Laboratory Evaluation of Airborne Sound Insulation of Lightweight Wooden Roofs

In a large part of Europe, roof systems of small residential buildings generally consist of tile roofing laid over a lightweight wooden frame with a thermal insulation layer. These roofing systems usually provide a poor acoustic performance and could be an acoustically weak link in a building facade. Codes of practice and building regulations sometimes contain calculation methods for insulation against external noise and show data for the sound insulation of different building elements such as external walls, windows, ventilation inlets and roof constructions. Nevertheless, it is difficult to find out reliable data for airborne sound insulation of lightweight wooden roofs. The paper shows the results from laboratory measurements of the airborne sound insulation carried out at the Acoustic Laboratory of Department of Applied Physics (DFT, Dipartimento di Fisica Tecnica) of the University of Padova, for different types of lightweight wooden roofs with several combinations of thermal insulation materials and constructing elements. A special laboratory arrangement was fitted out in order to install roof elements in a way as similar as possible to the actual constructions (both for connections and for sealing) and to reduce the assembly mistakes.