Description

When one speaks of stepped terrace housing, Harry Glück’s large-scale projects on the periphery of Vienna spring to mind, for instance Heinz-Nittel-Hof, Alt-Erlaa and Hadikgasse. The history of his stepped terrace projects, though, begins with a comparatively small, inner-city project. All of these projects were part of an urban utopia: the Green City.[1]

At the time, Harry Glück was a young Viennese architect who had just completed his first residential buildings. These were mainly inner city projects, often embedded in a traditional perimeter block structure. Structurally, the complex is still a conventional multi-story apartment building, although Glück was already testing and refining the basic logic which was later to be implemented at Inzersdorfer Strasse. The project became a test case for the stepped terrace concept Glück had already developed in previous years. The prototypical character and inner-city location make the complex highly unusual and interesting, with many elements that anticipate those used in many of the architect‘s later residential buildings.

In order to realize a stepped terrace building in the confined context of the inner city, Glück had to develop a series of creative solutions. The Inzersdorfer Strasse complex follows the surrounding block structure in a U-shape on three sides, with the communal greenspace opening up to the south to Angeligasse, a pedestrian zone. In particular, the terracing led to several essential structural features. Due to the stepped gradation, the depth of the floors decreases as the height increases, resulting in larger floor plans on the ground floor with potentially difficult-to-use depths.

In corner situations, geometrically speaking, the protrusion of the lower floors leads to intersecting areas facing the courtyard. Glück would later solve this problem at Heinz-Nittel-Hof with a bridge section, mitigating the problem by implementing obtuse angles. At Inzersdorfer Strasse he changed the terrace dimensions. At the corner and in the adjacent partitions, the terraces recede only every other story, while each alternate story is terraced. This provides greater depth in these areas, thus reducing the corner problem significantly. At the two south-facing ends of the U-shape, Glück placed two short blocks that provide a logical conclusion to the east-west oriented tracts and create a row of additional high-quality dwellings and at the same time further increase the site utilization and thus the economic efficiency of the project. These short blocks alone encompass a microcosm of stepped terrace housing: one east and one west-facing apartment are inserted into each of the five lower floors, also terraced. The dark interior areas hold storage rooms for the tenants and additional communal use rooms are located on the ground floor. The situation changes on the upper three floors. Due to the receding terraces, the depths are particularly shallow here. There are smaller dwellings here and apartments extend across numerous cross-wall partitions. The problem is particularly pronounced in the units facing Braunspergengasse, where the street side must also be stepped back to allow enough light for the neighboring buildings. This means that there are no standard apartments on the upper floors here; each apartment unit is unique and adapted to the specific situation.

The complex is accessed via four staircases. The two staircases on Inzersdorfer Strasse have a dual function, each serving two different areas of the building. On the one hand, they provide access to the apartments in the main wing via three central corridors that, highly economical, are only situated on every third floor. This is made possible by the split-level arrangement of maisonette apartments. Entering an apartment from the corridor, one first goes up or down half a level to the north-facing bedrooms and from there another half floor level further on to the courtyard-facing living areas, which are located either above or below the corridor level. Two of the three corridor floors also access apartments on the same level that are oriented southwards. From the middle wing, the same staircases also serve as a multi-level access to the side wings. Each floor has an additional short corridor to the side wings from which four to five east-west oriented apartments, including the corner apartments, can be accessed. The final two staircases, located at the ends of the U-shape, connect to seven apartments per floor in a similar manner. There is always a dwelling at the ends of the corridors, further optimizing the use of space. Only on the second floor does the corridor intersect with all the staircases, making it possible to pass through the entire complex internally.

In general, the high variability of access situations and block depths results in a wide range of housing types, in terms of size, orientation, and layout. The dwellings themselves —  222 in number —  follow a similar organizational logic despite all their differences. The distance of 5.6 meters between the partitions enables either one larger room, such as a living room, or two smaller rooms each 2.76 meters wide. This means that apartment size varies more in terms of unit depth than by width. Double partition apartments have an area ranging between 70 and 90 m2. The largest apartments are maisonettes in the central area, with about 139 m2 of floor area. There are, however, also far smaller units with a total area of about 32 m2. The living room, kitchen, and private areas can be accessed separately from the central entrance area of the apartments. Kitchens have a width of 190 cm and are generally located in the same cross-wall partition as the living room, connected to the living room via the dining area. Auxiliary spaces such as sanitary and storage rooms are accommodated in the interior, less well-lit zones.

In terms of design, Glück uses the cross-wall construction method, which — resembling an open shelf — allows him to dispense with a conventional facade on the terraced side. Floor-to-ceiling glazing elements are used here instead, which open up the living spaces towards the terrace and thus create a full experience of the greenery outside. This consistent opening of the rooms not only shapes the spatial experience, it also maximizes the incidence of light into the depths of the rooms, and reduces construction costs and time. The window profiles were specifically developed by Glück’s office using frameless all-glass panes in a mahogany frame. The planters were formative elements of Glück’s buildings and the subject of constant development. In this case, they are 62-cm-high precast concrete elements placed directly onto the floor slab. From the inside, they act as a simple parapet wall that reaches to the ground yet, due to its low height, allows more greenery and light to enter. A steel handrail fulfills the regulation height.

The 8-cm-thick partition walls were made of autoclaved aerated concrete. Kitchens, bathrooms, and toilets were equipped with a mechanical forced-air ventilation system above the roof. Thermal insulation was provided on the roof with 5 cm of expanded polystyrene, and the soffits of the cantilevered building components are insulated with cork panels.

The complex has a number of outdoor features such as a swimming pool on the roof, but also a large sundeck and two sauna areas. On the northeast corner of the ground floor there is now a kindergarten, which was formerly a super-market. Parking is in the basement.

The combined vertical and horizontal shared access typology will be seen again at the Heinz-Nittel-Hof, while the maisonettes are found again at the Hadikgasse housing estate.

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Originally published in: Gerhard Steixner, Maria Welzig (eds.), Luxury for All. Milestones in European Stepped Terrace Housing, Birkhäuser, 2020. Translated by Anna Roos, abridged and edited for Building Types Online.