Between Oberwil and Bottmingen, the area is located on the slope between Binningerstrasse and Kerngartenweg. The historic field name “Stallen”, which can also be found in the adjacent street names, means “slope” and aptly describes the topographical character of the site. Used as an agricultural area and popular toboggan slope since time immemorial, this place is deeply anchored in the collective memory of the municipality of Oberwil.
The immediate vicinity of the area is characterised by a heterogeneous settlement structure, in which small-scale single-family and multi-family houses stand next to allotments and medium-sized residential developments, surrounded by private gardens and spaced greenery. The buildings show differently successful approaches in dealing with the striking hillside location. A closer look reveals randomly created spatial qualities, niches and atmospheric peculiarities that give the place its subtle character. This diversity is also an expression of the fragmented structure of the area, in which different scales and building typologies create specific places, but also create diffuse transitions between the settlement areas.
Against this background, the central question arises: How can we succeed in creating a contemporary settlement building block that fits harmoniously into this heterogeneous townscape and at the same time provides forward-looking answers to the challenges of sustainability, social mix and quality of life?

Urban Placement
The urban planning response to the heterogeneous environment of private gardens and spaced greenery is achieved by two elongated, multi-angled buildings that stagger along the edge of the slope and follow the topography. Between the buildings, a spacious green space with differentiated degrees of publicity is created. The staggering and angular nature of the volumes create a variety of niches and spatial situations, while the structures are never perceived as a whole. In this way, the project fits into the scale of the site and at the same time efficiently reflects the required density.

Open Space
If you enter the area from Kerngartenweg, you are greeted by the open Piazzetta, which gives the business located there the opportunity to have an outward effect. Green and unpaved inlays with large, heat-resistant trees regulate the climate on the square and form a filter to the adjacent apartments.

Typology
The two multi-angled buildings that enclose the hill and follow its topography are accessed from entrances on the valley side and each have two stair cores that serve up to five apartments per floor via a split-level system. This organisation enables efficient development and creates a diverse range of housing.

The ground floor apartments are an essential part of the project, as they additionally enrich the housing supply through the specific handling of the topography and the adjacent outdoor spaces. The hillside location allows for a variety of living situations that go beyond the usual typology. Some of the ground-floor apartments have extra-high living spaces that create a special spatial generosity, while additional informal accesses or direct connections to the adjacent open spaces expand the possibilities of use.

Structure
The two residential buildings on Kerngartenweg will have a wood-concrete hybrid structure that makes optimal use of both materials and combines ecological and economic criteria.

The timber frame construction consisting of columns and beams connects to a core zone of in-situ concrete, with the beams spanning from the façade level to the concrete zone. The ceiling panels themselves are formed with prefabricated board stacked ceilings that span between the beams and parallel to the façade. The supporting structure concept allows for many years of flexible use, dismantling by type is possible and the materials used can be easily returned to the material cycle.

SNBS site and plus-energy quarter on the basis of Minergie-A-ECO form the basis for the Sustainability concept.