Sound insulation of lightweight external frame walls and the acoustic effect of additional thermal insulation

Abstract

The sound insulation of lightweight frame façades and the acoustic effect of additional thermal insulation were examined. The research aimed to investigate the contribution of different insulating layers to the acoustic performance of an external wall. In particular, the use of ETICS (external thermal insulation composite systems) was considered. This usually reduces the sound insulation of traditional massive partitions substantially whereas for lightweight frame structures the effect was not precisely identified. The study is based on laboratory measurements, and several full-scale models were tested. Wood and metal frame walls with various claddings were considered. The application of ETICS caused the reduction of sound insulation in a certain frequency range. The effect, however, seems not as harmful as for massive partitions. Another type of thermal insulation with a venting cavity demonstrated much better acoustic performance. Conversely, internal installation cladding, when rigidly fastened to the basic structure had practically no effect on the wall properties. Significant improvement was observed when resilient spacers or separate supporting structures were applied.