Planning Commission adopts preservation design standards to apply objective rules for historic properties

The San Francisco Planning Commission unanimously adopted preservation design standards on March 20 that add objective rules for additions and modifications to identified Category A historic properties.

Planning staff presented the chapter as a supplement to the citywide design standards adopted in November 2024; the preservation standards were developed to provide objective guidance for projects that, under state law and some state programs, may be reviewed ministerially using only objective standards. Rebecca Salgado, lead planner for the standards, told the commission the rules are designed to preserve character‑defining features while allowing compatible new additions and to provide predictability for project sponsors and reviewers.

The standards apply only to Category A properties (Article 10/11 properties, locally or state‑listed or eligible), staff said; the department intentionally did not apply the new standards to Category B properties because that would encompass more than 90% of the city’s parcels. “If we did that, 92% of the properties in the city would be subject to these preservation design standards,” Salgado said; staff noted surveying and additional outreach would be required before expanding applicability.

The preservation standards are organized into three sections: regulatory context and applicability; treatment of existing features (windows, storefronts, entrances); and site design and architecture for additions (massing setbacks, facade articulation, rooftop features and materials). Staff emphasized that many provisions are based on prior Planning Department guidance but were rewritten as objective rules to comply with state ministerial-review requirements. Where standards overlap with the citywide chapter, the preservation standards take precedence for Category A properties.

The commission and planning staff discussed specific elements, including setbacks for additions (staff proposed a 15‑foot setback baseline with limited exceptions), window materials, and rooftop railings. The American Institute of Architects’ Policy and Practice Committee had reviewed draft language with staff and offered detailed comments that staff said were incorporated; AIA representatives and local architects spoke in support of the standards and requested that standards be revisited as a living document once applied to projects.

Public commenters included preservation advocates, architects and community groups. Many encouraged the commission to adopt the standards but asked for a follow‑up process and for future chapters addressing new construction in historic districts and treatment of Category B properties. Telegraph Hill Dwellers and Neighborhoods United urged standards for new construction within historic districts to address context, massing and material compatibility.

Staff said the department will integrate the standards into project review, plan‑check letters and application materials, will treat the standards as a living document and will return to the Historic Preservation Commission and the Planning Commission after six months of implementation with a status report and recommended amendments. Staff also said the department plans to develop additional chapters — for cultural‑district application, new construction in historic districts and smaller‑scale residential projects — pending further outreach and resources.

The commission voted 7–0 to adopt the preservation design standards; staff said they will begin applying them to relevant projects and will return with implementation notes and any proposed refinements based on early experience.