✕

Since 2018, the Chicago-based American Institute of Steel Construction (AISC) has invited architects, educators, and students to submit innovative, problem-solving design concepts that employ steel as a primary structural component to its annual Forge Prize. 

This year, the $10,000 award went to Ho-gyeum Kim, an architect with Brooklyn-based Carlos Zapata Studio, for his Growing Rowhouses design. Kim’s modular housing concept, which was fine-tuned in partnership with Ralph Barone of Brooklyn’s Barone Steel, zeroes in on the untapped potential of rear yards behind single-family homes in New York City as spaces to create new, much-needed dwellings.

Growing Rowhouses was one of three finalists for the 2025 Forge Prize. The others were Pedestrian Bridge for Echo Park, Los Angeles (Kaikang Shen of K2SA, partnered with Phil Schlosser and Barry Gossler of Pennsylvania-based Schlosser Steel) and Transforming Galvanized Sheetmetal Waste Streams into Modular Living Wall Planter System (Ahmed K. Ali of Texas A&M University’s Resource-Based Design Research Lab team, which also includes Bruce Dvorak, Panwang Huo, Karishma Joshi, and Niti Tataria, in partnership with Tony Baffone of Delaware-based MSI Fab and Nat Killpatrick of Basden Steel).

Image courtesy Ho-gyeum Kim.

“These three finalists bring fresh ideas to some of today’s most pressing challenges in architecture,” said AISC Director of Architecture Nima Balasubramanian when the shortlist was revealed in February. “From innovative technology to material reuse and new housing solutions, each proposal offers a unique approach to shaping the way we live.”

Growing Rowhouses envisions the oft-unused and neglected rear yards of a full block of rowhouses as a single, 18-foot-wide lot as a place where vertical communities of duplexes with semi-private outdoor spaces can bloom. The approach “requires minimal foundations to leave the existing rowhouses untouched,” according to the prize announcement. “That’s where structural steel came into play. Steel cables on either side of the central structural core stabilize the building’s lateral movement.”

Image courtesy Ho-gyeum Kim

“Steel is the most viable solution to achieve the minimal touchdown in the centerline of the blocks,” explains Kim in a statement. “A prefabricated, modular construction system taking full advantage of steel’s unique potential to facilitate economical, rapid erection—and steel’s unique recyclability and circular supply chain add an additional layer of sustainability while preserving the existing rowhouses.”

In addition to the semi-private yards, outdoor communal spaces include a rooftop terrace and running track. “Curved hollow structural sections create a cohesive look across external stairs, roof structures, and trellis extensions—a detail that also allows for mass production,” states the announcement.

Growing Rowhouses is based on the size of the average New York lot width. The height of the structures can be adjusted to adhere with local zoning ordinances, and Kim believes that the concept can be applied to other dense urban areas where available housing is scarce and unutilized land is abundant.

Courtyard and roofscape views. Images courtesy Ho-gyeum Kim

This year’s Forge Prize jury included Emily Baker, associate professor at the University of Arkansas (and 2024 Forge Prize winner); Parke MacDowell, associate principal and director of fabrication at Boston-based Payette; and RECORD special sections editor Matthew Marani.

“It has a well-considered implementation strategy, including coordination with zoning and planning constraints, market demands, and erection efficiencies,” said Marani of Kim’s winning concept. “It also fits neatly into new approaches to zoning within the Department of City Planning, specifically the larger City of Yes policies that are being rolled out.”

Kim will present Growing Rowhouses at the AISC’s Architecture in Steel Conference (incorporated into NASCC: The Steel Conference), which takes place in Louisville from April 2–4.