With the construction industry responsible for around 60% of total waste in the UK, the need for a more sustainable, ‘circular economy’ approach is clear and urgent. But what does it mean in practice to design a building on circular economy principles?

Here is Cullinan Studio’s guide to how architects can design out waste from new projects and create enduring buildings that can renew as their use evolves.

We must move on from the take, make and dispose economic model that has underpinned development and GDP growth since the Industrial Revolution. Within this model, the construction, maintenance, modification and replacement of buildings and infrastructure is a huge consumer of material and a significant producer of waste.

Sunand Prasad – Founder Penoyre & Prasad and Trustee of UKGBC

The Ellen McArthur Foundation defines circular economy thinking as ‘designing out waste and pollution, keeping products and materials in use, and regenerating natural systems’. Its principles seek to change the way resources are consumed, in order to prevent ecological collapse, to create more secure supply and production lines, and to open up new economic opportunities. Circular economy thinking applies to everything from product packaging to financial services, and from food production to fashion.

In the building industry, the need for a more sustainable approach is abundantly clear: according to the government figures, some 60% of total UK waste is generated from construction, demolition and excavation.[1] The question then, is how to translate circular economy principles into actionable guidelines for architects, clients and contractors.

The UK Green Building Council (UKGCB) report Circular economy guidance for construction clients includes a methodology for architects and clients to adopt from the very outset of a new project, covering design, materials, and construction. For many architects, these methods will represent a radical change – they effectively banish the tradition of demolishing and starting from scratch with a design created on a blank page in a studio.

But for Cullinan Studio, the fundamental ideas underpinning circular economy thinking are second nature. Here are our nine key circular economy principles for designing a building…

[1] Defra and Government Statistical Service (2019)

1. Find and reuse what’s already there

In a circular economy approach, the architect should start a project not with an abstract design concept, but with a rigorous, detailed review of the existing site and its assets. They should actively seek to reuse, refurbish and repurpose materials and structures where possible.

Doing this well requires time, but also creativity and lateral thinking. It is an approach that goes right back to the philosophy of our founder Ted Cullinan, and underpins our specialism in retrofit: a preference for looking first at what is good and useful about an existing building; to preserve, adapt and reimagine before tearing down. (For numerous examples, see The Art of Retrofit: Ways to reimagine an existing building and revive its original potential.)

2. Source reclaimed and sustainable materials

In addition to reusing materials from onsite, designers should source reclaimed and donated materials locally or from national brokers such as the reuse marketplace Globechain; or from salvage organisations like Ashwells Reclaimed Tropical Timber Yard, which collects and treats structural timber from around the UK. Using reclaimed materials requires flexibility in the design process: being prepared to adapt a design according to what materials are available.

For products that can’t be reclaimed and must be ordered new, architects should assess their EPD (environmental properties declaration) to check their life cycle, toxicity, recycled content, and embodied carbon. Cullinan Studio has special expertise in working with timber, which is inherently low in embodied carbon.

3. Involve the local community from the outset

By involving local people in the very earliest stages of design, architects and clients can benefit from their knowledge of how to reduce waste and make use of local resources. On all kinds of projects, from the Stonebridge Park Estate to the Bunhill 2 Energy Centre, Cullinan Studio include extensive consultations and workshops with residents and users throughout the design process.

By discovering as much as possible about how diverse groups of people might use a space, architects can design them to be as multifunctional, flexible and efficient as possible. They can thus become ‘socially circular’ community hubs, of benefit to the maximum number of people as possible. Walk-in cafes in the daytime become community activity spaces in the evening; education facilities double as private event venues, and so on: a social circular economy.

The benefits of listening to local people when designing a building are long-term: buildings that are cherished by their communities are more likely to endure.

4. Design for the future

In circular economy thinking, buildings should make use of existing assets to reduce waste and demolition; but they should also be useful over a long period, so they will not themselves be demolished.

The designs should be flexible and adaptable, and current needs balanced with possible future requirements, so that the building can easily be reconfigured as technologies and the needs of users evolve.

5. Think of the building as a material ‘bank’

…But architects should look even further ahead, to what happens beyond the building’s useful life. A circular economy approach to the components of a building is to think of it as a material ‘bank’, in which elements can be taken apart and reused in future projects.

Similarly, interior systems and even the structure itself can be designed for simple disassembly, and using modular designs and standard elements will minimise waste by making their reuse easier in next life. 

6. Design waste out of the construction process

Architects have a vital role to play in designing waste out of the construction process, especially if they continue to collaborate closely with contractors once the build is underway. Cullinan Studio worked on the BCMIoT, one of the first major projects to use the collaborative Integrated Project Insurance system.

That project demonstrated that if all parties keep communication lines open they can dramatically minimise wastage, as architects can listen to feedback from constructors and make minor adjustments to the design that result in major time, cost, material and energy savings.

7. Share or lease where possible

A circular economy principle is to investigate what can be shared or leased instead of building permanent structures.

This principle can apply in unexpected areas. Many functions of a building can be structured so that clients have unlimited access to a resource but only pay for what is used, so that something that would normally be considered a product becomes a service. One example given by the UKGCB is ABN AMRO’s arrangement with Mitsubishi to lease a lift service, rather than purchase a lift system. When a lift eventually needs to be replaced, Mitsubishi recycles or reuses the materials so that over 95% of the lift’s parts are repurposed. Similar arrangements can be made for lighting and other resources.

8. Minimise operational energy use

Every new building should have a specific strategy to minimise its energy use, ideally aiming for operational net zero carbon. Installing renewable energy sources like solar panels, along with demand-reducing measures such as heat pumps can help create an energy balance.

Cullinan Studio takes a fabric first approach to reducing energy demand and creating a comfortable everyday environment for a building's users, applying Passivhaus principles where possible.

[See also: How architects can use Passivhaus principles to unlock operational carbon net zero.]

9. Connect to nature

Encouraging biodiversity and regenerative living systems is another essential element of circular economy thinking. Cullinan Studio prioritise connecting buildings and their users to nature across our projects, incorporating green spaces and gardens wherever we can. By enabling buildings and surrounds to be hosts for plants and wildlife, they can achieve net positive biodiversity.

Reusing and repurposing rather than demolishing, employing sustainable materials, minimising waste and energy use, connecting to nature…the principles of circular economy thinking are perfectly aligned with the ethos that has driven Cullinan Studio’s approach to architectural design for decades.

If you would like discuss any of the issues raised in this post, contact us.

See also:

• The Circular Economy, and how architects can help to build it

• Embodied carbon in buildings: How to measure it, how to minimise it