Impact Sound Insulation of Timber Floors: Interaction between Source, Floor Coverings and Load Bearing Floor

Abstract

It is well known that prediction of impact sound of timber floors contains large uncertainties. They partly originate from the dynamic interaction of impact sources and floor elements which makes it difficult to characterise the performance of the elements of a floor in the right way. First results of a project recently started at the Fraunhofer-Institut für Bauphysik on this subject are presented. Calculations reveal strong influences of impact source and load bearing floor on the acoustical performance of the floor coverings. There are considerable deviations between concrete and timber floors. The standard ISO tapping machine and human walkers interact quite differently with floors and coverings, thus modifying the impact sound improvement “of the floor covering”. To clearly separate performance of the floors, floor coverings and impact sources detailed information about their dynamic properties is necessary. Non-linear effects are expected especially with carpets. The results of the project should be helpful to design a laboratory measuring method for the impact sound improvement on lightweight (timber joist) floors and to design floors with a better impact sound insulation.