architect: Nieto Sobejano Arquitectos
location: Graz, Austria
Modernism opened up many doors, but it also closed others – as it happened with ornamentation, for instance – which was long disregarded as a source for other possible expressive paths. The roof is one of those architectural elements that in the past have played an essential role in the spatial and urban definition of buildings, and throughout most of the twentieth century modern orthodoxy has reduced it to the almost universal imposition of the horizontal roof. The Corbusian axiom of the flat roof only began to be questioned seriously beginning in the second half of the century, as it happened with some less-common works by architects who, like Kahn or Utzon, would recover the expressive potential of a building’s roof, not only in its formal and volumetric expression, but also as an element that generates space, light, and structure, or, in other words, its own architectural conception. Many historical urban centers have been defined by the silhouette of their roofs – roofs, vaults, domes – which stand out amid the buildings and are sometimes only perceptible from distant vantage points. This is the case with the Austrian city of Graz – whose historic center is listed as a heritage site thanks essentially to its harmonious roofscape – where our project for the expansion of a large department store took the interpretation of that reality
as its point of departure.
The series of buildings from different periods that was to be expanded offered the chance to intervene in the upper floors, up to now occupied by mechanical elements, storage areas, and services. The surrounding buildings, close to the Schlossberg hill, convey an overall coherent image thanks to their pitched roofs, even though they have different heights. Our expansion project took that same premise as its starting point: the desire to combine the unevenness of the existing constructions with the individual conditions that their use and property required, by means of a new roof generated by a simple geometric law. Geometry has often been considered as limiting the formal freedom of the architect. But in our view, it is quite the opposite, becoming a mechanism that liberates and allows the project to adapt to changing and unforeseeable circumstances. The interruptions in the folds of the roofs generate terraces that overlook the mountains and the city.
At the same time, these echo the meandering sequences of small plazas and courtyards that define the pedestrian itinerary on the lower level. A single material unifies the new expansion toward the exterior: weathered bronze panels that set up a dialogue with the color variations of the roof tiles. Clearly tracing a geometric profile that blends into the city skyline, it also seems to proudly express – paraphrasing a famous modern aphorism – that the roof is the generator.