Structural isolation of walls using elastic interlayers

Abstract

Resilient layers at joints provide a practical method for reducing structureborne sound transmission. Soft materials such as cork are readily available and can provide significant improvements in performance. When such materials are introduced into buildings the nature of transmission changes. The relative importance of transmission paths changes so that the benefits may be unclear. Placing a resilient layer under a wall will reduce transmission of bending waves between the wall and floor but will have less effect on the conversion of in-plane waves to bending waves. Thus, while bending transmission may be reduced, conversion from bending to in-plane and from in-plane to bending may not be changed significantly and may become the dominant transmission path. In real situations the details of the rest of the construction are important and may reduce the expected benefits of fitting a resilient layer. It is not sufficient to calculate the change in the direct path to estimate the change in overall performance.