660 Corbett Ave, San Francisco, CA 94114

The three-unit residential building at 660 Corbett Ave in Twin Peaks is a century-old structure built in 1914, classified as a Flats & Duplex building and currently owned by Peter W. Knuth. The property's documented history from 2012 raises several concerns, most notably regarding potential unauthorized modifications and unit conversions.

In March 2012, Housing Inspection Services received complaints about a possible illegal unit in what is officially classified as a two-family dwelling, with reports indicating an unauthorized ground-level unit accessible via exterior stairs. This complaint followed another filed just days earlier alleging irregularities with an alleged third unit's entrance and questioning the property's occupancy classification. Additionally, in February 2012, there were allegations of unauthorized interior construction work, including window and door replacements, as well as roof repairs, reportedly performed without proper permits.

The complainant also noted that a neighboring property (670 Corbett Avenue) had cemented its entire backyard area, though it's unclear how this relates to the subject property. More recently, in March 2020, there was a documented street cleaning issue involving loose garbage, though this was clearly a municipal matter unrelated to the building's condition or occupancy status. Notably, there have been no recorded complaints or incidents regarding the property in the past three years (2020-2023), and all aforementioned complaints from 2012 are listed as "Not Active," suggesting they have been resolved or otherwise closed without further action. The relatively lengthy period without new complaints or incidents could indicate improved compliance with housing regulations, though this should be considered with the understanding that not all building issues may be reported or documented through official channels.