Analysis of impact sound insulation properties of wooden joist and cross laminated timber (CLT) floor constructions

Abstract

During the last years, there has been an increased interest of developing lightweight constructions with improved sound insulation properties compared to previous, well-known solutions. There have been a progress on prediction tools as well as new solutions, for instance, from the WoodWisdom-Net project “Silent Timber Build.” Previous research establish the fact that including the frequency range below 100 Hz is crucial to get satisfying correlation between perceived and measured impact sound insulation quantities. Research work at SINTEF Building & Infrastructure concerning lightweight floor constructions include therefore frequencies down to at least 50 Hz. The paper will present analysis of a number of laboratory measurement results from joist floor constructions and CLT floor constructions. The paper will focus on the most challenging parameter, the impact sound insulation including the spectrum adaptation term CI,50-2500. Analysis will include parameters such as the mass of the floors, the height of the floors, and of course structural connections and properties of the resilient layers involved. Improved low frequency properties introduce of course more mass and or stiffness of the floor, but the result also show that optimization of the contributing components and material properties is necessary for the development of robust and environmental friendly solutions.