This framework surpasses the famous 3R (Reduce, Reuse, Recycle). The nine strategies Refuse, Rethink, Reduce, Reuse, Repair, Refurbish, Remanufacture, Repurpose, and Recycle and Recover provide a clear and actionable roadmap for a circular transition. 

Strategies at the top of the hierarchy, such as Refuse, Rethink, and Reduce, are the most effective at increasing a construction project's circularity level. These strategies focus on avoiding or minimising resource use and waste from the project's conception.

That is why a clear hierarchy exists where higher-level R strategies are preferred, and lower-level strategies are deemed more linear. 

In the original 9R framework, the last strategy, Recover, is often considered non-circular since it consists of energy recovery from material waste incineration, which is why it was left out of the scope of this case study collection.

They are applied to the built environment sector here as part of the [Realdania ](https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.realdania.org/&ved=2ahUKEwiF74KezMyJAxUpUaQEHURhOOEQFnoECBYQAQ&usg=AOvVaw0o-XWvSka80KCHtCG6XDS3) project.

The strategies can include:
- smart manufacturing
- designing for disassembly
- material passports for the building products, etc. 

🏢 Smarter creation and use of products 

The strategies eliminate the waste in the design stage itself.

 The strategies maximise their lifetime and give them a second life (e.g., take back strategies) when applicable.

🏢 Extending the lifespan of products and parts

Maintain, repair and upgrade resources while they are in-use.

The strategies usually require technical equipment and energy inputs to create a new value.

🏢 Useful application of materials

The strategies are applied to building products labeled ‘waste’ by the industry.

Turning a product redundant by cancelling its function, or by substituting it with a radically different product.

🏢 Refuse

Intensifying product use (e.g. via product sharing or multifunctional products).



🏢 Rethink

Replace typical brick and mortar wall with a dry-stacked wall with interlocking bricks will limit the amount of mortar required and ease the deconstruction efforts at the end of service life for the subsequent use.

More efficient use and/or manufacture of products through the use of fewer natural resources and materials.

🏢 Reduce

Reuse of discarded yet still usable product, for the same purpose, by a different user.

🏢 Reuse

The doors, windows, service installations, and even furniture are flexible compared to the building structure. If dismantled carefully, they can be reused elsewhere for the same or different purposes.

Repair and maintenance of broken or malfunctioning product, to enable continuation of its original function.



🏢 Repair

Refurbishing and/or modernising an older product, so that the improved version can be used in the product’s original function.


🏢 Refurbish

Using parts of a discarded product in a new product of the same function.

🏢 Remanufacture 

Using discarded products or their parts in new products with a different function.


🏢 Repurpose

Processing of materials to achieve the original high-quality or reduce to low-quality.



🏢 Recycle

Currently, the best practice worldwide for dealing with concrete and brick debris is to recycle it. The debris is collected, transported, manually or mechanically sorted, washed, crushed, and recycled into new building materials and products.

🏢 9R Framework

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The built environment sector largely exists to serve our universal need for shelter, and as such is one of the most important consumers of raw materials in the world.

We believe the built environment should be a ‘living’ system in which building materials and products are optimally used and reused— a system that operates within the boundaries of our planet, preserves the (business) value of its resources, and ensures the well-being of its inhabitants.

Tremendous opportunities to reverse the tide and prevent a state of lock-in from happening exist for regions where the built environment sector has yet to mature. There is also still hope for those regions where the fate of the construction sector may seem set in stone.

This is why two key strategies stand out: 

- Preventing lock-in through thoughtful design
- Optimising (material value) through transformative re-design

Built environment

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The construction industry in Europe stands at a critical juncture, facing a unique combination of challenges and opportunities that shape its future. As one of the largest and most impactful sectors, construction plays a central role in developing the cities and infrastructure of tomorrow. 

However, its environmental impact is significant: the built environment, driven by construction activities and building use, is responsible for 40% of global CO2 emissions and 40% of global resource use. This makes it a major contributor to the transgression of several planetary boundaries, including Climate Change, Land-System Change, and Biosphere Integrity. 

This case study selection highlights circular practices in the reviewed projects based on the 9R circularity framework, which serves as a set of guiding principles for transforming conventional construction practices into more circular and sustainable ones.