Five Delft solutions for circularity in the built environment

Facade panels made of walnut shells, an extra floor of biobased materials on top of an apartment building or even an entire building made of rammed earth – sounds a bit futuristic? Not for these five Delft architecture students. They are convinced that the future of construction is circular.

The construction sector accounts for a significant proportion of global CO₂ emissions and a lot of waste, while building materials are hardly ever reused or recycled on a large scale. That is why architecture students in Delft are being challenged to come up with innovative concepts for more sustainable and circular construction. Circularity in the Built Environment Graduation Awards. These are the winners.

#1 – A centuries-old construction technique with a modern twist

Like many other countries, Germany is facing a major housing challenge. The construction technique rammed earth can help to meet this challenge in an environmentally friendly way. In her graduation project Let's build a landfill, Larissa Götze investigated how we can breathe new life into the ancient technique of rammed earth to produce sustainable walls.

Excavated soil from our soil contains a mixture of gravel, sand, silt and clay – exactly the raw materials needed for rammed earth. By mixing these in the right proportions with water, a building material is created with which sturdy walls can be made. The material has a low CO₂ footprint, making it a sustainable alternative to concrete.

Larissa discovered that rammed earth can also be produced prefabricated, even with the help of robots. She developed a production scheme with which existing construction factories can be converted into rammed earth factories, allowing the technique to be used on a large scale for sustainable housing construction.

#2 – Local crops as building material to achieve climate goals

Adding an extra floor to apartment buildings, or topping them up, is a sustainable way to create new housing because it does not require a new concrete foundation. When this topping up is done with biobased materials instead of steel, it becomes even more environmentally friendly. In his graduation project 100,000 biobased top-ups, Frank Vahstal looked at how we can reduce the climate impact of housing construction by using locally produced crops.

Frank studied the environmental impact of various materials – such as wood, flax, hemp, straw, pampas grass, cattail and seaweed – and investigated where these crops could be grown in the Netherlands. He developed an approach for the three most important types of landscape in the Netherlands: clay, sand and peat soils. His calculations show that this will enable us to remain within the targets set by the Climate Agreement for housing construction.

#3 – A circular chain (in the Netherlands) for neodymium magnets

In her graduation project Extractivism to Circularism, Preksha Rautela investigated how the Netherlands can set up a circular chain for neodymium magnets, which are important for electronic equipment and wind turbines, among other things. Preksha outlined four different scenarios for what such a circular chain might look like. For each scenario, the required land use, infrastructure, ecological impact, energy supply and long-term feasibility were examined.

The result is a design with a spatial vision for the Netherlands, indicating where opportunities lie for the collection, recycling and manufacturing of these magnets. But perhaps even more important than the outcome itself is the method of “scenario building” that Preksha has developed. This approach can also be used to investigate circular chains for other critical raw materials.

#4 – A design for circular systems in a post-war neighborhood

In her graduation project Circularity of the Everyday, Elena Grimbacher outlined a design for circular systems in the post-war neighborhood of Schalkwijk in Haarlem. She investigated how circular systems for water, energy and food can be created and involved residents, entrepreneurs and other local stakeholders in the process.

Neighborhoods from the 50s and 60s often have outdated infrastructure and a sober design. The greenery usually consists of lawns between the monotonous building structures. Yet there is a lot of potential here. Lawns, for example, can be transformed into areas with fruit trees or vegetable gardens. Furthermore, many neighborhoods on the city's outskirts are connected to the polder and surface water, which offers opportunities for energy generation and the storage of rainwater for circular use.

Her research aimed to develop a “pattern language” that stakeholders—such as policymakers, food producers, urban planners, and waste collectors—can use when making choices. Elena's approach can be applied not only in Schalkwijk but also in other post-war neighborhoods in the Netherlands.

#5 – Rainproof facade panels made from walnut shells

Can we use food waste streams as building materials? That question was central to the graduation project Bio-composites from food-waste by Lara Neuhaus. In this project, Neuhaus developed a biobased composite made from walnut shells. The first material tests are promising. With her work, she hopes not only to find new applications for waste, but also to bring about a change in thinking.

Lara used coffee grounds and walnut shells to make a composite by mixing them with resin and compressing them at 150 degrees under high pressure. She then examined the flexural strength, water and frost resistance, and impact resistance of the material. The walnut shell composite performed best. The only building material that scores better in terms of carbon footprint is wood, but that first needs to be cultivated. However, waste from the food industry has already been produced, making it a cheap and sustainable alternative.