soundproofing cinder block

Posted: Tue May 23, 2006 4:15 pm

This is a bit unusual. I'm moving a new studio into a corner of a warehouse in Brooklyn. Two walls are being built well to spec (staggered studs, double drywall, etc), but the other two walls are pre-existing, cinder block. The tenant next door's radio is coming through the walls, enough to be bothersome. This isn't for my live room, just for a space that may eventually become an iso booth, or a control room of sorts.

There isn't enough space for me to build out an entire framed wall in front of the cinder block (16 foor ceilings, by the way). Is there anything I can put directly on the wall that will help reduce the sound? I know this stuff is expensive, but could I screw a layer of QuietRock directly into the cinder block, or some other kind of insulation? Maybe heavy soundproof blankets? I can really only take up an inch or two, due to the circumstances of the floating live room right next to it.

any advice is appreciated!

Posted: Wed May 24, 2006 12:06 am

Just a stab in the dark but is it possible that the sound is actually coming from the ceiling? Cinder blocks are pretty dense aren't they? Or are they porous? Just thought I'd throw another possibility in there. Maybe a solution would be better dealt with by sound proofing the ceiling or floor or both. Would it also be possible to fill the blocks with insulating foam? Yeah crazy talk, but since you're not getting any answers, I figure someone should be around to correct me any time now.

Posted: Wed May 24, 2006 11:27 am

Blankets or acoustic-board screwed into the wall will do little -- if anything at all -- to help stop the transmission of sound. The only two principles that are proven to stop sound transmission are 1) mass in the barrier and 2) an airtight barrier. These two principles must be used in concert in order to be effective.

If the block is hollow, the easiest solution would be to pour sand or pump grout into the hollows of the wall. This will significanly add mass to the wall, surely enough to stop a radio. You might want to research furthur, but off the top of my head, this will get you an STC rating of 45 or so. Sealing over your side of the block with clearcoat or paint may raise that to 50, higher if the other side can be sealed, as concrete is a relatively pourous material.

What are the dimensions of the room, exactly? On top of, or in lieu of sand/grout, you could potentially frame ONE leaf of stud/rockwool/gyp, seal it up good, and you should be golden. That should only take away about 8"-10" maximum off each concrete wall. If it's an iso room and you have the budget to spare I'd recommend adding an acoustically-spec'ed drop-ceiling for extra isolation. That way you don't have to take the walls of the booth all the way up to 16' -- just 10' instead.

This topic sponsored by: