Designing with Mass Timber

Mass timber is a category of engineered wood products made by bonding layers of wood together to form strong, solid panels, beams, and columns. Common types of mass timber include Cross-Laminated Timber (CLT), Glulam (glue-laminated timber), Nail-Laminated Timber (NLT), and parallel strand lumber (PSL).

In recent years, mass timber has become popular for a variety of environmental, aesthetic, structural, and economic reasons: 

• Because it sequesters carbon, mass timber can have lower embodied carbon emissions than materials such as concrete or steel. 

• Mass timber’s natural beauty often contributes to a warm, welcoming aesthetic and can eliminate the need for finish redundancy – further minimizing embodied carbon and potentially reducing material costs. From a design standpoint, mass timber can also elevate biophilic design, connecting people with nature through the built environment. 

• Mass timber is strong but lighter weight than concrete or steel, which can reduce foundation requirements. Unlike light-frame wood construction, mass timber can support larger loads and span greater distances, making it suitable for a wider variety of building types. 

• Mass timber panels and beams are prefabricated, which reduces on-site labor and waste and typically accelerates how quickly and cost-effectively construction occurs.
• While mass timber materials can sometimes carry a higher upfront cost compared to steel or concrete structural systems, the overall lifecycle economics can be favorable with lower labor costs, reduced foundation requirements, fewer finish material requirements, and operational savings thanks to superior thermal performance and energy efficiency.  

At Ayers Saint Gross, we’ve had the opportunity to design with hybrid mass timber systems across a variety of projects. In each design, mass timber has played an important role in the design aesthetic and overall sustainability goals. 

At Bryant University’s Puishys Residence Complex, scheduled to open in Fall 2025, our design team conceived of the project as a “house in the woods” for juniors and seniors on Bryant’s densely forested campus. Mass timber was chosen as a material both for its appearance to reflect the building’s natural surroundings, as well as its sustainable design attributes.

The design team utilized cross-laminated timber in a multi-story glass bridge connecting the building’s two wings, as well as the ceilings and floors for the main-level amenity spaces. The material’s pre-fabricated nature helped speed up the construction process while contributing to a warm and inspiring student environment.

At Duke University’s School of Nursing, our team incorporated mass timber into the design for a signature commons gathering space. This two-story space is designed to purposefully blur the distinction between indoors and outdoors, with large glass windows looking out on a landscaped terrace and large, mature trees. The wood structure of the commons relates to the natural landscape, while also recalling the traditional Duke gothic architectural brand.

Semans-Griswold Environmental Hall, our first project to earn a Living Building Challenge Petal certification, is a net-positive, non-combustion facility that serves as a living laboratory for Washington College’s programs in environmental science and wetlands ecology. It’s also a showcase for mass timber elements, with exposed wood trusses and PSL columns, as well as exterior cedar siding and screens.

Semans-Griswold’s design is inspired by the architectural heritage of Maryland’s Eastern Shore. The wood elements reflect the tidewater vernacular of boat sheds, warehouses, and fisheries, while helping students, researchers, and visitors feel more connected to the natural world around them.

The Nemours Mansion and Garden Visitor Center in Wilmington, Delaware, serves as a museum gallery that familiarizes visitors with the legacy of Alfred I. DuPont and his luxurious, French-style estate. The 5,000-square-foot building is supported by heavy laminated wood columns and beams with exposed steel connections, clad in fieldstone and wood, with roofs of structural wood insulated panels and copper cladding.   

Two stone pavilions recall old powder mills and are connected by an exposed mass timber colonnade. The design is unique with daylight exhibits that are completely integrated with the architecture.  Mahogany Duratherm windows span between the piers, providing views to the outdoors and surrounding landscape, allowing the visitor center to reflect the nature around it.  

While mass timber has certainly risen in popularity in recent years, we believe it to be a timeless and inspiring material choice. Its strength, sustainability, and beauty can help institutions of all kinds create memorable and welcoming environments, while reducing their overall carbon footprints.