# isolating celing and subflooring for my home theater.



## psuchit (Jan 6, 2009)

I have heard a lot about isolating the celing for better soundproofing using RSIC clips mounted to the joist and snapping the hat channel to it..leave 1/4 inchs from all the sides and attach the dry wall to this hat channel. I am a rookie so excuse me if I sound stupid but now this hat channel is made of metal right ? and when I install the dry wall on it I just use the dry wall screws to put this on ? . and once the first layer is done how does one go about attaching a second layer of drywall on the celing ?? if I have insulation in good amount on the celing and the celing is isolated and the drywall is a good 5/8 thickness can I get away with just one layer of dry wall... anyone has pictures close up of how this RSIC clips, hat channel and then the dry wall are attached ... I have seen numerous post trying to get a idea... 

Regarding subfloor .. my current height of the basement is 7.5.. is there an cheaper and better solution of subflooring than DriCore subfloor ...The rest of the basement is not getting DriCore even if I go along with Dricore in the theater ... would that nullify the whole purpose?? what would be a better cheaper solution...and should that be done to the whole basement ??


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## bpape (Sep 14, 2006)

To do the 2nd layer, you just use longer screws and go through the first layer into the channel. Green Glue between layers helps a lot though it's not cheap. You have to understand that sound travels in 2 ways - through the air and through the structure.

RSIC and hat channel helps decouple it from the joists above (structural isolation). The double drywall helps with mass which is what stops airborne transmission. 

In short, FULL cavities of insulation, RSIC-1 (NOT RC) and hat channel with 1 layer of 5/8" drywall will give you pretty good performance. Adding another layer and Green Glue will give you a significant increase in isolation, especially from 125hz down.

As for the floor, if you're already short on ceiling, and flanking via the concrete slab is your biggest issue, you're probably OK without it. Just caulk everything tight and use rim joist gasket under the walls. Otherwise, Dri-Core is the best you're going to get without losing a LOT of height. Think 4" or so. If you use Dri-Core, just in the theater is fine. Put it down first and build the walls on top of it.

Bryan


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