City building, fire officials establish guidelines for new single-stair apartment buildings

The City of Portland's building official and fire marshal issued a new Building Code Guide that allows just one stairwell in apartment buildings up to four stories in height. This is consistent with allowances provided in the 2025 edition of the Oregon Structural Specialty Code, which took effect Oct. 1.

There are 11 conditions outlined in Building Code Guide 25-10 that must be met to allow only one stairwell per new four-story building. Included in those conditions are requirements that the net floor area of each story not exceed 4,000 square feet and that no more than four dwelling units are allowed on any story. 

Building Code Guides provide answers about the application of building codes. They can also outline optional alternatives to meeting the intent of building codes. Building Code Guides are issued by the City's building official, who is authorized under Oregon law to provide interpretations of state and national building codes and oversee their implementation. Building Code Guides are not subject to public review or approval by elected officials before their implementation.

Learn more about Building Code Guide 25-10: Single-stair Apartments