Making circular building the standard

Circular building is on everyone’s lips, but the built reality still speaks a different language. Our publication “Zirkuläres Bauen in der Praxis” sheds light on why this is the case. We discussed challenges and opportunities with 17 experts from the (construction) industry and formulated specific recommendations for action on how to make circular building become the standard.

Since our practice was founded in the 1950s, we have been involved in building redevelopment and thus have extensive expertise in this area. Continuing to use existing buildings is no longer an isolated concept. It is part of a discipline that is becoming increasingly important: circular building. With circular building, a discipline is emerging in the (construction) industry that is not new in its principles. It is, however, one that is taking on a completely new momentum in the face of climate change. Although this discipline begins with the continued use of the existing building, it is much more than that: Circular building applies to new buildings, conversions and extensions. In recent years, we have implemented an increasing number of projects that cover all aspects of circular building in addition to building redevelopment. The spectrum ranges from the development of master plans for new urban districts, the modernisation of sports facilities and the conversion of industrial buildings to new residential construction projects and working environments.
We are convinced that projects of this kind can only be pursued through a cross-scale and interdisciplinary approach. We therefore see ourselves as a planning practice for architecture, urban planning and processes. For us, it is not just about the practical implementation of projects, but also about generating knowledge at a meta-level and communicating it both internally and externally. One of the fruits of our internal research department is the publication “Zirkuläres Bauen in der Praxis. Ein Status Quo[CS1] ”. We wrote it together with sustainability expert Marcus Herget on behalf of the Stuttgart Region Economic Development Corporation. It draws on our own practical experience of circular building projects and the experiences of other industry players to formulate a status quo of where circular building currently stands within the (construction) industry.

The status quo

The result we arrive at in our publications is as simple as it is complex: Circular building has developed considerable momentum in recent years. An increasing number of pioneers are committed to it, as planners, but also at the economic level. What is needed, however, to make circular building the standard and to drive the turnaround at all levels of the (construction) industry is, above all, binding political action that recognises this turnaround as necessary for a sustainable future. The course has already been set, for instance through the EU taxonomy for sustainable activities. In the context of the Paris Agreement on climate change, the European Commission developed the taxonomy as a tool for the uniform categorisation of economic activities in terms of their sustainability. Further steps are now needed at all levels of the (construction) industry to implement the criteria and requirements the taxonomy entails. Our proposed steps are summarised in the following theses, which we formulated as a result of the publication. They are designed to be read as instructions and recommendations for action, so that getting started is a quick process.

The 9 theses: Making circular building the standard

The design of building projects must be adapted so that as little waste as possible is produced during production, operation, conversion or dismantling. Once resources have been extracted, they should be kept in circulation for as long as possible, for example when using resource-saving concrete or wood.

In view of the enormous building stock and the gray energy tied up in it, the most effective and fastest-acting measure on the way to climate neutrality seems to be to find a way of dealing with existing buildings. Generally, the more of the building stock is preserved, the lower the CO2 emissions.

Without data on what has been installed in a building, it is difficult to assess and manage demolition. It is therefore essential to prepare documentation for all buildings. The building resource passport is an important tool in this process. It serves as the basis of information for the entire life cycle and provides details about the materials used, CO2 emissions and suitability for recycling. By documenting the materials and components used, their financial value can be determined. Another important tool is Building Information Modeling (BIM). Building materials can be digitally documented and the information made available to all parties involved in the construction process, right from the early planning stages.

There is currently hardly any local infrastructure to close material and substance flows. This requires comprehensive, structural offers, such as intelligent transport solutions, local processing and storage sites, networking between the companies involved and platforms that link supply and demand. The local infrastructure conserves resources and saves transportation routes and thus CO2
-emissions are saved. A positive side effect: the local economy is strengthened.

In many respects, both standardisation and legislation have been geared towards new buildings. The reuse of materials and components requires a different set of guidelines. It is therefore essential that the existing standards and laws are updated to cover used materials and components.

With the taxonomy for sustainable activities, the EU has created an instrument to assess the sustainability of a company’s economic activities. What has been in short supply so far are funding programmes for circular building. Funding programmes that promote research and implementation are therefore also needed to meet the criteria formulated at EU level, such as the transition to a circular economy.

Circular building also implies circular design. In principle, all building projects must be designed for dismantling. While the process remains the same whether new materials and components are used or not, the process changes when recycled materials and components are used, as does the design. Depending on availability, the design is repeatedly adapted during the course of the project. The further use of the existing building is preceded by an analysis to determine which parts of the existing building can be preserved and how. New tasks are emerging as regards cooperation, which are being taken on by an additional discipline (e.g. component hunter). In addition, co-operation with planning partners is becoming increasingly important.

As a rule, recycled components do not come with a warranty when reinstalled. Their continued use therefore depends on whether the building owners are prepared to waive a warranty. However, this is not a solution that can be applied to all components. One possibility would be a warranty that covers not the product but its installation. Another option would be a manufacturer-specific warranty. In other words, manufacturers accept the returned product, rework it, offer a new warranty and reintroduce it into the cycle.

There is already a vast amount of knowledge about circular building. To disseminate this knowledge, it is important to network and make it available. Not only are local contact points needed, such as NGOs or competence centres. Above all, it is important to integrate circular construction into (new) degree programmes and to create professorships, to offer continuous professional development, to conduct research projects and to incorporate the knowledge into vocational training. It is not about creating a new discipline. Circular building can only be scaled up if the knowledge is standardised and integrated across industries.

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