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Discussion Starter #1
Question on this type of ceiling in a basement. There are HVAC running in these both parallel and perpedicular. The span is about 19 feet about the only thing I can think of is trying this option.






In order to save ceiling height, is it possible to add a 2x4 along these joists for drywall that would hang about a 1/4" or 1/2" below the main 2 x 4?






1. What can I use to isolate the new 2x4 from the existing Truss?


2. I want to avoid a hat channel due to cost.


3. Is it even going to help or are there any suggestions.


thank you in advance
 

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I'm not sure a 2x4" would hold the weight of dual drywall 5/8, 5/8 or 5/8, 1/2. If 19' is the span of the ceiling, it might be bare minimal since there is not load on the top. Hat Channel was not really all that expensive. Now the RSIC clips can add up fast...


I would check with Ted White, he can help you out.
 

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Discussion Starter #4
Thank Guys,


I probably was not clear enough. I was not looking to cover the whole span but actually connect the "new" 2x4 to the existing one every 24" but was looking to see what I can put between them to isolate.


I think Dennis's idea would work if I ran a hat channel along the edge (side) of the existing truss joist (as you would for a wall for drywall application). Then attach the new 2X4 to the Hat Channel.


Hope that is what you meant
 

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Yes perpendicular will have much less contact area than the parallel blocks you described. There different resilient clip options that work very well that you might consider.


Next best option would be to install metal hat track (aka metal furring channel, RC-2 or Chicago bar). Avoid standard resilient channel (RC-1). Install perpendicular to joists as Dennis said. Rows of hat track are 24" apart, and drywall only gets installed in the hat track.


Does that make sense?
 

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Discussion Starter #8

Quote:
Originally Posted by Ted White /forum/post/14242538


Yes perpendicular will have much less contact area than the parallel blocks you described. There different resilient clip options that work very well that you might consider.


Next best option would be to install metal hat track (aka metal furring channel, RC-2 or Chicago bar). Avoid standard resilient channel (RC-1). Install perpendicular to joists as Dennis said. Rows of hat track are 24" apart, and drywall only gets installed in the hat track.


Does that make sense?


I do.


2 questions:


1. How far down would a hat channel and using the ISOMAX clips hangdown. (assuming DD 1/2" and GG)?


2. could you PM me to cost out a 18.5 x 12' ceiling using this system



My Truss Joist are 24" OC and run the long way (18.5')
 

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Please keep in mind flanking: http://www.soundproofingcompany.com/...icles/flanking


If you treat only the ceiling you'll have huge flanking through your walls.


The Isomax clip isn't one that we support, but looking at the Kinetics website it's about 1 3/8" from joist to surface of the 7/8" hat track. Add the drywall to that 1 3/8" dimension. I would really recommend you use double 5/8" for the mass. It would be a shame to do all of this and not go for the mass.


I'll PM you with info on the PAC clips we do support.
 

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Discussion Starter #10
Ted, I PM'd you.


I plan on isolating the side walls from the ceiling as well, so I will need some info on that if you carry those.


I am putting 1 1/2 foam board agains the foundation blocks (moister control), 2x4 studs with unfaced fiberglass in it, then DD. I am not sure about fire code along the top with the wall out from the foundation blocks so I am checking into that.


My floor is going to have to be raised and the walls are going to be on top of that. Had a sump pump issue this spring. Still need to work on that as well.


I am more concerned with the kitchen above rattling than anything so if I isolate the ceiling and the walls it will help.
 

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Additional detail about clip depths:

 
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