Los Angeles Single-Stair Housing Code: What to Know

Quick answer: Los Angeles single-stair housing code reform is part of a national push to reduce multifamily construction costs by allowing some four- to six-story apartment buildings to use one protected exit stair instead of two. California has not adopted a statewide single-stair standard as of June 22, 2026, but Culver City has a state-accepted local ordinance and AB 2252 proposes a statewide path for single-exit, single-stair multifamily buildings up to six stories. For Los Angeles owners and developers, the near-term takeaway is strategic: single-stair design may become a powerful infill housing tool, but projects still must be designed around current Title 24, fire access, sprinkler, egress, and local permitting requirements.

A single-stair housing code is a building-code framework that allows certain multifamily residential buildings to rely on one protected exit stairway, usually with added fire and life-safety measures such as sprinklers, fire-rated construction, smoke control, travel-distance limits, and unit-count limits.

What is the Los Angeles single-stair housing code debate?

The Los Angeles single-stair housing code debate is about whether California should permit a limited class of mid-rise multifamily buildings to have one exit stair instead of the two exits generally required once apartment buildings exceed three stories. The issue has become a housing-affordability question because the second stair, connecting corridors, and related shaft space can make small urban infill projects harder to design and finance.

The specific California rule at issue is not a local Los Angeles ordinance today. The Assembly Housing and Community Development Committee analysis of AB 2252 explains that Title 24, Part 2, the California Building Code, and Title 24, Part 9, the California Fire Code, both use Section 1006.3.4 to restrict apartment buildings with only one exit to a maximum of three stories and four units. To allow taller single-exit apartment buildings statewide, California would need amendments to both the building and fire code framework.

This is why the discussion matters in Los Angeles. Much of LA’s future housing capacity sits on constrained parcels near transit corridors, commercial streets, and older low-rise neighborhoods. A second stair can be a proportionally large burden on a narrow lot, especially where a developer is trying to build family-sized units, affordable housing, or a smaller multifamily project that does not pencil as a conventional double-loaded-corridor building.

What changed in California single-stair housing code rules?

California has not changed the statewide single-stair rule yet, but the policy pathway has changed. AB 835, Chapter 345 of the Statutes of 2023, added Health and Safety Code Section 13108.5.2 and required the State Fire Marshal to research standards for single-exit, single-stairway apartment houses with more than two dwelling units in buildings above three stories, with a report due by January 1, 2026.

That 2023 law did not itself legalize taller single-stair buildings. It created the technical research step. The State Fire Marshal’s work group charter states that the group was formed pursuant to AB 835 to advise on fire and life safety, emergency activities, risk to residents, fire service operations, housing inventory, cost impacts of mitigation features, and barriers to implementation.

The more direct 2026 bill is AB 2252 by Assemblymember Alex Lee, as amended March 16, 2026. The bill would require the California Department of Housing and Community Development to research, develop, and propose building standards for single-exit, single-stairway multiunit residential buildings up to six stories for inclusion in the next triennial edition of the California Building Standards Code, while consulting with the State Fire Marshal. The Assembly analysis also says AB 2252 would allow cities and counties to make specified local building-standard changes permitting single-exit, single-stair buildings up to six stories despite the existing six-year residential building-code moratorium.

The most concrete local change is Culver City’s ordinance. Culver City reports that the California Building Standards Commission accepted Ordinance No. 2025-013 and Resolution No. 2025-071 for filing on September 30, 2025. Those local measures amend portions of the 2022 California Building Standards Code to allow single-exit stairway configurations in four- to six-story multi-story residential buildings, including an elevator requirement for five- and six-story single-exit stairway buildings.

What is the current status of Los Angeles single-stair housing code reform?

The current status is that Los Angeles has no verified citywide single-stair ordinance comparable to Culver City’s, and AB 2252 has not created a statewide standard. The latest verified legislative materials reviewed for this article show AB 2252 was heard in the Assembly Housing and Community Development Committee on April 22, 2026 and remained in committee; the bill had not become operative statewide law in the sources reviewed.

That means a Los Angeles project submitted today should not assume a four-, five-, or six-story single-stair multifamily design will be accepted under existing city plan check. The design team must still work from the applicable California Building Standards Code, Los Angeles amendments, fire department access requirements, accessibility rules, sprinkler standards, and egress provisions in force at the time of permit submittal.

For owners, the practical move is not to redesign a project around an unadopted rule. It is to identify sites where a future single-stair option could improve feasibility, while maintaining a code-compliant baseline plan that can move through entitlement and plan check under today’s rules.

Why could Los Angeles single-stair housing code matter for infill development?

Los Angeles single-stair housing code reform could matter because it may make smaller multifamily buildings more efficient on narrow or irregular lots. Pew’s 2025 research found that four- to six-story single-stairway buildings with relatively small floor plates can cost 6% to 13% less to construct than comparable dual-stairway buildings, largely because the second stair and connecting corridors consume space and cost money.

The design issue is not simply construction cost. Conventional two-stair buildings often rely on long double-loaded corridors, which can produce many units with windows on only one side. Single-stair or point-access-block layouts can support more cross-ventilated units, more corner units, and more family-sized floor plans, depending on the site and code constraints.

In LA infill housing, that could be important for projects near Metro stations, along commercial corridors, or on parcels where lot width makes a standard apartment plate inefficient. It could also support missing-middle housing types that sit between a duplex and a large podium project.

