Airborne Sound Transmission in Cross-Laminated Timber Buildings: The Influence of Building Height

Abstract

Buildings with cross-laminated timber (CLT) has gained increasing popularity in several countries. In addition, buildings constructed with CLT are increasing in building height, which increases the load on the junctions and structural building elements lower down in the buildings. Furthermore, CLT offers sustainable features that can help the building industry to reduce greenhouse gas emissions. Several studies have investigated how the load affect the sound insulation between apartments. The majority of the studies show that increasing load tends to have a negative effect on the vertical sound insulation. However, most results are based on a limited number of measurements with investigations focusing on junctions with resilient interlayers. This paper will show in more detail how the building height, and thus the load, affect the vertical airborne sound insulation between apartments in several CLT buildings. Moreover, this paper will include buildings with and without viscoelastic interlayers in their junctions as well. Measurements were performed in four CLT buildings with varying construction systems, building heights and presence or absence of viscoelastic interlayers in their junctions. The vertical airborne sound insulation between different rooms in apartments located at both lower and higher levels was evaluated. By calculating the differences in airborne sound insulation for each building, the results clearly show a decrease in the vertical airborne sound insulation in the lower parts of the buildings compared to higher up. Consequently, these results show that an increased number of floors negatively affects the vertical airborne sound insulation lower down in the buildings.