Can you critique this plan to reduce ceiling impact noise and flanking?

[srj19]

I plan to pull the ceiling down to the joists, install at least 2 layers of regular drywall (with green glue between) directly to the underside of the subfloor above. Then R19 insulation (does it make sense to use Rockwool with the other steps I'm taking?)

Then installing channel to the exposed joists, (probably with sound reducing tape inbetween where they touch). Then installing either one piece of 5/8 quiet rock, or two pieces of regular rock with a green glue layer between to the channel.

Planning to seal the perimiter and other gaps with acustical caulk. How to deal with ceiling fans mounted directly to the ceiling joists? Also, is there a way to install ceiling cove or does that cause a faillure?

I don't think I'm able to put additional rock on the existing plaster walls of the rooms below. What about removing 12 inches of wall at the top of the room and repeating the rock/green glue sandwiches in each stud cavity underneath the top plate and making sure the edges this sandwich are also separed by green glue from the final drywall to close up that hole, with green glue applied bewteen the final drywal patch and the naked studs
 
Thoughts? Scott

[Randy S]

Ok your on the right track,
"Insert Quote
I plan to pull the ceiling down to the joists, install at least 2 layers of regular drywall (with green glue between) directly to the underside of the subfloor above. Then R19 insulation (does it make sense to use Rockwool with the other steps I'm taking?)
Rockwool or cotton fiber insulation are worth putting into the cavity.
I would do the double 5/8" with green glue over quiet rock, I would also use clips and channel over RC2 or RC1
As far as the adjoining walls thats a tough call due to the fact you do not know what the current value of the flanking issue. And as far as removing 12" of the walls around the room is overkill, if you are trying to decouple the walls then you could move the top plate down a couple inches but even then not sure its worth all the work.

My contact info is below, give me a call and we can throw a few ideas around.

[srj19]

Thanks for the response Randy, Sorry I'm late getting back to you. I didn't get any email notiication and didn't check back till now.

When you stated that you'd use two layers of 5/8 over quiet rock you meants in the joist cavities directly affixed to the underside of the subfloor? If not, I'm having difficulty comprehending (or motivating myself) with the idea of putting up 3 layers on the channel.

Any suggestions on how to handle things like ceiling fans? I don't think I've seen this addressed online while I've been researching this. Basically, the impact from  the upstairs transfers down and often shakes the glass globes on the fan lights so it would seem I've got challenges with the direct contact with the upstairs joist, as well as possible issues with the existing electrical box being too recessed with the final channel and rock install, and don't forget the air flow possiblities around the box. Hopefully acustical caulking or something similar can stop that.


Thanks,

Scott

[Randy S]

Sorry for the confusion. I meant instead of the quiet rock. However, we do add multiple layers of drywall /green glue to the under side of the substrate to improve the reduction of impact noise as well.
You will need to mount the boxes on a clip and channel section in order to decouple the boxes from the structure.
Always caulk any openings around boxes with acoustical caulk.

[srj19]

Thanks again for your help.

I did find these gadgets for decoupling ceiling fans and heavier items that typically would mount to a joist. From what I can tell they let basically eliminate the wood to wood contact on the cross block to which the box mounts. Anybody have feed back on these?
http://www.acousticalsurfaces.com/rsic_clips/risc_dco4_electrical_box.htm?d=46

I'm definately curious about how much sound reduction I can expect with the scenario we discussed. My main motivation is to eliminate foot impact and the sounds of kids being kids, which seems to include them falling down alot, walking hard on their heels, etc. Any online source on the "impact" sound rating reduction I could hope for with my scenario?

What's a ballpark price range for doing a 12X12 ceiling in this manner? Possibly $400ish?

Thanks, Scott