California Cities Consider Single-Stair Multifamily Buildings for Affordable Housing

Several major cities in California, including Los Angeles, are moving forward with changes to building codes that will allow for single-stairwell multifamily buildings up to six stories tall. This reform aims to pave the way for apartment developments with larger, family-sized units, providing more affordable housing options.
The shift follows a recent proposal by Los Angeles City Council member Nithya Raman, which seeks to eliminate the current mandate for two stairwells and dual-loaded corridors in multifamily buildings with four to six stories. San Diego and San Francisco are also considering similar adjustments, according to Urbanize LA.

This reform is part of a broader initiative that emerged after the passage of AB 835 in California last year, which directs the State Fire Marshal to establish standards for single-stair multifamily buildings exceeding three stories by 2028, aiming to make them legally permissible across the state.
Under the existing building code, apartments in four- to six-story buildings must include two stairwells and a hallway that connects them on every floor. This setup results in dual-loaded corridors, which can reduce apartment sizes, limit natural light and ventilation, and increase construction costs compared to designs with a central stairwell serving as an exit, a method commonly used in Europe.
London has already embraced similar reforms, allowing apartment buildings as high as 10 stories with single stairwells. In the U.S., only Seattle, New York City, and Honolulu have similar allowances for up to six-story multifamily buildings with single stairwells, each with specific regulations on floor area and unit density.
Councilmember Raman, who introduced the proposed code change, criticized the outdated two-stairwell requirement as a "relic of early 20th-century planning" that now hinders the creation of affordable, family-sized apartment units.
The California YIMBY (Yes In My Backyard) housing advocacy group supports the reform, calling the two-stairwell requirement “obsolete.” They argue that modern building technologies, which provide fire safety ratings that exceed older designs, make the two-stairwell rule unnecessary. According to YIMBY, the existing code has become a barrier to affordable housing and housing diversity, as the additional stairwell space required by current regulations forces developers to build only on larger lots, limiting the potential for family-sized apartments in smaller or irregularly shaped lots.
AB 835, which was unanimously passed by the California state legislature and signed into law by Governor Gavin Newsom in October 2023, lays the groundwork for reform across the state.
Raman’s motion instructs Los Angeles’ Department of Building and Safety, Fire Department, and the American Institute of Architects to assess the feasibility of implementing single-stair multifamily buildings. Additionally, the Planning Department is tasked with researching current and proposed regulations in cities where such buildings are being allowed.
In recent years, the pandemic has altered demand in the housing market. As hybrid and remote work become more common, there has been an increased demand for larger apartment units, moving away from the pre-pandemic trend of smaller, high-rent units.
This code reform represents a key step in the effort to make housing more affordable and adaptable to the changing needs of residents.
Originally reported by Jack Rogers in Globest.
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