Secondary school building in Isengrind in Zurich, Affoltern

Secondary school building in Isengrind in Zurich, Affoltern

Architecture competition Isengrind © Bruno Fioretti Marquez
© Bruno Fioretti Marquez

› 2020, Architectural competition explanatory report for Bruno Fioretti Marquez.


› In autumn 2020, the architects of Bruno Fioretti Marquez asked me for support in writing the explanatory report for the competition for a secondary school building in Affoltern. In collaboration with the architects and the specialist planners, I wrote a report of around 9,200 characters, structured with classical subtitles. (Translation from German)

Main idea

School buildings have undergone a great deal of change in recent years. The current Corona crisis shows that the development of school buildings is difficult to predict. This makes it all the more important to design school buildings that are as flexible and versatile as possible.


For the ALOSI project, the focus lies on a pragmatic, functional and concise structural and interior concept that promises spatial diversity and flexibility at the same time. The clear architectural expression is an embodiment of the internal, utility-oriented organisation of the building.


Urban setting

Within the green residential area of Unteraffoltern, the new school building appears as an independent, calm public building. An orientation on all sides allows for a strong relationship to the surroundings. As a compact, three-storey solitary building, its location on the south-western edge of the site – parallel to the Im Isengrind neighbourhood road – allows protected open spaces for the primary and secondary schools at the rear and ensures the required outdoor spaces. Together with the three-storey, horizontally emphasised new building, the openly designed outdoor area with an unobstructed view of the three-storey primary school building and the path connections give the impression of an overall complex. A further reference to the existing building is created by the materialisation, which is based on the kindergarten.


The present topography is used to achieve a level offset between the ground floor level and the outdoor sports field, which is one storey lower. The one-storey offset allows natural lighting for the underground double sports hall and, at the same time, direct access to the outdoor sports field as well as separate access to the sports facility. The lowered outdoor playing field is bordered on the north side by seating steps so that primary and secondary school students can interact here. Access to the recreation area is on the ground floor.


The main access to the Im Isengrind secondary school building is via the street of the same name, which is also used for the shared access to the parking and delivery on the east side of the building. In addition, the school is located on the adjacent bicycle and pedestrian paths, from which the outdoor areas that can be used by the neighbourhood as well as the school’s bicycle parking spaces are clearly visible. On the south-western long side of the building, which follows the street Im Isengrind, is the slightly elevated main entrance, which is accessible via a ramp or steps.


Facade design and materialisation

The materials and design of the school complex are kept simple and elegant, with the compact volume being uniform and the same on all sides. The building consists of a concrete base on which a three-storey wooden structure rests. The horizontal ribbon windows emphasise the horizontal structure and give the school a contemporary architectural expression. The upper façade grid conceals the teaching floors. The concrete base, which is mainly visible from the north-eastern outdoor sports field, contains the double sports hall. A folded gable roof that follows the inner grid brings the necessary movement to the façade.


Wood defines the school not only from the outside, but also constructively and atmospherically. The wooden components all remain visible inside and show the constructive structure. Well-lit, warm rooms characterise the interior.


Spatial organisation

The different uses are clearly stacked on top of each other: the public uses such as the canteen with multi-purpose hall, music rooms and the building’s internal access to the sports hall are located on the ground floor. Two staircases with lifts lead users either to the three teaching floors above or to the sports area located underground. The floors are zoned in three parallel layers throughout: In the central area is the generous access structure, on the street side the narrower strip, which is used differently per floor, and in the direction of the existing primary school building the wider floor area, whose deep room sequence is supplied with sufficient daylight by an atrium on the upper floors and by skylights on the ground floor. The staircases on the façades are also naturally lit.


The use of space on the ground floor provides a lively area between everyday school life and leisure time. The open room constellation of the shared spaces for lunch, recreation and the multi-purpose hall can be easily interconnected thanks to the simple skeleton structure without load-bearing partition walls, allowing a high degree of spatial flexibility and multiple uses. The covered lounge area in the outdoor space facing the west façade can be used as an extension of the communal areas. Pupils can take a break here, enjoy their lunch or observe what is happening on the ground level break area. A smooth progression of extracurricular activities is ensured by the possible separation and individual use of the rooms on the ground floor and in the basement.


Developed from the section, the largely recessed sports hall, lit from the north, appears as a storey-high plinth. An external access in the plinth allows entry to the sports area via the gallery on the first basement level, from where one can look down into the double sports hall. The visual insight can be prevented by shading elements in the interior and exterior areas, if required.


The regular school classrooms on the first to third floors form clear double clusters together with the group, supervision and therapy rooms. Three classes each, with group rooms in between, share a common, large corridor. The resulting spatial constellation promises a conducive learning landscape. While the open zone within the cluster allows for a variety of visual connections, all classrooms have an outside view. Through the centrally located atrium, additional daylight enters the classrooms, the access zone and the central area for the library, as well as the administration rooms and the combination workshop. The longitudinally oriented, centrally located classrooms thus benefit from two-sided lighting. In addition, the greenery on the interior façade of the atrium creates a friendly atmosphere in the building.


Energy and building engineering

The compactness of the new building both above and below ground and the lightweight construction on the upper floors help to meet the high target values for sustainability. The structural concept ensures the consistent separation of primary and secondary structure.


The use of natural materials, good window panes and external sun protection with intelligent control ensures a comfortable indoor climate even at the height of summer. In accordance with the «eco-devis» requirements, ecologically compatible and economically viable building materials are used. In order to achieve the Minergie-P standard, a solar power system is planned.


Heat is generally dissipated via the underfloor heating. In the large rooms, the heat-up process is additionally supported by ventilation. The underfloor heating is also suitable for light cooling of the rooms via a cooling and heating system. Active cooling should be avoided wherever possible. If cooling were necessary, the energy network can provide a limited cooling capacity (freecooling).


In order to allow for short air distribution systems with supply air overflows, the ventilation systems are centrally located. The active supply air overflow units are proposed as mechanical ventilation for the classrooms. The supply air is blown in centrally in the circulation space of the cluster. Small fans draw the fresh air from the access area and supply it to the classrooms. The stale air is extracted in the classrooms and returned to the ventilation centre via an exhaust air system. This significantly reduces the technical effort and the space required for air distribution. The storey heights can also be optimised using this system. In addition, the atrium offers good conditions for natural cross-ventilation. Rooms with special requirements or with large amounts of air are grouped on the south façade and are directly supplied with supply and extract air. The outside air is drawn in via the façade and the exhaust air is blown out via the roof.


Fire protection

For structural fire protection, the building is classified in the medium height class. Escape is ensured via two staircases, with a maximum escape length of 35 metres per storey. The double sports hall with open gallery level and the associated rooms form a common fire section. The unit of usage of the kitchen and canteen as well as the entirety of the upper floors and the atrium also form a separate fire section in each case. The fire brigade access can be realised via a long façade.

› 2020, Architectural competition explanatory report for Bruno Fioretti Marquez.


› In autumn 2020, the architects of Bruno Fioretti Marquez asked me for support in writing the explanatory report for the competition for a secondary school building in Affoltern. In collaboration with the architects and the specialist planners, I wrote a report of around 9,200 characters, structured with classical subtitles. (Translation from German)

© Bruno Fioretti Marquez