Typology of the slope

B9 in Küsnacht engages with an archetypal condition of building on asteep hillside: a small, sharply inclined plot along a major traffic axis withviews of the lake yet exposed to a high degree of neighbouring density. Thearchitecture does not respond with an iconic gesture, but with a precisereconfiguration of the relationship between topography, circulation anddwelling, aiming to turn the slope itself into the project’s defining typology.

In this context, Bergstrasse functions as an infrastructural seambetween the village centre and Forch, marking a threshold between thehorizontal logic of traffic and the vertical logic of the terrain. B9 positionsitself precisely within this field of tension and understands the steep sitenot as a formal constraint, but as a structural guiding figure: the inclinationof the slope determines orientation, vertical stratification, access andultimately the internal organisation of the four residential units.

Terraced units as an alternative tothe conventional multi-family house

Conceptually, B9 proposes an alternative typology to the establishedimage of the luxurious multi-family house on Lake Zurich. Instead of a centralstaircase that links all floors in a serial fashion, the four units are eachdirectly connected via the basement level and the terrain, behaving in theirspatial figure more like staggered single-family houses.

This shift from horizontal to vertical neighbourhood produces adifferent notion of exclusivity: not the number of rooms or the size ofterraces takes precedence, but the individual relationship of each apartment tothe slope and to the horizon of the lake. The two garden-level residencestransform the basement – traditionally a secondary, technical domain – into adifferentiated living level with stepped room heights (approximately 2.40 m,2.90 m and 3.35 m), double-height zones and daylight from above, therebygenerating an autonomous, vertically layered living landscape.

The levels above – ground floor and upper floor – continue this logicwithout simply being stacked on top. Rather, a spatial stratification emergesin which each unit develops its own degree of openness, retreat and visualconnection, while the overall figure remains legible as a coherent volume.

The two lateral incisions are more than formal gestures: they articulatean architectural response to the question of how light, depth and views can becreated for spaces situated in the “second row”. By cutting cones of light andvisual axes deep into the volume, they produce a sequence ofinside–outside–inside, in which living space, terrace, incision and landscapecondense into a continuous spatial chain.

This spatial dramaturgy makes the slope tangible as a succession ofthresholds: from the protected realm of the basement, across semi-publicterraces, to the open view towards the lake. The incisions operate on threelevels simultaneously: as instruments of illumination, as optical filters andas social regulators that calibrate proximity and distance within the verticalneighbourhood.

Green terracotta as a layer of memory

The decision to use a green glazed terracotta façade is conceived as adeliberate layer of memory. In the early planning phase, the plot was wrappedin dense tree vegetation that largely veiled the view of the lake and initiallyrendered the site as an introverted terrain enclosed by greenery.

With the clearing of the view, the perceptual focus shifts from the nearto the far, and the physical presence of the trees is lost in the process. Theceramic envelope translates this earlier condition into an abstract, pigmentedskin that acts like a sedimented recollection – a surface that does not imitatethe felled trees but preserves them as chromatic and material resonance withinthe project.

Through the reflection of light and the changing depth of colour overthe course of the day, a subtle dialogue unfolds between façade, vegetation andlake. In this way, B9 becomes a house that responds not only to its immediatesurroundings, but also to the site’s past – an architecture that understandscontext not only in topographical, but also in temporal terms.