I finally got all of the IB-1 clips and hat channel that I need to begin installing my ceiling. From there, I will do a 5/8" green glue sandwich. I have one last decision to make regarding the orientation of the channels themselves. The room is approximately 18' x 22'. The problem is that, along the 18' axis, the Joists run about 10 feet in one direction, then run the last 8 feet in perpendicular fashion. This is because of long, internal supports for a hanging balcony opposite the outside wall.
I'm basically left with 3 options:
1. run the resilient channels in 2 different directions so that they are always perpendicular to the joists above them.
2. Run the resilient channels east/west
3. Run the resilient channels north/south
I think that #1 would be the easiest and the cheapest. The problem is that, when I add my second layer of drywall, I would need to provide at least 2ft overlap on the seam that divides the two different orientations. Part of those single drywall sheets would be supported in one direction, and the other part in the other direction. I'm not sure if this would take away from the sound isolation in any way.
#2 and 3 provide a problem because it would mean that I'd have to space the channels every 16" instead of every 24" because that is how the joists are spaced. As well as being more expensive, I worry that this would also hurt the isolation. Lab studies show that less channels = better isolation.
What do you guys think?
