Sound transmission is one of the most common complaints about living in New York City apartment buildings — noise from neighbors above, below, and on either side is a real quality-of-life issue. Renovation offers some meaningful opportunities to reduce sound transmission, but it's important to understand what's possible and what isn't.
The Structural Reality
Most sound transmission between NYC apartments travels through the building structure — floor joists, concrete slabs, shared walls. No wall finish or floor covering eliminates structural sound transmission. What interior renovation can meaningfully address is airborne sound (voices, music, TV) through walls and some impact sound (footsteps) through floors.
Wall Treatments That Reduce Airborne Sound
Standard drywall walls with a single layer are the worst performers acoustically. Adding mass (additional drywall layers), decoupling (resilient channels that break the direct path of vibration), and absorption (insulation within the wall cavity) all reduce airborne sound transmission. For shared walls in NYC apartments, adding a second layer of 5/8-inch Type X drywall with Green Glue damping compound between layers provides meaningful improvement without full demolition — this is achievable as an interior renovation.
Floor Coverings and Impact Sound
Impact noise — footsteps from above — travels through the building structure and is difficult to eliminate entirely. Area rugs with thick pads absorb a meaningful portion of impact transmission. If you're the upstairs neighbor and your floors are hard (hardwood, tile, microcement), adding area rugs in high-traffic areas is both a courtesy to neighbors below and a comfort improvement for your own space. Co-op boards often require area rugs covering a specified percentage of hard floor area for exactly this reason.
What Decorative Finishes Do (and Don't Do)
Venetian plaster, roman clay, and other dense wall finishes add slight mass to wall surfaces, which technically improves acoustic performance marginally versus paint alone. This is not a primary acoustic treatment — it's a trivially small benefit compared to structural interventions. Don't specify a decorative finish for acoustic reasons alone.