The new Penn’s Landing Park will reconnect Philadelphia to its river’s edge by constructing a transformational civic space at the heart of the city’s waterfront. KieranTimberlake designed the Park's central pavilion. (Image courtesy KieranTimberlake)
Architects designed with wood for centuries, until modern fire codes made steel and concrete the go-to building materials in cities around the world. Now, with help from some Weitzman faculty and alums, mass timber stands to change that.
The International Code Council, the US-based nonprofit that writes the rules for making buildings safe, first recognized mass timber, specifically cross laminated timber (CLT) in 2015, and by 2018 had authorized buildings up to 18 stories, mostly due to improved fire resistance tests. By the end of 2025, 44 states had adopted it as part of the International Building Code (IBC).
CLT, a wood panel which consists of layers of lumber glued together, has myriad advantages. It performs like steel but with less weight. While it often costs more up front, it can save on costs in the long term, as it cuts down time and labor needed for construction. Moreover, it is a renewable resource that sequesters carbon and helps meet sustainability goals across the building’s life cycle.
So why then, has mass timber not taken over the skyline?
“It really comes down to education,” said Andrew Saunders, an associate professor of architecture who asked his Master of Architecture students to use the material in a second-year architecture studio this semester. “Clients are interested, but there are so few examples, that they aren’t always able to justify the risk.”
Model for a performing arts center designed by Laura Ellis and Wenyu Wang for Andrew Saunders' 602 Studio. (Consultants: Jessica Young (heintges), Bonghwan Kim (SOM), and Robert Hibbard (HDR); TA: Taely Freeman)
One notable exception is Penn Engineering’s Amy Gutmann Hall, designed by Texas-based Lake Flato and completed in 2025. The six-story, 115,000-square-foot structure offers a unique opportunity for architecture students and architects in Philadelphia to see mass timber in action, and it was on the syllabus this semester for Andrew Saunders' students to visit.
Architect Jon McCandlish (MArch’06), principal and managing director at sought-after Philadelphia firm KieranTimberlake, says that while students and recent graduates are excited about the possibilities that mass timber presents, clients are less familiar with the material and its benefits. That initial hesitation can often be addressed by referencing successful built projects and providing life-cycle analyses that look beyond first cost.
McCandlish is one of the Weitzman alums and faculty members who are leading the way in mass timber construction around the US. KieranTimberlake, which was founded by Stephen Kieran (MArch’76) and James Timberlake (MArch’77), who are also professors of practice at Weitzman, used mass timber in designing a new pavilion at Penn’s Landing, a park that will reconnect Philadelphia to the Delaware River. The centerpiece for the city’s most-anticipated public space in years, KT’s pavilion will house several park amenities and will host events and gatherings. The pavilion’s use of mass timber is part of a holistic strategy to achieve a low carbon footprint and a target goal of net-zero energy consumption. It is also expected to be Philadelphia’s first mass timber public building.
Saunders (back row at left) and his students visited the New York office of Skidmore, Owings & Merrill, where they saw a CLT staircase designed by Bonghwan Kim (second from left), one of the studio's consultants.
Saunders is trying to bridge some of these gaps in his semester-long investigation, part of the second-year required studio sequence for Master of Architecture students, where structure, mechanical systems, and building facade are integrated into the project. It is the semester of the degree program most rooted in real world practice. Students work with invited consultants like mass timber expert Robert Hibbard, a design principal at Philadelphia firm HDR Architects, to develop models and sections with real-world detail.
“The challenge for teaching about CLT is that the material has its own properties, which take many years to master,” says Saunders says. “If we want adoption, we have to challenge the conventional workflows.”
One issue with traditional CLT and mass timber is that construction is often very simple, using orthogonal post and beam systems with little architectural design. Saunders wants to change that. So he asked students to work with “space-filling” angular geometries inspired by artist Robinson Fredenthal (a well-known figure on Penn’s campus for his 1977 tetrahedron sculpture Black Forest), as well as the reinforced concrete space frames and diagonals of architects like Anne Tyng, Louis Kahn, and Paul Rudolph. The result will be a CLT structure with ceramic cladding, breaking from the planar nature of the mass timber.
The ARCH 602 studios bring in architects with expertise in advanced technologies to advise students as external consultants, and Saunders’ studio also included visits to consultants’ offices in New York City. The students visited Bonghwan Kim, a senior associate principal specializing in structures at the Manhattan office of Skidmore, Owings & Merrill. They also got a glimpse of the office of Heintges Consulting Architects & Engineers, where they visited Principal Jessica Young, who is a facade engineer.
Saunders says visits and collaborations like this are key to innovating with mass timber. “These geometries exist at the smaller scale, but this geometry has not been explored at this scale in this material,” says Saunders. “We are going to see a lot more of it. It is very relevant to what professionals are doing today.”
Before coming to Penn, Laura Ellis (MArch’26) worked full-time in an architecture office where she worked on a mass timber project. She says that students are excited to work on it because there is so much excitement around it and it feels like the future. “It has a stronger connection to nature,” she says. “And it is an interesting material to design with because it makes you think about structure and assemblies from the beginning.”
Ellis, who took the ARCH 602 studio in the spring of 2025 and is now a teaching assistant for Saunders’ studio, appreciated the opportunity to help bridge the gap between academia and practice. “I wanted to see how buildings can come together,” she said. “Visiting the firms and walking with them to see their structures was a unique experience and helped understand the material.”
Mass timber was the focus of alum Clayton Monarch's MArch thesis. The building he designed is intended to function as a community center, providing work space for timber craftsmen focused on preserving the culture of Scandinavian timber craft.
Another Weitzman alum who has also been experimenting with mass timber is Clayton Monarch (MArch’24), who now works as a designer in the New York office of Morphosis. His thesis, A Necessary Part: Timber as Cultural Artifact, explores how historic Scandinavian wood details could be reinvented using modern materials like CLT.
“The industrialization of timber has led to a narrow focus on standardized, homogenized products,” Monarch says. “I wanted to reintroduce the cultural role of craftsmanship, building tradition, and preservation that timber construction can embody.”
Monarch first worked with timber in his second-year MArch studio with former faculty member Nate Hume as an advisor. This led to his thesis, where he developed a series of case studies on details. “There weren’t a lot of examples in the United States,” he says. “Then I watched Guttman Hall be built on Penn’s campus, which helped me understand it.”
Since he joined Morphosis, Monarch has used several CLT concepts in competitions, though it wasn’t common practice at the firm. “I have always tried to advocate when I can.”
Saunders and McCandlish agree that recent graduates like Monarch will be leading the way, and are starting to evangelize mass timber in the professional world.
“People are coming out of school very excited about the application of mass timber,” KT’s McCandlish says. “[There's its] performance, sustainability, and visual qualities. Emerging architects here are saying, ‘Why aren’t we doing more projects with mass timber?’”
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