How Can I Soundproof My Apartment Walls?
Updated
Soundproof apartment walls by sealing the spots where sound leaks through (outlet boxes, the gap at the base of the wall and pipe holes), then the entry door, using fixes that come out at move-out. Sealing matters most, because one unsealed 1/8 in. gap 1 ft long drops a wall from STC 46 to 36 in PABCO's Sound Design Guide (opens in a new tab).
- Outlets: with the breaker off, press an acoustic putty pad around each box on the shared wall, or ask the landlord to do it.
- Wall base: run acoustic sealant along the baseboard edges. Get written permission before you pull any trim.
- Entry door: fit a sweep and adhesive gaskets until you can't see light anywhere around the slab.
Watch out: spray and tube foam adhesives can cost you your deposit. Auralex calls its Foamtak and Tubetak "permanent adhesives" whose removal "will damage the product and most wall surfaces" (adhesives spec sheet (opens in a new tab)). Go with removable strips or freestanding panels, listed in soundproof panels for apartments.
Panels on the wall only cut echo, as the soundproof panels guide explains. If you own the place, you can go further: in USG's lab tests (opens in a new tab), resilient channel on one side took an insulated 2x4 wall from STC 34 to 48. The full sequence is in how to block noise from a shared wall, and there are more answers in the soundproof panels FAQ.