551-553 42nd Ave, San Francisco, CA 94121

The three-story building at 551-553 42nd Avenue in the Outer Richmond, owned by Paul E Borchardt and Chua Gao, is a two-unit multi-family residential structure built in 1947. The property has undergone several significant improvements over the past two decades, with a particular focus on seismic safety and energy efficiency.

Between 2008-2009, the building underwent substantial seismic strengthening, including voluntary non-engineered substructural work, followed by the installation of a steel moment frame in the lower level garage, demonstrating the owners' commitment to structural safety. More recent upgrades include the replacement of two gravity furnaces with 95% efficient forced air systems in 2018, and the installation of a grey water subsurface irrigation system and rainwater catchment system in 2016, indicating a dedication to modern sustainability practices. Notable improvements to resident comfort and aesthetics include the 2010 replacement of seven street-visible windows with vinyl double-pane alternatives, and a 2003 kitchen remodel on the third floor.

The building has experienced two complaint incidents related to unauthorized construction work, one in 2003 regarding extensive interior remodeling and bedroom addition, and another in 2007 concerning unpermitted work, though both issues were resolved promptly. Recent maintenance history shows regular attention to the building's needs, with no current active complaints or violations. The property has experienced recurring issues with sidewalk parking, with three incidents reported between 2018-2022, though none resulted in enforcement action as officers were unable to locate the offending vehicles.