[Potatogod93]

My room is about 25'x16', give or take a couple inches. My room is being built with a room in a room premise. Doubles walls around all four sides. Walls decoupled from the ceiling using IB3 clips. DD and GG for the walls and ceiling construction. The ceiling will be decoupled using IB1 clips and 7/8" 25 ga drywall channel. I am building 5 soffits; three of which will be inside the room shell after drywall, the two sides of the room and one in front of the screen, while the other two will NOT be inside the shell, but they will be part of the outer shell. Both soffits will run the entire width of the room, be about 12-14 inches in height and one will be almost 4 feet while the other will be a little more than 4 feet. THey will both be starting just inside of an I-beam and run to the wall, one at the front of the room and one at the back of the room.

Since the walls will not have clips and channels on them I know that if I tie in the soffits which are not decoupled from the ceiling, as the decoupling will be done with clips and channels, to the coupled walls that I am defeating some purpose here. What I would like to know is how much of a difference would this make? And what should I do here? I would like the soffit in the back of the room to be strong enough to support the projector as I will need to hang the projector off it somehow.

Sound coming in would have to transfer from the floor above to the soffit to the wall then through the DD and GG and vice versa. I am trying to soundproof and have money in doing so. I don't want huge holes in my room for doing so, but is this something I should be struggling with?

 

[doublewing11]

If I understand what you are describing..............the double wall construction should be already decoupled from ceiling since you are using IB-3 hardware......................your ceiling too is decoupled using clips and channels. No problem tying into both structures.

Hopefully, you have planned extra clips and channels in ceiling for added soffit load...........should be fine attaching soffit structure to walls as long as isolation has been accomplished using IB-3 clips to ceiling.

 

[Potatogod93]

Hmm well what I was figuring was to tie in the soffit wood to the ceiling without IB3 clips so they would be coupled. I thought the way around this would be IB1 clips + Channels on the connection points on the walls which would be somewhat cumbersome. I suppose that way may be cheaper but the IB3 clips would be easier.

Also for these two soffits I'm asking about the IB1 and channel will be between soffit and drywall, not between soffit and ceiling.

 

[doublewing11]

Once you attach side walls to ceiling with IB-3 clips, that wall is decoupled. You use clips and channels to decouple the ceiling. I'm suggesting adding more channels/clips in ceiling to account for soffit load. With both ceiling and walls all decoupled, you can use DD with Green Glue or OSB layer+GG+ 5/8" drywall.

Soffit can be framed after shell is complete.........................ie frame directly into side walls hitting studs and into ceiling channel. No need to use clips once shell is complete.

 

[Potatogod93]

So if I put the soffit lattices into channel above on the ceiling then according to the Soffit documentation from Ted at the Soundproofing company clips need to be spaced every 16" to support the weight of the soffit and I remember him telling me it was important to keep the soffit lightweight and use 2x2's

Does anyone know how much weight the clips and channels can support besides a double layer of drywall or a layer of Drywall and a layer of OSB? These two soffits I'm asking about are a little longer and I can put in more lattices to the width of the room, I'm not really worried about that part. The that does worry me though is the soffit in the back of the room is there I would like to hang the projector. I would like to hang it right underneath an I-beam so I could have a lattice immediatly at each side of the I-beam connected to channel above and have OSB that the projector platform connects to. Would that be too much weight? WOuld it help if I ran clips every 8 inches on that side of the room?