What are fire safety experts worried about?

Fire safety experts are worried that one stair means less redundancy if smoke, fire, debris, or emergency operations compromise the stair enclosure. The core concern is that the same stair may need to serve residents evacuating and firefighters entering, while also remaining clear of smoke and heat.

Those concerns explain why the California process has focused on research, technical standards, and Fire Marshal consultation rather than a simple repeal of egress rules. A safe single-stair framework would likely need strict limits on building height, floor area, number of units per floor, travel distance, stair pressurization or smoke protection, automatic sprinklers, fire-rated assemblies, self-closing doors, alarms, standpipes, emergency lighting, maintenance, and inspection obligations.

Pew’s research argues that modern sprinklered single-stair buildings can perform safely when designed with modern fire-safe materials and systems, limited floor plates, and protected stairways. But that does not eliminate the need for local fire review. In Los Angeles, hillside conditions, narrow streets, high fire hazard severity zones, staging constraints, and existing infrastructure can all affect how a code-compliant concept performs in a real emergency.

How should Los Angeles owners plan projects while single-stair rules are unsettled?

Los Angeles owners should treat single-stair reform as an emerging opportunity, not a permit strategy by itself. The best approach is to test multiple code scenarios early: current two-exit compliance, possible future single-stair layouts, fire department access, unit mix, elevator requirements, construction type, sprinkler systems, and financing assumptions.

For a constrained multifamily site, that means architecture and code analysis should happen before land acquisition terms are final. A parcel that appears viable under a future single-stair rule may be marginal under current Title 24 requirements. Conversely, a two-stair design that pencils today may become more efficient if state or local rules evolve.

Developers should also track AB 2252 and any Los Angeles Department of Building and Safety or Los Angeles Fire Department guidance if California adopts statewide standards. The exact details will matter more than the headline. A single-stair rule with strict floor-area, unit-count, elevator, pressurization, or construction-type requirements could help some sites and leave others unchanged.

How can 121 Design Build help with Los Angeles single-stair housing code planning?

121 Design Build helps Los Angeles property owners and developers evaluate code, entitlement, design, and construction feasibility under one roof. For a site that could benefit from future single-stair reform, the right first step is a concept study that compares today’s code-compliant design with possible future scenarios.

For ground-up multifamily or mixed-use development, our New Construction team can assess massing, egress, circulation, unit efficiency, and permit strategy. For deed-restricted or incentive-based housing, our Affordable Housing / ED-1 team can help evaluate whether code efficiency changes would materially improve feasibility. For smaller ownership lots, our ADU & JADU and SB9 services can identify density options that are available now, without waiting for statewide single-stair reform.

If you are analyzing an LA infill parcel, a multifamily redevelopment, or a value-add site where stairs, corridors, and fire access control the entire building plan, contact 121 Design Build for a design-build feasibility review.

Key Takeaways

• California has not adopted a statewide single-stair multifamily code as of the latest verified sources reviewed for June 22, 2026.
• Current California Building Code and California Fire Code Section 1006.3.4 generally restrict one-exit apartment buildings to three stories and four units.
• AB 835 required State Fire Marshal research on single-exit, single-stair apartment houses above three stories; AB 2252 proposes a path for standards up to six stories.
• Culver City is the verified California local precedent, with a state-accepted ordinance allowing four- to six-story single-exit stairway residential buildings under local standards.
• For Los Angeles projects, single-stair reform could improve infill feasibility, but fire-life-safety design and current permit rules still control.

Frequently Asked Questions

Does Los Angeles allow six-story single-stair apartment buildings now?

No verified citywide Los Angeles rule reviewed for this article allows six-story single-stair apartment buildings as a general standard. Los Angeles projects should be planned around current Title 24, Los Angeles amendments, and fire department requirements unless and until a specific adopted rule applies.

What bill is California considering for single-stair housing?

AB 2252 is the 2026 California bill tied to single-exit, single-stairway multiunit residential buildings. As amended March 16, 2026, it would require HCD to research, develop, and propose standards for buildings up to six stories while consulting with the State Fire Marshal.

What did AB 835 do?

AB 835, Chapter 345 of the Statutes of 2023, directed the State Fire Marshal to research standards for single-exit, single-stairway apartment houses above three stories and report by January 1, 2026. It was a research mandate, not a statewide authorization to build taller single-stair apartments.

Why do developers want single-stair buildings?

Developers and housing advocates argue that one protected stair can reduce circulation space, lower construction costs, and make small infill lots feasible. The potential benefit is strongest for four- to six-story multifamily buildings where a second stair and corridor consume a large share of the floor plate.

Are single-stair apartment buildings safe?

Safety depends on the final code standard, building design, fire protection systems, maintenance, and local emergency response conditions. Research cited in the policy debate supports modern sprinklered single-stair buildings under strict limits, while fire service stakeholders continue to raise concerns about egress redundancy and firefighting operations.

Sources

• California Assembly Housing and Community Development Committee analysis of AB 2252
• AB 2252 bill text, as amended March 16, 2026
• Culver City Single Stair Exit Ordinance
• Pew Charitable Trusts report on small single-stairway apartment buildings

This article is general information from a design-build and permitting perspective and is not legal advice.

#LosAngelesHousing #SingleStair #Title24 #MultifamilyDesign #LAInfill #AffordableHousing #PermitReady #FireSafety #Architecture #DesignBuild #ADU #SB9