Senate Approves Legislation to Update Building Codes, Make Housing More Affordable

DENVER, CO – Today Senators Matt Ball, D-Denver, and Nick Hinrichsen’s, D-Pueblo, legislation to make housing more affordable by updating building codes to only require one stairwell for certain multi-family buildings passed the Senate.

“Single-stair buildings are a safe and practical solution that make it far easier to build apartments with enough bedrooms to comfortably house Colorado families,” said Ball. “Single-stair buildings can also be impressive architectural additions to our neighborhoods. I’m proud to sponsor legislation that modernizes our building codes and positions Colorado at the forefront of innovative solutions to our housing crisis."

“Colorado is facing a housing crisis and we must explore every option to build more homes that families can afford,” said Hinrichsen. “Modernizing outdated building codes to allow for single-stair apartment buildings, where modern technology and building materials makes doing so safe, is a simple and effective solution that will open up opportunities to build more affordable housing and revitalize our neighborhoods. This legislation is a critical way that we can increase housing supply, drive down costs, and ensure that every Coloradan has a safe, affordable place to call home.”

Beginning December 1, 2027, HB25-1273 would require a municipality of 100,000 or more residents that is served by an accredited fire protection district, fire department, or fire authority to ensure that their building code allows certain multi-family residential buildings up to five stories to be served by a single exit.

Additional requirements to qualify for a single-stairway exit include:

• Buildings no more than five stories tall with up to four dwelling units per floor,

• Safety features throughout the building that satisfy building codes and other relevant codes, including an automatic sprinkler system and fire resistance and smoke control systems,

• Stairways no more than twenty feet away from a door to each dwelling unit and 125 feet from the stairway to any point in a dwelling unit, 

• Aerial access by the building’s applicable fire department or protection district, and

• Buildings constructed of non-combustible or fire-resistive construction materials.

The bill would also require a jurisdiction to notify their local International Association of Fire Fighters affiliate and the Colorado Professional Fire Fighters Association (CPFF) when they begin the code adoption process and when considering code changes relative to buildings impacted by the bill. These buildings would also be required to include signage to identify that it is a single stair building and a fire-resistant box that contains keys to the buildings for relevant firefighters to access the building and necessary units. 

Under the bill, the Department of Local Affairs would be required to consult with CPFF on implementation and data collection regarding single stair buildings constructed in each jurisdiction and the reporting of that data to the legislature during annual SMART Act hearings. 

According to a 2025 Pew Study, there has been no evidence of safety risks in New York City, Seattle, the Netherlands, and other jurisdictions that allow single stair apartments to be built. Adding a second stairway to an apartment building can increase building costs by six to 13 percent, and single stair apartments can reduce cooling costs by up to 80 percent.

HB25-1273 now returns to the House for consideration of amendments.