RC1+5/8 dw or 5/8+1/2 on the ceiling?

[rcktdg]

My walls are floated with rc1 and I have only to do the ceiling. The problem is that it's large and high: 9' 7" on the low end and 11' 4" on the high side, 900 sq ft. One issue besides the size and height is that fact that there are 3 sprinkler pipes that extend into the room.

I have to put seams over the pipes to minimize the risk of any damage to the sprinkler system during the installation. I do not want to accidentally break off any heads. The amount of space is limited and I am trying to figure out which will work best.

I don't think there is room to do RC1+5/8+1/2 and still keep correct clearance with sprinklers. I can do any combination of 2 out of 3. It might be possible to drop the sprinklers a little but this is not something I want to undertake and I do not want to get that involved with the infrastructure of the building.

Ceiling is 12" joists 24" centers.

My goal is more about limiting the amount of sound leaking out of the room, not total soundproofing.

Any thoughts would be appreciated.

Still on schedule and under budget. RD

 

[Alex W]

I vote for rockwool in the cavity and two layers of gypsum; skip the RC channel.

Alex

 

[rcktdg]

rockwool=unobtainium

Might as well be moon rocks in southern Ca, US. Every building supplier in my area has no idea what it is. Granted these are not the sharpest knives in the drawer but no web site on the elusive substance lists any west coast US distributors either. As many words as it gets in this forum I would expect it to be a little easier to come by.

I opted to lower the sprinkler pipe that was giving me the problem and install the RC1. Tonight I will add the first layer of drywall and hope that gives me enough obstruction to keep the volume low enough to not be annoying to the neighbors.

I will have r-19, rc1 and 5/8 dw mounted on 12" joists. My nearest clear air neighbor is about 100' away. The ceiling is so large that I hope I dont have to add the 1/2". The channel was a pain, 5/8" will probably kill me.

Cheers, RD

 

[Alex W]

RD-

Check out the Thermafiber website. The stuff you want is the 3-in FS-15 Fireblanket. I was able to pick some up from a distributor in San Diego County. If you call them they can give you the name of someone in your area.

http://www.thermafiber.com/

Alex

 

[rcktdg]

die is cast

It is good to know but at this point it will be advice I give to the next guy when he says "what would you differently?". I don't believe my $/time budget would allow for 900 sq ft of fire blanket too. I have to have a minimum of functionality by the end of the month.

Thanks, RD