Denmark’s climate ambitions depend on the extensive reuse of existing building stock, yet demolition remains the default in many planning and development programmes. The country’s new Preserve or Explain principle, Bevar eller Forklar, aims to change this.

Across Denmark, a national shift is underway: from demolishing outdated buildings to preserving and transforming them. Arup is contributing to this national effort by co‑developing the ‘Preserve or Explain’ approach - a standardised, easy‑to‑use method to support real estate players and municipalities to assess and evidence options for retaining or transforming existing buildings as part of Denmark’s local planning process. 

By providing a consistent way to explore and compare retrofit options, the Preserve or Explain approach helps deliver lower‑carbon outcomes, reduce resource use and support more informed planning decisions. This approach enables municipalities and developers to identify credible alternatives to demolition, retaining and transforming Denmark’s existing building stock while protecting the cultural and social value it holds. 

A tool to guide better decisions 

Inspired by international best practice, including the City of London’s Carbon Options Guidance and Westminster’s Retrofit First policy, Denmark’s ‘Preserve or Explain’ approach helps market players and authorities compare development options objectively before demolition is decided upon. 

The approach includes a scalable, three-step method for early-stage demolition decisions as part of the local planning process. Transparent, comparable scenarios also showcase technical, architectural and environmental implications for each option, enabling evidence‑based decision‑making that aligns with Denmark’s climate goals. The approach offers a replicable workflow that municipalities can embed directly into demolition permit reviews, creating a cohesive method to refurbishment across the country. 

By making renovation the default starting point, Denmark can significantly reduce embodied carbon, limit resource use, and preserve architectural and cultural value across its cities. 

Collaboration across the value chain 

Arup’s experts in sustainability, building design, and retrofit-first policy worked alongside a consortium of Danish and international partners, including municipalities, researchers, contractors, and consultants. The approach is co‑created with more than 13 organisations to ensure it works for both authorities and market actors. 

Arup’s specialists conducted background research, held workshops and interviews to adapt international best practice to the Danish context. This work led the development of the Bevar eller Forklar tool, a user friendly tool designed to support Danish municipalities and clients.  

Early insights were shared at the Building Green Copenhagen conference in 2025, where Arup joined the Danish Minister for Social Affairs and Housing, policymakers and municipal leaders in discussing what the tool could unlock for Danish cities. 

The team is now working with industry and municipal users to test and refine the tool, develop case studies and align with ongoing Danish policy discussions — ensuring the method is easy to adopt and ready to scale nationwide. 

Arup’s goal is to help Denmark adopt a simple, scalable tool that accelerates building reuse, supports climate ambitions and strengthens decision making.  

If your project involves renovation, retrofit or change of use, our team can advise on how to apply ‘Preserve or Explain’ as part of your early design and planning process.

Imagine a Denmark where our cities and towns don’t just whisper stories of the past but shine as living proof of our ability to grow, evolve, and rethink what already exists. Where we choose not to demolish and replace, but to transform, reuse, and preserve — strengthening our climate, our culture, and our shared economy. The Preserve or Explain tool seeks to help make that future possible.

Excerpt from the preface to the Preserve or Explain tool by Sophie Hæstorp Andersen, the Danish Minister for Social Affairs and Housing.  

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Preserve or Explain - Part 1: Tool (English)
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Preserve or Explain - Part 1: Tool (Danish)
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Preserve or Explain - Part 2: Background report (English)
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Preserve or Explain - Part 2: Background report (Danish)
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Aaen, Aarhus Kommune, Roskilde Kommune, City of London, 3XN/GXN, Hilson Moran, DOMINIA, CG Jensen, the Ministry of Social Affairs and Housing, Plan22+, Kommunernes Landsforening (Local Government Denmark)