SKY

Meeting the sky is an instinctive human desire and has for centuries shaped how we built our cities. The contact between human body and sky is formative, it orients us within the cycles of time, rhythms of weather, and the wider context of environment and the universe. The sky serves simultaneously as orientation and as inspiration, mediating our exposure to light and shifting atmospheres. 

The shape of the roof, initially reflecting climate, technology and available materials defines the transition between buildings and the sky and has changed fundamentally throughout the past 150 years. Until the mid 19th century, Zurich‘s cityscape was characterised by steep pitched roofs and only with the rapid densification of the city around 1900, a new typology emerged. Thriving for sun and air in the industrial city, trimmed hipped roofs offered „Dachzinnen“, open platforms as spaces of appropriation. They were used for photography studios, drying laundry, overlooking the city and as far as the alps, spaces for dancing, for representation through advertisement, sunbathing or watching the first Zeppelins and hot air balloons rise above the city. The use of the roof became strongly embedded in Zurich‘s culture, functioning as a common space, almost perceived as part of the public sphere.

TERRITORY

Observing today‘s city we find ourselves below inaccessible landscapes of technical installations. Our societal understanding of comfort—driven by expectations for climate control, convenience, and technical services— has taken over large surface areas and completely cut our connection to the sky.

The phenomenon of the infrastructural roof emerged in the 1990s, through advancing technologies and consequently established norms and regulations. Since the introduction of §292 PBG in 1995, technically conditioned roof structures are even considered an exception from building law and may exceed the highest point of a building. Whilst described as an aesthetic norm aiming to keep the city’s roofscape calm, this exception is paradoxically doing the exact opposite and represents the value of infrastructure for society.

Adding up to 2.8km2 of roof surface across Zurich, these spaces appear as no-mans land, only ever accessed for the purpose of maintenance, offering potential for new projections. Its potential lays in its low economic value, as due to safety regulations and aesthetic expectations, the sole presence of technical devices excludes commercial programs and functions.

PLATFORM

The project proposes to re-claim these roof spaces as public platforms. Within the ongoing discourse of densification, open space is becoming increasingly scarce. While the roofs of residential buildings are privatised or extended upwards for further housing development, it is the technical roofs of administrative, industrial and public buildings that will be activated. Bordering densification zones, these roofs supplement the existing network of public spaces as open platforms of appropriation. Their character and type will range in use, typology and scale but their interrelation is the exposure to the sky and their collective quality. Projecting social activities, places for gathering and shared encounters relates back to the historical use of roof spaces in Zurich.

SYSTEM

Reclaiming space means reclaiming agency or transforming the roof means transforming the buildings infrastructure. As the life span of buildings far exceeds the life span of technical devices, roofs can be described as fluid spaces. Ranging from 5-25 years, systems have to be replaced. Each technical conversion becomes a moment of intervention, enabling a significant spatial impact throughout the city within a short period of time. To overcome these spaces as a „domain over which architects have lost all control“, the project translates the exact program of the technical renovation and proposes a spatial deconstruction of systems as means to transform.

Questioning conventional building practises and today‘s understanding of comfort and climate control, it aims to disrupt the autonomy and rigidity of the existing and to re-embed the building in its social, ecological and environmental surroundings. Following a strategy of passive systems allows to decrease the infrastructural surface within the building and especially on the roof.

The project consists of a series of 4 interdependent spatial systems thatintervene at moments of exchange between inside and outside: A new facade, a ventilation system, an atrium and a layer of circulation. Replacing conventional mechanical systems, they orient themselves towards environmental conditions and activate the roof space for public uses. Their invasiveness depends on the programmatic necessity for change, ranging from minimal temporary interventions to larger built adaptations and continuing the fragmented character of the roof territory.

BODY

The roof space emerges through a new type of order between internal systems and external surroundings. Overlapping the view and the relation to the sky, the spatial systems and its appropriation, the roof functions as a layered scenography. It constitutes in a space of co-existence between humans and infrastructure and with different climatic conditions, orientations and gradients of exposure to external conditions, it allows for a variety of uses and is able to adapt with needs. Its qualities lay in its location as a high place, its relation to the sky and the external environment, but also particularly in the characteristics of the infrastructure space itself.