Impact-Sound Transmission through Concrete and Wood-Joist Floors

Abstract

A wide-spread source of complaints by apartment dwellers is the transmission of impact noises through floors. A program has been conducted to determine the impact-sound-transmission characteristics of concrete and wood-joist floor constructions. The concrete constructions consisted of the 12-in. slab forming the roof of a 10 000-cu-ft reverberation room with test panels of various types and areas up to 16 sq ft laid over the slab. The wood constructions were built into a 10-ft-sq opening in the roof of the reverberation room. Impact-transmission tests were conducted according to ISO/R 140-1960, using the standard tapping machine specified. The criterion used thus far for evaluation of the test results has been the British grade I and II curves that denote relative degrees of apartment-dwellers' satisfaction as determined by extensive field surveys. The grade I curve can be met with a number of practical constructions over a concrete slab, for which data are presented. In wood-joist construction, the grade I requirement is easily met at the higher frequencies, but equivalent low-frequency performance is difficult or impossible to attain because of the inherent lack of mass and rigidity of wood construction in comparison to concrete.