On the Kochareal at Flurstrasse 72 in Zurich, work in May 2026 was not only taking place on the ground. Around 90 meters further up, the foundation for a green roof area with added value for biodiversity was created on the high-rise rooftop.
For AEZ AG Bedachungen und Spenglerei, our greening specialists were at work on the roof. Their task: bring substrate, gravel, deadwood, sand, and other elements to where a vibrant roof area is later to be created. Sounds simple, but at this height it is not. Material logistics, crane, storage space, access, and construction site processes had to work together seamlessly.
Green roof Kochareal with substrate, gravel and hydroseeding
With the Kochareal green roof, it was about more than just a green surface layer. Various areas came together on the roof surface: substrate areas, gravel strips, graveled flat roof areas, hydroseeding, and biodiversity elements.
Our work included substrate blowing, blowing of the gravel strips, gravelling of the flat roof, hydroseeding, as well as the delivery and distribution of deadwood. A sand island with a boulder border was also implemented.
A total of 561 m² of substrate was applied. This was supplemented by 578 m² of hydroseeding, 230 m of gravel strips, and 49 m of gravel strips between the PV substructure. The installation was complemented by smaller areas and various biodiversity elements.
At the time of the work, the PV system had only been laid as a substructure. The panels were not yet mounted. As a result, the gravel strips had to be neatly installed between the existing substructures. Exactly these connection areas demand attention because later sealing, greening, technology, and usage must be coordinated with one another.
Working with good preparation
An operation at a height of around 90 meters begins long before the first substrate is placed on the roof surface. Access must be functional, the staging area must be ready, the crane must be available, and the material must be delivered in the correct order.
This preparation was particularly important on the Kochareal site. Substrate, gravel, deadwood, and sand cannot simply be moved around at will on a high-rise roof. Every step of the work builds on the previous one. What is prepared below must be ready to be processed above at the right time.
The advantage of this method becomes particularly clear when blowing substrate. The material gets directly to where it is needed. Long transport routes across the building are avoided and the area can be structured efficiently. This is a major advantage, especially in a high-rise building.
The hydroseeding was also tailored to the roof surface. In this process, the seed is mixed with water and distributed evenly. This creates the basis for the subsequent vegetation.
Small elements with a big impact
Besides substrate and gravel, the biodiversity elements were also an important part of the work. Deadwood, sand islands, and boulder frames bring structure to the roof surface. They create different areas that can later benefit plants and insects.
Such elements might seem small at first glance, but they are important for the later development of a green roof. This means an area is not simply planted with greenery, but is given different materials, heights, and structures. It is precisely this that creates a roof structure that can do more than just look good.
Green roofs on the Kochareal as part of a new urban quarter
The Kochareal in Zurich is developing into a new piece of the city. Living and living space is being created on the building plot at Flurstrasse 72, and the roofs are also contributing to this. The Kochareal green roof project shows how new buildings and urban nature can come together.
This deployment was special for our team. Working at such a height, with this material, and in this environment is not part of everyday life. It is all the more rewarding when individual work steps come together to create a structure that will later be visibly and tangibly beneficial to the neighborhood.
A heartfelt thank you to TU: HRS Real Estate AG and AEZ AG Roofing and Sheet Metal Work and HRS Real Estate the trust in our cooperation.
