Traditionally, multi-family houses have been constructed using heavy, homogenous materials like concrete and masonry. But as a consequence of the progress of lightweight building systems during the last decades, it has been questioned whether standardized sound insulation evaluation methods still are appropriate.
An extensive measurement template has been applied in a field survey where several vibrational and acoustical parameters were determined in ten Swedish buildings of various constructions. In the same buildings, the occupants were asked to rate the perceived annoyance from a variety of natural sound sources. The highest annoyance score concerned impact sounds, mainly in the buildings with lightweight floors.
Statistical analyses between the measured parameters and the subjective ratings revealed a useful correlation between the rated airborne sound insulation and R0 w þ C50—3150 while the correlation between the rated impact sound insulation and L0 n;w þ CI;50—2500 was weak. The latter correlation was considerably improved when the spectrum adaptation term with an extended frequency range starting from 20 Hz was applied. This suggests that frequencies below 50 Hz should be considered when evaluating impact sound in lightweight buildings.
Project contact is Sylvain Ménard at Université Laval
In order to ensure the acoustic performance of timber constructions, the research group of the Sustainable Building Institute at Napier University has established a series of proven solutions. These, called rugged construction details, are based on a series of designs that are most likely and proven for the performance they will bring into the building. The advantage of this approach is to provide designers with solutions that have been the subject of technical validations, thus allowing them to free themselves from the burden of offering the builder an acoustic solution. The tools to develop this concept will involve an understanding of the propagation of impact and airborne noise in the main building design typologies in CLT, to validate the main solutions through laboratory tests and to propose proven solutions. Many tests performed at NRC could have been avoided. Performing tests is expensive, and it would be interesting to make the link between the test results and the modeling results. Having a solution guide is great, but having a model that would predict the behavior of a design would be even better.