The key feature of the 708-student housing complex that opened in 2019 at the University of Arkansas in Fayetteville is embedded in its name—Adohi Hall. Adohi is the Cherokee word for “woods,” and wood is what makes this $79 million project stand out.
The facility is the first large-scale mass timber residence hall in the United States, says Tom Chung, an architect and principal with Leers Weinzapfel Associates, which led the design team on the project. Using mass timber construction, schools and universities can build facilities more quickly, more quietly and more sustainably.
“Mass timber is changing how construction is done,” says Chung. “Construction is completed more quickly, there is much less labor needed, it’s quieter, and there is significantly less construction waste,” says Chung.
According to the American Wood Council, mass timber involves the use of large solid wood panels for wall, floor and roof construction. The panels typically are formed through lamination, fasteners or adhesives, and give the resulting product strength that enables it to compete with steel and concrete as a building material.
The use of mass timber construction has become popular in Europe, and in recent years it has made inroads in the United States. For advocates of sustainability, the appeal of this type of construction is that by using wood instead of steel or concrete, a building project will leave a much smaller carbon footprint from the construction process.
Embodied carbon
The typical large building uses steel and concrete as key construction components. But even if such a building has been designed and constructed to operate efficiently and have minimal environmental impact, the process of extracting, manufacturing and transporting the material needed for construction can release a significant amount of greenhouse gases. Those carbon emissions already are embodied in a project before a building begins operating.
The drive to address climate change through reduced embodied carbon emissions has prompted some builders to turn to mass timber construction as a more sustainable building technique.
Wood, particularly when it is from trees grown in sustainably managed forests, is a renewable resource. Trees absorb carbon dioxide as they grow, and the wood used in constructing a building sequesters the carbon it contains for the life of the building. At the end of a building’s life, the wood can be recycled for other uses.
Fears that buildings constructed primarily with wood would be more susceptible to fire are unfounded, Chung says.
“These are heavy chunks of wood,” he says. “It takes a lot longer for them to catch on fire.”
Before becoming involved with the University of Arkansas project, Chung and Leers Weinzapfel Associates gained experience with mass timber construction through their work on the John W. Olver Design Building at the University of Massachusetts in Amherst.
When it was completed in 2017, the 87,500-square-foot facility was billed as the first and largest cross-laminated timber academic building in the United States. It houses the university’s architecture, landscape architecture and building technology programs.
Pressed together
Cross-laminated timber is also the type of construction employed for Adohi Hall. It involves gluing together multiple layers of wood at 90-degree angles to create structurally strong building material.
Because the timber pieces are prefabricated away from a construction site and measured with precision, a mass timber building can be constructed more quickly and quietly, Chung says.
The wood used for Adohi Hall was processed at nearby factories and the wood was harvested from nearby forests to keep costs down. Mass timber was seen by people in Arkansas as a potential benefit because it would enable them to make good use of the abundant forests in the state.
“It’s good for the economy of Arkansas,” says Chung.
From an aesthetic perspective, the wood in a completed building—the textures, the smells—is more appealing to people than the steel or concrete spaces they are used to seeing.
“Wood has an inherent warmth,” Chung says. “Steel and concrete buildings feel cold.”
The 202,000-square-foot development consists of two residential buildings of five stories each and a third building that connects the two and provides a gathering place for students. It houses students in living-learning communities focused on architecture and design, art, entrepreneurship and innovation, music and theater.
Back to nature
Chung and his firm also are working on a much smaller mass timber project—a preschool facility that will be built in a nature preserve at Auburn University.
Plans call for a 3,000-square-foot classroom building situated within the 120-acre Kreher Preserve and Nature Center that will be constructed from timber harvested on site. Cross-laminated timber will be produced at a nearby plant in Dothan, Ala.
The building will serve as the home base for Woodland Wonders Preschool and help young children explore nature. It will have two large classrooms and a central space, called the learning trail, that will be full of interactive and live-animal displays.
The exposed natural wood ceilings, walls, floors and open decks will make sustainable forestry a tangible part of an outdoor-based educational experience for the students.
“It will feel as if you’re immersed in a forest,” says Chung. “It will be the first school experience for these children. It will teach them how to be good stewards of the environment.”
The building will be supported on wood piles, avoiding the use of concrete and further minimizing the embodied carbon of the project.
Other sustainable elements: A butterfly roof structure, ceiling fans and operable clerestory windows will provide ample daylight and natural ventilation.
Biophilic design will reinforce a connection to nature; exposed local yellow pine will be found throughout, and all spaces will have direct views to the outdoors. Potable water use will be significantly reduced through grey water management; rainwater collected from the butterfly roofs will be used for flushing toilets.
The completed building also will serve as a demonstration project to show the potential mass timber construction offers for Alabama’s forestry-based industries.
