soundproofing

Soundproofing is the set of techniques used to prevent or reduce the transmission of sound from one space to another. It focuses on limiting airborne sound and, to a lesser extent, structure-borne sound, and it is distinct from sound absorption, which lowers sound reflections within a room rather than transmission between spaces.

Sound travels through air, walls, floors, and structural connections. The effectiveness of soundproofing is often described by transmission loss measurements, such as the sound transmission class (STC), which estimates how well a building assembly blocks airborne noise. In-room sound behavior is sometimes described by the noise reduction coefficient (NRC), which relates to sound absorption within a space. Good soundproofing requires a combination of mass, airtightness, decoupling, and damping.

Key strategies include increasing mass to impede sound transfer, decoupling timbers and surfaces to break vibration paths, applying damping materials to reduce resonances, and sealing gaps and joints to prevent air leakage. Common implementations include resilient channels and staggered or double stud walls for decoupling, layered wall assemblies with dense boards, damping compounds, and careful door and window detailing. Floating floors, resilient mounts, and well-sealed penetrations further reduce transmission.

Materials commonly used include dense substances such as mass-loaded vinyl, concrete, or layered gypsum board, along with mineral wool or fiberglass for insulation, acoustic sealants, and damping agents like adhesive compounds. Windows and doors are critical points; options include laminated or double/triple glazing and acoustically sealed doors with proper thresholds.

Standards and testing (e.g., STC ratings) guide performance, but real-world results depend on the entire assembly and installation quality.