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STC 63?
Posted: Thu Nov 13, 2003 3:31 am
by arathercoolguy
I'm planning my live room and I have aquestion about my current wall and its similarity to the picture on the STC chart rated at "STC 63". The chart shows two layers with only sheets on the outer edges of each wall. I'm wondering if my current wall of stucco-3/4" shiplap siding could be used in thins combination. If I were to build 2 new walls and use this method, my live room would just be too small.
THanks,
ARCG
Posted: Thu Nov 13, 2003 5:59 pm
by knightfly
Read this if you haven't already -
http://johnlsayers.com/phpBB2/viewtopic.php?t=598
Basically, you have to consider ALL centers of mass when sound proofing. A center of mass, otherwise known as a "leaf", can have as many layers/types of layers as you like, as long as there is NO AIR SPACE included. So in your case, your outer wall mass is one leaf, then if you build an inner frame (or mount Resilient channel on your existing frame) and then mount 2 or 3 layers of Gypsum wallboard on the INSIDE of this framework, you now have a "mass-spring-mass" wall, and you should NOT add anything else other than acoustic treatment of the inside space.
Note that the STC 63 example uses exactly the same amount of material as the STC 40 example, only in different places. This "2 leaf" construction is by far the best use of materials, period... Steve