Living in a hexagon

Baden-Baden, in April 24 – Screen façades with a honeycomb structure are a familiar feature in architecture. With the ‘honeycomb house’ in Munich's Riem district, however, the architectural practise Peter Haimerl Architektur is extending the concept to the inside of the building. The architect has shifted the hexagonal structure inwards and adopted it as the construction principle: intersecting hexagonal tubes stacked in a large cluster to form a kind of beehive. The reliable connection of the precast balconies to the honeycombs is ensured by the Schöck Isokorb load-bearing thermal insulation element. It also separates the structural components thermally and minimises thermal bridges. It is therefore indispensable in constructing the building to the passive house standard.

For the construction site in Munich's Den-Haag-Straße the principal, Wogeno München eG, had set itself the goal of making a special contribution to urban planning and architecture: The creation of an experimental residential building at this location that would contrast with the existing uniform building typology in the neighbourhood. The modern, provocative design by award-winning architect Peter Haimerl interprets this in an unusual way and radically breaks with the cuboid, standardised building structure - the ‘box structure’, as he calls it: “We consciously chose to design a range of different living and spatial configurations. The hexagonal structure that is widely found in nature allows for a large variety of possible combinations of room units, clusters and interconnected spaces”.

Honeycomb structure satisfies new residential needs

The honeycomb as a symbol of communal living lends itself to revitalising and interweaving residential landscapes. “Times have changed, and with them our way of living. It's no longer just about putting up bookshelves, but about creating atmospheric living spaces that work well,” says Haimerl. The use of the space in the honeycomb house is therefore innovative and fluid: each room extends into another, walls disappear or become connecting staircases and pockets of space. There are no vertical walls or conventional staircases in the honeycomb house – as standard, each honeycomb forms an apartment. There are also larger apartments that extend over two floors. These house smaller residential units and a large, shared apartment. A shop is planned on the ground floor for the building community and the neighbourhood, which will be run and used by the residents.

Split-level construction with a difference

“The hexagonal form results in a split-level construction with several levels offset from one another at half-floor height. Due to the hexagonal form, the staggered half-floors are separated by sloping and not vertical walls,” explains Thomas Beck, project manager and managing director of the planning office a.k.a. ingenieure Beck Hintermann v. Kameke PartGmbB in Munich. The honeycombs consist of horizontal in-situ concrete slabs and inclined hybrid precast elements. There are practically no limits to the variety and variability. The honeycomb house was built using conventional solid construction methods. Only the connection of the balconies on the west and east side of each honeycomb cell, required a special construction solution.

 Schöck Isokorb – the right solution for every challenge

The precast balconies are 3 metres wide and 1.50 metres deep. “In order to anchor them to the honeycomb structure, we had to design them with ‘legs’,” explains Thomas Beck. These extend downwards to the right and left, over a depth of 1.50 metres and a length of 2.70 metres. However, this reduced the normal joint length and increased the total weight of the balcony – with far-reaching consequences for the balcony connection, as Thomas Beck reports: “The classic Isokorb that we otherwise always use in our projects was therefore not sufficient to transfer the forces.” Various ideas of constructing the balconies in steel instead of concrete, for example, were rejected for both economic and aesthetic reasons.
The structural engineers finally found the solution by using the Schöck Isokorb XT Type Q-P load-bearing thermal insulation element in combination with Isokorb XT Type H. Isokorb XT Type Q-P absorbs positive shear forces with point support, while Isokorb XT Type H is designed to absorb horizontal forces parallel and perpendicular to the insulation plane. Type H may only be used in conjunction with other Isokorb types that transfer moments or shear forces. Some 200 Isokorb units in total were used to connect the 22 balconies and canopies.

Insulation to passive house standard

In addition to the structurally secure connection of the balconies, Schöck Isokorb also acts as a load-bearing thermal insulation element to ensure thermal separation of the structural components in the honeycomb house. This minimises thermal bridges and the resulting increased heat losses and structural damage caused by damp walls and mould. Together with the conventional insulation, Schöck Isokorb thus makes an indispensable contribution to energy efficiency and to achieving the passive house standard for the building.

Honeycomb house ‘Mama’ as a pilot project

Even though the honeycomb house in Den-Haag-Straße in Munich already stands out due to its unusual architecture – the conventional solid construction method was planned “only” as a pilot project from the outset and therefore bears the name ‘Mama’. Series production is being planned. And that gives joy and hope to all those who want to get out of the box and into the honeycomb because all the apartments in the ‘Mama’ pilot house have already been reserved.

Project information

Location: Den-Haag-Straße, Munich – Riem South
Construction period: 2021-2023
Principal: Wogeno eG München
Architecture: Peter Haimerl Architektur, Munich (all construction phases)
Structural engineering: a.k.a. ingenieure - Beck Hintermann v. Kameke PartGmbB München
Precast plant: Sager Fertigteile GmbH, Bodenkirchen, Germany
Construction firm: Baugesellschaft Rank GmbH, Munich, Germany
Products: Schöck Isokorb XT Type Q-P, Schöck Isokorb XT Type H