This article looks into circular economy principles. This is the final part in a three-part series looking into this topic.

It is based on the work of David Cheshire and his book Building Revolutions.

In part one, which you can find here, we looked into the principle of designing out waste. In part two, which you can find here, we looked into the principle of building to last and adapt. Both are crucial to delivering the circular economy within the built environment.

Principle 3: Obey the technical or biological cycle

This principle is about selecting building components that flow in either a technical or biological cycle. This will vary depending on their expected lifespan, what they are being used for and what is available.

Materials that are part of the technical cycle are durable and are suitable for reuse, remanufacture and disassembly.

Materials that are part of the biological cycle are less durable but are simpler to return to the biosphere at the end of their useful life.

The key is to select materials with the right lifecycle for the intended purpose.

Designing for disassembly is something that would make a really big difference for advancing the circular economy within the built environment. However, it is still something that there is a lot of room for improvement on. In Building Revolutions, David Cheshire had the following to say:

“It is conceivable, though rarely done, to have a strategy for reclaiming components and materials at end-of-life, and to enable disassembly of the building.”

It is understandable why this is not seen as a priority. As when you are constructing a new building, the primary focus is on how it will perform for its primary function and the costs of doing so. But for achieving circularity in the built environment it is important that more emphasis is put on design for disassembly.

In a survey of demolition contractors, they point out that techniques such as having mechanical and reversible not chemical connections, ease of access to connections, independent a separable building elements and not using resins, adhesives or coatings on the elements can go a long way to making the deconstruction of the building simpler.

There are two really good examples in Building Revolutions. One is of the F87 Efficiency House Plus in Berlin by Werner Sobek, which is pictured below.

This project took the technical and biological materials cycle philosophy to the limit, meticulously selecting the correct material for its intended end use.

For materials that are recyclable at the end of their life, this included: cellulose insulation, recycled rubber as protective matting, wooden bearers for the structure of the roof and upper floors, hemp insulation and cork board.

At the end of the construction period, a manual was prepared that detailed the various materials that were used and the potential for reclamation or recycling.

Another example was project XX in Delft, which is pictured below.

The aim was to design an office building with a 20-year lifetime, on the basis that such buildings often undergo a major refurbishment roughly around this time.

The following criteria were used to select materials; they should be simple to reclaim as uncontaminated raw materials. They should be reusable without any alteration. They should be fully seperable and recyclable.

Interestingly on this project, they used ventilation ducts made of cardboard, which I have never seen or heard of before, with sand fill used on the first floor for sound insulation. It has proven to be very popular with occupants, showing that the focus on sustainability and circular principles enhanced value.

What you need to know

This article looked into circular economy principles.

This week we looked into biological and technical cycles and why it is important to select the correct material for a specific purpose.

No building is designed to last forever, so it is sensible to design buildings so that they can be demolished easily, and the parts sent for recycling and recovery to the greatest extent possible.

We looked at two highly successful, sustainable buildings which prove if circular economy principles are acted upon, that the result is a building that is highly desirable and sustainable at the same time.

Thank you for reading,

By Barnaby Nash

Please share your thoughts in the comments section below, or reach out to me on social media. What do you think needs to be done to make the circular economy a reality in the built environment?

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