Sistering 2x4s for 2nd Ceiling
Hello all, I could not find an answer to my question in other posts, this will be my first.
I live in a woodframe construction condo building and live below very noisy neighbours. The low-frequency noises they create are unbearable (stomping, creaking floors, dogs running around, balls bouncing, etc).
I am thinking about putting in a second ceiling, a couple inches below the existing. I plan on running wood joists across the span, insulating between joists, and drywalling from underneath.
My plan is to run 2x4s around the perimeter of the room with a 2 or 3 inch gap in between the existing ceiling. I then would like to run 2x4s across the ceiling to fasten the drywall to, constructed similarly to a deck frame. My problem is the room is 15' x 21'. I do not want to fasten the 2x4s to the existing ceiling so that there is no contact and the sound will not transfer between new and old ceiling. Would sistering 2x4s across a 15' span work? the only weight that would be supported is the wood itself and the drywall.
Please let me know if this would work, or any suggestions you might have. I realize I will lose about 5 inches of ceiling height doing this, but would rather this then have to deal with these annoying noises all day.