Over 200 million tons of construction waste are generated in Germany every year. In Augsburg, too, landfill space is now becoming scarce and new landfill capacity for construction waste needs to be created. If the regional construction and real estate industry has its way, this situation should change and more building materials should be reused. On the initiative of A³, a whole network of organizations had invited all industry stakeholders to a joint dialogue on circular construction in mid-October, including the Innovative Construction theme platform.
The topic met with outstanding interest among companies in the region, the rush of participants even forced the organizers to change locations. So the will is there, but there are still some challenges to be solved in implementation.
Whoever wants to recycle building materials does not have it easy: "We tried to separate modern polystyrene insulation from a wall in the hall on a model. The attempt ended in a snowy landscape of white beads - imagine that on a construction site when it's windy," Prof. Andrea Kustermann of Munich University of Applied Sciences explained the challenge to the 150 or so visitors to the event.
Recycling should actually be the standard and not the exception in the 21st century. But what has long been common practice for many materials is nevertheless a more complicated challenge when it comes to buildings. The large wrecking ball is already predominantly a thing of the past on the demolition construction site. Demolition companies already try to separate as many materials as possible neatly at the construction site. However, this is not always made easy for them in view of pollutants, unclear ingredients of building materials, composite materials and material compounds that are difficult to separate. Under the catchphrase "circular building", the industry is now trying out new ideas from planning to demolition.
Whoever wants to build in a circular way must above all adhere to two essential principles: "Firstly, dismantlability and separability, i.e. no full-surface bonding, but better screws; secondly, freedom from pollutants, i.e. no wood preservatives, biocides, flame retardants," demanded the experts on sustainable building Prof. Susanne Runkel of the university Augsburg and Jens Glögger of atp sustain.
Who builds in used construction units?
If these principles are considered, nothing would actually stand in the way of a re-use - presupposed it finds itself at all a buyer. Who would want to install an old building component in his new building? Kathrin Fändrich from the State Building Authority and Prof. Mikala Holme Samsoe from the Augsburg University of Applied Sciences asked themselves the same question and, without further ado, dared to try it out: before the demolition of the Old City Library in Augsburg, students measured and photographed everything that was not nailed down and posted it on the online platform Concular for the marketing of used components. 400 usable parts were offered for sale, 70% of which could be sold. Above all private house builders (70% of the Nachfrager) and architect's offices (20%) fell back gladly on the used construction units: There was for example the family, which dismantled the escape stair for its building project even. Also in demand were light fixtures, doors, grates, radiators, concrete slabs and sanitary objects - even the toilets and washbasins found buyers. "Recycling is also worthwhile for the building owner," emphasized Kathrin Fändrich from the Augsburg State Building Authority. "Not because we generate high revenues from the building components, but because we have saved on disposal and landfill costs."
When is construction waste waste?
The weightiest substance of most structures - concrete - should actually be easy to recycle, one would think. After all, there is recycled concrete. Here, too, there are some challenges to be solved, as the example of the Bayernkaserne in Munich showed. Here, new recycled concrete was to be generated directly from the 1.2 million tons of demolition material and used again. 50% were contaminated and had to be disposed of, but at least 50% of the materials could be processed and reused. But here, too, builders are needed who are willing to use recycled concrete. The fact that recycled concrete can be relied on in terms of quality was shown by the tests conducted by Prof. Andrea Kustermann of the Munich University of Applied Sciences. However, it is important to note that "if you want to recycle the concrete of a building, you have to plan it early on before demolition," Andrea Kustermann appealed to builders. "It goes more than one thinks, if the building materials are analyzed, sampled and prepared in accordance with the regulations," also emphasized legal and recycling management expert Holger Seit from the Bavarian Construction Guilds Association: "Appropriately tested quality-assured mineral recycling building materials are no longer waste, but building products."
The examples presented also inspired the real estate and construction industry present. A quarter of the participants stated that they would like to realize a project in the field of circular construction, and 20% already had concrete plans here. At the topic interested owners, planners and building contractors can turn gladly here to the organizer network, the partners support gladly with the switching to suitable experts or co-operation partners.
- Martina Medrano, Regio Augsburg economics GmbH -
