Our building projects are focused on sustainability and circularity.
Turning old into new: STRABAG subsidiary ZÜBLIN is leading the design and construction of a new administrative building for the Esslingen district government as a pilot project for environmentally friendly construction. As the old administrative building on the banks of the Neckar was in need of renovation and had become too small, the decision was made to demolish and replace it with a modern, two-part office building of four and five storeys.
Top priority for the client is to save resources during construction and ensure the sustainable realisation of the project in all respects. To achieve this, the project follows a specially developed two-step concept for environmentally friendly construction. In step one, the systematic demolition of the old building, the raw materials are separated as much as possible and professionally reprocessed for reuse (urban mining). In step two, ZÜBLIN will use the recycled building materials during the turnkey construction of the new building. The structural framework, for example, will be cast to a large extent from resource-saving concrete (R concrete) . The ZÜBLIN team is also drawing up a catalogue of ecologically sound building components as well as a special demolition concept for the new administration building.
More than 90 % of the building materials are recycled.
In May 2022, the recycling specialist Heinrich Feeß GmbH & Co. KG began systematically gutting and dismantling the old six-storey Esslingen district office building on behalf of ZÜBLIN. In order to optimise the recycling of the rubble and debris, the demolition works follow a “material flow balance sheet” drawn up in advance that details the quantities of each material as well as their respective recycling and disposal paths. More than 90 % of the materials recovered from the old building can be recycled and reused.
Specifically, this means, for example:
- The 31,500 t of concrete from the old building are crushed and screened directly on site (up to 1,800 t/day). The concrete granulate is then recycled in the Feeß wet separation plant in Kirchheim to produce an aggregate for resource-saving concrete for delivery to nearby concrete plants.
- At the Kaatsch metal processing plant in nearby Plochingen, more than 1,220 t of metal from the old building – from reinforcing steel to aluminium windows to copper cables – are processed for reuse.
- In Zweibrücken, Remondis recycles around 400 t of gypsum planks and cardboard for future use in building construction.
“Our planning not only creates a higher number of workplaces in a modern administrative building, it also allows us to set high environmental standards.”
From design to operation: new building constructed in the name of sustainability
Once the old building has been completely demolished, the project team of ZÜBLIN Subdivision Stuttgart and ZÜBLIN subsidiary Wolfer & Goebel Bau GmbH will realise the new administrative building between Merkelpark and the banks of the Neckar on a turnkey basis by September 2025. The two-part building complex in the shape of a horizontal figure of eight follows the design of BFK Architekten and will be connected to the existing administration high-rise on two levels. The two polygonal structures with four and five floors as well as two basement floors offer a total net floor area of 33,000 m² to accommodate 675 workplaces for administrative staff from 11 different departments.
The focus is on energy efficiency, environmental friendliness and resource conservation in all phases of the building project.
- ZÜBLIN will design all processes on the construction site in accordance with the broad sustainability standards defined by the German Sustainable Building Council (DGNB) for construction site certification. A DGNB Sustainable Construction Site pre-certificate has already been granted. Full certification is awarded at the conclusion of the construction phase for end-to-end sustainability quality – including construction site organisation and resource protection as well as aspects such as health, social issues and communication with the public, and the quality of the construction work.
- As a rule, low-pollutant building materials are used that have been found to be harmless to human health according to the AgBB testing scheme and/or at least meet quality level 3 of the DGNB criterion NBV 2018 ENV 1.2 “Risks to the Local Environment”.
- In accordance with the principle of circularity, ZÜBLIN is constructing the new building with the highest possible percentage of recycled building materials,e. the material recovered from the old building is reused as much as possible.
- The new district administration office is being built to the KfW Efficiency House Standard 40. This means that the primary energy demand in operation is at most 40 % of the standard for new buildings. This level is ensured, among other things, by use of a heat pump fed with river water for heating and cooling the building via combined thermal radiation/forced-convection ceiling panels as well as the extensive use of photovoltaics to generate electricity on-site. A PV system with an output of approx. 375 kWp on the green roofs, along with additional façade-integrated PV modules with approx. 75 kWp, will generate the electricity for the new building and for the planned EV charging stations for electric cars and pedal-assisted electric bikes.
- Resource conservation is an important guiding principle for the interior design as well. The furnishings and fittings include cradle-to-cradle certified products, such as office system partitions and wood flooring with FSC/PEFC certification.
- With its sustainability standards, the new administration building will also meet the lifecycle-oriented sustainability criteria for DGNB Gold certification for new buildings.