Demolition Mapping and Second-Hand Buildings

Translated by Jennifer Di Giacomo

Disposable Construction

In 2026, we are constantly building and demolishing. Buildings, like clothes and sometimes relationships, have become disposable: we build them and, when a building becomes old, inefficient or simply ugly, we tear it down and send everything to landfill. Easy, right?

This is the logic of the linear economy: we extract resources, manufacture goods, generating emissions and waste already during production, and at the end of their life, the products themselves become waste. In the midst of the climate crisis, however, recycling and reuse should be the rule. The circular economy can be understood precisely as a set of strategies to reduce waste and recover materials that are still usable but that the linear model throws away.

The construction sector is one of the most important testing grounds, because of its enormous impact in terms of resource and energy consumption and waste generation: according to Eurostat, construction and demolition waste accounts for more than one-third of all waste generated in the European Union. One of the approaches being tested in Northern Europe is demolition mapping.

What Is Demolition Mapping?

Demolition mapping is the systematic mapping of a building's components before its demolition, in order to determine which can be recovered and reused: bricks, beams, windows, doors, flooring and sanitary fixtures. If components are inventoried and made visible years in advance, designers can plan to use them, and the materials can be carefully dismantled, refurbished and stored instead of ending up in landfill.

Future Baltic Bauhaus: Three Cities, Three Stages of Reuse

This is the focus of Future Baltic Bauhaus, a project co-funded by the European Union through the Interreg South Baltic programme (2024–2027) and coordinated by the Danish municipality of Holbæk. The project explores practices and regulations for the reuse of construction materials, working closely with small and medium-sized enterprises and public administrations. Its stated objectives are to reduce CO2 emissions, improve the supply chain and strengthen the sector, while also creating new jobs and specialised skills.

The project is structured around three pilot projects, each dedicated to a different stage of the process.

Holbæk (Denmark): Demolition. Recovered materials can be used in new public buildings, as demonstrated by a new kindergarten in Svinninge built with bricks from the town's former school. Meanwhile, a dental clinic in Holbæk, scheduled for completion in November 2026, reuses bricks from a building in Vipperød. All the buildings involved are registered according to defined parameters, and the municipality is developing a shared tool to document and assess buildings before demolition, making the supply of materials visible.

Kalmar (Sweden): Logistics. This is where demolition mapping becomes a genuine management model. Together with the company GodaHus and Linnaeus University, the municipality is testing digital tools to identify reusable materials and developing a physical and digital marketplace for second-hand construction materials, in collaboration with the county's construction and housing companies. The process follows a precise sequence: locate, store, distribute. The aim is to shorten the time needed for dialogue between those who demolish and those who build, bringing supply and demand together in a market that is currently fragmented. There is no shortage of interest: 95 public and private stakeholders attended the project's Swedish launch in Kalmar. The municipality, moreover, has set itself the goal of becoming a circular society by 2045 and achieving circularity in its own operations by 2030.

Wismar (Germany): Design. The third pilot focuses on how to design and construct buildings using reused materials and components.

The Norwegian Case: When Mapping Becomes Mandatory

Although Norway is not a member of the European Union, it has gone beyond experimentation. Between 10,000 and 20,000 buildings are demolished in the country every year, some well before the end of their useful life. For this reason, since 1 July 2023, the national building regulations (TEK17, § 9-7) have required reuse mapping for projects requiring a permit involving apartment buildings and commercial buildings: for example, when more than 100 m² of floor area is demolished or when the work generates more than 10 tonnes of waste. Those carrying out the demolition must also prepare a report listing all components suitable for reuse.

Stavanger is one of the municipalities that has gone beyond the national standard. Between 2021 and 2022, with funding from the Norwegian Environment Agency, it created a temporary warehouse and new forms of cooperation between its departments to reuse materials and furnishings instead of buying new ones: furniture reuse alone prevented approximately 63 tonnes of CO2 equivalent emissions. Since autumn 2022, the municipality has had a full-time reuse coordinator, a permanent warehouse and a digital platform accessible to all municipal employees. The new municipal plan also extends the mapping requirement to all types of buildings and brings it forward to the urban planning stage, rather than limiting it to the demolition phase.

Not Everything That Circulates Is Gold

Like any choice, this one has costs and benefits. As with many green policies, the benefits materialise over the long term, while the costs are immediate and concentrated, especially at the beginning. Sending everything to landfill remains much cheaper in most cases.

The barriers are well known. The first is that this is a new field: standardised models and procedures are lacking, and progress is made mainly through learning by doing. Since reuse is more complicated to manage, private-sector actors rarely choose it. The second barrier is regulatory: rules on warranties, safety and certification are designed for new products, not used ones. A brick or a window that has already served its purpose must be tested and documented, and such items are often unavailable in standard sizes or within the timeframes required by the design process. Without legal certainty, investment is slow to materialise.

Reusing "pre-loved" construction materials therefore requires new skills and knowledge, both on the part of clients and construction companies.

However, things are beginning to change. In Denmark, a long-established demolition company in Roskilde has resumed selling salvaged materials to private customers after years of inactivity. Demand has started to grow again thanks to life-cycle assessments, which show lower emissions for reused materials, and national requirements for more selective demolition, which increase supply.

How to Reduce the Costs of Reuse

The experience of the pilot projects points to several ways of making reuse economically viable:

1. mandatory quotas for reused materials in new buildings: in Norway, for example, industry organisations have proposed a minimum national requirement of 5% reused components;
2. scaling up good practices from the municipal to the national level, moving beyond the logic of pilot projects;
3. separating materials during demolition through selective demolition;
4. creating a market that encourages investment, including through public-private partnerships and regional storage facilities;
5. strengthening cooperation throughout the entire value chain, from demolition contractors to designers and builders.

Conclusion

The most effective way to save resources remains, whenever possible, not to demolish at all. Nevertheless, this approach has the merit of changing our perspective. Reuse also has an economic, social, aesthetic and cultural dimension. Europe's challenge is to turn these local experiments into a genuine market, with clear rules and appropriate incentives. It may seem difficult, but something similar has already happened in other sectors. Just look at fashion: the very industry that made clothes disposable has seen the emergence, thanks to digital platforms, of a structured second-hand market in which buyers and sellers can find each other in just a few clicks.

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