Influence of panel fastening on the acoustic performance of light-weight building elements: Study by sound transmission and laser scanning vibrometry

Structural details and workmanship can cause considerable differences in sound insulation properties of timber frame partitions. In this study, the influence of panel fastening is investigated experimentally by means of standardized sound reduction index measurements, supported by detailed scanning laser Doppler vibrometry. In particular the effect of the number of screws used to fasten the panels to the studs, and the tightness of the screws, is studied using seven different configurations of lightweight timber frame building elements. In the frequency range from 300 to 4000Hz, differences in the weighted sound reduction index RW as large as 10dB were measured, suggesting that the method of fastening can have a large impact on the acoustic performance of building elements. Using the measured vibrational responses of the element, its acoustic radiation efficiency was computed numerically by means of a Rayleigh integral. The increased radiation efficiency partly explains the reduced sound reduction index. Loosening the screws, or reducing the number of screws, lowers the radiation efficiency, and significantly increases the sound reduction index of the partition. [Display omitted] •The effect of screw fastening on sound insulation of a lightweight wall was studied.•The physical mechanisms were investigated by means of laser Doppler vibrometry.•Fastening of gypsum boards to wooden studs can lead to differences up to 10dB.•This difference in sound insulation is partly explained by an increase of the radiation efficiency.•The material properties of the panels were estimated from dispersion measurements.