soundproofing common wall
I have the same construction in my house. I did one wall with furring and drywall and filled the voids with Styrofoam panels. Cut the noise down around 50% (or more). Wasn't really satisfied, so the same wall next room, I hung a layer of floating wood floor padding, then put my furring strips up (over the padding, which had a side benefit of reducing shim use). I used a higher insulation rated foam to fill the voids. Markedly better results. I also left a quarter inch gap, top and bottom of the drywall and filled with mastic (probably overkill).
Next time just as an experiment, I'm going to staple foam on top of the furring. The stuff they use for cement slab edges is cheap.
Sound basics, air is a poor conductor, for heat and sound. Most anything that works for heat insulation, works for sound insulation. To enhance sound deadening, changing the direction of the sound also reduces it, so they make special sound deadening panels, with knobs or angles. Something rigidly attached transmits sound, something as free floating as possible absorbs sound. Or in other words, loose insulation is better than rigid or tight insulation
One by product of the whole exercise, was the room requires about half the heating in the winter time. The old stone wall doesn't leech the heat like it used to.
Green glue sounds promising, I'd have to try it to be convinced.
As a side note, the walls in my kitchen are furred and hung with early drywall type panels, the voids filled with sawdust. Probably built 60 years ago, by an old timer. It actually works well. A granular insulation may be an answer, but likely hard to work with.
Last edited by Bigfoot; 06-05-2009 at 01:13 PM.