The obstacles and opportunities of mass timber construction in the United States
The opportunity to reduce carbon emissions within the building sector is great news for design professionals who specialize in mass timber construction, but it comes with challenges.
With the United States reentering the Paris Climate Agreement and climate’s inclusion as an immediate priority, the new Biden administration has signaled a renewed focus on immediate greenhouse gas emission reductions. Setting the US on the path to a more climate-resilient future will require us to overhaul our approach to the key sectors currently driving those emissions in the US — one of which is the building sector. The opportunity to reduce carbon emissions within the building sector is great news for design professionals who specialize in mass timber construction, because it suggests that this underutilized, low-carbon material may finally have its moment. However, to successfully pave the way for mass timber’s broad adoption in the US, it will be necessary for us to understand the barriers currently hindering its progress and develop actionable strategies to overcome them.
Understanding the gating factors and how to surmount them
As a structural engineer who has spent the past six years working on mass timber projects in and around Washington D.C. and elsewhere, there have been sustainably-minded developers shy away from using mass timber on their projects due three key factors: cost, building code restrictions, and a lack of federal, state, and local policies incentivizing its use. None of these obstacles are insurmountable. In fact, there are numerous examples of developers overcoming them to make ambitious mass timber projects a reality, like the Ascent Tower in Milwaukee and 80 M Street SE here in Washington D.C. To promote the widespread adoption of mass timber in the US market, design professionals, developers, investors, and government decision-makers will need to work together to address impediments and make mass timber a more attractive and affordable option.
The high premium on mass timber
Cost is always a key consideration when embarking on a new project and mass timber’s popularity is not helped by the fact that it’s currently more expensive than conventional building materials. Thankfully, mass timber’s higher cost is not baked in; it’s dictated by the realities of today’s market. The US currently has a very limited number of mass timber suppliers, so clients pay a premium to access a finite production supply.
As market demand grows, more American suppliers will continue to come online and current suppliers will increase their production capacity, making mass timber products more cost competitive with conventional materials like concrete and steel. In the meantime, it’s instructive to look at the progress mass timber has already made in some areas of the country to help us identify market drivers and point the way forward.
Commercial developers in markets like Portland, Seattle, Denver, and beyond are increasingly willing to shoulder the higher upfront costs of mass timber construction because they recognize that sophisticated consumers are willing to pay a premium for its aesthetic and sustainability benefits. While there is little public data currently available on the increased rent that potential mass timber buildings would offer, Consulting-Specifying Engineer estimates mass timber projects can command rent premiums $7 higher per square foot or more. There is also ample anecdotal evidence from mass timber projects across the US supporting the economic viability of commercial developments. For example, the T3 tower project in Minneapolis opened in 2016, quickly sold in 2018 for $87m, and was 82% leased at the time of sale. For the 80 M Street SE project, the building owner was able to lease approximately half of the new mass timber leasable floor area prior to the start of construction.
Why policy and regulation matter
Many mass timber projects also stall out due to restrictive code requirements. In cases where municipal authorities aren’t well versed in tall mass timber construction practices and lack insight into how it can be applied to meet fire safety requirements, they are often quick to “no-go” mass timber projects at the concept design stage. However, this is already changing. The publication of new tall timber provisions within the 2021 International Building Code (IBC) will help provide new code pathways for mass timber construction, which is limited to 85 feet in height under the current code.
That said, the IBC 2021 timber provisions don’t remove all the code barriers mass timber faces in the US, particularly for tall timber buildings. While the IBC 2021 provisions allow mass timber buildings up to 270 feet in height, they come at a cost — the higher you build, the more timber must be concealed. For commercial developers looking to expose mass timber because it helps garner higher rents, the need to conceal timber above a certain height will change the cost-reward ratio, especially given that there are also substantial costs associated with concealing the timber.
