We are witnessing a revolution in how we build with engineered timber in the United States.
In January 2019, the International Code Council (ICC) approved changes that would allow high-rise wood buildings in the 2021 International Building Code (IBC). Oregon and Washington were early adopters of these code changes, and Denver, Colorado, recently followed suit. Other states and municipalities are expected to adopt the 2021 IBC timber provisions early, but it is anyone’s guess what California will do. Will the state decide to adopt now, or will it wait till the code becomes part of the new issuance of the 2021 IBC? This is an important question not just for California, and by extension the City of Los Angeles, but also for the future of mass timber in the U.S. and beyond. California standards and codes transform markets, and a mass timber movement in the U.S. without the state that is also the world’s fifth-largest economy is not going to move the needle fast enough. The opportunity to scale a low-carbon, renewable supply chain to address catastrophic climate change is closing quickly, and it is time for California to step up and demonstrate the progressiveness and leadership that have been key to its prosperity.
What does early adoption mean in practice? Today, an architect in Oregon or Washington who follows the provisions of the new IBC can stamp drawings to build a timber building up to 270 feet in height as of right. This is a significant change. Just over four years ago, my firm’s design for a wood high-rise called Framework was selected as one of two winners of the first U.S. Tall Wood Building Prize Competition. At that time, there was no code path in the U.S. for wood buildings over 75 feet. To receive a permit, our team of designers and engineers worked with the State of Oregon on a performance-based design process. Partly funded by the competition prize, this process included 40 tests on full-scale timber building assemblies to demonstrate their fire, seismic, structural, and acoustic performance relative to high-rise life-safety requirements. It was a fascinating, exhausting, and exhilarating experience, and we are proud that this work and research impacted the timber code changes. Thanks to the new code provisions, it is unlikely that another design team will ever have to go through this process in quite the same way again.
Early adoption of the timber code provisions isn’t just about tall buildings, though—it is a critical opportunity to encourage wider investment and innovation in sustainable mass timber development of all scales. Why should California (or any place else) care about mass timber construction? Building with engineered timber products addresses our most pressing global challenges. It has the potential to decrease carbon emissions relative to construction, spur rural economic development, encourage forest practices that prevent fires, and increase the speed at which we can deliver projects, including much-needed affordable housing. The promise of a major market like California supporting mass timber construction will be an incentive for manufacturers to invest in a more advanced supply chain, back new research, and encourage more sustainable forest management. California’s early advocacy of renewables and electric vehicles moved the market (see Tesla), and I believe it could have a similar impact on the development of mass timber.
We are currently in the permit process for one of the first multistory office buildings in Los Angeles with a cross-laminated timber (CLT) floor system. The building is essentially a hybrid, with CLT floors and steel columns and beams. It meets the current code and does not use the provisions of the 2021 IBC because the highest occupied floor is not over 75 feet. That said, it is still a 125,000-square-foot building—not a small undertaking. We have been working closely with Los Angeles authorities and our engineer to clarify and explain how the CLT performs structurally in the project and how it fits within the current code. We have made incremental steps that will allow for subsequent projects to better navigate permitting this type of building, as well as open up options for multiple CLT suppliers to serve the Los Angeles market. I believe these small steps are significant, but I know that my team could have gone further faster if California had already adopted the new timber provisions. Building officials in California are justifiably cautious. The optics of approving tall wood construction as the state faces devastating wildfires is difficult. However, moving in this direction creates a market that will advance the sustainable forest management that prevents these fires in the first place. If we are serious about addressing the major environmental issues of our time, we need California to adopt the 2021 IBC now. We are simply running out of time.
Of course, there is more to do. I believe as architects we must rethink design as a wider ecosystem of environmental and regional economic choices. Where our materials come from and how they are produced should drive and inspire our designs. This is not a limitation but an invitation to innovate with regional, renewable materials to create more compelling architecture that truly addresses both local and global issues.
Source: The Architect’s Newspaper