Sound insulation properties of single and double CLT walls

Abstract

Cross laminated timber (CLT) elements have rapidly gained in popularity in Norway and other European countries. Experimental data and improved engineering tools are essential for the development of sustainable solutions. During the last decade, an increasing number of measurement results and experiences from completed buildings became available. Several studies have been performed both regarding wall and floor constructions, and several handbooks and papers offer data and prediction methods. For the development of a Norwegian design guide on CLT inner walls, we have collected and analysed both laboratory and field measurement data on CLT single and double walls. In this paper, we present results of the analysis over the building acoustics frequency range focusing on two aspects; the comparison of the collected measurement data with predictions based on the transfer matrix method and secondly the comparison between laboratory measurements and relevant field measurement results. Results show that the estimate of the stiffness properties and thereby the determination of the coincidence frequency is crucial to obtain reliable prediction results. A positive observation is the relatively small deviation between laboratory and field measurement result when the workmanship on site is according to recommended practice and flanking transmission plays a minor role.