# Theater above my living room



## wraunch (Apr 18, 2012)

All,
I am in the planning phase of building my theater. My theater will be on the second floor of my house, adjacent to my game room. Here is a picture of my plans so far.
View attachment Visio-Upstairs Floorplan - Without hallway, screen on south.pdf


This space is completely unfinished currently. It has 2x10 floor joists filled with fiberglass insulation and topped with 3/4" OSB. I am concerned with too much sound traveling downstairs and I am wondering what is the best/most cost efficient way to reduce the sound traveling downward. I am not concerned with sound bleeding out the top of the room or into adjacent rooms, just downstairs. 

What do you guys recommend? I have seen a wide variety of floor dampening material being used on here such as roofing felt, auralex sheetblock, kinetics RIM isolation sheeting, etc. 


Here are the links to what I'm talking about:
http://www.kineticsnoise.com/arch/rim/wood.aspx 
http://www.auralex.com/sound_isolation_sheetblok/sound_isolation_sheetblok.asp

Thanks,
Chris


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## wraunch (Apr 18, 2012)

Lots of views but no responses. Would love to get some thoughts from some of the Gik guys.


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## Tonto (Jun 30, 2007)

You're going to have to decouple that floor, many products that can do that. Clips, pads with rings in them, then place another floor on top. You will have to worry about the side walls because the sound will bleed through & then through the floor from there. Can you swing a second floor & a second wall. When you say unfinished, is the sheetrock installed up there yet. You can at least double/offset stud those walls that don't go outside & insulate them. They make clips for the offset studding as well. The point being to decouple everything. Nice to have time to work on these kind of projects.


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## bpape (Sep 14, 2006)

If the ceiling below would handle the weight you could lay another layer of drywall in the joists before you put the insulation in. You can certainly use some decouplers and run another set of smaller joists, then your new floor. Just remember you only want 2 layers of mass - your floor and the ceiling below. If you do a floor on top of the existing one, you can actually make the transmission worse. Plus the single larger cavity depth will have a lower resonance which is good. Finish it off with 2 layers of 3/4" subfloor and that's about as good as you're going to get.

Bryan


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## wraunch (Apr 18, 2012)

There is nothing in this space now. No electrical, HVAC, drywall, etc. This is truly a blank slate. I can see the trusses up there. I will be putting down another layer of OSB on top of the 5/8"s sheet that is there now. I do not plan on pulling up the existing OSB so I am somewhat limited in decoupling the first layer from the floor joists. 

Do you think the Kinetics roll out RIM sheets would be sufficient to isolate the next layer of OSB? What about using Green glue instead? What else should I consider?


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## bpape (Sep 14, 2006)

It will do a little bit but not a lot to be honest. In a floor application, I don't think the Green Glue will do much either to be honest. 

At a minimum, you'll need to poke holes in the flooring and blow in insulation if it's not there already.

Bryan


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## wraunch (Apr 18, 2012)

Bryan,
I currently have fiberglass batts under the OSB in this space. The joists are 2x10s that have the batts with 5/8"s OSB on top.


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## bpape (Sep 14, 2006)

That's good. The additional layer of OSB or MDF on top will help block some sound. Floors are just tough to isolate really well if you can't float the whole floor system. Best you can do is increase the mass, damp the cavity, and lower the resonance of the cavity.

Bryan


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## wraunch (Apr 18, 2012)

Yeah it's going to be tough to isolate the floor and that was my biggest concern from an isolation standpoint. Do you think it would be worth it to do the green glue on the extra layer of OSB? Would I get an equal improvement from doing roofing felt under the OSB instead?


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## bpape (Sep 14, 2006)

The additional OSB - yes. The Green Glue, not really sure how well it's going to work when it's being weighed down so it can't really move with all the furniture on it.

Like I said, if you really want isolation on the floor, you'll have to take up the existing floor, float it, get a larger cavity, then do the double layer on the floor. The more mass you put on the better. MDF is going to be more massive than OSB for the same thickness.

Bryan


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