Different districts, the same goal: sustainable building and refurbishment for future-proof housing

The construction of new wooden buildings in Elstal in Brandenburg and the refurbishment of multi-storey 1960s buildings in the heart of Kreuzberg in Berlin – the two measures sound very different, but they have one major thing in common: both pursue the goal of sustainability and seek to reconcile environmental, economic and social aspects as best they possibly can.

The six- and eight-storey buildings of the Spring estate located between Franz-Künstler-Straße, Alexandrinenstraße, Neuenburger Straße and Alte Jakobstraße in Berlin-Kreuzberg were built in the 1960s. 1,136 apartments and nine commercial units – space totalling 69,360 sqm – have been undergoing refurbishment here since 2016. In addition to bathroom modernisation and pipework renovation in approximately half of the apartments, the focus is above all on energy-related refurbishment, the windows, and insulation of the external walls, the basements and the attics. The measures improved energy efficiency by an average of 53% to approximately 88 kWh/sqm per annum. This will cut carbon emissions by around 980 tonnes per annum – an average of 58%.

Spring estate, Berlin-Kreuzberg
Spring estate, Berlin-Kreuzberg

The outdoor areas are likewise being thoroughly redesigned in line with sustainability principles. “The Spring estate is characterised by large green spaces between the buildings,” explains David Weinert, Technical Project Manager at Deutsche Wohnen Construction and Facilities GmbH. “Environmentally valuable flowering meadows are being created here as a source of food and a habitat for bees and other pollinators.” The existing trees and shrubs are to be retained as far as possible, to be replanted right there at the site. In addition to large blooming shrubs, newly planted indigenous deciduous trees will play a key role: “The trees will be specific to the particular building and will thus help people with orientation,” explains Weinert. The two new playgrounds at the heart of the estate will be given an inclusive design. “Snacking islands” featuring edible fruit varieties will give them added educational value. “From their hands into their mouths, children can experience nature with all their senses here,” the team leader says. The green roofs on all the six-storey buildings likewise contribute to greater sustainability in this living environment.

Spring estate, Berlin-Kreuzberg

Refurbishment period: 2016–2022
Houses: 18
Residential units: 1,136
Commercial units: 9
Investment sum: Approx. EUR 69 million
CO2 reduction: 980 tonnes per annum (58%)

More space is also being dedicated to eco-friendly mobility with plans for e-car share parking spaces and charging points. New and more bicycle stands will be installed at the entrances, some of which will offer greater security by being covered. The existing 1960s lamp posts in the outdoor area will be refurbished and fitted with more efficient LEDs.

To ensure the refurbishment work is socially acceptable for the residents, Deutsche Wohnen recorded appropriate measures in an agreement with the Friedrichshain-Kreuzberg borough council. As a result, the allocation of modernisation costs for insulation of the facade is capped, cases of hardship are taken into account and could also be reported to Deutsche Wohnen over an extended period. In addition, tenant meetings were held per building section. With good reason: “The meetings are a good forum for sharing information because, with modernisation announcements being very extensive, people understandably have queries,” says Linda Kalex, Commercial Project Manager at Deutsche Wohnen Management GmbH. Tenant support also results in ongoing on-site dialogue during the refurbishment in the form of regular consultation hours. Tenants also have the option of contacting the Deutsche Wohnen staff over the phone.

Elstal Eisenbahner estate
Elstal Eisenbahner estate

The topic of sustainable building is what it’s all about in Elstal, ten kilometres west of Berlin, too. This is where Deutsche Wohnen integrated four new multi-occupancy buildings made of wood and comprising 24 apartments in total into the listed Eisenbahner estate dating back to the 1920s which had already undergone refurbishment. “With this new construction project completed in 2019, Deutsche Wohnen consciously ventured into new ground. But from the perspective of sustainability, it is exemplary,” explains Sebastian Höfker, Project Manager at Deutsche Wohnen Construction and Facilities GmbH. “From an environmental perspective, it is above all the use of renewable resources that justifies the innovative and modular solid wood construction style. When building with wood, greenhouse gases are stored, rather than being released in large quantities, as is the case when other building materials are used,” says Höfker.

Elstal Eisenbahner estate

Start of building work: March 2018
Completion: October 2019
Houses: 4 multi-occupancy buildings
Residential units: 24
Investment volume: EUR 7.4 million

Wooden construction boasts other advantages in addition to the environmental added value: the high degree of prefabrication of the wall and ceiling elements using solid wood allows for quick construction – it takes the carpenters just 20 days to complete the building shell. The building time is reduced overall by around six months, among other things because drying times are eliminated. “What’s more, the buildings are durable and are relatively easy to maintain,” emphasises Höfker. The project’s sustainable character is reinforced by decentralised heat and power supplies from an on-site combined heat and power system.

The residents of the new buildings benefit from their positive structural attributes such as breathability and insulation. The insides of the external walls and ceilings were left untreated; these surfaces warm up quickly when the heating is on, resulting in a healthy interior climate and a cosy, natural home atmosphere.

The building measures were overseen by the German Sustainable Building Council (Deutsche Gesellschaft für Nachhaltiges Bauen – DGNB) from the beginning. Deutsche Wohnen was awarded the DGNB’s highest certification category, platinum, which recognises the especially sustainable quality of buildings over their entire life cycle.

DGNB

The DGNB system is used for planning, evaluating and recognising sustainable buildings. It does not evaluate individual measures, but rather the overall quality throughout a building’s entire life cycle. It certifies the outstanding fulfilment of 37 sustainability criteria in the areas of environmental, economic, sociocultural and functional, technical, process and site quality.

The DGNB’s certificates in platinum, gold and silver can be awarded both to new builds and portfolio properties. For portfolio properties, there is also an additional bronze certificate. The certification system was introduced in 2009 and has been continuously further developed ever since. It is one of the most widely recognised certification systems for sustainable building in the world.

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