Energiesprong on tour: Serial retrofitting in Berlin

Serial retrofits based on the Energiesprong principle can greatly accelerate the heating transition in existing buildings. Using a digitalised construction process and prefabricated elements for façades, PV roofs and plug and play energy modules, buildings can be retrofitted much more quickly and efficiently than before. dena is working with its market development team to ensure that this key technology quickly becomes widely available. To this end, it bundles demand, strengthens the transfer of knowledge, networks pioneers, screens innovations and provides impetus for further development as well as for optimum framework conditions.

One building block for this is the ‘Energiesprong on tour’ format to which dena invited interested parties to Berlin on 20 March. Around 80 attendees took the opportunity to experience serial retrofitting live, take a look behind the façades of completed administrative, school and residential buildings and discuss best practices and lessons learned with those involved. The following projects, some of which are still under construction and some of which have already been completed, were visited.

In Charlottenburg, Berliner Immobilienmanagement (BIM) is having Germany's first fire station serial retrofit. The retrofit is part of its InnoLab initiative which BIM is using to drive forward pioneering topics and establish them as a new standard. Designed by ZHN Architekten, the building will have a new building envelope consisting of 86 façade elements. The modules, including insulation, windows, sun protection and ventilation, will be prefabricated in the factory by timber construction specialist Sieveke, transported to the construction site by lorry and simply assembled there. The attendees were able to follow these ‘flying’ facades and assembly on site in real time. This innovative retrofitting process shortens the renovation of the building envelope from several months to just a few weeks.

The building made with GDR era precast concrete slabs dating back to the 1960s was dilapidated and actually due to be replaced by a new building. But when looking at the old plans, it quickly became clear that it was a highly innovative skeleton construction for its time that could be easily converted. With this knowledge, the zoo decided to bring the old building back to life. The project realised according to the plans by ZRS Architekten was not only serially retrofitted with prefabricated façade elements, but also planned according to circular principles.

The apartment block in Berlin-Tempelhof was retrofitted back in 2013 using serially prefabricated façade elements - one of the first residential buildings in Germany to undergo this process. During the retrofit, architects Schaller Sternagel, in cooperation with Hildebrandt Lay, looked for new ways to transform the inefficient 1960s building into a Passivhaus building in the shortest possible time. The decision was made to carry out a serial retrofit, which was completed in around four months. The higher investment costs compared to conventional refurbishment at the time have been offset by savings in longer-term operation: The façade system is virtually maintenance-free. Heating costs have been reduced by up to 70 per cent. Further savings were achieved through solar thermal energy and a decentralised ventilation system with heat recovery.

Many schools, sports halls and day care centres are also prime candidates for serial retrofitting. As most of the work switches from the construction site to the factory, it can ideally even be carried out during the holidays. The serial retrofitting of a primary school in Berlin-Marienfelde is an important pilot project on the way to achieving this: Following the retrofit concept planned by Dörr Ludolf Wimmer in cooperation with Felix Dechert Architekten and executed by Sieveke Holzbau using prefabricated façade elements in timber panel construction, decentralised ventilation units and geothermal probes, the energy consumption of the primary school built in 1971 fell by more than 80 per cent.

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