4363 26th Street

A 1,014-square-foot single-story house transformed into a 3,446-square-foot residence in Noe Valley, San Francisco, completed in 2022 with Bill Egan. The original floor structure and two side walls were retained while excavating approximately 12 feet beneath the house across a 25-by-70-foot footprint, creating an entirely new level of living space at street grade. The original floor plate was then extended 26 feet and an additional story added above.

The defining challenge was excavating beneath a standing structural shell on a narrow 25-foot-wide lot with neighboring homes tight to both property lines. Careful sequencing of shoring, underpinning, excavation, new foundations, and vertical construction kept the retained structure secure while transforming the original house into a substantially larger home.