Roof Gardens and Urban Reserves

For Corbusier it was his second point of a new architecture and the garden on top of the city. For Josef Frank it was his own apartment and the archetype of modern domestic space. For contemporary Vienna it is the new urban frontier and a showcase for emerging architectural talent. Meter for meter, Vienna’s rooftops represent the most expensive real estate in town, and, in the course of the last few years, developers and private clients have been increasingly bold in pursuing ambitious designs for this valuable property.

Whereas radical designs such as the coop himmelb(l)au’s Falkestrasse rooftop from 1988 or delugan_meissl’s House Ray 1 of 2003 have become internationally acclaimed icons of this building form, these projects have not occurred within a creative vacuum. Within the last 10 years, the problem of rooftop additions has produced a large body of works and has spurred one of the liveliest debates on architecture and urbanism within Vienna. For this metropolis emeritus, the theme of the penthouse is a reflection of its particular urban development as well as the city’s own, often highly ambiguous attitude towards modernism itself. As the city’s historical relationship to its rooftops has singularly shaped its idiosyncratic discourse on this building type, it is useful to reflect upon the evolution of the rooftop in there, before proceeding to examine three recent, exemplary projects in somewhat more detail.

Roof Tiles and Glass Pavilions

At the end of the 19^th century, while Paris built its zinc-clad roofscape of chambres-de-bonnes filled Mansards and New York began to reach for the sky, the attics of Vienna – then one of the world’s most dynamic urban centers and its fifth largest city in 1910 – remained, by and large, laundry rooms. This had much to do with Viennese attitudes to living arrangements as well as the history of the city’s building code. The many major conflagrations over the city’s long history made fire prevention a priority, and historically the building codes prohibited use and inhabitation of the roof-top zone. Although, as in Paris, Berlin or Milan, the Belle-Etage was the most desirable location and the upper stories were reserved for the socially inferior, the most desperate classes of the city were banished to the souterrain. Thus, unlike in Paris or London, for example, there existed little or no tradition of substandard accommodations for the servant classes in the attics of Vienna’s housing stock. The exploitation of this urban reserve was further hampered by local building practices. The standard Viennese apartment house clogged its attic with a longitudinal, chimney-filled and load-bearing wall (a situation that still haunts contemporary attempts to rationally build-out and utilize the city’s huge reserve of roof-top space). As a result of these various factors, roofs in pre-modern Vienna were predominately low-pitched and clad with red-brick roof tiles.

The rare developments that occurred above the cornices of imperial Vienna were usually related to unusual and even exotic usages. During the late Gründerzeit and Jugendstil eras, some roofs were built-out into broadly glazed studios for the city’s academic painters. Even more radical were the rooftop pavilions that sprouted after the emergence of commercial photography. Often fully glazed and using an exuberant formal language, these constructions were the avant-garde of their time. One of the best surviving examples of this type is Otto Wagner’s Ankerhaus am Graben from 1884. But these projects were exceptions to the generally uninspired roofscape of Vienna, although they did lend an aura of bohemian extravagance to the idea of the penthouse itself.

Despite Josephs Frank’s documented fondness for rooftop living, not much happened to Vienna’s roofscape during most of the 20^th century. The housing boom of Red Vienna concentrated upon reducing building density and creating accessible, green courtyards. For all its social radicalism, the architecture of Austro-Socialism was rather conservative in form and construction and continued the tradition of low pitched, red-tiled roofs. The urban development of the post war years concentrated upon the production of standardized housing and pursued the sort de-urbanization that was typical for that period throughout the western world. The nineties finally brought a new paradigm, however. Fed by reborn prosperity and the economic energy that arose from the fall of the iron curtain, a new desire for urbanity gripped the city. A Restaurants and clubs sprung up in the districts, and the young and well-to-do began to move back into previously unfashionable Gründerzeit quarters. The rooftop apartment became a hot commodity. Not only did it expand the inner-city building stock, it presented a new urban life-style. One could enjoy the amenities of the city while living in an individually-crafted dwelling outfitted with a terrace and a view. Perched on top of the city in loft-like spaces, the young and successful began accustoming itself to the light, the air and the aura of modern extravagance that came with roof-top living.

Old Lines, Emerging Ideas

The turning point was the revision of the city building code of 1996. Whereas the previous building laws prohibited dwelling above the cornice line, the new regulation allowed the whole of the building envelope to be used (The expressive roof form of Coop-Himmelb(l)au’s Falkensteinstraße were only possible because its floor-level lies below the building’s eaves). Formerly neglected and once hardly profitable, the 19^th century housing blocks turned out to contain a spatial reserve that has transformed them into very attractive properties; Robert Kniefacz, director of the department of architectural assessment of the MA 19 in Vienna has termed this reserve as a potential building site of gargantuan proportions He has also vocally supported the realization of progressive architectural solutions for this program An important contribution, for the emergence of this new field of architectural opportunity coincided with the appearance of a new generation of young Viennese architects whose formal sensibilities stand in stark contrast to the historic fabric of the city. Conflicting visions of how the will to form should be applied to roof-top development has become a topic of long and often heated debate.