In jurisdictions with forward-thinking building authorities, IBC 2021 provisions can serve as a basis for solutions that balance the desire for exposed timber with fire safety needs. The 80 M Street SE project, on which I served as Arup’s project manager, moved forward because of the local DC authority’s support for building innovation and willingness to review and approve project-specific solutions fulfilling all fire and life safety standards, using the IBC 2021 tall timber provisions as a basis. To continue leveraging tall timber’s full potential as we wait for codes to evolve, it will be necessary for clients and project teams to collaborate with jurisdictions supportive of ambitious projects that might not fit squarely within the prescriptive requirements of the building code.
Advancing mass timber will deliver a host of benefits
Over the coming four years as the new Biden administration’s climate policies are rolled out and more local jurisdictions commit to ambitious climate targets, addressing building-sector carbon emissions will take on increasing importance. As a renewable, carbon-sequestering building material, timber can play a key role in helping us meet our decarbonization and sustainability goals. But only if we can successfully remove the barriers currently hindering its ability to scale in the US. So, what can we do at the federal, state, and local level to encourage wider-spread adoption of mass timber construction?
For precedent, we can look to Europe — one of the world’s leading markets for mass timber. Mass timber was quicker to take hold in Europe, in part because it’s the birthplace of cross-laminated timber (CLT), a product that paved the way for new applications of timber using longer spans and taller building heights when it was introduced in the 1990s. However, supportive government policies and commercial investment also played a key role in helping mass timber scale.
Countries with healthy forestry sectors, like Austria, Sweden, and Finland, were among the first to remove code restrictions and introduce incentives for using mass timber, and it’s there that mass timber took root first. Seeing the success of these countries, other countries, like France, England, and Finland, followed suit and are now experiencing their own boom in mass timber construction.
As in Europe, the areas in North America working hardest to promote the use of mass timber tend to have established forestry sectors that stand to benefit from its broad adoption. British Columbia’s Wood First program, for example, requires provincially funded projects to use timber as the primary construction material. Here in the US, several states have provided economic incentives for the forestry products industry that include mass timber production. The incentive programs are often supported, in part, by federal funding. For instance, the Maine Mass Timber Commercialization Center was founded with the help of a sizeable grant awarded by the US Economic Development Administration. At the state level, California, Oregon, and Washington are helping to remove code barriers for mass timber by adopting IBC 2021 tall timber provisions early. Following this decision, these states have consistently seen an increase in timber projects, demonstrating that supportive code changes can also serve as a type of incentive to spur growth.
This is a good start. But to drive more rapid scaling of mass timber across the nation, expanding federal, state, and local incentives on both the supply and demand side will be necessary. Expanding funding incentives to timber-rich areas in the Southeastern United States could further help to increase mass timber production. These incentives can also help us ensure that the timber used in mass timber production is sourced sustainably, using proper forest management practices. The introduction of policies aimed at cutting building carbon would also make low-carbon materials, like mass timber, a more appealing option and would likely increase demand for mass timber products.
We have already started on the right path. The adoption of low-carbon procurement policies, known as Buy Clean legislation, at state and local levels nationwide signals a policy shift toward considering embodied carbon. Potential future policies targeted at incentivizing mass timber construction can come in many forms, including direct tax reductions, density bonuses, code updates, or expedited permit approvals. Large corporations with sustainability goals can further increase the impact of federal, state, and local incentives by using their purchasing power to help grow economies of scale within the mass timber market.
There is already precedent for this as well. For example, Walmart has committed to building its new corporate headquarters using mass timber — a decision that has already spurred the establishment of a new CLT production facility in Arkansas. Adidas recently completed construction of their North American headquarters utilizing CLT panels throughout. Microsoft intends to do the same with its new Silicon Valley campus, which is currently under construction. Other companies, including Apex Clean Energy and First Tech Credit Union, have also chosen to construct their headquarters using mass timber.
Regardless of which strategies we choose to implement, it’s clear that facilitating the broad adoption of mass timber in America will require government decision-makers, investors, and industry practitioners to join forces to remove the cost, code, and policy obstacles currently standing in its path. Doing so will take significant effort and investment but will be necessary to support the use of mass timber in addressing carbon emissions within the building sector.
Original content can be found at www.arup.com.