Acoustical Properties of Southern Pine Cross-Laminated Timber Panels

Cross-laminated timber (CLT) is composed of a series of lumber layers placed orthogonally to create a thick panel. Advantages of CLT construction include reduced construction time, lighter structural elements, and reduced carbon footprint. As part of an effort to explore the use of a southern pine CLT panel for building code acceptance, the transmission loss (TL), associated sound transmission class (STC), normalized impact sound pressure levels (NISPL), and associated impact insulation class (IIC) of CLT walls and floors were measured. Wall and floor configurations were tested both as bare CLT panels and with one side covered with studs/joists, insulation, and gypsum wall board. STC results of the bare wall and floor configurations produced identical STC values. The wall and floor configurations using CLT with one-sided studs/joists met or exceeded the STC values in the International Building Code (IBC), but did not meet the IIC values in the IBC. Comparisons of the one-third octave band TL of the CLT panels with conventional wood frame and concrete sections were discussed. The TL performance of the CLT panels mirrored the mass–law relationship. The NISPL associated with CLT bare floors mimicked the NISPL values of a bare concrete floor, except at higher frequencies at which the CLT outperformed the concrete.