The use of cross-laminated timber (CLT) as structural floor and roof panels has seen incredible growth in the US over the past decade. However, using CLT as part of a seismic and wind force-resisting system was only recently codified. This has resulted in the design of CLT diaphragms through alternative means and/or the use of structural toppings, such as a layer of wood structural panels or concrete, as the diaphragm. This session will review the new provisions for CLT diaphragm design in the American Wood Council’s 2021 Special Design Provisions for Wind and Seismic (SDPWS), the code-referenced standard for wind and seismic design of wood systems. The session will also cover practical detailing options to address constructability and performance goals.