Circular Economy: What, Why and How in Construction

There is only one planet Earth, yet by 2050, the world will be consuming as if there were three. Global consumption of materials — such as biomass, fossil fuels, metals and minerals — is expected to double in the next forty years, while annual waste generation is projected to increase by 70% by 2050 ^[1].   

The construction sector, in particular building and demolition, represents the largest waste stream in the EU. In fact, in 2018, the buildings and construction sector accounted for 36% of final energy use and 39% of energy and process-related carbon dioxide (CO₂) emissions, 11% of which resulted from manufacturing building materials and products such as steel, cement, and glass ^[2]. In the same year, the total waste generated in the EU by the construction industry amounted to roughly 813 million tonnes — contributing 35.7% of the total ^[3].

Furthermore, despite its potential and high material recovery, the level of recycling of construction and demolition waste varies greatly across the EU, ranging from less than 10% to over 90%. On the other hand, the building sector hardly uses any secondary materials – in the Netherlands, secondary materials only represent 3–4 per cent of all materials used in buildings ^[4]. Therefore, despite high recycling rates, the recycling of construction and demolition waste (C&DW) is largely downcycling. 

‘Although this may suggest that the construction sector is highly circular, scrutiny of waste management practices reveals that C&DW recovery is largely based on backfilling operations and low-grade recovery, such as using recycled aggregates in road sub-bases.’ ^[4]  

This means that the construction industry needs to take different circular-inspired actions to help achieve waste prevention, reduce consumption of materials, and increase both the quantity and quality of recycling – ultimately decreasing greenhouse gas emissions.  

How? But, above all, what is a circular economy? Let's explore this together.   

What Is Circular Economy? 

In our current system of a linear economy, materials and products lose their functionality after being used, ending up as waste often burned or landfilled. The concept of circular economy aims to overcome this model of consumption that is “throwaway”, by creating a virtuous circle i.e. looping resources — reducing the requirements of virgin resources and focusing on local economic activities. 

This method helps maintain the value of products, materials, and resources and avoid or at least significantly reduce the production of waste that cannot be recycled.  The International Resource Panel has strengthened this assumption, estimating that material efficiency strategies would reduce natural resource use by 28% and GHG emissions by 72% and yet improve economic growth ^[5]. 

In this interesting diagram created by the Ellen Macarthur Foundation, one can see the process, called the “Circle of Value”.

The circular economy pursues a harmonious intergrowth and sustainable development of both the economic and the social system without harming the natural ecosystem. 

After defining what a circular economy actually is, this learning path explores the concept of circular construction, including the benefits as well as how to proceed.  

What are the Pathways to Circular Construction?  

With the 2008 Waste Framework Directive, the European Community set a target of 70% recycling of construction and demolition waste by 2020. However, 14 countries hardly excel in this respect ^[6].  

Even though people are trying to use greener practices today, the past still affects us. This is because of the way buildings were built in the past and how we failed to retrieve high-purity materials during demolition. 

What Are the Benefits of Circular Construction? 

As discussed above, the construction sector is — unfortunately — not yet fully engaged in the circular process, mainly due to the lack of circular design practices and difficulties to retrieve and recycle materials.   

Yet, it is precisely the circular economy that can trigger a virtuous circle, driving construction to be more sustainable, while enjoying its many benefits.    

This is because interventions inspired by the circular economy focus not only on increasing the quantity of recycling but also on:  

1. ensuring a longer lifespan for materials;  
2. maintaining a high correlation of the value of the product to its quality;  
3. reducing the use of hazardous substances in products and their presence in waste; 

The circular economy gives us the chance to revitalise our economy and make it more sustainable and competitive. This has a number of advantages for European businesses, industries, and citizens, including: 

1. more creative and efficient methods of production and consumption; 
2. protection for businesses against resource scarcity and price volatility; 
3. local job opportunities and social integration; 
4. waste management optimisation that increases recycling and reduces landfill; 
5. energy savings attributed to the fact that fewer production processes necessitate less energy; 
6. environmental benefits in terms of climate and biodiversity, air, soil, and water pollution. 

This interesting infographic from the European Environment Agency (EEA) shows how a virtuous process of circular economy in construction should be structured. 

How to Achieve Circular Construction? 

To foster the development of the circular economy in construction and other sectors, companies, manufacturers, and regulators need to work together to chart the course and identify the best regulatory and pragmatic solutions to make the transition more organic, and increasingly sustainable. 

