Study: Single-Staircase Buildings Pose No Additional Risks

Multifamily buildings with a single staircase don’t put residents at greater risk than double-staircase construction, according to a new study from Pew, contradicting a common belief that has led to restrictive zoning codes that outlaw single-stair buildings in most U.S. cities.

According to the Congress for New Urbanism’s Public Square, double stairwell requirements are “partly responsible for the dull, generic streetscapes” of most mid-rise neighborhoods because they “create large, long facades on a block that may suck the vibrancy out of streetscapes” and limit the amount of light that can enter the building.

Single-stairwell buildings can be built at a small-to-medium size in walkable neighborhoods. Single-stairwell buildings can fit onto small, irregularly shaped infill lots, contributing to missing middle housing.

In the past, “Cities required two stairwells for fire safety, but modern fire safety advancements and new building materials make the requirements superfluous.” Today, New York City, Seattle, and Honolulu are the only major U.S. cities to allow single-stair construction up to six stories, but the movement to legalize single-stair construction is growing, with bills to reform stair requirements proposed in jurisdictions including the Washington, D.C. region.