Future’s green wall composes of recycled materials

In the past summer, a novel vegetated wall was built in Otaniemi, next to Aalto University’s Väre building. What’s exceptional, almost all of the materials used for this green wall are recycled. The structure, called Circular Green Wall, is a result of multidisciplinary collaboration aiming to develop urban greenery into a circular direction. The project was ran by InnoGreen, Kekkilä-BVB and Spolia design as a part of Espoo’s Sustainable Future Districts programme.

‘Flourishing and diverse vegetation is a crucial factor improving cities’ resilience, but it should be implemented within the planetary boundaries,’ says Mikko Sonninen, the head of InnoGreen’s research and development. Diverse urban nature supports the wellbeing of citizens and the environment by, for instance, mitigating urban heat island effect and other negative causes of climate change. On the other hand, building new green areas or producing urban green furniture tends to generate greenhouse gas emissions and increase use of natural resources. In the Circular Green Wall project, the partners decided to find solutions to this challenge by inventing a green wall where all the possible materials are both recycled and recyclable.

‘The project succeeded well. In the end, the only components that we had to buy as new were the pipes used for irrigation, and biochar for the soil. However, both of these components can be reused when they won’t be needed in this structure anymore,’ Sonninen tells. The modular building blocks of the structure are made of facade panels that were rescued from deconstructed buildings, and the supporting structure is recycled wood. The growing composite is a mixture of soil from Otaniemi’s construction site fertilized with Espoo’s city garden’s compost and biochar. ‘We wanted this green wall to give a new life to the materials and soil composite that doesn’t otherwise have a direct use,’ Sonninen fills in.

The green wall was designed to be both material efficient and adaptable. It ended up being a modular structure, which can easily be implemented in tightly built urban spaces, reused in different locations, and survives from the Nordic winter. ‘In the future, it would be exciting to test the Circular Green wall with different plant selection, rather challenging locations, or maybe on a bigger scale. Combining the plant modules with benches or planting boxes might also open new, communal aspects to the structure,’ Sonninen innovates.

The Circular Green Wall project was executed in 2025, as a part of Espoo’s Sustainable Future Districts programme, co-funded by the European Union. Its goals were to accelerate the neighborhoods’ sustainable development, offer opportunities to pilot sustainable solutions, and to shed light on novel circular products and services. The programme includes green structures for urban spaces and services improving nature literacy, to mention a few.