Can we build tall buildings out of wood? We can. Modern mass timber is a new system of building materials that also beats steel and concrete in strength by weight, with only a fraction of their “carbon costs.” It’s time to learn about this revolutionary material, and we have the perfect professionals to explain: Michelle Roelofs, a structural engineer at Arup who specializes in mass timber; and Tanya Luthi, the director of engineering at Timberlab, a contractor specializing in mass timber structures. They will lead us through a primer on the history and types of mass timber, especially cross-laminated timber (CLT) and explain its virtues and challenges.