Program and context
The site is located in district six in the city of Zurich, originally a residential neighborhood with large gardens.
The project was an apartment building with three rental apartments, one apartment on the ground floor with a garden, an apartment in the middle, due to the slope, with a garden, too, and on the top floor, a duplex penthouse. The clients wanted the living rooms to be outside with maximum views and optimal exposure to receive light while keeping utmost privacy in the dense context of the city. Therefore, the goal was to achieve spaces you normally only get in private houses, not in an apartment building.
Another topic we follow is to leave the context of the house in the architectural connotation, not the façade, as separation between inside and outside, so the tempered space generates the volumetric face of the building. A figure independent from the heated space generates presence and power.
Architectural concept
In this project, the architectural concept eventually led to the figure of a stone H.
The letter H under the bridge has a covered outdoor space and over the bridge, a patio. We put yet another stone, the attic, which makes this patio turn into an outer space above the H. Thus, the living spaces are considered outdoor rooms because they are outside the mass of the H.
The H is a well-known letter on the top of which we have put a stone. This produces less a volume of a house rather than two stone elements, two masses almost without glass. In cold weather, the outdoor spaces, which are the living rooms, can be closed with large sliding windows so that they become inside spaces.
This figure is inhabited below and above it, a shaped mass that develops an original force and almost a ruin equal, and evades the dictates of civilized, ‘conformist’ concepts of home, from exterior and interior. It is the desire for freedom and renewal that let us bring well-proven elements of architecture in new contexts. It creates powerful habitats without additional cost.
Mass and light, program-free and periphery
The stone H has a two-shell concrete structure. The outer shell of the H is casted with oriented strand board (OSB), which generates a rough, almost organic surface. On the inside of the H, the surface is smooth concrete. The different casted surfaces enhance the feeling that the living room is actually an outer space.
In the concrete, recessed light fixtures provide indirect light, enhancing the impression of mass communication in space, components becoming alive with light.
In our understanding of program-free architecture, all programs are hidden in the periphery and can be deployed into the room as needed. The leitmotif of the mass is articulated by the sculpture of the H and even the interior walls, as they appear 1.5-foot-thick. These massive stone elements generate a strong force and attraction.
On the contrary, normal dividing walls between six and eight inches only suggest separation. We formed these masses into a communicating topography, with programs like kitchen and concrete benches in the periphery to interact with the space.
Construction and cost effectiveness
Contrary to popular belief, a twin-shell concrete structure is not the most economically expensive system and, therefore, also not luxury. We have calculated that it amounts to the same cost as a standard façade, because the shell, once completed by the builder, is finished and no additional work is needed.