Author: Jakob Fischer
The crane-assisted, element-oriented dismantling of buildings is far more than just the controlled demolition of structures; it also involves planning new buildings using the dismantled and recovered concrete elements. Particularly in the context of the ReCreate project, it becomes clear that well-planned dismantling processes are a key prerequisite for the reuse of building components. The manner in which a building is dismantled plays a decisive role in determining whether materials are merely recycled or can actually be preserved as building components and reused. This requires precisely coordinated collaboration between all parties involved: the client, planners, demolition contractors, authorities and recycling companies.
The client (building owner) plays a key role in this, bearing overall responsibility for the demolition project. Their decisions in the early project phase directly influence whether the reuse of building components is even possible. Comprehensive information on the building must therefore be compiled as early as the preliminary planning stage, including existing documentation, details of the building’s history of use, and information on the materials and structures used. This data is essential for identifying potential for selective dismantling and component recovery. In the deconstruction projects of the ReCreate project, this has worked smoothly thanks to early consultations. New insights have also been gained, which have already been documented in detail and published.
Furthermore, the client is responsible for commissioning suitable specialist planners who possess the necessary expertise to view demolition not merely as a demolition process, but as a recovery process. In the case of the pilot project in Hohenmölsen, for example, the law firm Dageförde was consulted to ensure legal certainty during the tendering process and subsequent contract award. For most local authorities and private clients, this type of demolition and reuse of building components remains a novelty. Despite this delegation, responsibility remains with the client. Likewise, they must ensure that a waste management plan is drawn up which not only regulates the treatment of waste but, ideally, also takes into account the separation and potential reuse of materials. In parallel, they bear responsibility for health and safety measures, the organisation of the construction site, and compliance with legal requirements, including permits and notification procedures.
Planners play a central role in translating these objectives into concrete technical concepts. Whilst in most demolition and reuse projects already implemented in Germany, an external scientific body – such as the Structural Recycling Research Group led by Prof. Angelika Mettke – has taken on these tasks, it is necessary for the stakeholders to assume the pre-planning tasks and coordination independently. Based on the inventory, planners develop a demolition plan that not only ensures safe dismantling but also creates the conditions for the highest possible quality reuse of the resulting materials. In this context, the detailed recording of building components, building materials and potential pollutants is of particular importance, as these factors significantly determine the possibilities for recycling and reuse.
A crucial aspect is determining the sequence of demolition and the degree of material separation. Whilst conventional demolition processes are often optimised for efficiency and speed, reuse requires a more nuanced approach. Building components must be removed as undamaged as possible, which in turn places specific demands on planning, logistics and scheduling. In addition, structural analyses for intermediate stages are required, particularly when load-bearing elements are selectively removed.
Practical implementation lies with the demolition contractor, who plays a central role in determining the quality of the material streams. Through the selection of suitable methods and careful organisation of the site, it determines whether materials can be cleanly separated and components recovered intact. Particularly with regard to reuse, dismantling must be as selective as possible, ensuring that materials are not mixed but specifically separated. This applies both to the separation of mineral and non-mineral materials and to differentiation within individual material groups.
At the same time, the demolition contractor is responsible for compliance with comprehensive occupational health and safety requirements. These include risk assessments, safety plans and the training of employees. Coordinating all parties involved during the execution of the work is just as much a part of their remit as ensuring that the work is carried out in accordance with the plans and applicable regulations. Against the backdrop of rising demands for quality and resource efficiency, the selection of qualified and specialised companies is becoming increasingly important. Both ReCreate’s industrial partners, who are already familiar with deconstruction projects, such as Ecosoil, and traditional demolition contractors who have acquired new skills and capabilities during the project’s duration, are well prepared for the future of circular construction.
The authorities play a dual role. On the one hand, they act as clients, particularly in public construction projects, and are thereby bound by public procurement regulations. On the other hand, they monitor compliance with legal requirements. In the spirit of the circular economy, they also have a role to play as role models. This involves, in particular, promoting measures that prevent waste, separate material streams and enable high-quality recovery or reuse.
Finally, the recycling contractor is responsible for processing the remaining material streams. Even though, ideally, as many components as possible are reused directly, a significant proportion of materials remains that must be recycled. A prerequisite for high-quality processing is the separation of materials by type as thoroughly as possible, already on the construction site. The quality of the recycled products depends largely on the level of contamination and the purity of the raw materials. Dilution of pollutants through mixing is not permitted, making careful separation all the more important.
In the context of ReCreate, it becomes clear that demolition cannot be viewed in isolation but is an integral part of a circular construction process. The reuse of building components does not begin with new construction, but already during the selective demolition of existing buildings. Only if all stakeholders fulfil their respective roles and align them with this objective can the full potential of reuse be realised.
In the following blog posts, some of the stakeholders from the German Cluster mentioned above will be interviewed about the challenges and opportunities that the pilot project participants see in this ‘new way’ of building.
