Granny flats on rise in San Francisco

With concerns ranging from parking to added density heating up the argument around granny flats in San Francisco, these properties (also known as accessory dwelling units, or ADUs) were long contested in the City by the Bay. Additionally, local opposition served to stifle any proposals that might encourage the construction of these naturally affordable, low-impact homes.

However, over the past two years, there have been several critical new pieces of legislation either adopted or underway allowing for the creation of new granny flats and the legalization of existing ones. A recent San Francisco Housing Action Coalition panel, co-hosted with SPUR and AIA San Francisco, investigated the history and future of these homes.

The panelists were Kearstin Dischinger of the San Francisco Planning Department, Mark Hogan of OpenScope Studio, District 8 Supervisor Scott Wiener and Kevin Casey of New Avenue Homes. You’ll find Dischinger’s presentation here and Hogan’s presentation here. Dischinger found that suburban development patterns favored more parking while density limits restricted construction between the 1950s and 1980s. Previously, during World War II, granny flats housed many of the city’s workforce.

There were three efforts to incentivize building new granny flats during the 1990s, but these all ultimately failed. However, today’s political climate sees the need for more housing – and the chance to use granny flats as a smart way to add to the city’s housing stock in a way that is seen as both affordable and flexible.

During the presentation, Wiener admitted that the attempt to pass citywide legislation in the past was a mistake, but still champions building new granny flats in the Castro. He asserted that it is best to focus on this effort in a neighborhood-by-neighborhood way and also approves of expanding granny flats in Noe Valley, Diamond Heights and Twin Peaks.

OpenScope Studio has created a handbook providing different prototypes and financial models for this effort. It’s interesting to remember that building a new granny flat can cost as little as $200,000, as compared to $500,000 for a unit in a new multi-family building – something for San Francisco investors to consider.

Dreaming of San Francisco? Cece Blase offers local advice to San Francisco buyers, sellers and owners– and feeds the dreams of those who wish they could live in Tony Bennett’s ‘City by the Bay.’ Call 415-577-0809 or email

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