Washington state has recently enacted legislation to legalize the use of scissor stairs in apartment buildings, a move proponents claim could significantly increase living space and reduce housing costs. According to a tweet by Saad Asad, this building code reform "frees up to 56% more living space per floor," leading to "cheaper homes on smaller lots." The change addresses a long-standing ban on such designs in most U.S. states since the 1970s.
The legislative action, primarily through House Bill 2228 and Senate Bill 6001, mandates the State Building Code Council to convene a technical advisory group. This group is tasked with recommending amendments to the international building code by the 2027 update, specifically to permit scissor stairs in multi-dwelling unit occupancies. Scissor stairs are defined as two interlocking stairways with two separate exits, enclosed and separated by fire-resistance-rated walls, offering a compact solution for egress.
Advocates highlight the substantial benefits of this reform, including the potential for more flexible and efficient building designs. While the tweet suggests up to 56% more living space, a comprehensive report by the Pew Charitable Trusts on small single-stairway buildings, a related concept, indicates that such designs can save approximately 7% of a building's floor area and reduce construction costs by 6% to 13%. These savings enable developers to build on smaller, often underutilized, infill lots, contributing to increased housing supply.
The historical prohibition of scissor stairs in many U.S. building codes, often stemming from safety concerns, is now being re-evaluated in light of modern fire safety advancements. The Pew Charitable Trusts report concludes that contemporary single-stair buildings, equipped with sprinklers and fire-rated walls, demonstrate a safety record comparable to traditional dual-stair configurations. However, some architectural perspectives suggest that while seemingly compact, scissor stairs can sometimes create planning complexities and lead to less efficient overall building layouts.
Washington's initiative positions it as a leader in a growing national movement to reform building codes to address housing affordability and supply challenges. Several other states and cities are actively studying or enacting similar measures to allow more flexible and cost-effective building designs. This trend reflects a broader recognition that innovative building practices, like the legalization of scissor stairs, are crucial for expanding housing options and making homes more attainable.
