Stone H / Gus Wüstemann Architects

Architects: Gus Wüstemann Architects
Year: 2014
Photography: Bruno Helbling, homegate
Design Team: Jan Kubasiewicz, Marta Balsera Goni, Eftychia Papathanasiou, Silvia Pujalte
Engineering: Born Partner AG
Builder: Corti AG
City: Zurich
Country: Switzerland

Stone H, an apartment building in Zurich designed by Gus Wüstemann Architects, features a unique architectural concept that emphasizes outdoor living spaces. The structure, inspired by the letter H, uses a twin-shell concrete system to create a powerful presence and allows the living areas to function as both indoor and outdoor spaces. The design challenges conventional notions of home by integrating mass and light while maintaining cost-effectiveness.

The project site is situated in District 6 of Zurich, originally a residential area with large gardens. The development involved constructing an apartment building with three rental units: a ground-floor apartment with a garden, a middle-floor apartment, also with a garden due to the sloped terrain, and a duplex penthouse on the top floor. The architects aimed to create living spaces that function as outdoor rooms with maximum views and optimal light exposure, while maintaining privacy within the dense urban context. The goal was to provide spaces typically found in private houses, within an apartment building. Another design principle was to move beyond the conventional architectural context of a house, where the facade acts as a boundary between inside and outside. Instead, an independent form from the heated interior space was created to establish presence and strength.

In this project, the architectural concept resulted in the creation of a “Stone H” figure. The H shape includes a covered outdoor space beneath its bridge and a patio above it. A stone structure was added on top of the H, turning the patio into an external space above the H. As a result, the living spaces are treated as outdoor rooms, positioned outside the mass of the H. The familiar H shape, combined with an additional stone element on top, creates a design that is less about forming a conventional house volume and more about two stone masses with minimal glass. During colder weather, the outdoor spaces, which serve as living rooms, can be enclosed with large sliding windows, transforming them into interior spaces. This form, inhabited above and below, generates a unique strength, akin to a ruin, challenging the conventional, conformist concept of home, both inside and out. The design reflects a desire for freedom and innovation, bringing well-established architectural elements into new contexts and creating powerful living spaces without added cost.

The Stone H employs a twin-shell concrete structure, with the outer shell cast using OSB, giving it rough, almost organic texture. inside the H, the surface is smooth concrete. The contrasting texture enhance the perception that the living room is, in fact, an outdoor space. Recessed light fixtures in the concrete provide indirect lighting, making the mass feel alive as light interacts with the space. In line with the architects’ approach to program-free architecture, all functional elements are concealed in the periphery and can be deployed as needed. The theme of mass is emphasized by the sculptural from of the H, with interior walls appearing 0.5 meters thick, reinforcing the sense of strong, attractive stone elements.

These masses were shaped to create a communicating topography, with peripheral features like kitchens and concrete benches designed to interact with the space. Despite common perceptions, the twin-shell concrete structure is not the most expensive construction system and does not constitute a luxury. The architects calculated that it costs the same as a standard facade, as the shell, once completed, requires no additional finishing work.