Development of laboratory sound insulation measurement methods of cross-laminated timber elements

Cross-laminated timber (CLT) is a construction material that has gained significant popularity since the start of 2000s in numerous countries worldwide. Wooden-based structures have traditionally given rise to acoustic challenges in buildings. Since CLT is not a traditional wooden laboratory tests on sound insulation of CLT-elements with various build-ups and configurations are in high demand. However, physical properties of the CLT-element lead to ambiguity in the ISO-standards regarding its classification as an either lightweight or heavyweight construction material. In consequence, practical aspects like the mounting condition vary based on the choices made by the test facilitator and the acoustic laboratory, which gives rise to uncertainty around the trustwhorthyness of the results. This paper presents the findings from a project focused on the test procedure and on the test arrangement for conducting laboratory sound insulation measurements on CLT floor elements. A variation of mounting conditions have been investigated and the impact they have on the sound insulation properties, structural reverberation time and the loss factor of the floor.