To mark Open Heritage Day on 13 September 2020, with this year’s theme of ‘Sustainability’, Stefan Degen, Managing Director of Deutsche Wohnen Construction and Facilities GmbH, explains how Deutsche Wohnen bridges this gap. Together with his team, he has already refurbished pretty much every kind of building in the Deutsche Wohnen portfolio – whether they’re 1950s or 1960s properties, prefabricated high-rise blocks or all kinds of listed buildings.
Mr Degen, what sets Deutsche Wohnen’s listed buildings apart?
Listed buildings capture a zeitgeist. They bear witness to the culture of their time. And the most exciting thing of all: we can use them to draw conclusions for the future. Specifically, many of our old estates have a great deal of substance, architecturally and in terms of construction. We draw on this, as do our customers, neighbours, visitors, and the entire neighbourhood. These kinds of estates are really attractive locations.
When refurbishing listed buildings, I’ve discovered designs and components with a longer lifespan than their equivalents in new constructions. We try time after time to follow this approach, reinforced by what we know today – from restoration to new construction.
Which concrete measures is Deutsche Wohnen taking to bring sustainability together with preservation of listed buildings?
Our listed buildings bring the skills of sustainability with them as a matter of course. They include the Weisse Stadt in Reinickendorf, the Carl Legien Estate in Prenzlauer Berg, the Britz Horseshoe Estate, of course, and the Zehlendorf Forest Estate. These are all estates of Berlin Modernism that demonstrate stunning feats of urban planning and aesthetically pleasing architecture. Their layouts are outstanding and efficient. They are designed to be low in emissions. Even when we’ve refurbished them and construction costs have been a little higher, when you look at the costs over the entire life cycle, they’re real winners.
We have to preserve what exists. By maintaining these buildings in their condition, we save on grey energy. This is the energy produced in the manufacture, transport and storage of building materials. In the case of constructions and materials which can be maintained instead of demolished, resources and energy are not required to reproduce them. That’s sustainability.
So we can learn a lot from the methods and materials used to build the estates of Berlin Modernism and apply this to modern construction. How sustainably can we build in big cities in this era of housing shortage?
As we all know, demand for living space is high. New construction is necessary. However, we can try to close the grey energy loophole, for example, by using materials from sustainable resources for the new build. Above all, however, the urbanism of cities is key: adding to existing buildings, increasing densification, and extending upwards. In these cases, the properties are already available, developed, and connections are there, too. It’s not just the density of living that is made more compact – it’s the density of function, of supply, and of work.
Of course, every project is different. Two examples of existing and new construction works shaped by sustainability are the refurbished Argentinische Allee 221, which neighbours the previously mentioned Zehlendorf Forest Estate, and our newly built solid timber buildings in the Wustermark/Elstal region. Both projects have obtained a certificate from the German Sustainable Building Council [DGNB] – Argentinische Allee 221 was awarded ‘Gold’, and Elstal ‘Platinum’.