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Discussion Starter · #1 ·
I will be constructing a floating ceiling. By doing this, no contact is made with the joists, there by controlling to some degree sound vibrations going through the floor above. But I would like to install a drop ceiling, instead of drywall, does it make sense to do all that work and have a drop ceiling? If so, is 3 inches from the new joists enough clearence for the drop ceiling? Originally I have 7 feet 6 inches to begin with, minus 1 inch for new joist and 3 inches for drop ceiling that brings me down to 7 feet 2 inches. I do not want to go below 7 feet, that is the limit.


When I say a new joist, I will be placing 2 2x4X12 screwed and glued together as opposed to a single 2x6 or 8, using the 2x4 method I can leave the cross braces intact. Since my original joists are 12" OC I will place these double 2 x 4's 16" or 24" OC


Again, is all this work worth it for a drop ceiling?


Any comments, would be appreciated.
 

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The big thing with the "drop ceiling" is to make sure it's not touching - so 1 inch should be just fine.


Your "drop ceiling" is going to be drywall, right? If it's not, then it's not worth the work. The separate joists are for mounting drywall. If you're going to be doing a drop ceiling, then your isolation issues are quite different.


If you're planning to do drywall, then 2X4's aren't going to have enough strength for a 12 foot span (in my opinion, at least). I used 2X10's for a 16 foot span and have a tiny bit of sag with that. The sag is going to be mitigated by having a taller board - not a wider one. Take a 2X10 (or any 2X) and turn it so the 10" is parallel to the ground - it will have a big sag. Turn 90 degrees it so the big side is perpendicular and the sag goes away. Gluing two boards side by side will help a bit, but doesn't address most of the sag issue.


Of course, if you're planning a drop ceiling, then most of this goes away - the joists won't really be necessary in that case anyway.
 

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Discussion Starter · #3 ·
Thanks for your input Peteness.


So, in your opinion, because I will be doing a drop ceiling(acoustical 2 x 2 tiles) its not worth doing a floating ceiling. I just thought that if I decouple the joists even though I will not use drywall that it will decrease the amount of vibrations from the bass. So the question really what I'm asking is if I'm going to do a drop ceiling is there a difference in containing the sound whether I touch the joists or not? As a side note 2 2x4's glued and screwed together essentially becomes a 4 x4, you think that would sag, even though I will not attach any drywall to them?
 

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Discussion Starter · #4 ·
Thanks for your input Peteness.


So, in your opinion, because I will be doing a drop ceiling(acoustical 2 x 2 tiles) its not worth doing a floating ceiling. I just thought that if I decouple the joists even though I will not use drywall that it will decrease the amount of vibrations from the bass. So the question really what I'm asking is if I'm going to do a drop ceiling is there a difference in containing the sound whether I touch the joists or not? As a side note 2 2x4's glued and screwed together essentially becomes a 4 x4, you think that would sag, even though I will not attach any drywall to them?
 

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Greetings,


2x2 tiles, by themselves, won't do much for retaining the lower freq's.

You'll want some mass up there, if this is your concern.


As a general rule the optimum build out would be floating clg. with new joist, insulation in the cavities, and double drywall, 1/2" over 5/8".


One pain of a smaller space for the grid panels (2x2 tiles) is getting them in place. If you want fiberglass on top of these, you'll need even more room. If the panels rattle, you want some space to sneak some wieght on top of them.


I don't know your needs but am thinking it may be a more sound idea to use the exsisting joist, double drywall that, then attach your 2x2 tiles straight to the dry wall. Thus saving your headroom, to boot. (7'-4")


Do you have your walls up? jdb
 
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