The University of Washington’s Founders Hall at the Foster School of Business demonstrates how mass timber material specifications can achieve long-term carbon storage while delivering high-performance academic spaces. This six-story, 84,800-square-foot building uses cross-laminated timber (CLT) floors with glulam post-and-beam construction to store over 1,000 tons of carbon dioxide for the lifetime of the structure. Designed by LMN Architects, the project reduces embodied carbon by nearly 60 percent in the structure, envelope, and interiors compared to conventional construction methods. The building’s approach to biogenic carbon storage represents a significant shift in how building professionals evaluate the environmental performance of timber structures, moving beyond operational energy savings to address the carbon footprint of the materials themselves.
The Carbon Storage Potential of Mass Timber Construction
Mass timber construction stores carbon through a process called biogenic carbon sequestration. Trees absorb carbon dioxide from the atmosphere during their growth cycle, converting it intoæœ¨è´¨çº¤ç»´ç´ (woody biomass). When harvested and manufactured into engineered wood products such as CLT and glulam, this carbon remains locked within the material for the life of the building. Unlike steel or concrete manufacturing, which release significant carbon emissions during production, mass timber fabrication requires substantially less fossil fuel energy, creating a net carbon benefit from the outset.
How Biogenic Carbon Storage Works in Building Materials
The carbon storage mechanism in mass timber follows a straightforward lifecycle pathway:
- Carbon absorption: Growing trees capture CO2 through photosynthesis, storing carbon in trunks, branches, and roots.
- Harvest and manufacturing: The harvested timber is processed into CLT panels or glulam beams with roughly 75 percent less carbon emissions than equivalent steel or concrete production.
- Installation in buildings: Once installed, the carbon remains sequestered in the building structure for decades or centuries.
- End-of-life considerations: At the end of a mass timber building’s life, the wood can be reused, recycled, or used for biomass energy.
Carbon Storage Quantification at Founders Hall
Founders Hall stores more than 1,000 tons of CO2 in its mass timber structure, equivalent to removing approximately 200 gasoline-powered cars from the road for one year. The carbon storage value was monetized through Aureus Earth, a provider of carbon offset incentive programs for the construction industry, marking the first transaction to value long-term biogenic carbon storage in a mass timber building.
| Metric | Founders Hall Performance | Conventional Building Baseline |
|---|---|---|
| Carbon emissions reduction (structure) | Over 90 percent reduction | Standard steel/concrete frame |
| Embodied carbon reduction (structure, envelope, interiors) | Nearly 60 percent reduction | Conventional construction methods |
| Operational carbon reduction | 92 percent reduction | Standard campus building performance |
| Biogenic CO2 stored in structure | Over 1,000 tons | Zero (steel/concrete does not store carbon) |
| Projected energy use reduction | 79 percent reduction | ASHRAE 90.1 baseline |
The table above compares Founders Hall’s environmental performance against conventional building benchmarks. The combination of NFPA tall mass timber provisions compliance and advanced energy strategies makes this project a benchmark for sustainable academic construction.
Structural Design and Material Selection for Mass Timber Performance
The structural system of Founders Hall integrates multiple material types to optimize performance across different building functions. The primary structure uses CLT floor panels supported by glulam columns and beams, creating an exposed timber interior that serves both structural and aesthetic purposes. Concrete shear cores provide lateral load resistance, while steel long-span beams accommodate the larger column-free spaces required in classrooms and lecture halls.
CLT and Glulam Specifications for Six-Story Construction
The project uses a hybrid structural approach that leverages the strengths of each material:
- Cross-laminated timber floors: Five-layer CLT panels spanning between glulam beams, providing both structural support and a finished ceiling surface that requires no additional cladding.
- Glulam post-and-beam frame: Engineered timber columns and beams supporting the CLT floor system, with connections designed to accommodate timber shrinkage and movement over the building’s lifespan.
- Concrete shear cores: Two concrete cores housing stairs, elevators, and mechanical shafts, providing the primary lateral force-resisting system for seismic loads in the Seattle region.
- Steel long-span beams: Steel beams in classroom areas where longer spans are needed, reducing the number of columns and providing flexibility for future space reconfiguration.
Connection Design and Moisture Protection Strategies
Successful mass timber construction requires careful attention to connection detailing and moisture protection. The design team at LMN Architects, with structural engineering support from Magnusson Klemencic Associates and Katerra, developed connection details that accommodate wood movement while maintaining structural continuity. Key strategies include:
- Elevated steel embed plates at concrete-to-timber interfaces to prevent moisture wicking from concrete into timber members.
- Slotted connection holes to allow for differential movement between timber and concrete elements as wood equilibrates to interior humidity conditions.
- Protective membrane systems at all exposed timber surfaces during construction to prevent moisture damage from weather exposure.
- Continuous air and vapor barriers at the building envelope to control moisture migration into the mass timber structure.
Acoustical Performance in Mass Timber Buildings
Mass timber structures present unique acoustical challenges compared to concrete or steel buildings. The lower mass of timber floor assemblies requires additional acoustical treatment to meet code requirements for sound transmission between floors. Founders Hall addresses this through a combination of strategies: topping slabs on CLT panels for impact noise reduction, resilient underlayment systems, and careful detailing of penetrations and flanking paths at partition walls.
