Small Single-Stairway Apartment Buildings Have Strong Safety Record
We’re excited to share a new research article we contributed to from The Pew Charitable Trusts and the Center for Building in North America that modern four-to-six-story buildings with a single stairway are as safe as those with two stairways and can be a cost-effective and safe piece of the solution to the housing shortage in the United States. 
Relative to standard apartment buildings that require two staircases, single-stairway buildings are easier to fit on infill lots, cost less to build, can incorporate more family-sized units, and can be designed with better ventilation and natural light. Despite these advantages, only a handful of U.S. cities currently allow single-stairway buildings. A lack of information on their fire safety has prevented wider adoption.
To fill that gap, we analyzed real-world evidence from the two U.S. cities that have the most single-stairway buildings—New York City and Seattle. In both Seattle and New York City, no fire deaths were associated with having only one stairway. Moreover, looking at every individual fire death and its cause in New York City from 2012 to 2024, we found that the fire death rate in the thousands of single-stairway buildings in the city was indistinguishable from the fire death rate in other residential buildings. With modern safety features, like sprinklers, self-closing doors, and fire-rated walls, single-stair apartment buildings have proven to be just as safe as other residential buildings.
To address housing shortages, a growing number of states are already taking action. In the last two years alone, eight states have passed legislation to study or allow single-stair construction and more are expected to follow. Our research demonstrates that modern single-stairway buildings are safe and can increase housing supply where it is needed most.