Former City Hall continues its life in different forms
Espoo has set an ambitious target: to recycle more than 70% of demolition materials. Many materials recovered from the demolition of the former City Hall, such as concrete and window glass, have found a new life elsewhere. Granite light fittings and concrete guardrails were also recovered. Plans are in place to turn the guardrails into benches for the Lakelanpuisto park.
The City Hall, located in Espoon keskus, was demolished last year. The building had stood empty since 2008.
Espoo is committed to the Green Deal on sustainable demolition, which is a voluntary agreement between the state and municipalities. The main objective of the agreement is to increase the reuse and recycling of demolition materials. The aim is to utilise at least 70% of construction and demolition waste for something other than energy production or fuel.
Concrete was the main material recovered from the demolition of the City Hall. The recovered concrete was reused in earthworks. The window glass recovered from the demolition project was transported to Forssa, where Uusioaines Oy uses it as raw material for foam glass. Foam glass is used in building structures, for example.
Other recovered materials included paving slabs, granite setts, a slab decorated with a ‘technology student’s footprint’, and ten granite light fittings dating from 1971. An idea has been presented to place the elegant granite light fittings in the vicinity of Espoo House, which will be built in Espoon keskus in the near future. The light fittings are in good condition and only need new LED light sources.
Plans are also in place to turn the old concrete guardrails into benches for the nearby Lakelanpuisto park. The benches would provide residents with a place to rest and enjoy the beauty of the surrounding area while honouring the heritage of the City Hall. Planning of the bench project continues in the autumn.
Sustainable demolition keeps materials in circulation – but there are challenges
Espoo aims to reach carbon neutrality by 2030. In the Urban Environment Sector, this means that the impacts on carbon sinks and reservoirs are taken into account in planning and construction. This is one of the reasons why the city favours dense urban construction along good public transport connections. This saves forests that, in turn, absorb carbon dioxide from the atmosphere.
Sustainable construction also includes sustainable demolition in line with the principles of the circular economy. The idea of a circular economy is to minimise waste and reduce the acquisition of new raw materials. Other principles of a circular economy include repairing, renting, recycling and careful planning of the life cycle of materials.
The management of demolition waste is also determined by the Waste Act.
The primary aim is to recycle all the materials generated from demolition projects. Demolition materials can be reused or recycled and reprocessed into new products. Reuse means, for example, using old bricks in a new construction project. An example of recycling and reprocessing is manufacturing new products from recycled plastic. Plastic waste generated from a building demolition project can be recycled and reprocessed into new plastic raw materials.
The Structural Engineering Unit of the Premises Department is in charge of overseeing Espoo’s demolition projects.
Manager of the Structural Engineering Unit Vesa Pyy says that the majority of recovered demolition material is concrete. The concrete is reused, but it must first undergo a treatment process. Rudus, a company based in Lohja, crushes the concrete into aggregate that can be used, for example, in roadbeds. Hypericon Robotics, a company based in Kera, uses recycled concrete for 3D printing of new building materials.
Pyy points out that concrete may sometimes contain harmful chemicals. In this case, the concrete must be decontaminated before it is reused. However, decontamination is not always possible.
“We were planning to use the concrete from the demolition of the Jupperi school building as raw material for stone walls around the yard of the new school. However, the painted surface of the concrete contained a substance that could not be removed.”
It is therefore not possible to reuse all materials due to previously made choices. As part of the circular economy, we should also plan ahead for the reuse of a material, for example by avoiding the use of harmful mixtures.
Continued efforts to improve recycling rates
Demolition projects are usually carried out by contractors. In the future, the Premises Department aims to prioritise contractors based on their recycling rates. This means that contractors must present a pre-demolition audit.
The pre-demolition audit provides information on the harmful chemicals and the materials generated from a demolition or repair construction project and on the reuse and recyclability of the materials. Preparing the pre-demolition audit well ahead of the project will make it easier to reuse and recycle demolition materials and manage the demolition process.
In this way, Espoo encourages its partners to promote circular economy solutions, and the goal in the future is to only work with companies with high recycling rates.
- Urban development