# sound proofing condo ceiling



## Twin A (Mar 10, 2009)

My current client is tried of hearing neighbors up stairs and would like the whole unit sound proofed from the ceiling up. The Slab is" above 7" with 1x2 furring strips with 5/8" drywall. Do you think adding another sheet of 5/8 plus green glue is enough for impact sounds. Or should I go a little further and tear the current ceiling down to add the sound resistant aluminum studs 5/8" then green glue and 5/8" again. and a sound barrier between studs. Or to the extreme and hang the ceiling from sound clips where it is suspended and leaving 1/4" gap at all intersecting wall to be caulked in with green glue. Then 5/8" green glue then 5/8". 

Thanks for all the input in advance

Mike


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## MarcD (Sep 18, 2009)

Twin A said:


> My current client is tried of hearing neighbors up stairs and would like the whole unit sound proofed from the ceiling up. The Slab is" above 7" with 1x2 furring strips with 5/8" drywall. Do you think adding another sheet of 5/8 plus green glue is enough for impact sounds. Or should I go a little further and tear the current ceiling down to add the sound resistant aluminum studs 5/8" then green glue and 5/8" again. and a sound barrier between studs. Or to the extreme and hang the ceiling from sound clips where it is suspended and leaving 1/4" gap at all intersecting wall to be caulked in with green glue. Then 5/8" green glue then 5/8".
> 
> Thanks for all the input in advance
> 
> Mike


Mike I worked on a condo redo a year back and we added another layer of 5/8 on 5/8, it really didnt help. and that was where the powers that be said the checkbook stopped. I always thought it would be a good idea to add in 1" foamboard and then another layer of rock.


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## Big Shoe (Jun 16, 2008)

How old is the building? If the unit owner above has tile on slab with no corkboard......good luck. HOA's don't allow flooring without it around here.

I think it would be cheaper to move,or install a new floor for the person above.

Seriously,Your plan *might* *help,* but does ceiling up include the drop ceiling areas and intersecting walls?


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## Mayer (Sep 14, 2010)

*Green Glue*



> My current client is tried of hearing neighbors up stairs and would like the whole unit sound proofed from the ceiling up. The Slab is" above 7" with 1x2 furring strips with 5/8" drywall. Do you think adding another sheet of 5/8 plus green glue is enough for impact sounds. Or should I go a little further and tear the current ceiling down to add the sound resistant aluminum studs 5/8" then green glue and 5/8" again. and a sound barrier between studs. Or to the extreme and hang the ceiling from sound clips where it is suspended and leaving 1/4" gap at all intersecting wall to be caulked in with green glue. Then 5/8" green glue then 5/8".


If Impact sound is the main concern than you should go with the clips, hat channel, 2 layers drywall with Green Glue in between. At *"OUR COMPANY"* we have installed many ceilings like that between apartments with excellent results. If the main concern is airborne sound (voices, music etc) then you should be OK with just another layer of drywall and GG over the existing wall. BTW you don't use GG at the intersecting walls, you would use acoustical caulk.


> Mike I worked on a condo redo a year back and we added another layer of 5/8 on 5/8, it really didn't help. and that was where the powers that be said the checkbook stopped. I always thought it would be a good idea to add in 1" foamboard and then another layer of rock.


Another layer of rock without the Green Glue will only add about 2-3 STC points. The 1" foamboard would do almost nothing to stop sound. Green Glue will add about 10 STC points.


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## Sir Mixalot (Jan 6, 2008)

Twin A, I recommend,
Hat channel > 1/2" or 5/8" ToughRock > green glue > and this http://www.gp.com/build/product.aspx?pid=5467 :thumbsup:


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## Ted White (Jun 23, 2009)

Mayer said:


> If Impact sound is the main concern than you should go with the clips, hat channel, 2 layers drywall with Green Glue in between. If the main concern is airborne sound (voices, music etc) then you should be OK with just another layer of drywall and GG over the existing wall.





Mayer said:


> Another layer of rock without the Green Glue will only add about 2-3 STC points. The 1" foamboard would do almost nothing to stop sound. Green Glue will add about 10 STC points. Big Difference.


 
This is not a straightforward issue and this is simply bad advice. Sorry. The small air cavity you recommend leaving next to the slab is the limiting factor.

When you introduce an air cavity next to that massive slab that exists currently you will improve things _slightly_ in the upper frequencies, but worsen things in the low frequencies. Green Glue will _not_ add 10 points at all in this application. Likely there would be a net gain of 1 point. Hardly a good return on investment. Again the air cavity is the limiting factor. See the lab data here: http://www.soundproofingcompany.com/library/articles/triple_leaf_effect/

The best course to follow is at the end of that article. Essentially (just as Twin A said) removing what you have currently, introducing as large an air cavity as practical, then resilient clips and channel. Low / medium density insulation (R19 fiberglass if the air cavity is 5” or larger) should be in the air cavity. This will expand the frequency range of improvement, however any solution will reduce performance at some low frequency range.

Soundboard would be effective on the floor above, but does not contribute to the solution from the ceiling side.


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