Next months, these posts deal with the challenges of Earthlings of bringing humane cities closer. These posts represent the most important findings of my e-book Humane cities. Always humane. Smart if helpful, updates and supplements included. The English version of this book can be downloaded for free here and the Dutch version here.
Structural waste in the build environment. Source: The circular economy: Moving from theory to practice, McKinsey & Company 2015
The impact of circular principles in the construction sector is huge, because buildings are responsible for more than 50% of the total use of materials on earth, including valuable types such as steel, copper, aluminium and zinc. Moreover, they produce about 40% of all greenhouse gases.
By circular construction we mean designing, building and demolishing a building in such a way that, in addition to the high-quality reuse of materials, justice is done to sustainability ambitions in the field of energy, water, and biodiversity and ecosystems.
In case of demolishment, nowadays many components are reused, but at a very low level, for instance concrete and stones as the foundation of new roads. Apart from the question how many new roads are still needed, this type of recycling destroys the intrinsic quality of materials and does not diminish the recovery of new materials. At least, separation of glass, steel, wood and other materials can be made mandatory. In addition, valuable materials can by ‘saved’ by operating in a targeted manner, even though these buildings are anything but circular. This is called ‘urban mining’. The biggest problem is that recycled materials are often more expensive than new ones.
Anyway, a first step is more efficient use of existing buildings. Evidently, progress can be made by planning, designing, developing and building circular buildings. A number of options are mentioned below[1].
Urban planning
Challenges for planning are the use of inner-city vacant land and issuing mandatory requirements regarding the construction of new buildings, for instance the use of less cement, glass and steel, the mandatory application of a certain percentage of reused materials, and becoming energy positive or at least energy-neutral. Switching to sustainable timber is an option for 90% of homes and 70% of offices being built.
Mandatory reuse of existing components
Reuse of existing materials means than glass is reused as glass and concrete pillars as pillars. The same applies to doors, frames, carpets, wall-cladding materials and so on.
The materials passport, which contains an overview of all materials and components that are used to construct of a house or building, is a useful tool as well. The obligation to reuse a large percentage of existing components has far-reaching consequences for the design and construction of new houses. To start with, after demolishment all materials must be selected, cleaned, registered and stored in new-to-develop warehouses.
The Circl pavilion of the ABN-AMRO bank
The Circl pavilion of the Dutch ABN-AMRO bank is an example of a new building that uses as many existing components as possible. For instance, 1200 m2 of wooded floors, partition walls of a demolished building and 16.000 garments of employees for isolation purposes. All components of the building are designed to be reused[2].
Industrial production and 3D printing
Construction of components in factories, deploying industrial processes, will reduce costs by 30 percent and the delivery time by at least 50 percent.
Decreasing size of apartments
The size of apartments will decrease, partly due to costs, but also because of the presence of shared guest rooms, lounge areas and terraces for working and socializing, spaces for washing and drying laundry.
The need for office space will decrease rapidly due to sharing space and working in an external environment. So IBM has only one desk available for 12 employees. Given the presence of 300,000 employees, this has led to savings on real estate of around € 1 billion in the past 10 years.
Modularity and durability
A key barrier for better use of floor space is the lack of flexibility in the design of buildings and room configurations. A modular design, which provides for easy replacement of partitions and placement of complete functional units (kitchens and bathrooms) facilitates adjustments as the use of a building changes.
Forget new construction at all
As families become smaller and offices need less space, existing space becomes more underused. Well-thought adjustments to the lay-out of existing houses and buildings can improve their efficiency without reducing their amenity. That is what adaptive reuse stands for: instilling a new purpose on an existing “leftover building.”. A number of inspiring examples can be seen here[5].
[1] https://www.mckinsey.com/business-functions/sustainability/our-insights/the-circular-economy-moving-from-theory-to-practice
[2] https://www.duurzaambedrijfsleven.nl/infra/24589/abn-amro-opent-deuren-van-innovatief-en-circulair-paviljoen-circl
[3] http://www.winsun3d.com/En/About/
[5] https://www.archdaily.com/931659/10-plus-proposals-to-promote-adaptive-reuse-and-introduce-transformative-ideas?utm_medium=email&utm_source=ArchDaily%20List&kth=
Science for Society 