bond and thereby couple it. Use resilient channel for acoustical isolation.

http://www.arcat.com/arcatcos/cos31/arc31984.html

Insulation for soundproofing has different characteristics than what is used mainly for heat/cold. You might look into using blown-in insulation designed specifically for sound.

http://www.asc-soundproof.com/wd-articles-soundproofing.htm

hj
06-25-2011, 08:04 AM
ANYTIME you have two surfaces attached to an intervening web, such as a floor and ceiling attached to the joists, that becomes a sound transfer medium. You have to "separate/decouple" the two surfaces, either by creating a separate structure as a sound break, or fastening one of the surfaces to acoustic limiting strips. Additional "mass" will give a minimum amount of sound deadening. There are many ways to minimize water noises in pipes, although I am not sure if carpet is a very effective one.

alanrudy
06-25-2011, 04:03 PM
Thanks all for the quick good responses. Jimbo, I meant a $1k difference of option 4 over option 3 would be okay, though I didn't think the project would get as high as 10k. Thanks LLigetfa and hj, just to be clear, you are recommending option 5 then of adding insulation and the 2nd drywall. Any idea of a general guide of how effective this would be?...50% reduction in sound?, 30%?
Also, just to be clear, my desired result is to block noise from upstairs unit, not necessarily block noise that I am making downstairs from going upstairs, don't know if it's the same thing or that changes the recommendations at all. What would be a cost effective good solution for the pipes then? Thanks again in advance.

jadnashua
06-25-2011, 04:17 PM
Cast iron is a lot quieter than pvc or abs, but is harder to retrofit. Supply lines shouldn't be noisy, but some valves can be at low flow (they'll whistle).

They make special clips that decouple drywall layers. You want these, as a minimum. The new layer you install could have a lead lining, but not sure they are designed for ceiling use. Sound will travel through any opening, so sealing those with an appropriate material will help.

On a common wall, tear the drywall off, make the top and bottom plates wider, then, install a second set of studs offset towards the inside wall (the other edge won't come in contact with the drywall on the other side. Wind high density insulation around the studs, then drywall the new side on the studs that are sticking out. Some carpeting in the treads will help of the stairway - use a good pad, too. If the people walk like a pile driver, the sound will propagate.