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Zeleke Belay Architect
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Looking back on my journey of architecture, ‘stairs’ seems an intuitive response to the contradiction I had with my experience of architecture. Growing up in a climate that had no difference between an inside and outside of a building my instinct to design of buildings has always been for an open and interactive inside out.

My first exposure to buildings in cold climates was as a graduate student in Finland. The buildings I saw in Finland were simple and clean boxes. But I had difficulty appreciating their quality. It was not the kind of architecture I had expected to see. In a way, I was disappointed with what I was experiencing. It took me a while to realize where the whole contradiction has come from. I realized buildings in cold climates need to limit their exposure to the outside to save heating costs. As a result, they end up becoming simple boxes, simple prisms. Intuitively, I had already felt the buildings in my place would do the opposite. Buildings in my climate would rather want to extend the length of their external walls, to open to the outside. Every room, every space would want to expose itself to the outside, for a breeze.
‘stairs’ is a building that recognizes the unique climate of Addis Ababa and responds to the inside-out equal temperature story. The main circulation of the building is open to the outside. The stairs, the passage, that lead to every office space is open to the outside. There is no physical separation between the inside and the outside. As you climb the stairs you are at the same time part of the building and part of the city. This is a unique experience. Visitors would often stop and watch the street life around them. The building in effect interacts with the city directly.

An optimal moment where the climate, function, and scale of a building become a means to carve a distinct architecture naturally. ‘stairs’ is basically a simple box cut out around its periphery for vertical circulation. It is an ideal situation where the very act of cutting becomes a means for access, light, ventilation, shading, view and to formulate a complete architectural expression. Windows are not arbitrarily opened on the facade. But the recessed space created by the passage provides a shaded window position naturally.

The virtual absence of windows on the external skin, seemingly an intrinsic element of architecture, creates an illusion of scale, enhancing a sense of intimacy. The outer layer accommodating the stairway creates a niche around the building and provides a natural detail. The stairway becomes a mediator between the inner and the outer space, belonging at the same time to the solid and the void. The voids function as shading devices, rendering air conditioners obsolete, producing an absolutely minimal and economical building solution. This cut-out space is painted with a strong red color amplifying the extraction.

Designed for an office function the building sits on a 9x9m base at a shallow corner plot and rises to 19m height above ground. Each floor is accessed at a landing of stairs through deep doors that create a sense of gate to each floor. The top floor accommodates the architect’s studio. Toilets are provided under the stairs around the periphery, shifting on each floor.

‘stairs’ is supported only by four columns. These four columns were designed as an L-shape to align to the wall system seamlessly when joining the stairway. Coincidentally, the L-shape columns also work better for the structure. Beams and columns were designed to seamlessly vanish in the architecture, in effect becoming part of the architectural expression.

Though ‘stairs’ look like a simple building it has a number of peculiar details that helped preserve its visual simplicity. One of such features is how its sanitary system was resolved to conceal its pipe system. Every floor is provided with a toilet. The toilets are placed under the rotating cantilevered stairs. Since the stairs are open to the outside, if installed conventionally, the pipes would cross the open stairway and would ruin the façade. A special solution was provided. The solution was to give every toilet its own separate drain pipe that would connect independently to the ground piping system.

One of my favorite details of ‘stairs’ is how we managed to provide a toilet to the fourth floor by just raising the toilet floor by a few steps, high enough to allow passage under (Section AA). It is a detail no one notices but a key that fixed ‘stairs’ as a functioning building. This arrangement aligns the three toilet floors one over the other, including the roof downpipe. Another detail was required though to conceal these pipes, once they reach the first-floor slab. The first-floor slab bottom was then recessed to receive these pipes to redirect them to the ground floor piping system. All worked out during the design period.

Creating transparency without losing solidity, a trend we repeated in later projects, was first experimented on ‘stairs’. This happened out of necessity. The red-painted recessed core that makes part of the interior space remains solid on all floors except on the fourth floor. But the fourth floor where the architect’s studio is situated required transparency without having to lose its solidity, where the idea of the tiny punches came as a solution.

The rainwater drainage system of the winding stairway was something we thought about during the design. We realized that if we would not arrest the water on every floor it would flood the stairs down. The outer edge of the flight of stairs was grooved as a channel to drain water down. Every landing was then sloped to that edge arresting water at each level. This channel also takes care of draining water during floor washing in regular cleaning time.

‘stairs’ has now found a companion bridge that connects it to the next block. An open bridge is generated from a series of Cubocta blocks. A bridge perforated all the way around.

The Cubocta bridge is designed to connect ‘stairs’ to an adjacent building. Basically, a simple function elevated to an artistic solution. Walking in the bridge, your experience will be like passing through a series of rhombuses pinned on a single corner vertically making it obvious that you can only walk in this bridge by design.

On the Cubocta bridge, dominant building material such as steel is obscured from the attention of the user and completely overwhelmed by the feeling created by the architecture. The material in this case is devoid of its lightness and strength and rather forced to appear as solid from the outside and completely porus from the inside. This duality of appearance creates a feeling of immateriality in the architecture.

The Cubocta like the cube packs on itself to form a continuous row both horizontally and vertically. Four of this solids were lined up to form the bridge. In reality you walk inside a row of cuboctas, which makes the structure efficient owed to the fact that you are actually walking inside a 3D structure.

The bridge extends about nine meters horizontally to the adjacent building with out the need to employ any special technique or expensive material rather by taking advantage of the three-dimensional nature of the structure. Which was also the reason why it ended up being super light.

‘stairs’ is a favorite building for architecture students and probably one of the most repeatedly made physical model, including by high school students. Every member of our staff, architect or engineer, has made a model of it out of curiosity.

Offhand people ask if ‘stairs’ is a waste of space. I tell them it is the opposite. In fact, ‘stairs’ is a building without a stair. I know this question comes from an experience of a conventional stair that consumes a dedicated space that has no use except as vertical circulation, a space often considered as wastage. But ‘stairs’ has revolutionized the whole concept of stair design by giving it a double use. In terms of physical use, the space under is utilized as a toilet and a storage space. The space above is reclaimed back. On top of that, the stair is now a floor, a corridor, a balcony, a roof; and a means for shade and breeze. Not to talk about its expression as a diagonal element in a world of an orthogonal building system.

The design of ‘stairs’ was given more time and thought than the actual construction period, a trend that we as an industry fail to practice.

The construction was completed in just six months. More design time provides a number of benefits. It helps in obtaining better-designed buildings, reduces construction cost and most importantly reduces construction time. The construction industry should adopt a system for more design time and less construction period. Unfortunately, the current trend for most commercial and even governmental projects here is for a very brief design time, which naturally induces a long construction period.//

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© May, 2023 Ketema Journal

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