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Discussion Starter · #1 ·
It’s Suspended ceiling under existing one...


Hello!


Do you think it’s feasible to install a drop ceiling under an existing one? I live in a condo that is already pretty well soundproofed, but I know it need an extra isolation to achieve the STC I need. The actual ceiling is 2'' concrete with 8'' blown cellulose, resilient channels (but I would not be surprised if I learned they have not been correctly installed) and 2 1/2'' gypsums.


Cuuld the actual reislient chanels supports one or two additional layers of gypsum (with GG between if 2)?


Is it possible to just drill holes in the actual gypsums and attach wires to the 2''x10'' that would support the drop ceiling? Il would fill the holes around the wires with gypsum pieces and acoustic sealant.


The room is only 8' x 12'. Ceiling is 9'.


In addtion, I would place resilient channels with Clips, with 2 gypsums (Green Glue between) on all walls.


Thanks!


JMG
 

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JMG,


I would not count on the existing resilient channels being properly installed. I would also not count on having more sheets of drywall hanging on the original RC. Too much weight, likely.


In general, you would use resilient channels, furring strip clips & hat channel directly on bare studs and joists, not on existing drywall. The small air cavity created if you install these over drywall will have high frequency resonance issues.


Best to either apply more drywall to what you have (walls can support) or drop down from the ceiling and create a more significant airspace. Consider a new joist system for real isolation, but it doesn't sound like you need that.


You could certainly install more drywall to your ceiling and have the drywall screws shoot straight into the ceiling joists. Again, sounds like the existing RC may be short circuited anyway.
 

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Discussion Starter · #3 ·
Thanks, Ted

Quote:
Originally Posted by Ted White /forum/post/12916784


JMG,


Best to either apply more drywall to what you have (walls can support)...

Something like that?


[/URL] [/IMG]






Also, I plan to soundproof (yes, I konw REAL soundproofing is an impossible dream) my floor like this. What do you think?


[/URL] [/IMG]


**********************

**Barymat 1C =


[/URL] [/IMG]


**Freedom Steps panels =

[/URL] [/IMG]



Thanks!


JMG
 

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Holy smokes what nice drawings! Yes, that's what I was describing for the ceiling.


That floor you have shown there... is that your basement floor? If so, just carpet pad and carpet. Or maybe consider some brand of plywood squares (there are many) and then carpet and pad.
 

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Discussion Starter · #5 ·
No, I live in a condo, 2nd floor. Down- and upstairs neighbours...

Quote:
Originally Posted by Ted White /forum/post/12918700


Holy smokes what nice drawings! Yes, that's what I was describing for the ceiling.


That floor you have shown there... is that your basement floor? If so, just carpet pad and carpet. Or maybe consider some brand of plywood squares (there are many) and then carpet and pad.
 

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So your floor was re-surfaced with the poured gypsum (the 2 1/2" concrete you mentioned)? That's a good amount of weight, which is a good thing.


Decoupling from that floor is a good idea if you can get enough height in that airspace. Are the black "spacers" inder the freedom panels 2x4 sleepers, by chance?
 

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Discussion Starter · #8 ·
Ted,


Sorry, I don't know what is a «sleeper»...



Here's the product info (Yeah, I like posting images...
):


[/URL] [/IMG]

Quote:
Originally Posted by Ted White /forum/post/12920154


So your floor was re-surfaced with the poured gypsum (the 2 1/2" concrete you mentioned)? That's a good amount of weight, which is a good thing.


Decoupling from that floor is a good idea if you can get enough height in that airspace. Are the black "spacers" inder the freedom panels 2x4 sleepers, by chance?
 

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I'm sorry... a sleeper is a 2x4 laying flat on the floor. So that the "4 inch" surface is in contact with the original floor, leaving a "2 inch" air cavity. Actual measurements are 1 1/2" x 3 1/2" of course.


The system would work better if the 2x4s were tiped up so that the resulting airspace was 3 1/2". That's a lot of floor height to lose, though...


Have you looked at existing doorways and cabinets? Generally these things limit the height you can add to the floor.
 

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Discussion Starter · #11 ·

Quote:
Originally Posted by Ted White /forum/post/12921097


I'm sorry... a sleeper is a 2x4 laying flat on the floor. So that the "4 inch" surface is in contact with the original floor, leaving a "2 inch" air cavity. Actual measurements are 1 1/2" x 3 1/2" of course.


The system would work better if the 2x4s were tiped up so that the resulting airspace was 3 1/2". That's a lot of floor height to lose, though...


Have you looked at existing doorways and cabinets? Generally these things limit the height you can add to the floor.

Four or five inches would be OK -- albeit not esthetically pleasing...
 

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If it were my floor I'd build a new 2x4 floor joist system on top of the old floor, use R13 in the spaces. On top use layers of standard OSB. Start with a 3/4" sheet for a solid floor. So maybe a 3/4" layer followed by 1 or 2 layers of 7/16" OSB.
 
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