Using Single-Stair Buildings to Unlock Attainable, Efficient Housing

As cities across the U.S. deal with housing affordability challenges, a recent zoning change in Colorado could serve as a blueprint for adding attainable housing for both market rate and affordable housing developers. Under Colorado’s HB25-1273 legislation, cities throughout the state will have to update zoning to allow for the development of five-story, single-stair housing. 

According to KGA Architects, an architecture firm based in Denver, these buildings offer several design benefits. With only four units per floor, many apartments can have windows on multiple sides, allowing for more natural light and fresh air. Additionally, their slim, efficient layouts offer lower construction costs while still providing communal spaces, such as shared courtyards and the potential for ground-floor retail or dining space.

In Denver, it creates a missing middle product that bridges the gap between townhomes and large multifamily podiums. For developers, this means there are suddenly vastly more potentially buildable lots for creating successful projects. And for future residents, this means there may soon be a whole new segment of housing that is both affordable and livable.

• Greater housing density on small infill lots
• Lower construction costs relative to podium or double-loaded corridor buildings
• More units with dual orientation for daylight and ventilation
• Reduced shared circulation space, increasing net-to-gross efficiency
• Enhanced livability and community interaction, particularly with atrium and courtyard schemes