Floor Impact Sound Insulation and Airborne Sound Insulation on CLT Model Building

For effective use of the Japanese wood, CLT (Cross Laminated Timber) was standardized by JAS (Japanese Agricultural Standard) as a building material. We, however, have little knowledge about performance of CLT building for satisfaction of Japanese standards. Therefore we built a 2-story CLT model building for experiments. Among the objections and the troubles of buildings in Japan, the sound insulation is one of the most serious issues. We also measured the floor impact sound insulation of a right below story and an obliquely downward story. The results showed that the heavy-weight floor impact sound insulation is low and it is needed to be considered the influence of the floor impact sound insulation of an obliquely downward story. Besides it is necessary that the airborne sound insulation is more than the sound reduction index Rr-40 as separation wall between each unit of apartment houses. Hence we have measured the sound insulation of CLT separation wall in the CLT model building. The wall, which had the specification of extra gypsum board wall for one side with independent furring strip from CLT panel, was shown to be effective to improve the sound insulation of CLT separation wall.