While CLT floor panels are fairly common in mass timber buildings, their use as a diaphragm (the structural system transferring wind and seismic loads through horizontal panels and connections to the vertical force-resisting system) has been limited despite their inherent appropriateness for this application. As a result, building designers have had to incorporate other materials or get special approval from building officials through an alternate means process. However, with building codes and standards evolving to address CLT to a greater degree, the American Wood Council standard, Special Design Provisions for Wind and Seismic (SDPWS), now includes new CLT diaphragm design provisions. WoodWorks’ CLT Diaphragm Design Guide provides insight into the analysis, design, and constructability of CLT diaphragms that follow these provisions for practicing engineers working on mass timber projects.