Building for a new world: Embracing construction’s “circular economy”

When we think about the pioneering industries embracing innovative methods to reduce their environmental impact, construction isn’t necessarily at the top of the list. Instead, we tend to consider construction as being synonymous with waste.

This is a fair assessment, at least in modern times, where buildings are largely made of virgin and non-recyclable materials, and are not necessarily built to stand the test of time. In fact, most modern buildings are rarely expected to exceed 100 years, and if we are talking about residential buildings, that figure is more like 60 years.

To drive this point further, let’s also note that the construction industry is one of the biggest consumers of resources. It constitutes around 50 percent of the total use of raw resources, along with 36 percent of global final energy use.[1]

These are some pretty significant figures, which suggests that if the construction industry can find a way to embrace sustainability on a broad, global scale, this could make a huge impact in the fight against climate change.

While it’s certainly not there yet, there is a beacon of hope in the industry’s growing recognition of the circular economy model.

Understanding the circular economy

As far as concepts go, the circular economy is complex. But essentially, it can be understood as an alternative economic system that replaces our current “take, make, dispose” ideology with one that is more akin to “reduce, reuse, recycle”.

To further explain the concept, we can imagine the “take, make, dispose” ideology as a linear economy model, where resources are extracted to create products that exist for a finite period of time before becoming waste. The circular economy model is instead inspired by nature’s ecological cycle, which creates a closed loop of material and energy cycles that are renewable.[2]

So, what would buildings be like if they were built based on a circular economy model? Well to start, they would be built with the intention of utilising the surrounding land in the most optimal way possible. And the buildings themselves, for example, could be modular, mixed-use buildings made from recycled and sustainable materials. These buildings would also be designed with ESD principles in mind, and would include plenty of shared and multi-purpose spaces.

Clearly, implementing this on a wide scale poses a massive challenge to the construction industry, which is heavily embedded in the linear economy model. There are also many moving parts to a build, and the transition to a circular economy model would require cooperation from all stakeholders involved, including consumers, producers and industry regulators. But the payoff is worth it: According to modelling by PwC, infrastructure’s transition to a circular economy model could enable Australia to generate $1,860 billion in direct economic benefits over 20 years, while saving 165 million tonnes of CO2 per annum by 2040.[3]

How architects and builders can contribute

Shifting entire industries to an alternative economic model represents a colossal challenge, but there are a number of ways that architects and builders can support the transition.

As mentioned previously, the use of modular construction is a good example of circularity in the built environment. Some of the benefits include a quicker construction process, higher quality control and reduced waste. In terms of materials, architects should also favour recycled or reclaimed materials wherever possible, as these materials have the potential to be just as durable and aesthetically pleasing as virgin materials while significantly cutting down on environmental impact.

Another interesting prospect is the use of 3D printing in construction. Adoption of this technique allows buildings to be constructed at a fraction of the cost, while also significantly reducing the consumption of materials. And according to research by PwC, 3D printing for construction might add an additional 12 percent in capital and operating expenditures, but it can result in around 20 percent material savings and 32 percent labour savings.[4]

Throughout the lifetime of a build, it’s also important to prioritise shared and mixed-use spaces. Some possible examples include facilitating co-working spaces in commercial buildings; use of residential spaces as an alternative to traditional hospitality spaces; and shared use of school campuses as community spaces outside of school hours.

Once a building reaches the end of its lifecycle, disassembly should also be favoured over demolition whenever possible. This allows the materials to be recycled and reused, reducing the demand for virgin materials and the energy required to source and process them.

Finally, embracing the circular economy will require the widespread adoption of new business models among firms. In particular, the “design, bid, build” model will need to transition towards more progressive models such as “design, build” and integrated project delivery (IPD), as well as “design, build, operate”.

A circular economy prototype: Spiral Village, Bellingen

Located in Bellingen, NSW, Spiral Village is a trailblazing prototype for a circular economy village. The concept was developed by town planning consultancy PolisPlan, directed by town planner and political economist Dr Steven Liaros, as well as water engineer Nilmini De Silva, with design by Valentino Gareri Atelier.

