For the renovation and expansion of the Daniels Faculty of Architecture, Landscape, and Design building at the University of Toronto, NADAAA proposed a seemingly complex, warped ceiling surface in the main studio. Conventional construction methods suggested the ceiling could only be realized using expensive and time-consuming hand-troweled plaster on metal lath. But the firm built a 1:1 mock-up of a simple frame with drywall, proving the viability of the concept and convincing the construction team to reduce its estimated costs by more than half.

That’s why NADAAA—the top firm in design for the third straight year—invests so much in research (14 percent of its annual profits). “With each project, we look at its innate qualities not only in terms of its material behavior, but also how it engages the protocols of the construction industry,” says NADAAA partner Nader Tehrani. “We reach out to the building industry at an earlier phase to understand the logic of construction.”

NADAAA's Nader Tehrani
NADAAA NADAAA's Nader Tehrani
NADAAA frequently partners with the trades to design building elements, but also experiments in-house with its own fabrication lab. “This is where we do the making and research of pieces for which there is no precedence or that are speculative,” Tehrani says. “Sometimes we hand them off to the building industry; other times we deliver them ourselves.”

The firm’s portfolio was lauded by the design judges, one of whom wrote that “the projects exhibited a very unique, sincere, and sophisticated voice … and made me feel convinced and happy that architecture with a capital ‘A’ is alive and well.”


Stephen Kieran, FAIA

Kieran is a partner at KieranTimberlake in Philadelphia, a leader in practice-based architectural research and innovative buildings. The co-author of five books, he teaches a design-research studio at the University of Pennsylvania School of Design.

Roberto de Leon, AIA, and M. Ross Primmer, AIA

De Leon and Primmer co-founded De Leon & Primmer Architecture Workshop in Louisville, Ky., which focuses on cultural, civic, or not-for-profit projects. Both partners earned master’s degrees in architecture from the Harvard Graduate School of Design.

Mary-Ann Ray

Ray is a principal of Studio Works Architects in Los Angeles and a co-founder of the experimental lab BASE Beijing. A professor of practice at the University of Michigan’s Taubman College of Architecture and Urban Planning, Ray is a winner of the Rome Prize. 

Check out the overall list to find out which firm rose to the top, and discover which firms made the cut in business and sustainability. To find out how we generated the rankings, read our methodology, and take a look at some of the data submitted by firms