Nation’s Largest Mass Timber Building Opens at University of Arkansas

What Is a Mass Timber Building? A mass timber building is one whose load-bearing structure is made primarily of wood. Previously, such buildings were made of solid wood, which had limitations. Increasingly, however, builders are using engineered wood, such as cross-laminated timber, which is growing in popularity as an alternative to steel and concrete. Cross-laminated timber is created by gluing together wood boards in layers aligned perpendicular to each other, and then putting the material under pressure to create a solid panel. This results in a very strong, durable, and fire-resistant construction material. For more information, check out: Mass Timber—A New Tool in Fight Against Climate Change Wood: The Building Material of the Future? Image Credit: Oregon Forest Resources Institute

You don’t have to be on the frontier to live in a log cabin: timber is gaining attention as an environmentally-friendly building material option in commercial and large residential construction projects. The largest mass timber building in the United States, a residence hall at the University of Arkansas, opened for the fall 2019 semester. Adohi Hall covers 202,027 square feet, can house up to 708 students, and was constructed using cross-laminated timber.

The hall was named after the Cherokee word for “from the woods,” in honor of the Cherokee who traveled on the Trail of Tears near the hall’s location. The name also reflects the building’s construction using sustainably-sourced mass timber. Mass timber construction can both sequester carbon from the atmosphere and shrink the building’s carbon footprint compared to similarly-sized construction projects. Proponents of mass timber cite several advantages, including faster construction times, improved strength, and decreased weight.

One of the most promising characteristics of mass timber is its potential to reduce building carbon emissions. The United Nations Environment Programme reported that 11 percent of emissions from the building sector come from embodied carbon, which is the emissions generated by a building’s construction and materials before it begins operation. In most buildings, steel and concrete are the main sources of embodied carbon. The World Steel Association reported that steel production is responsible for 7 to 9 percent of global carbon emissions, and the International Energy Agency reported that the production of cement, a major component of concrete, is responsible for 7 percent of global emissions. In contrast, trees absorb CO₂ as they grow, and wood used in mass timber buildings continues to sequester that carbon after the buildings have been constructed. One study found that the lifetime carbon footprint of buildings comprised primarily of wood could be as much as 30 percent smaller than similar buildings constructed from concrete or steel.

Although there are many proponents of mass timber as a sustainable building material, some experts have raised questions about the impact a transition to wood buildings would have on forests. According to the head of the Global Institute of Sustainable Forestry at Yale University, Chad Oliver, if global construction switched from wood to steel, annual levels of logging would have to triple. This could lead to other environmental problems, such as species extinction in logged forests. More research needs to be done to determine the full life cycle effects of mass timber, but projects like Adohi Hall show that the building sector is increasingly interested in reducing its contribution to climate change.

Adohi Hall is only one component of the University of Arkansas’s efforts to reduce its campus’s carbon footprint. According to the University’s Office for Sustainability, long-term goals are in place for carbon neutrality and 90 percent waste diversion from landfills by 2040. The University is also planning on using Adohi Hall as a study site for further research into cross-laminated timber as a construction material.

Climate solutions must address all stages of activity in all sectors of the economy. Reducing buildings’ embodied carbon is an important component of reducing their overall contribution to climate change, and Adohi Hall and other mass timber projects show that reducing emissions can be an opportunity for innovation and creativity in existing industries.

 

Author: Abby Neal