“Our vision is for a network of high-tech, regenerative villages that strive towards self-sufficiency and zero waste within their bioregion. In our planning model, each village houses a diverse community of up to 200 people and will integrate affordable co-working and co-living spaces with water and energy micro-grids and a regenerative agricultural system,” says De Silva.

“We are envisioning a new way of living where people can experience a closer relationship with nature and the food they eat, building a strong sense of community in the process. At the same time, we are looking to incorporate technologies in innovative ways to improve our lives and reduce the cost of living,” adds Valentino Gareri, founder of Valentino Gareri Atelier.

The proposed ‘Spiral Village’ is the pilot for this new, replicable model of mixed-use development that is based on circular economy principles. Set on a 40-hectare site in northern NSW, its design is inspired by the spiral shape of a nautilus. It includes eight residential spaces that increase in density as they get closer to the centre of the spiral, with the lines of the spiral serving as roads and pathways.

The plan is to construct the buildings using materials sourced from the site, while also using 3D printing techniques. One of the key design elements is the roof, a circular structure that connects the buildings and is designed to harvest energy and rainfall. According to the architect, its shape and slope maximises sunlight capture, while its large size maximises rainwater capture and provides coverage for outdoor spaces.

Another key element is the village’s water system, which will be facilitated through the creation of a chain of ponds along a gully, feeding into a nearby river. The lowest pond will be a man-made wetland that functions as a means of cleaning water on the site, with some of this water being pumped to the topmost reservoir and recycled through the site. Other proposed functions for the reservoirs include recreational swimming and aquaculture.

To minimise waste, the village will have a waste-to-resources hub that converts inorganic materials into useful resources or new products. A diverse regenerative agricultural system will also help provide food for residents while managing organic waste.

According to Liaros and De Silva, the circular building model is best suited to rural and regional areas, like Bellingen, which are trying to attract post-COVID migration from the major cities. One of the biggest challenges with this model however, is the lack of precedent within the current planning system, which makes getting approvals difficult.

“[Spiral Village is] … about identifying a clear pathway for that to happen that can be incorporated in the planning system. [It’s also about enabling] developers and councils to work collaboratively towards an outcome that benefits both, rather than the antagonistic system that we have now, where councils regulate and developers try to push the envelope with the regulation,” says Liaros.

Innovative new materials: Green ceramics

Embracing the circular economy model certainly requires “big picture” thinking, but it’s also worth highlighting some of the smaller, more specific solutions to the construction industry’s sustainability issues. This is where innovative new materials like green ceramics come in.

The product of a collaboration between the UNSW SMaRT Centre and Mirvac, green ceramics were first trialled in furniture and artwork within sustainable multi-residential development Marrick & Co, a project in Sydney’s inner west that won the Waste Elimination award at the 2020 Sustainability Awards. Following the commercial success of the trial, green ceramics were then used as a construction material for the first time in the Pavilions multi-residential development at Sydney Olympic Park, where they were included in flooring, kitchen splashbacks and island fronts, shelving, feature walls, artwork, light fittings and furniture.

According to the SMaRT Centre, green ceramics are made with MICROfactorie technology, which uses heat and compression to transform waste materials into ceramics and other materials for the built environment. Specifically, the tiles are made from a combination of yellow bin glass and textiles. The advantage of using glass is that it is a strong material that can be recycled many times without losing its valuable properties. Textiles are also important for providing colour and aesthetic qualities while helping the tiles meet strict building standards.

Collaborating on the development of green ceramics is just one example of the industry-leading work that Mirvac has been doing in the sustainability space. In FY21 for example, the developer ensured that 95 percent of construction waste and 69 percent of operational waste were diverted from landfill, significantly decreasing waste management costs and associated emissions. This is part of Mirvac’s pledge to achieve zero waste by 2030. A bold aspiration for such a large developer, it’s safe to say that if other firms were to follow Mirvac’s lead, we might just have a chance at making the circular economy a reality – not just another complex academic analogy.   

Image: Spiral Village by Valentino Gareri Atelier