A pioneering new neighborhood, the Koch Quarter, is currently taking shape across four building plots in a former industrial area of Zürich. Alongside a park, the development will feature not-for-profit housing and a range of commercial and business units. The Kraftwerk1 Housing Cooperative’s newbuild sits on the 111 m x 34 m plot C at the south-eastern corner of the site, parallel to Flüelastrasse, and creates a direct link to the neighborhood park.

Standing 29 meters high, the block is divided – both structurally and functionally – into two distinct parts. The ground, first and second floors take the form of a solid reinforced concrete plinth and accommodate a wide variety of uses ranging from a circus company via a kindergarten and childcare provision, cafes and restaurants and business space to shell units for residential and workshop use. In the center of the building, a spectacular three-turn cycle ramp leads down to the basement, which houses sufficient cycle parking space for all residents: this is a car-free development.

Built atop this solid base is a six-story hybrid timber-concrete skeleton-frame structure. With the exception of the areas surrounding the stair cores, the floors are prefabricated composite timber-concrete slabs, mounted on I-beams, with a span width of 6.1 meters. The cast-in-situ concrete above the beams creates a composite section that also serves to join the floor elements in one continuous slab system, to form a single floor diaphragm and to make the connection to the solid cores.

The beams and columns are made of beech LVL, a high-strength material that permits the building’s slim design. The six upper floors contain a varied mix of affordable apartments for younger and elderly residents. The rectangular footprint of these upper stories features three interior courtyards that rise to the top floor where they come together in a single, large courtyard space. Intensively greened, the roof itself provides a refuge for residents. It also plays a role in rainwater retention, contributing to the creation of a positive building and city climate.

The building’s foundations comprise around 150 large-diameter bored piles, each extending to a depth of approx. 30 meters. Their purpose is twofold: to transfer vertical loads down into the ground and to provide a fixed support for the four stair cores, thereby transferring horizontal loads to the ground. A full-surface soakaway layer beneath the base slab and along the external walls of the basement will also help to ensure unrestricted ground water circulation.