Author Topic: room within a room at roof framing  (Read 3232 times)


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room within a room at roof framing
« on: August 22, 2013, 04:33:57 PM »
I am building a sound isolation room using the room within a room concept the inner room will have a ceiling at  approx. 9' from floor. The outer room will be framed up to the existing roof framing.  Inner room will have double 5/8 drywall on the interior of the room, the same on the outside surface of the outer wall. The inner ceiling will also have double 5/8 on the underside.  All will have green glue.  Is it necessary to drywall the underside of the roof framing and if so what about the top 3' of the outside walls and the ceiling areas outside the isolation room.

Randy S

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Re: room within a room at roof framing
« Reply #1 on: August 22, 2013, 05:55:35 PM »
the goal for doing complex structure is to have equal mass on the outer shell. The walls, ceiling and floor (if its a raised foundation or second story) if concrete slab your OK for the floor.
And having the same equal mass on the inner shell, walls and ceiling.
Insulate both cavities and make sure you seal outer and inner shell to the best of your ability. This is critical. Air tight / water tight = best results!.


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Re: room within a room at roof framing
« Reply #2 on: August 23, 2013, 02:14:48 PM »
+1 to Randy's post - although you don't really need to make the mass equal.. i.e.; If your exterior partition is a concrete foundation pour... well, you get my point. ;) The mass of the partitions determine the low frequency cut-off of the partition Sound Transmission Loss.

Are your ceiling and walls fully decoupled?

In answer to your question about the roof ... I am not following what you are doing there. The roof is a partition, then the 'interior ceiling partition' (room-in-a-room) is the OTHER partition. Will you add drywall to the bottom of the roof sheeting?? - not recommended. This will require ventilation and you should provide an air path from the eaves/soffit vents to the top ridge vent to prevent moisture condensation and the eventual mold problems. ;)

Make the interior ceiling mass the same as the interior wall mass and you're probably good.

Can you post a drawing or a link to your build?