Approximately 60 percent of Koreans are living in apartment houses in 2013. One of the big residential environment concerns in living apartment houses is noise pollution induced by floor impact sound. Korean government regulates several standards on floor soundproofing to reduce the impact noise of apartment houses. The maximum of light-weigh impact sound and heavy-weigh impact sound was enforced to be lower than 58dB and 50dB, respectively. To reduce floor impact sound, soft resilient materials or resilient materials with small slab contact area are commonly used, which are placed between concrete slab and finishing materials. Though soft resilient materials are satisfied with the limitation of light-weigh impact sound or heavy-weigh impact sound, these materials may not support load on the floor. As a result, there is some possibility that cracks develop on the finishing mortar and the floor sags. This paper investigates the influencing factors of the deflection of floor sound insulation systems. An analytical method was used to investigate the influencing factors. The analyzing results indicated that the modulus of elasticity of resilient materials, loading point in slab, and weights were most significant influencing factors to induce the deflection of floor sound insulation systems.
