Stairway to Housing

A change in statewide building requirements could unlock an untapped source of new housing.  Currently, the California Building Standards Code (CBSC), Title 24 of the California Code of Regulations, prohibits the use of single-stairway exits in multifamily residential buildings with more than three floors. Buildings with four floors or more must have at least two stairways leading to two exits.  Depending on recommendations from the State Fire Marshal, which are expected this month, the state could extend the height limitations for single-stairway exits.      

To the uninitiated, this might seem like an inconsequential, uncontroversial change.  But as California cities and lawmakers explore multiple ways to increase the state's housing stock and hit their goal of creating 2.5 million homes by 2030, allowing single-stairway residential buildings above three-stories could allow builders to add units on small, odd shaped lots where a two-stairway configuration would not be possible.  

Typically, because of the additional floor area required to accommodate a second stairwell, dual stairwell buildings can only be built on larger lots.  As a result, according to Sean Jursnick, an AIA architect, “[s]mall lots are often overlooked for their ability to create urban density, and allowing the construction of mid-rise single-stair housing offers US cities the chance to support more housing types and create denser, more walkable communities in the existing urban fabric, whether in a historic district like Pike Place Market (in Seattle) or an emerging neighborhood yet to make a name for itself.” Jursnick co-authored a policy brief, dated February 19, 2025, with Peter Lifari on single-stair residential buildings which was made available by the Mercatus Center at George Mason University.  

Single stairway buildings might also reduce construction costs and allow for more three and four bedroom apartment units, which are difficult to fit in buildings with a hall connecting two stairwells, according to California YIMBY.  

Despite the potential upsides of single-stairway apartment buildings, changes to the CBSC may be hard to come by.  The State Fire Marshal, which is required to prepare a report and recommendations on these changes by Assembly Bill 835 (Alex Lee, District 24), held working group meetings throughout 2024 that raised significant concerns about fire safety.      

According to minutes from those meetings, the concerns centered on whether occupants would be less safe, in the event of a fire, with only one stairway exit.  Also, would the lack of a second stairway prevent first responders from effectively fighting a fire and rescuing occupants?  With just one stairway, escaping occupants might block entering firefighters.

In addition to the State Fire Marshal's evaluation of single stairway buildings, the National Fire Protection Association (NFPA) held a symposium on the topic in September 2025. The NFPA appeared to bristle at the idea that legislators, not fire-safety experts, would alter restrictions on using single-stairway construction.  It is NFPA's position that "discussions related to increasing the allowable height of an apartment building with a single exit stair need to occur in a consensus-based standards development process and not state and local legislatures."  Despite this rejection of legislatures' involvement, the NFPA stated that it would "remain neutral during the technical discussion."

It's unclear whether this neutrality would take into account other findings on the subject that found single-stairway buildings are safe and serve an important function to increase the availability of housing.  A February 27, 2025 analysis (the "first" of its kind) by Pew that examined fire death rates in modern four-to-six-story buildings with only one stairway "show[ed] that allowing these buildings to have only one staircase does not put residents at greater risk: Single-stairway buildings as tall as six stories are at least as safe as other types of housing. And allowing the construction of such buildings could provide much-needed housing, including homes for people with modest incomes."  

One way to address both safety concerns and housing needs may be to employ the use of scissor stairways.  Scissor stairways are two sets of stairs using one stairwell, with each set providing exits at alternating floors.  In other words, such a system can provide two exits with one stairwell.  The State Fire Marshal's working group found that in at least one scenario, egress times were equal to "near-baseline levels, suggesting it could be a promising design solution to mitigate counterflow issues in the future."  

Meanwhile, the City of Los Angeles might pass an ordinance amending the City's Building Code to allow single-stairway, single-exit, multifamily unit residential buildings of up to six stories.  In August 2025, the City Council passed a motion instructing the Department of Building and Safety (DBS) and Los Angeles Fire Department (LAFD), in consultation with the City Attorney and the Department of City Planning (DCP), to draft an ordinance updating the City’s Building Code to allow for the construction of such buildings.  The draft ordinance is pending.  

Also pending is the State Fire Marshal recommendations mandated by AB 835.  The law required that the marshal submit the report to the Senate Committee on Governmental Organization, the Assembly Committee on Emergency Management, the Joint Legislative Committee on Emergency Management, and the California Building Standards Commission by January 1, 2026.  However, the deadline passed without the marshal's submission. According to the marshal's legislative office the "report is still going through the review process."

If the state modifies the CBSC, California could join the Cities of Seattle and New York and a number of nations around the world that have abandoned the two-staircase exit requirement in favor of single-stair buildings to grow more housing.  California could also share something in common with the Lone Star State other than an interest in congressional redistricting.  Senate Bill 2835, authored by Texas state Sen. Nathan Johnson, D-Dallas, and sponsored by state Rep. James Talarico, D-Austin, established a state-level regulatory framework that outlines safety standards specific to single-stair buildings.   Under this framework, Texas cities can supplement their development codes with standards that might accelerate housing development.