Author Topic: Rockwook sound batts  (Read 7439 times)


  • Guest
Rockwook sound batts
« on: November 30, 2006, 06:39:36 PM »
I am currently finishing my basement and I want to reduce general noise transmission between rooms and floors.   I plan on sending the kids downstairs to make noise with friends so my wife and I can enjoy quiet upstairs.  I also want to reduce the sound coming from the copper water pipes in the floor.  I am also adding a theater room in the basement.  

I had an insulation contractor give me a bid for insulating the interior walls and floor for sound.  The contractor recommended using Rockwool sound batts rather than fiberglass.  The price is about double for rockwool.  Is it worth it?  Do I need insulation if I use the resilient channels or homasote?  What would your recommendation be?

Also, if I use the resilient channel, do I need to tell the electrician to hang recessed lights lower than he would normally?

Any suggestions are appreciated.


  • Guest
Re: Rockwook sound batts
« Reply #1 on: November 30, 2006, 07:25:45 PM »
Normally, canned lighting and recessed lighting are not good for sound proof ceiling applications. The problem is that sound can get thru these type of lighting.

Indirect and/or track lighting is preferred method for soundproof rooms.

Rockwool can absorb more sound than that of fibreglass insualtion. Yes, it does cost more.

Suggest that you also look at FR Cotton Denim Sound Insulation material at:/


  • Guest
Re: Rockwook sound batts
« Reply #2 on: December 01, 2006, 01:31:36 AM »
First, the copper pipes:  Get some pipe insulators (4 foot lengths, about 2 bucks/pk of 4) from Home Depot/Lowes and insulate all the offending pipes.  You'll also have to rip off all the copper brackets and improvise some new ones.  I've used PVC brackets for 1.25" conduit - they seem the perfect size to mount 1/2" copper pipe + the foam insulators (but test for size at the store). Make sure no copper pipe is rigidly mounted to a joist or stud - that's where all the noise is coming from, the structureborne vibration.

Rockwool is 'better' than fiberglass, since it has a higher density and NRC.  But since you're using resilient channel, don't sweat it.  Fiberglass works just fine.  Don't use homasote on the ceiling - it won't last, and your ceiling might come crashing down on your head.  Hat channel and the SSP clips (sold on this site) plus 2 layers of drywall, sealed well make a nice system.  You can get very good sound isolation that way.  

There's no real issue with using recessed lights with resilient channel, but keep in mind that recessed lights are basically big holes cut in the drywall and leak sound badly.  You'll have to find a way to seal, cover or somehow deal with the hole you cut, or all your work will be for nothing....    


  • Guest
Re: Rockwook sound batts
« Reply #3 on: January 09, 2007, 12:04:19 AM »
Rockwool is better than fiberglass and bonded cotton is better than rockwool.  For info see  bonded cotton insulation has an NRC of 1.15 and also adds 20+ STC inside the ceiling/walls.  When combined with SSP Clips and standard 7/8" dry wall furring channel (DWFC) it is really effective.  To block low frequency sound (bass) use 2 layers of 5/8" drywall with Green Glue sandwiched between.  This system has proven itself for countless customers all across the country! 
If you must have recessed lights (and remember - 3-5% openings in a sound control ceiling reduces the effectiveness of all your work by over 50%) then you will need to box them in and soundproof them like a little room.