Buildings to become materials banks

Wednesday 24 May 17
by Karoline Lawætz


Foto: Peikko

Foto: Peikko

These concrete columns produced by Finnish Peikko can be disassembled and reused, which makes them climate-friendly and economically viable.

Building materials

Foto: Leonora Malabi Larsen

Tomorrow’s building materials are designed to be disassembled and re-assembled—again and again.

In the next 40 years, we will be building just as much as we have built so far in human history. This requires a radically different mindset. Circular economy is the key word—also in the construction industry.

A sustainable future places considerable demands on the construction industry. Tomorrow’s buildings must be designed for disassembly to ensure components and materials can be reused. At the same time, CO2 emissions resulting from the solutions must be minimized.

This inspired DTU student Leonora Malabi Larsen to do a quite unusual master's thesis, in which she and her fellow student Sara Diraoui in collaboration with the contractor MT Højgaard and the firm of architects 3XN analysed the environmental benefits and technical possibilities of reusing building materials.

The project demonstrated that it is possible in practice to design buildings that allow building materials to be disassembled and used in future building projects with their current properties—and that such solutions can produce considerable resource and CO2 emission savings.

“The arguments in favour of incorporating reuse into the construction industry are gradually increasing, so the industry is facing a historic challenge,” assesses John Sommer, Sales Director at MT Højgaard.

New mindset

At MT Højgaard, where the thesis work took place, intensive efforts are being made to analyse and forecast future building projects.

“The demand for solutions that streamline our resource consumption will increase significantly in the coming years. That’s what everyone is talking about, and as one of the major players in the construction industry, we need to be at the forefront of developments to ensure we maintain our position in the future,” says John Sommer.

For example, many industry players have introduced the concept of circular economy, the goal of which is to ensure that essential building elements can be resold after use. This includes, for example, concrete columns, beams, and walls.

“It’s a completely new type of economy, which is appreciably different from the traditional way of thinking, where the costs of a building project are a one-off investment. When the building is to be demolished or renovated, the materials are no longer of value, which entails costs for disposal of the materials,” explains John Sommer.

The success of a circular economy requires three important factors: First, all building materials must be designed for disassembly. This involves architects, engineers, contractors, and manufacturers.

Second, the circular mindset must be widespread—just as with electric cars, where at some point, there will be a sufficient number of electric cars on the road, providing the capacity to establish a sufficient number of charging stations.

Third, a well-organized infrastructure must be established for selling and transporting the reusable building elements. And it may be digital. For example, there could be a special portal for uploading information about the elements that will be available after demolition, and the recipient can order them directly on the site. Physical stocks can also be established, for example in Roskilde and Horsens, from where 60 per cent of Danish construction sites can be reached within an hour.

Architects want high quality

The firm of architects 3XN has expanded the concept of a circular economy with the ‘cradle-to-cradle’ principle to create the concept of ‘circular sustainability’, which means that all resources must be recycled to avoid waste entirely.

“When taking about sustainability, often nothing ever becomes of it. It’s also necessary to find cost-efficient solutions to create a business case at the same time. This provides a dual benefit, and we believe that’s the basis for producing the scalable solutions needed. First and foremost, the materials must be of a high quality to withstand assembly and disassembly,” says Kasper Guldager Jensen. He is a partner and head of 3XN’s innovation unit.

Buildings made from high-quality products are generally expensive, but we must learn to think about building economy in an entirely new way, according to Kasper Guldager Jensen:

“We need to rethink building projects. What determines the outcome are the costs throughout the building’s life. And this paves the way for new business models, in which a building is a materials bank and not a one-off cost like today, where you don’t have the option of reselling any of it,” he explains.

Photo: Adam Mørk
Visible structures and joints may be inspiring. Here is 3XN’s own office in an old, modernized building.Photo: Adam Mørk.

A chain with many links

"About two billion people form the global middle-class today. In 2030, the number will be more than four billion, so the pressure on resources will be massive. "
John Sommer, MT Højgaard

In future building projects based on circular sustainability, the architect’s role will be to understand and incorporate the many different professional groups at the beginning of the process.

“We need to know the contractor’s and the demolition company’s work equally well and understand how they get hold of the valuable resources. And we need to collaborate with manufacturers to ensure the products they make can be reused. So there are many elements that need to work together, but the most important thing is to include the client and the user from the outset. They should feel that it enhances the quality, and that it’s relevant to work with pure quality materials,” explains Kasper Guldager Jensen.

Requires a large number of players

In her master's thesis, Leonora Malabi Larsen asked the industry, for example a producer of concrete elements, whether the company would be interested in producing standard elements that can be dismantled and reused. The answer was clearly no, if the company was one of the first movers.

“If it’s to become a success, we need a very large number of actors to adopt the new approach to create a market involving supply and demand,” explains John Sommer, who estimates that the industry needs 10 years to introduce ‘design for disassembly’, which was also the title of the thesis.

So we need to get started, because forecasts indicate that we will be building just as much in the next 40 years as we have built in human history. This includes everything from infrastructure to buildings, dams, etc.

“The pressure on resources is enormous, and how we choose to build over the next decades may be crucial to the future of the planet. One of the solutions is circular thinking. This is where Leonora’s thesis is useful to us, because apart from the economic gain, we must be able to document that our model also reduces CO2 emissions,” says John Sommer.

Leonora Malabi Larsen has subsequently been employed at MT Højgaard.

Green Challenge 2016

Leonora Malabi Larsen and Sara Diraoui studied Architectural Engineering at DTU when they won first prize in the category: master’s thesis concept at the Green Challenge student conference for their “excellent pitch, very interesting perspective. Good and applicable idea. All steps have been taken into consideration.”

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