Energy Performance and Operational Sustainability Features
Beyond the carbon storage benefits of its mass timber structure, Founders Hall achieves exceptional operational energy performance through an integrated approach to mechanical systems, envelope design, and site strategies. The building operates entirely without fossil fuels, forgoing the campus steam system and relying instead on electric heat pump technology for heating and cooling.
Natural Ventilation and Passive Cooling Strategies
The building takes advantage of Seattle’s moderate climate by integrating natural and mechanical ventilation strategies. Night flush cooling in office spaces uses cooler nighttime air to pre-cool the building’s thermal mass, reducing daytime cooling loads. Operable windows in perimeter spaces allow occupants to control their immediate environment, while the mechanical system provides backup ventilation when outdoor conditions are unfavorable.
Envelope Design for Energy Performance
The building envelope plays a critical role in achieving the projected 79 percent energy use reduction. The facade features a peeled-away brick exterior with carefully positioned high-performance glazing that achieves low air infiltration rates of 0.06 cfm per square foot. This envelope strategy delivers three simultaneous benefits:
- Thermal performance: Continuous insulation and air barrier systems minimize heat loss through the envelope, reducing heating energy demand during Seattle’s cooler months.
- Daylight optimization: Strategic glazing placement maximizes natural daylight penetration, reducing the need for artificial lighting while maintaining views of the historic Douglas fir trees on the site.
- Visual connection to site: The transparent facade strategy gives upper floors an immersive experience with the northwest forest character of the site, reinforcing the connection between the building’s timber structure and its natural context.
Water Efficiency and Site Sustainability Measures
The project achieves a 53 percent water use reduction through low-flow fixtures and water-efficient landscaping. Native and drought-resistant plantings eliminate the need for permanent irrigation systems, while bike commuting facilities and a solar-ready roof prepare the building for future renewable energy generation. These measures, combined with the mass timber carbon storage strategy, position Founders Hall as a model for hybrid mass timber embodied carbon reduction in the Pacific Northwest.
Implications for Building Professionals and the Construction Industry
Founders Hall demonstrates several important lessons for building professionals considering mass timber for their own projects. The project validates that mass timber construction can achieve deep carbon reductions while meeting the programmatic requirements of complex academic buildings. The successful monetization of carbon storage through Aureus Earth opens new financial pathways for offsetting the potential cost premiums of mass timber construction.
Economic Considerations for Mass Timber Projects
While mass timber construction can carry a cost premium of 5 to 15 percent compared to conventional steel or concrete structures, the Founders Hall project illustrates how carbon offset revenues can help bridge this gap. Building professionals evaluating mass timber should consider the full lifecycle economics:
- Material cost: CLT and glulam pricing varies by region and project scale. Early engagement with timber suppliers is essential for accurate budgeting.
- Construction schedule: Mass timber projects typically see faster erection times, reducing overall construction duration and associated general condition costs.
- Carbon offset revenue: Programs valuing biogenic carbon storage, such as those offered by Aureus Earth, can generate additional project revenue or offset material premiums.
- Operational savings: The thermal performance of mass timber buildings, combined with exposed structure that reduces finish material requirements, contributes to lower operating costs over the building’s lifetime.
- Tenant and occupant appeal: The aesthetic and biophilic qualities of exposed timber interiors can command higher rents or lease rates in commercial applications.
Regulatory Landscape and Code Compliance
The regulatory environment for mass timber construction continues to evolve. The adoption of tall mass timber provisions in the 2021 International Building Code, including Type IV-C, IV-B, and IV-A construction types, has expanded the allowable height and area for mass timber buildings. However, building professionals must navigate a complex landscape of local amendments, fire protection requirements, and seismic design criteria. The Founders Hall project, located in a high seismic zone in Seattle, demonstrates that mass timber can meet stringent structural performance requirements when designed by experienced structural engineers.
Fire Protection and Life Safety in Timber Structures
Mass timber buildings achieve fire resistance through charring behavior rather than chemical fireproofing. When exposed to fire, the outer layer of timber chars at a predictable rate, creating an insulating barrier that protects the unburned wood below. This inherent fire resistance, combined with automatic sprinkler systems, fire-rated gypsum board encapsulation where required, and careful detailing of penetrations, allows mass timber buildings to meet or exceed the fire safety performance of steel or concrete construction. The Washington state mass timber building codes provide a regulatory framework that other states are increasingly adopting as the body of research on timber fire performance grows.
Future Directions for Mass Timber Carbon Storage
The success of Founders Hall points toward several emerging trends in mass timber construction. First, the monetization of carbon storage through verified offset programs is likely to expand as more building owners seek to certify net-zero carbon buildings. Second, hybrid structural systems that combine mass timber with concrete cores and steel elements for specific spans will become more common as designers learn to optimize material selection by building function. Third, the development of mass timber supply chains in regions outside the Pacific Northwest will reduce transportation costs and embodied carbon associated with long-distance shipping of CLT and glulam panels.
Building professionals who develop expertise in mass timber design, specification, and construction will be well positioned to deliver projects that meet increasingly stringent carbon reduction targets while creating inspiring spaces that connect occupants to the natural environment. Founders Hall provides a compelling precedent for how thoughtful material selection, integrated design, and innovative carbon accounting can transform the way buildings contribute to climate solutions.