Originally Posted by Canesfan27
On your additional layers for the ceiling are you leaving a small gap between the wallboard and the ceiling boards each time? It's been difficult finding information regarding the second/third layers as the butt up each time to the wallboard.

Inside floor joists: safe&sound | air gap | safe&sound
then nailed on the bottom of the joists 1lb MLV | over that clips & channel (which by default is an air gap)
attached to the channel ... the HT ceiling (which is what I think your talking about) ...
no gaps:
1/2" OSB | 1/8" FloorMuffler | 5/8's wall board | green glue | 5/8's wall board


Note: The boards are staggered so the seams don't fall in the same place.