Construction is the largest material storage and waste stream in the economy. Every year, 1.4 million tons of demolition material is processed in the Amsterdam Metropolitan Area alone, with a potential value of €688 million. At the same time, the production of new building materials has a heavy impact on the environment. With high-quality recycling, dismountable and modular construction, this value can be capitalized and the environment saved.
This article discusses the opportunities and barriers to closing material flows in the construction industry, with examples of entrepreneurs who have done so.
Figure 1: In the Netherlands, almost 66 thousand new homes were built in 2018 (CBS, 2019).
The opportunities
Construction has so many facets that companies and administrators can work with many strategies to make it more circular. Five important methods are:
- High-quality recycling of demolition waste, so that fewer primary raw materials are needed;
- Administering materials, so that the value of raw materials is preserved;
- Demountable construction, so that parts of a building can be reused;
- Modular construction, so that buildings can be adapted to new functions;
- Designing for collective use, so that residents can share buildings and belongings.
Many entrepreneurs are active with these strategies. Below are examples of companies that are committed to high quality recycling, administration of materials, and dismountable building.
Selling recycled concrete
Concrete is the most widely used raw material in construction (see box on concrete below). The Rutte Group and New Horizon have set up a processing plant together that can recover the most valuable component from used concrete: cement. They successfully market this cement under the name Freement, and are currently scaling up their processing plant.
Companies wanting to start working with recycled building materials can offer or buy products via the website: www.oogstkaart.nl and the Excess Materials Exchange.
Offices as material depots
In order to preserve the value of materials in a building, their type and quality must be known. The Madaster company facilitates the capture of this information by means of a raw materials passport and an online platform. The raw materials passport establishes the identity and use of materials, after which this information is disclosed through an online platform. This platform functions as a public library of materials in the built environment. Madaster shows that it is literally worthwhile to take stock of the flows of building materials and make them available.
Companies that want to work with circular construction can obtain information from the secretariat and the partners of Platform CB’23.
Earning with a demountable court
A consortium that has shown the potential of dismountable construction is DPCP. This consortium of eight companies was commissioned by the Rijksvastgoedbedrijf to build a temporary court. This replaced the original court during a renovation. DPCP designed the building in such a way that after 5 years they could disconnect the walls, floors and windows to build elsewhere. DPCP remains the owner of the parts, so after the first use they can rent the building in a new form to another party.
Companies that want to start working with circular building strategies, including demountable building, can seek advice from Copper8.
Ecological and economic benefits
Closing cycles in the construction sector would significantly reduce material costs and environmental impact. As mentioned earlier, demolition material has a high value, provided it is reused in a high quality way. Currently, 90% of all material in construction is reused after use, but often in a low-value way, such as in concrete. Dr2 New Economy and Metabolic (2018) have calculated that more than €300 million could be earned each year in the Amsterdam Metropolitan Area by adding value to demolition material. For the whole of the Netherlands this amount would probably amount to one billion euros.
Switching to a circular construction sector offers opportunities for almost all partners in the chain. According to ING Research, only suppliers of low-tech building materials would benefit less from this transition (2017)
In addition to this economic value, high-grade re-use of building materials would also significantly reduce the sector’s environmental pressure. Currently, construction is responsible for 5% of the total Dutch CO2 emissions. A large part of this goes to the production of building materials. These emissions would therefore be significantly lower if construction was carried out using recycled materials. However, it should be noted that the Netherlands builds more buildings than it demolishes, so net imports of raw materials will continue to exist.
Concrete as an example
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Concrete is the most widely used building material in the world. In the Netherlands, too, almost half of our building material is concrete: 15 million m3 per year (Dr2 New Economy, 2018). Concrete is made from gravel, sand and cement and is popular because of its low price, strength and lifespan. The disadvantage of concrete is that the production process of cement requires a lot of energy. As a result, the production of concrete currently causes the emission of many greenhouse gases. The environmental impact of concrete would be considerably reduced if old concrete were used for new concrete. At present, however, the majority of concrete is used after use as an embankment or road foundation. Thanks to new processing techniques, half of the cement can be recovered from used concrete. The remaining half can be used elsewhere in construction. In order to enable the use of these types of techniques on a large scale, 4 ministries and 50 construction companies signed the Concrete Agreement. In this agreement, producers, clients and contractors agree to collaborate extensively in order to re-use 100% of the concrete released in 2030. To this end, the government has promised to include the use of recycled concrete as a criterion in its tenders from 2023 onwards (Rijkswaterstaat, 2018).
The barriers
Despite the advantages of a circular construction sector, there are still four factors hindering its development: market development, measurement methods, policy, and knowledge (Nelissen et al. 2018).
Market development
The demand for circular construction projects still relies heavily on public tenders, because modular or demountable construction projects are often even more expensive than linear construction approaches. The innovative nature and limited supply of circular construction solutions results in higher investment costs. At the same time, it takes years before any savings or gains from renovating or dismantling the building pay for themselves. In order to be accepted in the market, therefore, circular construction must be given added value. For this it is essential that there are measurement methods and more knowledge about this value among builders, clients, financers and other parties in the chain.
Measurement methods
If the added value of circular construction for the environment, health, comfort, safety and operating costs can be demonstrated, the demand for circular construction will increase. As soon as a lender is unable to assess the value of the raw materials in a dismountable building, he/she cannot include them in the calculation. Therefore, standardized measurement methods are needed. However, all partners in the chain must be involved in order for a measurement method to be effective and accepted. However, such a measurement and certification method can build on existing methods, such as the Dutch Environmental Achievement Buildings (MPG) and the Netherlands Environmental Database (NMD).
Knowledge
Necessary for the development of the market and standardized measurement methods is to build up knowledge in all parts of the chain. A building can still be designed circularly, but if a subcontractor closes the joints with pur foam, it is still not circular. In order to achieve this level of knowledge, training courses at all levels – from WO to VMBO – need to be updated. In addition, special refresher courses must be offered.
Policy
As explained, circular construction only becomes interesting when the added value is measured and acknowledged. Government policy can contribute to this by acting as a launching customer and directing the development of measurement methods and knowledge in the chain. In addition, there is also room for experimentation in the rules, so that companies can experiment with new building methods and financial constructions. In addition, the merits of circular construction can only be felt in the long term. The government is therefore pre-eminently the party that can deploy the development of circular construction.
