Silence Starts at Rough-In
Noise control is easiest before the walls close. Specify cast-iron or double-wall PVC for vertical waste stacks to dampen water roar. Decouple plumbing walls with staggered studs or resilient channel and fill with mineral wool. Use isolation clamps for supply lines so thermal expansion doesn’t creak against framing. Keep vents properly sized and routed to avoid trap suck and gurgle.
Short, Smooth, and Accessible
Keep drain runs short with long-sweep fittings and correct slopes; insulate PEX home runs and provide accessible shutoffs behind a knee-wall panel. For showers, a bonded waterproofing membrane over a sloped pan prevents leaks that can travel into the roof assembly.
Fans You’ll Actually Use
Choose a low-sone (≤1.0 sone) exhaust fan, duct it outdoors with smooth, insulated pipe, include a backdraft damper, and add a timer or humidity control so it runs long enough post-shower. Never terminate into soffits or attic cavities.
Finish Details That Muffle Sound
Use soft-close seats/doors, solid-core doors with drop seals where possible, and continuous gaskets at penetrations to preserve the air barrier and acoustic seal.
Grab our attic bath quiet-build checklist (materials, details, and inspections) on the NYC Attic Remodeling Service page.