borrweg school zürich

competition . 2019

ZURICH . Switzerland

the design of the new borrweg school at zurich's uetliberg forms a centre on all side open to the homogeneous, fine-grained friesenberg neighbourhood. clearly visible from the schweighof street, the large, compact volume sets itself back with due respect for the existing school complex and the small-scale residential buildings. with its permeable nature, it clarifies the surrounding by creating versatile, generous outdoor spaces. despite its solitary character, it combines with the filigree complex from the 1930s to an overall figure.

organization and form

the building is articulated into three main parts, both architecturally and functionally; the base, which continues the existing terracing of the hill slope, accommodates the sports and service facilities, the raised volume, which provides a protected space for classes open to all sides, and the ground-level joint, which gathers all semi-public functions around a “village square” with the library in its centre.

the free form of the inner courtyard separates the individual schooling clusters, creating privacy without isolation. open visual references support orientation. spaces created between the courtyard and the classrooms give the day students an additional, relaxing space to rest, play and socialise when weather hinders staying outdoor. the classrooms have a modular structure and allow a high degree of flexibility for future usage adjustments.

traffic and network

the site is both a school yard and an urban park between the green veins along the two streams. existing and new foot and cycle paths cross the entire premises, link it with the neighbourhood and ensure necessary security. the new school court pavilion also serves as a meeting place for the residents of the neighbourhood outside school hours.

motor vehicle parking is combined with material delivery and is set apart from other zones to avoid traffic flow overlap. cars should only be allowed access to the extension of the georg-baumberger path in emergencies. views of the city’s surrounding hills and the church towers are largely retained.

landscape

surroundings become landscape and landscape becomes a place for playing, learning and ecological compensation. the existing topography is changed as little as possible, the old stock of trees is largely preserved and supplemented with native species of deciduous trees. living spaces are created through the sensitive and conscious use of green spaces, biodiversity is increased and the microclimate is improved through shading.

hard pavement areas are kept to a minimum. these only appear as an asphalt surface in the delivery area and as a sports surface on the fenced hard court. finely paved surfaces made of alpine limestone accompany pedestrians to the two entrances and the various places in the park. the rainwater is naturally cleansed, evaporated and seeped away on the premises via drainage depressions, permeable surfaces, the green roof and three wet land areas. the evaporation also has a positive effect on the microclimate. the main roof areas are green and thus store the rainwater. in addition, the solar panels on the roof surfaces are cooled by evaporation what impacts their capacity positively. natural, local materials are used in the outdoor areas. all plant species are native and ensure biodiversity for a rich small animal fauna.

eNERGY AND CLIMATE

generous thermal insulation, extensive green roof areas, passive and active solar gain, a minimal mechanical ventilation with heat recovery and access areas as buffer zones lead to low energy consumption. the automatically controlled ventilation flaps in the façade ensure optimum cross-ventilation and night-time cooling in the summer on the school floors and the sports hall. a copper grill prevents rainwater from entering the ventilation openings and ensure burglary protection. the ground floor is ventilated during the day on demand. a geothermal heat pump compensates for the heat deficit.

Materiality

ISheet copper elements together with window frames and ventilation boxes made of oiled oak form a durable façade composition that is harmoniously integrated into the park landscape. The base made of coloured, bush-hammered in-situ concrete connects the building with its raw design with the terrain and the existing school complex from the 1930s. The light, warm colors, the polished terrazzo covering, the acoustic wall plaster and the glazed exposed concrete ceiling create a fresh, friendly atmosphere throughout the interior. Subtly colored acoustic ceiling elements in the rooms with high occupancy keep the background noise at a pleasant level.