A design concept that turns unused space in dense urban neighborhoods into new communities has taken the top award in the American Institute of Steel Construction’s 2025 Forge Prize.

Architect Ho-gyeum Kim of CZS tapped into the potential for rear yards of single-family homes to meet New York's housing demands. A modular system based on the average rowhouse lot width could bring duplex units with semi-private outdoor areas. Kim partnered with Ralph Barone of Barone Steel in Brooklyn, N.Y. to optimize the design.

"It shows how structural steel is critical to unlocking buildable space in dense urban settings within New York and further afield," said juror Matthew Marani, special sections editor for Architectural Record.