The EEA suggests the following actions:   

1. Secondary materials need to be competitively priced, e.g., through the introduction of instruments such as Green Taxes;  
2. Standardisation of secondary raw materials at EU level, but mainly at national level, would help to alleviate the lack of confidence in these materials;  
3. Communication between stakeholders and sharing and storing of information facilitate the selective demolition, renovation, and modernisation of buildings;  
4. Research and development of technological solutions, with a focus on the development of circular construction products, has the potential to increase the reuse of construction components and prevent waste, increasing the life of the construction itself;  
5. More ambitious waste management policy objectives with a focus on quality management, such as the introduction of requirements for the reuse of construction and demolition waste, would reorient current waste management practices towards a more circular approach.   

Rockfon in Building a Circular Future 

At Rockfon, we look at waste as a valuable resource that can be recycled and transformed into something new. Our circular business model enables us to convert waste into new raw materials while also collecting and recycling construction site waste and used products. More specifically, our circular business model is comprised of 5 pillars: 

Our Raw Materials

Our core raw material is volcanic stone, which is natural and one of the most abundant resources in the world. Discovered in Hawaii at the beginning of the nineteenth century, our stone is a natural by-product of volcanic activity that is melted and then spun into natural fibres. Additionally, we upcycle secondary waste from other industries and use them as raw materials in our production. In this way, we divert materials from the landfill keeping them in the economy as much as possible.  

• Earth produces 38,000 times more stone material than is used to make ROCKWOOL stone wool annually.  
• The stone is used very efficiently by us as 1 cubic meter of stone can correspond to 2,200m2 or eight tennis courts of ceiling tiles. 

Fully Closed Loop, Recyclable Stone Wool

Stone wool is a fully closed-loop product that can be recycled countless times without losing its quality. That is why we don’t downcycle but instead we recycle old stone wool material as well as our own production waste and feed it back to the production system. Also considering the secondary materials that we source from other industries; we manage to produce new high quality acoustic solutions with a high percentage of recycled content. 

Our products had from 29% to 64% of recycled content in 2020, including wool waste and secondary materials from other industries.

Operational Efficiency  

We have developed our production systems to support our circular business model the best way possible. In our ROCKWOOL factories, we transform the wool waste we receive into briquettes together with other secondary materials from other industries and feed them back into our manufacturing process. Additionally, we have optimised our operational activities so that none of our factories send stone wool waste to landfill. All wool waste generated during the production is fed back into our production system. 

Designed for Modularity and Disassembly 

Our acoustic solutions are designed for modularity and disassembly, which is another important aspect of Circularity. Building materials that are modular can be reused and reconfigured if you need to make changes to your space. This is better for the environment because it means fewer materials will be disposed. 

Recycling Services  

In many European markets, we give our customers the option of recycling old stone wool ceiling tiles or cut-offs from installation. We turn our products into new durable solutions repeatedly without affecting their properties or down-cycling them into other products with lower value. We offer recycling systems in many of the countries where we operate while we are actively looking at continuously expanding our network. 

• 163.000 tonnes of stone wool waste were recycled by the ROCKWOOL Group in 2020 

On top of all that, our products are characterised by high durability maintaining its properties for long time. A durable construction product that maintains strong performance throughout its lifetime does not need maintenance or regular replacement, and effectively helps to extent the lifespan of the building. It also helps to use less resources, create less waste and its manufacturing impact is spread over a longer period of time. 

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Sources: 

1. ^{“Circular Economy Action Plan: For a cleaner and more competitive Europe.” 2020. European Environment Agency. 2020. https://ec.europa.eu/environment/pdf/circular-economy/new_circular_economy_action_plan.pdf}    
2. ^{“2019 Global Status Report for Buildings and Construction Sector.” UNEP - UN Environment Programme. December 11, 2019. https://www.unep.org/resources/publication/2019-global-status-report-buildings-and-construction-sector.}   
3. ^{“Energy, Transport and Environment Statistics 2020 Edition.” 2020. The European Commission. 2020. https://ec.europa.eu/eurostat/documents/3217494/11478276/KS-DK-20-001-EN-N.pdf/06ddaf8d-1745-76b5-838e-013524781340?t=1605526083000.}   
4. ^{“Construction and Demolition Waste: Challenges and Opportunities in a Circular Economy — European Environment Agency.” n.d. European Environment Agency. https://www.eea.europa.eu/publications/construction-and-demolition-waste-challenges.}      
5. ^{I Hertwich, E., Lifset, R., Pauliuk, S., Heeren, N. “Resource Efficiency and Climate Change: Material Efficiency Strategies for a Low-Carbon Future.” 2020.  A report of the International Resource Panel. United Nations Environment Programme, Nairobi, Kenya.} 
6. ^{“#NoTimeToWaste: Member States Delay Meeting the Inevitable Targets”. 2020 European Environmental Bureau (EEB). 2020. https://eeb.org/wp-content/uploads/2020/11/Member-States-delay-meeting-inevitable-targets_report.pdf}