California fire marshal report weighs “single stair” apartments up to 4 stories

California publishes delayed report on whether to allow “single stair” apartments

California’s fire safety regulators published a report Monday on whether the state should allow mid-rise apartment buildings with a single stairway—late by more than two months and at the center of a debate over how to balance housing construction with fire-safety redundancy.

The report was released by the Office of the State Fire Marshal, and it comes as lawmakers and local advocates consider changes to stairway rules that currently require apartment buildings over three stories to have at least two separate staircases.

In the report, the fire marshal’s office took what the story described as a “fairly dim view” of the “single stair” cause, while still laying out potential guardrails for legislators if they choose to move forward. The report argued that even with modern fire mitigation measures, relying on one stair does not provide the same level of backup when unexpected problems arise.

The report said modern safety measures “do not fully substitute for the redundancy of two independent stairway,” adding that the redundancy is “important for maintaining safety in the face of unforeseen failures,” according to the description of the report’s wording.

For any legislative overhaul, the report recommended a narrower approach than many proponents have sought. It suggested that single-stair apartment buildings should be limited to four stories rather than three, and that they should face additional safety rules. The report also said the state should not consider allowing structures up to six stories without another second fire marshal study, citing a higher-story model already used in New York City, Seattle, Honolulu and Culver City.

The report also examined the financial implications of adding a second staircase by evaluating three mid-rise apartment projects. It found that a second staircase made up between 7.5% and 12% of estimated total construction costs.

The findings followed an earlier draft of the report that CalMatters obtained in February, but they still disappointed some supporters of loosening stairwell requirements. Bubba Fish, the Culver City councilmember who spearheaded a single-stair ordinance in Culver City last year, called the report’s four-story maximum “ridiculous” in a text message, saying it would keep California’s building code out of step with many other places.

The report missed a January 1 deadline set by a 2023 bill authored by Milpitas Democratic Assemblymember Alex Lee. Lee said his office was still reviewing the report’s findings late Monday afternoon, but in a written statement he expressed enthusiasm for future changes to the building code.

Lee’s statement said “Stairway requirements can have a profound effect on what does and does not get built in our neighborhoods,” and that “With the development of modern fire mitigation measures, it is critical that we re-evaluate our building codes and unlock previously undevelopable properties to build more housing.” He previously introduced a bill intended to allow buildings with “4 or more stories to have a single stair entry and exit,” though the measure as described so far includes no additional detail.

A key question for lawmakers will be whether to follow the fire marshal’s suggested limits—especially the report’s emphasis on redundancy and its recommendation against jumping directly to higher, six-story allowances without additional study. The outcome will determine whether California’s statewide code continues to require multiple stair exits for mid-rise apartments or begins incorporating single-stair designs under stricter conditions.