Abstract
In order to improve the floor impact sound level of the standard rectangular void slab which is 5〜10dB higher at 1kHz band compared to that of ordinary RC slabs, we made several series of experiments. By experimenting light floor impact sound and impedance on the various types of void slab samples, we found that the ones with upper and lower shells fixed tightly were the best against the light floor impact sound and that considerable improvement on the rise of sound pressure at 1kHz. Then, we examined the effect on one of them by measuring the sound transmission loss, and as a result, this improved void slab got better result than 200mmRC slab.