Mass timber is poised to join concrete, steel, and light-wood framing as a primary structural material for multifamily projects. …“Architects and developers are becoming increasingly interested in the technology,” said Mitch Warren, who represents Kalesnikoff, a Canadian mass timber supplier. That interest is being fueled by the 2021 edition of the International Building Code, which increased the maximum allowable height for mass timber structures in the U.S. to 18 stories. In Canada, the 2020 National Building Code allows wood buildings up to 12 stories high. California, Maine, Oregon, Utah, Virginia, and Washington have adopted the IBS update in some form, as have Denver and Austin, Texas. Georgia, Idaho, and Wisconsin are in the process of adopting the new IBC height allowances. …We asked architects, builders, and developers involved in “big timber” work to share their advice and insights. Here’s what they told us.