In the present paper the application of the diffusion index method to beam-slabs is discussed. Through numerical calculation study (FEM), it is confirmed that both a resonance of the slab vibration and a restraining effect by slab-ends can be dealt with in the same manner as the flat-plate slabs. The calculated results of heaby-type floor impact sound by this method agree with the measured results. Thus, this method can be use widely for a prediction of the floor impact sound of architectural slabs.
