CHAPTER 3: CASE STUDY - SERPENTINE PAVILION 2017

CHAPTER 3: CASE STUDY - SERPENTINE PAVILION 2017

Diébédo Francis Kéré was the 17th architect invited to design the Serpentine Pavilion in Kensington Gardens, London. The choice of the architect responsible for the 2017 pavilion was made by the artistic director of the Serpentine Gallery, Hans Ulrich, the CEO, Yana Peel, together with advisers David Adjaye and Richard Rogers, architects of great worldwide relevance.11

The Pavilion was purchased in 2017 by Galeria Ilham, from Kuala Lumpur. The structure will be located in Malaysia, and according to the gallery director Rahel Joseph, it will be displayed in a public space to encourage many people to visit.

Looks

The study of Francis Kéré’s Pavilion will be divided into two parts: the first with a personal look, that is, supported by the object of study, and what is possible to learn about it directly, in a way that is detached from the architect’s discourse. The second part is the understanding of the architect’s gaze, that is, of his intention behind the design choices.

Personal look

Francis Kéré positioned the pavilion perpendicular to the Serpentine Gallery, establishing a main path connecting the two. This path makes the pavilion the last space to be visited by those who enter through the gallery’s main entrance. He created two more routes to/from the pavilion, one on each side of the main axis, with relatively close distances, serving the public that arrives on ‘West Carriage Drive’ street and through Kensington Garden itself (there are two more entrances to the pavilion internally, created by the arrangement of the walls). Like the architects Toyo Ito, Rem Koolhaas, Jean Nouvel, and Peter Zumthor, Diébédo chose to create a more compact pavilion, with 330 m², which does not exceed the limit of the lawn adjacent to the gallery, unlike the architects Álvaro Siza and Eduardo Souto de Moura and the Japanese office SANAA.

The translucent polycarbonate roof covering the pavilion area is supported and fixed to the steel space trusses. It has the shape of an ellipse, whose center is dislocated on the horizontal axis (x axis of the Cartesian Plane) to the left, creating two cantilever moments with different sizes - around 8 meters on the left and 14 meters on the right. There is a hole in the center, between the cantilevers, measuring about 5 meters, formed by three rings: the perimeter of the ellipse, the ring that delimits the size of the opening (also responsible for determining the slope of the roof), and the ring that allows the extension of the roof, for about 1.5 meters, as part of the surface of a cone.

11 David Adjaye is an architect, born in Tanzania, naturalized British, known mainly for designing the National Museum of African American History and Culture, which opened in 2016. Richard Rogers is an architect, born in Florence, naturalized British, known mainly for designing the Georges Pompidou Center, alongside the Italian architect Renzo Piano, in 1971.

The structural system in steel is formed by hollow pieces, of square sections (with rounded edges), whose junction is made by welding. The elliptical shape of the roof generates a pattern of radial lines that form the design of the space trusses, constituting 28 modules of different sizes, with each module being narrower near the central hole and wider at the end of the roof. 14 modules have pillars and the other 14 do not, so they are interspersed with each other, forming a compression ring around the opening. The pillars are like the continuity of the truss, supported at four points welded on a square steel base. It is anchored in a part of the concrete floor, inside a permeable area in the center, in the open part of the roof.

The steel structure is partially covered by wooden slats at the bottom. The slats are fixed (or are glued or screwed, it is unlikely that they will be fitted) on a wooden support that surrounds each span of the space trusses, which causes the slats to create light and shadow effects, both by the void between them (apparently of the same dimension as the slats themselves) and by the transparency of the polycarbonate roof above them.

In addition, the slats form triangular panels that vary in height in the central part of each truss module. The central pieces follow the height of the truss mullions, like the diagonals between one mullion and another, forming angles that allow different slopes. Being that the closer to the hole in the cover the opening is larger and the further away, that is, closer to the perimeter of the roof, the smaller the angle formed and, consequently, the smaller the opening. Due to the slope of the lower chord of the truss, which reduces the height of the uprights and therefore reduces the diagonals that promote openings in the wooden panels, the last ring of the truss that surrounds the perimeter of the ellipse has no opening, that is, the wooden slats are in the same plane.

The walls are made of a single, prefabricated piece, used as a replicated module. Of solid wood and painted blue, the piece is formed by eight slats that decrease in size in length, creating a pyramidal shape. In addition, each slat has a trapezoidal shape in section, with a right angle on the inside and an angle of inclination of about 30° on the outside.

