Towards A Circular Built Environment: Opportunities and Challenges
- Kshitija Mruthyunjaya
- Jul 1, 2024
- 5 min read
Updated: Jul 2, 2024
Kenneth Boulding's "Spaceship Earth" metaphor laid the groundwork for the circular economy, highlighting the importance of sustainable resource management and waste reduction. In architecture, this translates to designing buildings as adaptable entities using strategies to extend material lifespans. These practices aim to keep materials in continuous use. However, the question persists: can buildings be truly circular?
Written by Kshitija Mruthyunjaya Edited by Shivangini Tandon
Imagine our planet as a vast spaceship hurtling through the cosmos. In his groundbreaking 1966 essay, "The Economics of the Coming Spaceship Earth," economist Kenneth Boulding used this powerful metaphor to reshape our understanding of Earth's resources. Boulding painted a vivid picture: Earth is like a self-contained spacecraft on a long journey. Just as astronauts on a spaceship must carefully manage their limited supplies and deal with their waste, we earthlings face similar challenges. Boulding argued, we must find our place within a cycle of reuse and renewal—a system that can keep reproducing materials even as it relies on a steady input of energy from the sun. This "spaceman economy," as Boulding called it, laid the foundation for what we now know as the circular economy.
Spaceship Earth at Epcot in Walt Disney World. Source: Wikipedia
The Circular Economy, as defined by the Ellen MacArthur Foundation, is "an industrial economy that is restorative or regenerative by intention and design." It has three main ideas:
Get rid of waste and pollution
Keep using products and materials as long as possible
Help nature recover
These ideas aim to protect and improve nature, use resources wisely by keeping materials in use, and reduce harmful effects on the environment and society. It's about changing from an ‘extract, make, consume, discard’ way of doing things to a smarter way of using resources, designing better, and rethinking what we do with things when they stop being usable for the purpose they were originally produced for.
The circular economy isn't just about recycling more. It's about doing things differently in all parts of the economy. It tries to keep materials useful for as long as possible by: Recovering, Recycling, Repurposing, Remaking, Repairing, Reusing, Reducing, Rethinking, and Refusing.
This approach aims to get the most value from resources while putting people and the environment first, instead of just using up materials.
Rethinking Buildings in a Circular Economy
Within the traditional ‘extract, make, consume, discard’ built environment framework, materials are assumed to be infinite and can be extracted without limit. Buildings are seen as temporary structures that are torn down and rebuilt from scratch. But buildings don't quite have an end of life that demands to be broken down and discarded. And we know that there isn't an infinite supply of materials on our planet. What if we reverse this conventional understanding and recognize that materials are finite in nature and buildings can be long-lasting entities?
"There isn't any such thing as a building. A building properly conceived has several layers of longevity of built components". Architect Frank Duffy.
Like living organisms, buildings are not one single product but rather consist of various layers and components. They breathe, age, change, or at times transform into new entities. Architect Frank Duffy expressed this idea by saying, "there isn't any such thing as a building. A building properly conceived has several layers of longevity of built components". Through his 'Shearing Layer' concept, he explains that a building can be broken down into components: Shell (structure), Services (mechanical, electrical, plumbing), Scenery (internal layout), and Set (furniture). All of the layers are characterised by different longevity and impact.
This concept was later adopted by Stewart Brand in his book “How Buildings Learn: What Happens After They’re Built” where he expanded the layers into site (infinite); structure (30-300 years); skin (20-50 years); service (7-15 years); space plan (3-30 years), and stuff (0-3 years).The idea is that there are processes in nature, which operate in different timescales and as a result there is little or no exchange of energy/mass/information between them. Brand transferred this process to buildings and noticed that traditional buildings were able to adapt because they allowed "slippage" of layers: i.e. faster layers (services) were not obstructed by slower ones (structure). Understanding this dependency between the building layers is crucial to make conscious choices after one layer has reached its end of life (either worn out or stopped meeting its purpose over time).
Shearing Layers of Change, Stewart Brand. Source: https://www.openbuilding.co/manifesto
By understanding that buildings are constantly changing and viewing them as "material banks" - sources of valuable resources for future use - we can transform 'waste' into valuable materials, effectively closing the loop in material cycles.
Let's consider building facades (the 'skin' layer) as an example. The average lifespan for facades is about 30 years. When a facade reaches the end of its life, the whole building doesn't have to be demolished. Instead, buildings should be designed so that different components can be easily separated and replaced. This is called "design for disassembly." The Triodos building in the Netherlands which is wooden and reconstructible is a good example of this approach.
Buildings should be designed so that when materials and products are removed from a building, they retain their value. They can be made into new products or, if biodegradable, safely return to the earth. This keeps materials in a continuous cycle of use, or a "closed loop". Instead of throwing everything away, we can use strategies like reducing, reusing, refurbishing, remanufacturing, and recycling to extend the usefulness of materials and minimise construction and demolition waste.
By understanding that buildings are constantly changing and viewing them as "material banks" - sources of valuable resources for future use - we can transform 'waste' into valuable materials, effectively closing the loop in material cycles.
Material banks. Source: https://www.bouygues-construction.com/blog/en/batiment-banque-materiaux/
Can buildings be truly circular?
In the real world, it's impossible to have a perfect system where: all resource loops are completely closed, materials can be recycled endlessly, and all used-up energy is fully recovered. This is because of the laws of thermodynamics, which put limits on how efficiently we can use and reuse energy and materials. “The more complex a product, the more steps and processes it takes to recycle. In each step of this process, resources and energy are lost.”
For instance there are material limitations like in the case of Aluminium which needs some new material added when recycled or plastic which degrades with repeated recycling. There are technological constraints in cases where recycled materials (like industrial sludge or ash) can be reused but may contain more pollutants than virgin materials. This can make it hard for companies to switch from new to recycled resources. Capturing, changing, and moving energy always uses up some energy making it difficult for a fully closed energy loop with current technology. These factors show that while we can make a shift by adopting circular principles, a completely waste-free, endlessly circular system may take time or may not be possible at all.
“The more complex a product, the more steps and processes it takes to recycle. In each step of this process, resources and energy are lost.”
What we can do keeping in mind these limitations is move towards using resources as minimally as possible, reduce waste and implement context-specific solutions with longevity in mind. By designing buildings to last longer we can lessen the strain on natural resources and ensure sufficient materials are available for future generations to build with. This gradual process allows for innovation, adaptation, and the development of efficient practices over time, ultimately moving us closer to a more sustainable future.
Further Reading :
Spaceman Economy :
Circular Economy :
Shearing Layers :
Limitations of Circular economy :
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