H1 HIGH-RISE RESIDENTIAL BUILDING, ZWHATT AREA, REGENSDORF, 2019-2025

Trass lime rammed earth, version

Venue: H1, Zwhatt Areal, Althardstrasse 60, 8105 Regensdorf
Built: 2024-2025
Material: Prefabricated rammed earth elements stabilized with trass lime
Partners: Boltshauser Architekten AG, Pensimo Investment Foundation, SEFORB, Schnetzer Puskas Ingenieure AG, Keller Unternehmungen
Photos: LEHMAG, Sandro Livio Straube, Cynthia Ruf

As part of the Zwhatt site in Regensdorf, a high-rise residential building with a hybrid load-bearing structure has been under construction since 2019. The H1 project, designed by BOLTSHAUSER ARCHITEKTEN and developed on behalf of the PENSIMO investment foundation, combines timber, concrete and clay construction in a latest-generation high-rise building. SEFORB and SCHNETZER PUSKAS INGENIEURE are responsible for the structural design of the façade.

The entire building is constructed as a timber-concrete hybrid: The access core, ceilings and base floors are made of concrete, while the façade elements, beams and columns are made of timber.

The solid, monolithic-looking plinth area also characterizes the architectural appearance of the building. The lower three storeys are encased in a self-supporting façade made of trass limestone rammed earth. These façade elements were prefabricated in collaboration with LEHMAG and KELLER UNTERNEHMUNGEN in Pfungen and delivered to the construction site. The elements were precisely positioned on site in collaboration with CPS Schneider GmbH, after which all joints were carefully retouched.

Although the façade is largely protected by the building components above it, it remains exposed to the weather. To increase its resistance, the rammed earth was therefore minimally stabilized with trass lime. To achieve the specific reddish color of the elements, pigments were added to the excavated earth to match the color scheme of the entire building.