This angular variation, combined with the arrangement between the pieces - positioned one opposite to the other, sometimes with the larger base supported below, sometimes above - creates an optical effect of changing the shade of blue when exposed to the sun or even by artificial night light, on the outside. The inverted pyramid pieces (with the smaller base supported below), appear to be lighter than the others. Each piece is assembled at a small distance from the other, allowing partial visual permeability, in addition to the passage of air. In addition, they are perforated in two vertical points, through which steel bars pass, which guarantees the stability of the five rows that compose the wall, interspersed between horizontal wooden slats.

The four curved fragments that create different passages and visual effects - the walls - delimit the spaces, providing different functions in the pavilion. The concave walls facing inwards are places that promote the gathering of people, such as near the bar and at the other end, in an even wider area. The other two walls, with their concavities facing outwards, have a more intimate character, with fixed benches designed in line with the walls (solid wood seats painted in blue), which favor permanence and rest. The walls were set up at the same level as the central living area as if they were on small stones such as gravel, but they are actually fixed by a metal bracket anchored to the concrete floor. In the uncovered part, there are cylindrical concrete benches also for permanence. Finally, there is furniture specially created for children - a wooden slide with a conical shape, very similar to the geometry of the roof itself, as an ellipse with an offset center - installed between the outdoor area and the covered area of the pavilion.

Architect’s look

We have a big tree in the center of the village that provides shade and during the day multiple activities take place there. It could even be a kindergarten. So adults would be talking and children would be playing, elders would be arguing, but sometimes it can turn into a small hospital when there is a vaccination campaign or it becomes a school. So I wanted to bring that spirit, that element in Burkina Faso culture here, using the tree as a reference and with all the activities happening on it. (KÉRÉ, 2017)12

Francis Kéré reinterpreted a very striking element in his experience in Africa, the tree, and from there he began to develop the components that could represent it. He chose steel as the structure to give the pavilion longevity, “to push this structure to its limit,” he said (the pavilion was made in partnership with Aecom, an American multinational engineering firm). In addition to steel, he also took advantage of the availability of wood in London, both for the roof slats and for the walls.

Diébédo compared the roof to a treetop and attributed another function to it: “in the center of the pavilion, the roof ends as a funnel for collecting water. I wanted with my team to celebrate water as the most important element and a vital asset”. Drinking water proper for consumption is one of the consequences of Diébédo’s work in some regions of Burkina Faso, which is why he opted for the permeability of the central winter garden, which absorbs the water later used for irrigation of the green area around the pavilion (KÉRÉ, 2017).

The walls were assembled in the same way as the buildings proposed by Francis Kéré in Africa, for example, the Primary School of Gando described before, in which there are side openings in the walls and these do not touch the roof, as they allow the passage of hot air from inside to outside. More symbolically, Diébédo proposes the pieces slightly apart from each other and disconnected from the roof as a wall in the pavilion. The indigo blue applied to the wooden modules was a precise choice, as the blue color in the architect’s villa represents celebration, it is used on special occasions: “I wanted to show my building in its best color” (the painting of the pieces also protects against weather). In addition, the blue pieces refer to African fabrics, with vivid colors and striking geometric patterns, such as the triangular one. Diébédo says that “it looks like fabric, but it’s not, it’s wood. Very solid but feels like fabric, almost light and flexible.” (KÉRÉ, 2017)

The vivid night lights applied to the pavilion also carry a purpose linked to Diébédo’s relationship with his roots in Gando. It is common for young people to climb to a higher part of the terrain to look for a source of light and a celebration in the midst of much darkness. That light, according to him, “becomes greater as more and more people arrive to join the event. In this way, the Pavilion will become a landmark of light, a symbol of narrative (storytelling) and union” (KÉRÉ, 2017).

The sense of community is very expressive in Francis Kéré’s speech and architectural language. The study design made by him for the pavilion mentions the word “community” four times, a possible reflection of childhood in Gando, where collective life is not just a factor of subsistence, but a cultural expression and

12 (KÉRÉ, 2017): excerpts from the interview entitled ‘Serpentine Pavilion 2017: Francis Kéré’, promoted by the Serpentine Gallery. Authorial translation.