Urban Mining & Recycling

The Urban Mining & Recycling unit demonstrates how a responsible approach to dealing with our natural resources can go hand in hand with appealing architectural form. The project is underpinned by the proposition that all the resources required to construct a building must be fully reusable, recyclable or compostable. 


This places life-cycle thinking at the forefront of the building design created by Werner Sobek in collaboration with Dirk E. Hebel and Felix Heisel: Instead of merely using and subsequently disposing of resources, they are borrowed from their technical and biological cycles for a certain amount of time before being put back into circulation once again. Such an approach makes reusing and repurposing materials just as important as recycling and upcycling them (both at a systemic and a molecular/biological level, e.g. via melting or composting). This conceptual emphasis means that the Urban Mining & Recycling unit functions simultaneously as a materials laboratory and a temporary material storage.


The following approaches lie at the heart of the design:

  • Temporary removal and borrowing instead of permanent acquisition and disposal
  • Maximal modularisation and prefabrication
  • The potential for all materials and products to be extracted cleanly, separated out and sorted


The innovation objects in the Urban Mining & Recycling unit
Modular primary structure

The supporting structure is made of wood – a primary material that (if used correctly) can be salvaged and recycled without diminishing its value. The innovation lies in the joints and an appropriate use for the material: the nodes of the system that are exposed to pull and pressure are reversibly connected. Adhesive joints are overlooked entirely in favor of plug-and-socket and screw joints. Conventional coatings, which rule out single-variety recycling and a purely biological disposal, are replaced by constructive wood protection.   
The resulting unit consists of self-supporting modules, which, if need be, can also be exchanged while «still in operation». This enables them to be refitted and upgraded in the workshop, a key prerequisite for the full re-usage of the materials or products they contain. As a rule, however, it will be sufficient to exchange the wall and ceiling panels during the project to conduct the intended tests on the materials.

Partners: Werner Sobek Design, Heisel/Hebel Architekten, Kaufmann Zimmerei und Tischlerei GmbH

Material resource: waste

Recycled materials from waste as a material resource are already available in a large number of prototypical products for use in the unit Urban Mining and Recycling. Through the use of exemplary product groups, the innovation object reveals the potential of this source of material and answers questions on the appropriate and safe handling of waste as building material. When selecting the individual materials, it is important to remember that converting refuse into a building material does not extend the dead-end road; instead, the raw material is transferred into a cycle (partly accepting a one-off downcycling).
The materials in this innovation object can be divided into three groups, categorized according to the production process: (1) compressed, (2) physically transformed and (3) chemically transformed. The aim is to use at least one material from the aforementioned product groups in the unit Urban Mining und Recycling and test its suitability for use on a larger scale. The manufacturers of the individual building materials have shown great interest in a collaboration to test their products (subject to certain conditions) in a real environment on a 1:1 scale in NEST.

Partners: Karlsruher Institut für Technologie KIT, various

Material resource: urban mining

Currently, as a material resource, urban mining mainly involves the recycling or further use of approximately 1 percent of the products characterized by a collector’s or fair value. Due to improper use or non-recyclable compounds, the majority of the resource becomes «hazardous waste», which is difficult to re-use – if at all – on account of the material mixture. The prevalent method therefore involves a downcycling process for this resource in the form of aggregates or fillers for new material mixtures. 
Few materials sourced from urban mining are currently available as prototypical products for use in the unit Urban Mining and Recycling. Therefore, this innovation object pursues two different strategies: (1) The exemplary use of existing products to reveal the potential and test the handling of such sources of materials; (2) the improvement of the status quo by facilitating the full re-use of the NEST unit as a material resource. The building can be regarded as a materials store.

Partners: Karlsruher Institut für Technologie KIT, various

Material resource: cultivated materials

Concrete is humankind’s most used building material – with one major drawback: The raw materials needed to produce it are becoming scarce. Sand is already a coveted resource and terms like «sand war» and «sand mafia» are doing the rounds. Consequently, Professor Hebel from Karlsruher Institut für Technologie KIT is researching alternatives that will leave the age of «mining» behind and describe a path of «harvesting». 
In Phase 2 of the NEST unit Urban Mining and Recycling, we are therefore planning to introduce a third materials group – the resource of cultivated building materials. Mycelium describes all hypha, the threadlike cells of a fungus. Combined with organic waste materials (e.g. sawdust or agricultural waste), the mycelium of certain fungus species can be «woven» into pressure-resistant building materials and the physical properties of the construction material controlled locally during the process. This pressure-resistant, natural building material can grow in freely malleable forms.

Partners: Karlsruher Institut für Technologie KIT, various

Visualization of materials and 4D cadastral plan

In common building practice, architectural and static plan data of all the buildings approved and constructed is lodged two-dimensionally with the respective local building authorities (in the form of plans and sections and with the aid of the so-called cadastral plan). While this information (and the established data transfer system behind it) is extremely important for common building practice, the information stored within is insufficient to operate an urban mine in the sense of a circular construction economy. Interestingly, the City of Zurich is currently working on the development of a three-dimensional cadastral plan to record additional information – primarily with regard to the building volume. Such a step will probably pave the way for the inclusion of other data, such as BIM (Building Information Modelling), and thus facilitate the location and quantification of certain building components within the building model and city. Based on the following considerations, this 3D cadastral plan represents a good basis for the development of a 4D cadastral plan of the urban mine.

Partners: Karlsruher Institut für Technologie KIT, various


The NEST unit Urban Mining & Recycling is taking shape

UMAR explained by Felix Heisel, one of the project initiators (in German).

UMAR - Urban Mining & Recycling Unit / NEST
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Here you find all publications concerning Urban Mining & Recycling.