Mass Loaded Vinyl

Mass loaded vinyl (MLV) is a thin, dense, flexible sheet material (typically 1–6 mm thick, 2–5 kg/m²) used to increase the mass of lightweight partitions for improved sound insulation. MLV is loaded with barium sulfate or calcium silicate to achieve high surface density in a minimal thickness. It is installed within wall cavities, wrapped around pipes, or layered onto existing surfaces to reduce airborne sound transmission. MLV follows the mass law principle, providing approximately 6 dB improvement per doubling of surface mass. Common applications include stud wall upgrades, ceiling barriers, pipe wrapping, and enclosure linings. MLV is not a sound absorber and must be combined with absorptive materials for comprehensive acoustic treatment. It is particularly effective at blocking mid-to-high frequency sound but has limited impact at very low frequencies. STC values of single-layer MLV range from STC 26 to STC 32 depending on weight.