Achieving Better Sound Insulation of CLT Partitions

During the last 5 or more years, the direct airborne and impact sound insulation of over 100 different cross-laminated timber (CLT) floor and wall assemblies have been measured at the National Research Council Canada. The installation of a lining such as a floor topping, a ceiling lining or a wall lining on CLT elements is often necessary to achieve good sound insulation. A large data set of airborne, impact and vibration test results of CLT assemblies with various linings were analyzed to determine sound insulation improvements and similarities. The airborne sound transmission loss was measured according to ASTM E90; the light impact sound insulation was measured according to ASTM E492; and the heavy impact sound insulation was measured using the heavy/soft impact source. The structural reverberation times and the wavenumbers of select CLT floor assemblies were also considered. As the 2015 edition of the National Building Code of Canada now has a requirement for the Apparent Sound Transmission Class (ASTC) which includes flanking sound transmission, the improvement of flanking sound insulation due to the addition of linings on CLT elements will be discussed.