Between innovation and reality
With the H1, the Zwhatt site in Regensdorf has become the tallest timber hybrid high-rise in Switzerland. The project by Boltshauser Architekten represents a paradigm shift in urban residential construction with technical, ecological and social ambivalences.
In the middle of the Zurich conurbation, the new H1 residential tower towers above the Zwhatt site. With a height of 75 meters and 24 storeys, the building is a visible marker for the Regensdorf skyline and for hybrid construction methods between concrete and wood. Despite its striking red hue and eye-catching façade, the interior is dominated by natural and neutral materials. The architecture remains restrained, the structure classic. Three solid base storeys and a central concrete core support the building, while timber columns, timber-concrete composite ribbed ceilings, lightweight façades and solar panels ensure resource efficiency.
The HBV structure allows for a high degree of prefabrication and a significant reduction in gray energy. Compared to conventional solid buildings, 20% of emissions are saved, a total of around 670 tons of CO₂ over a life cycle of 60 years. The horizontally positioned photovoltaic modules serve as a brisesoleil and generate around 155,000 kWh of electricity per year, which covers around 36% of the apartments’ energy requirements.
Quality of living, community and urban density
At the base of the H1, three-sided arcades connect the building to the neighborhood and ensure an urban quality of living. Inside, a clear, modular structure ensures compact, flexible apartments. 156 units are organized around the central core and are reached via short, bundled access routes. There is space for community halfway up the building with a two-storey meeting room, a launderette and spectacular views. The wooden elements create a pleasant indoor climate, while exposed beams and clay surfaces ensure a cozy atmosphere.
Sustainability and the ambivalence of the high-rise principle
H1 is a project of transition. The high proportion of wood reduces the CO₂ profile, but does not make the use of concrete superfluous. The climate-friendly construction method, local raw materials such as beech wood from the Jura or clay and the focus on renewable energy make sustainable construction a reality. Nevertheless, the high-rise building remains an ambivalent concept. The densification saves space, but the statics and fire protection still force hybrid constructions.
In terms of urban planning, the Zwhatt site represents a new development perspective for Regensdorf. The silhouette of H1 and other towers characterizes the skyline. The quarter combines living, working and open spaces and stands for an urban development that remains flexible and adaptable.
The H1 residential tower exemplifies change in the construction industry. It combines advanced timber hybrid technology, a high degree of prefabrication and urban integration. H1 is thus a “building of transition”, a step towards net zero, but also a reflection of the challenges and potentials facing sustainable residential construction in urban centers today.