Multi-purpose Music/Home Theater/Recording Studio

[goodwater]

Yes, « the bolt and washer attached to the top plate also the bolt that runs through the pad and into the slats » but before inserting the bolt we inserted a piece of rubber hose up to the top of the slat, so the bolt and the washer do not touch the wood (the washer crushes the piece of hose that protrudes on the slat and on the bottom of the top plate) as we did to fix the walls on the exterior wall.

Does this change your recommendation?

Stef

[gullfo]

in looking closer - you have a bolt with a washer contacting the lower plate, the bolt threads are wrapped with hose, a pad between the plate and ceiling slats, a hose through the opening in the slat, then a washer and nut on the bolt. the members are still coupled because the bolt transfers from the plate to the slat at the washer connecting point - what you want is a decoupling of the washer as well. see Kinetics Noise KSR 25 assembly for the concept.

on sealing the wall-ceiling gap - typically your sheathing on the walls and ceiling are staggered to around 1/4" separation on each layer and those are sealed. the depth of (typcially) 1/2" plywood/osb + 2x 5/8" type-x drywall would give you 1-3/4" thick "edges".