Good Afternoon - I have a question about existing soundproofing already installed in my condo unit. The building was built in 1984 and the ceiling drywall was mounted to sound channel attached to the joists. Problem is, we still hear a lot of impact noise from foot traffic overhead. In doing a little research, it turns out the edges of the drywall ceilings are not floating, rather sitting on top of the drywall panels that make-up the walls. Would there be any benefit to cutting away the edges of the ceiling drywall from the walls by 1/4" so the ceiling is in fact "floating". Then apply acoustical sealant to the perimeter? The installation seems pretty decent other than the edges shorting-out the whole system. Figured I could always try it in a smaller room and see if there is improvement before ripping down the entire ceiling to re-build.
That approach has worked in prior projects with some value based on the ease of the solution. The real question is did they short the channel in the field as well by running screws through the channel and making contact to a joist. If this happens the perimeter cut will do very little.
Do you know if they used RC-1 or RC-2 (1 leg vs. 2 leg) if RC-2 you could add a second layer with green glue to get a much better reduction.
I view this as a hail mary prior to full demo a rebuild. if you have to rebuild use a clip and channel for best results along with double rock and insulation if needed.
If you have questions or concerns feel free to contact me direct.