On May 29, 2026, the International Code Council (ICC) announced that the Center for Building’s single-stair proposal, E24-24, won the support of a majority of the ICC’s governmental membership in its Online Governmental Consensus Vote. This was the last hurdle to our single-stair proposal being included in the next version of the International Building Code (IBC) in 2027.

Our original proposal in 2024 would have allowed up to six stories of up to four apartments per floor to have one stairway. After the original proposal was voted down by the IBC Means of Egress committee, we reached a compromise with other stakeholders to reduce the story limit from six stories to four, along with some other mitigations.

You can read the full code text here, but the basics are that the new code section allows single-stair apartment buildings to be four stories, rather than the previous three, as long as each story is limited to 4,000 square feet of net floor area (this does not include common circulation space).

New mitigations include a requirement to install a manual fire alarm system and automatic smoke detectors in common spaces like corridors, and a ban on electrical receptacles (what most people would call an electrical outlet) in the stairway. Sprinklers are also required to be installed in the stairway as required by the NFPA 13 sprinkler standard for combustible stairways (although full NFPA 13 systems are not required), whether the stairway is combustible or noncombustible.

Importantly, a number of cost-increasing mitigations that have been proposed or enacted in some jurisdictions, especially for code sections allowing single-stair buildings above four stories, were not adopted. The stairway may be interior or exterior, and apartment doors are allowed to open directly into an interior exit stairway without an intervening corridor, as they have been in the IBC for three-story buildings. There are no requirements for pressurization of the stairway or extra requirements for pressurization of the elevator hoistway beyond those required by the base code. The stairway width requirement has been left unchanged, in effect requiring a minimum of 36 inches. Any construction type otherwise permitted by the code is allowed. The code’s baseline NFPA 13R sprinkler requirement for buildings up to four stories is left in place.

The Center for Building encourages policymakers and advocates interested in single-stair reform to adopt the text as it will appear in the 2027 IBC. While adopting the 2027 IBC will serve to update your jurisdiction’s single-stair code section to allow four stories, jurisdictions may also adopt this section ahead of full adoption of the 2027 code. Jurisdictions that have already adopted code sections allowing taller single-stair buildings than were allowed in the 2024 or prior codes should update their IBC adoption to reflect this new text, as even if they currently allow five- or six-story apartment buildings with a single exit, it is likely under a stricter set of conditions for four-story buildings than will appear in the 2027 IBC. For further questions or if you require technical assistance, please reach out to William Skudlarek.