3557-3559 20th St, San Francisco, CA 94110

The three-story, six-unit multi-family residential building at 3557-3559 20th Street in the Inner Mission, owned by the Kenneth A Tonna Revocable Trust, has undergone significant structural and safety improvements since its construction in 1904. Most notably, the building completed a mandatory soft-story retrofit in 2017 (with an additional revision in 2018), demonstrating compliance with San Francisco's seismic safety requirements, with all associated work being properly documented and given a Certificate of Final Completion. The building has experienced several maintenance and safety issues over the years, with the most serious violations occurring in 2003 when multiple interior surfaces, plumbing, electrical systems, and fire safety features required attention, including repairs to damaged ceilings and walls, a malfunctioning central alarm system, and issues with the fire escape drop ladder.

These violations were addressed and abated by January 2017. Recent history shows improved building maintenance, with the most recent significant building permit being the baseboard heater installation in 2003, and no major building violations recorded since 2016. While there have been recurring issues with garbage and debris in the vicinity of the building, as evidenced by multiple 311 calls between 2022 and 2025, these are street-level maintenance issues rather than building-specific problems.

The property has also been subject to routine housing inspections over the years, including a 2016 inspection that identified several safety concerns which were subsequently resolved. The last recorded fire safety complaint in 2021 regarding blocked exits was quickly addressed the following day, indicating responsive management to safety concerns. The building's documented history reflects a pattern of resolving violations and completing required safety upgrades, culminating in the successful implementation of the soft-story retrofit program, though it also reveals periods of neglect requiring multiple interventions, particularly during the early 2000s.