The discourse became, in many ways, a question of the image of the city. Many in the field of architecture, in the press and in the city administration maintain that the aesthetic integrity of the historic urban fabric required that the traditional Viennese roof form be perpetuated; others believed that this new and singularly intensive urban expansion should be allowed to reflect the architectural standards of our time. The city building code is somewhat schizophrenic on this issue. While most paragraphs insist upon a traditional roof form with dormer windows over 1/3 of the length of the façade, there is a certain amount of freedom in interpreting what a dormer is (an ämtliche flexibility that allowed the sculptural form of ray-1 to wiggle its way through approvals) while the (in)famous §69 allows for “insignificant deviations” from the standard building code in certain circumstances. What insignificant means in this situation is often a matter of long discussion and negotiation. The ultimate result of this struggle between context and expressionism is a great deal of rather uninspired rooftop build-outs that is partially balanced-out by a good number of surprising, built statements which have successfully harvested the architectural potential that Corbusier and Frank had both foreseen.

While the three projects shown here have their own individual approach to working with the roof-top context, the do share a number of traits. They are all, essentially, single-family houses built above the eaves. They radically question role of the roof as a form and space-making envelope. And they integrate the Corbusian roof garden intimately into the living space they produce. Taken together, they offer a brief survey of how contemporary forms for living can be layered into historic urban fabric.

An Atrium House in the Sky

Completed  by Gerner°Gerner plus in 2002, Dach-8 is an attic conversion with an enigmatic solution to its corner site. Combining a single-family dwelling with a separately accessible office space, the project’s composition negates any sense of a continuous roof surface. The architects pull their metal and glass-clad construction back from the corner pediment, and use an uncompromising geometry to create powerful tension between the glazed cross section of the living room and the knee-wall of the building’s cornice. This concentrated space of the in-between flows into an atrium-like terrace that separates the sleeping tract from combined volume of the living/dining room and kitchen. This atrium, with its sheltered, almost intimate space, is the heart of the project, being both a perch over the street-crossing below and an extension of the open, almost floating space enclosed underneath the inclined and articulated roof plane of the living room. Finely worked out detailing of the exposed, rolled-steel structure underscores both the lightness of the construction and the faceted forms of the finished assembly. The house, nestled into the eaves of its Gründerzeit host and gathered around an open atrium, appears as an airy, light-filled crystal, set on top of Vienna’s Josefstadt.

Roof as Landscape

Mom takes name from its Mommsengasse address in Vienna’s 4^th District. Completed by pool Architektur in 2003, the loft conversion extends over the roofs of two adjacent buildings and is itself divided into two private dwellings, one unit for the client and second that was built speculatively. All the main rooms of both apartments open via sliding doors upon an open terrace that stretches along the cornice line of its host building. The clients’ lodgings feature a swelling and folded roof plane that wraps itself around a dramatic, open staircase - partly interior, partly exterior - that connects the loft-like living room to a rolling, romping roof terrace which floats like a ship’s deck above the 19^th century houses that surround it. This deck is no simple, two-dimensional surface. Keeping with the spirit of the folded planes and interlocking spaces of the living and dining areas, this roof top garden is an articulated and sculptural place that flows through and around the existing chimney walls and climbs like a stepped tribune up to the ridge of the roof, offering a set of bleacher-like seats ideal for taking-in a view of Vienna’s Rooftops.

Roof, Peeled Away

Vienna’s Bernardgasse is a unique genus loci. Embedded in the densely-built 7^th district of the city, the street is filled with two- and three-storey officers’ barracks dating from out of the Biedermaier Era. Martin Wakonig’s Penthouse in der Bernardgasse creates a joint between the taller buildings that abut the Kaiser Straße and its lower-lying neighbors in its street. The roof of the loft-conversion begins as a plane which continues the existing lines of the higher roof lying to its west, then uses a series of well-conceived slices to peel itself open to the east, creating a finely-shaped, sculptural transition piece that responds well to the adjacent, lower lying urban fabric. This opening-up of the roof allows an interpenetration between the interior spaces (design: Lara Rodrigo Segua) and the roof terrace that extends out over the bedroom tract to the rear. The resulting exterior spaces, planned by the landscape architects 3zu0, seem to emerge from under the roof as it is peeled away and opened up. What begins as well-mannered contextualism evolves over the course of the façade into a series of interlocking open, covered and enclosed spaces that offer spectacular vistas of the city.

Aus der Ausgabe 04-2006