4 min

Building a circular construction industry: the role of certification

Global demand for new buildings and infrastructure is growing fast, yet the availability of raw materials is dwindling. Our linear economic model – take, make and waste – relies on the Earth’s limited resources. If we are to cater for an increasing population, expected to breach 10 billion by mid-century, we need new approaches. Circularity is gaining momentum globally as a solution, and as it becomes more prominent, we will need ways to measure and monitor its effectiveness – including through testing, inspection and certification.

The OECD predicts global materials use will increase from 90 billion tons today to 167 billion tons in 2060. The construction and real estate sector contribute significantly to this: it is responsible for an estimated 50% of the total raw materials, 40% of energy and 30% of water used globally. In addition to the depletion of resources, there is a large environmental impact associated with the life cycle of a construction.

If we want to ensure the long-term survival of humans, we urgently need to find a way to live without depleting the planet’s resources or harming the environment. The answer lies in joining the ends of the linear journey from raw material to waste: building a circular and sustainable economy.

More than recycling

Circularity requires a completely new way of thinking about resources, design, construction and waste. It’s a new economic model, synonymous with sustainability, designed to ensure humans and the planet can continue to thrive as the population and the economy grow.

According to the Ellen MacArthur Foundation, the circular economy is based on three principles:

  • design out waste and pollution;
  • keep products and materials in use;
  • regenerate natural systems.

This means using discarded materials as raw materials – it’s reuse at the same value level, in a way that promotes reuse in the future.

We are more likely to achieve the UN Sustainable Development Goals (SDGs) with a circular economy – in particular SDGs 8 on economic growth and 12 on sustainable consumption and production. The World Economic Forum (WEF) estimates the circular economy model is worth over $1 trillion in material savings.

Yet the global economy is only 8.6% circular, according to a report by Circle Economy. The Netherlands is setting the bar higher: at 24.5% circular, the country is pioneering circular approaches, especially in the construction sector.

“We in the Netherlands can set an example for the rest of the world,” said Wim van Vreeswijk, Director of Kiwa’s Division of Building and Civil Engineering. “Ideally, we want to make the world better. We’re using too many raw materials, endangering our future and putting our children at risk. Construction is a great place to start.”

Circularity throughout the process

As Wim explains, the two main parts of the construction industry are divided by the ground: buildings are primarily above it, infrastructure mostly below. There is much more circular activity happening in infrastructure at the moment, but there is huge opportunity in building construction too. “When we make a building, we must try to make it so that we can reuse it,” Wim said.

How can a process that has always been linear be changed? We have to go back to the drawing board – literally. “You have to start with the architects,” Wim said. “When a building is not designed with circular materials, such materials never fit, and they end up not being used. If the architects are thinking from a circular perspective, they will adjust the design to the materials, so they will not be wasted.”

Take floors, for example. Reusing environmentally critical building materials would reduce the negative impact on the environment. But if the design of the new building has not taken circularity into account, the dimensions can be a challenge: the floor might not fit.

This, Wim says, is why design is such an important factor. “It must be a core vision; without designing circularly you can never make it grow in practice.”

Ideally, we would continue using existing buildings rather than demolish them and build new ones. But if a building needs to be demolished, considerations like keeping each type of waste pure are important. The challenge there is that there is no process certification for demolition, so no way of tracking it.

“You have to monitor the total chain,” Wim said. “And the weakest link in the chain is the construction site. Contractors don’t want regulation for things like demolition, and they are looking for the cheapest materials, not necessarily the most sustainable.”


Wim van Vreeswijk, Director of the Division of Building and Civil Engineering, Stefanie Knijnenburg, Marketing Coordinator and Stan Jansen, expert on circularity in construction, from Kiwa Netherlands.

Overcoming challenges

Circularity is currently difficult to measure, and many companies have been slow to get started because of this. By contrast, sustainability has been a major feature for many years, so schemes such as Leadership in Energy and Environmental Design (LEED) and the Building Research Establishment Environmental Assessment Method (BREEAM) are well established. But measuring and assessing circularity is more complex, and it covers many levels.

Initiatives are being established in different countries; for example, in the Netherlands, Platform CB’23 has developed a core method for measuring circularity in the construction sector that provides a set of key indicators that allow for a circularity measurement, and the environmental performance of buildings (MPG (Dutch)) that is based on life cycle assessment. At the international level, there is the Material Circularity Index (MCI), and an ISO standards committee is working toward developing six international standards.

Stan Jansen, expert on circularity in construction at Kiwa, commented: “There is no generally accepted objective measuring method of circularity. Ideally, we would have a uniform method for assessing companies’ circularity; we are not there yet.”

Circularity also requires a new look at existing schemes for specific aspects. For example, there is the question of how to assess construction materials to ensure accuracy and safety. “When it comes to building materials, we are mostly very strict in certification,” said Wim van Vreeswijk. “You can measure the characteristics of new materials such as concrete and stone accurately. But with reused materials, we do not always have enough knowledge about the characteristics of the material. And testing is very expensive.”

As a solution, a materials passport aims to track an original material used in the building, detailing its quality and characteristics and thereby providing a complete archive of the materials. It can be used at the point of demolition to ensure pure materials for reuse, and it reduces the risk of materials being wasted.

This requires another way of thinking, Wim said. “Normally we check the materials via the manufacturer and determine if they can deliver. But with a circular approach, you have to look to the total building and follow the materials through the whole chain.”

Materials passports are becoming increasingly popular, especially in the Netherlands. In 2019, 13% of Netherlands Enterprise Agency clients were already using materials passports. Some organizations are pushing to make materials passports mandatory for construction projects. For example, Guidelines from CB'23 advocate requiring a Bill of Materials (BOM), a sort of materials passport, in order to “improve the quality and increase completeness of data.”

What companies need to go circular

Kiwa is now working with materials passports in several countries, including the Netherlands, Germany, Switzerland and Norway. “Companies need validated data,” Wim said. “When Kiwa can certify and inspect, they can guarantee to the user what is in the database is the truth.”

As the demand increases for more validated data through measuring and monitoring circularity, Kiwa’s role is becoming more central. This has an impact on the sector more broadly. Stefanie Knijnenburg, Marketing Coordinator at Kiwa, said: “By expanding into circular construction, we hope to stimulate the market to build circularity internationally.”

“Something that a lot of companies struggle with is how they can actually integrate circularity in their business process, and in the construction,” Stefanie added. “They want to know what steps they can take and what indicators they can use to put it into practice. Certification is part of the solution.”

The early steps involve looking for opportunities to set up inspection and certification schemes for circularity more broadly. Clients have critical input here, and finding out what businesses need in order to move forward with circular projects can help drive the circular economy.

Process certification can therefore be important for clients, including for management systems. The Circular Performance Ladder (BRL K11006) is one such scheme, through which companies can show their development of products and services follows the principles of circular entrepreneurship.

Kiwa offers BRL K11006 certification. In 2019, recycling organization EPS Nederland was the first company to be certified. Henk Bos, Director at EPS Nederland, said: “Together with Kiwa, we looked at how we could make circularity in our company practical. The implementation of circularity will be different with every company and every product. Certification should be used as a tool to reach your goal – to not just say that you are being circular, but actually are a circular company. Take the time to do this and talk a lot with Kiwa about it, just like we did, and start the plan from that.”

As construction becomes more circular, the next phase will be developing a standard for circularity that incorporates all the relevant elements for the industry. “There's a long way to go before we can tell the market, ‘circularity is a part of the world’,” Wim said. “But it's vital that we stimulate the market to move to circular construction, as we can't sustain our current way of life.”