I live in an old house 1920s house with plaster walls and ceilings. On the second floor I have a rental apartment. Above my bedroom is the apartment kitchen. In the morning I can hear foot falls, squeaking sub-floor boards and the blender.
I would like to soundproof this 10' x 12' kitchen, from the floor down as much as possible. The ceilings in my bedroom is plaster and lathing, with nice molding which I would like to keep in tact, so resilient channels and two layers of drywall on the ceiling is not an option. The floor in the kitchen is floating (engineered wood) floor, a thin foam under layer, 3/8" plywood, 3/4" sub-flooring, on joists. I was wondering if it would be effective to put 2x10 joists in between the existing joints (2x12), raise a 1/4" higher than the existing joists (similar to a double stud wall)as a decoupling measure. Then add Quiet Roc insulating bats between the joists, 3/4 sub-floor (screwed and glued plywood or osb), acoustic mat and re-install the floating floor. I haven't seen anything on the web about using offset joists for decoupling, but I'd like the best possible result without having to tear out my plaster ceiling.
Thank you for your help