Which product is described as a dense, flexible material used to block sound in walls, ceilings, or as flooring underlayment?

• A. Sound Absorption Coefficient
• B. Mass-loaded vinyl
• C. IIC
• D. Sound Batting

Answer: (B)

Blocking sound effectively relies on adding mass to the barrier. A dense, flexible barrier like mass-loaded vinyl fits that purpose well: it’s a heavy vinyl sheet that can be installed in walls, ceilings, or used as flooring underlayment to significantly impede airborne sound transmission while remaining pliable enough to fit around framing and other obstacles. Its density is what makes it effective at blocking noise, according to the principle that more mass reduces sound transfer through a barrier.

The other options don’t describe a product with this specific blocking function. Sound absorption coefficient is a measurement of how well a material absorbs sound, not a material itself. IIC is a rating for how well a floor-ceiling assembly isolates impact noise, not a material you install. Sound batting is a type of insulation used mainly to dampen sound by absorbing within cavities, rather than providing a dense barrier to block sound transmission.