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Split Switchback Housing

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Socially rich, straw-filled single-stair housing
Primary Projects + RUKA Design
Currently, most US housing over three stories requires two means of egress. This generates hotel-style housing, where units are entered from long, dark hallways. This model has many problems. Allowing windows only on one wall leads to inefficient unit layouts that are ill-suited for families, difficult to ventilate naturally, and more. The excess circulation—an extra set of stairs and a long hall—requires large rectangular plots of land, which are increasingly rare and costly in urban settings. Because these codes predate the invention of modern technologies like fire sprinklers, many municipalities are revisiting them to encourage the development of infill sites and lower housing costs.

Split Switchback Housing answers Denver’s call to imagine American single-stair housing. After completing this project, we tested the prototype at three additional sites with varying constraints. (See Single Stair Housing Studies.)




The first floor caters to residents’ daily needs with spaces for chance meetings, play dates, package deliveries, bike parking, recycling, composting, & trash disposal.




The mid-level landings at the South protrude to signal entry and create covering at the side entry Corrugated galvanized metal is low-cost, durable, fire-resistant, and materially-efficient cladding (shape + thin=rigidity).



Widespread Adoption

In surveying emerging single-stair legislation across the country, firefighters’ concerns have been the biggest barrier to adoption.

Before starting we worked to understand these concerns better, using them as the foundation to our approach. Building off of Seattle’s code, the design addresses these concerns in the following ways:

(Denver’s Capitol Hill, Station 8, has a truck with a 105’ rear-mount ladder. Denver has adequate hydrant capacity and quick fire department response times. The proposed building has fire sprinklers and properly fire-separated occupancies. All of these are essential factors for taller single-stair buildings.)

Short Travel Distances

The furthest unit is 12’ from the stair. (Also, the stair’s travel distance is equivalent to a typical switchback: 8’ across the landing.)


Fire-Rescue Balconies

Every unit has a balcony facing a right-of-way, allowing for easier rescue and refuge from smoke.


Smoke-Free Stair

The stair is covered, but open at the sides, preventing smoke build-up (and allowing more light & fresh air).


Increased Visibility

The alternating switchback increases visibility between floors (because they aren’t blocked by the level above).



The building’s design fosters connection and community, beginning with two street-facing social spaces—one at grade and one on the rooftop (left of image) If you want to, it’s easy to chat with neighbors above or below you from your landing.


Ground Floor. From Left: Social Lawn, Covered Cafe Seating, Community Room, Bike Room, Utility Rooms, Stair & Elevator, One-Bed Units, Rear Balconies, & Retention Ponds Second through Fifth Floor Plans. From Left: Street-Facing Balcony, Three-Bed Unit, Stair & Elevator, One-Bed Units, & Rear Balconies Sixth Floor Plan. From Left: Street-Facing Balcony & Roof Deck, Shared Laundry & Communal Living Room, Stair & Elevator, One-Bed Units, & Rear Balconies



Unrolling a typical switchback stair opens up views & creates a portion of each landing where residents can pull over to chat, without increasing the travel distance! In the case of a fire, the stair allows firefighters to see multiple levels more easily (normally views are obstructed by the stacking of the stairs).




The project consists of two living blocks organized around a central stair. Conceived as a prototypical solution, the blocks can grow or shrink to fit deeper or shallower sites, as long as their inner face abuts the stair.



Click through the gallery below to learn more about the project ︎︎︎

A bike room at the ground floor is a natural spot for residents to store and repair their bikes and strollers. Recycled brick at the ground level & stair provides fire resistance & durability while recalling Denver’s brick legacy. A combination of sliding balcony doors and operable windows allows residents to ventilate their units naturally during nice weather. The balconies allow low winter light and screen out summer heat gain. (They also create a social interface with the neighborhood.) Shared washers activate the rooftop communal space and save energy. Clothes-lines further conserve electricity. A 500 gallon cistern on the roof captures runoff for plants (and communal compost converts kitchen scraps to fertile soil).


Sponsor

Buildner and ArchDaily

Location

1338 Emerson St / Denver, CO 80218

Awards

Denver Single-Stair Housing Challenge, Shortlisted

Stats

  • 6-stories
  • 16 units:
        12 studios
        4 three-beds
  • Lot Size: 5,678 sf (0.13 acres)
  • Dwellings per Acre: 122.7
  • Amenities: Covered Outdoor Cafe Seating, Community Room, Bike Room, Communal Living Room, Shared Laundry, Rooftop Deck, Social Stair

Services

  • Architectural Design
  • Zoning Analysis
  • Interior Design

Tags

Attainable, Communal, Housing, Carbon Smart, Prefab, Missing Middle, Point Access Block



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