In mainland Europe, many policies and strategies have been developed to support the installation of green roofs. In Basel, Switzerland, the motivation for developing green roofs was an interest in energy savings, and promoting the protection of biodiversity. Since 2002 the Swiss Building Regulations stipulate that all new and renovated flat roofs must be greened to provide valuable habitat (primarily for invertebrates), using specified materials. This has been supported by a reduction in electricity tax for buildings with green roofs which has, in turn, provided energy savings of approximately 4 GW/year. Basel Exhibition Centre roof includes an extensive green roof with an array of solar panels, which will perform more efficiently with a green roof (below, image from Green Roof Design).
Germany has also been pro-actively supporting the use of green roofs for a number of years. In Munster, a green roof policy was developed over concerns on flood water management and the need to create more green spaces within the urban setting. The local government introduced a reduction in fees associated with storm water management by 80% for buildings which had a green roof. This was in recognition of the attenuated run-off rates that can be achieved. This policy had resulted in approximately 12,000m2 of green roofs being installed by 2002.
In Stuggart, the motivation for a green roof policy was slightly different. Stuggart is positioned in a valley area where pollution and air quality can be problematic. The reduction in the urban heat island effect was also a strong driver for the implementation of a green roof policy. The policy that has been in effect since the late 1980s has included the installation of green roofs on public buildings. It has also introduced regulations which state that all flat and gently sloping roofs should be ‘extensively greened’. These approaches have led to more than >300,000 m2 of green roof being installed in the Stuggart area.
Green roof in Stuttgart (Amica)
Novel projects are beginning to emerge as more people take an interest in the advantages that green roofs and living walls can provide. The “Green box” project in the Italian Alps developed during the renovation of a small disused garage into a weekend house. The structure is covered with a lightweight galvanized framework and steel wires, transforming the builiding into a tridimensional support for the climbing vegetation.
The Green Box (Act Romegailli)
The first 2 towers in Milans Bosco Verticale (Vertical Forest) are due to be complete in mid-2013, and comprise of 2 residential tower blocks of 110 and 76 metres in height covered in over 900 trees of between 3 and 9m tall, along with a range of shrubs, bushes and plants on 9000 m2 of terraces. This equates to approximately 10.000 m2 of forest. The Bosco Verticale is a system designed to optimize, recuperate and produce energy. It will aid in the creation of a microclimate and in filtering the dust particles contained in the urban environment; the diversity of the plants and their characteristics will produce humidity, absorb CO2 and dust particles, produce oxygen and protect from radiation and noise pollution; improve the quality of living spaces and saving energy.
In June 2013, Danish firm BIG won an international design competition for a new green-roofed city, currently in the works for the suburbs of Paris. Europa City is a massive sustainable project topped off with a huge park that will combine the urban density of Paris with the bucolic setting of the suburbs. Intimate streets, connections to the metro, trains and adjacent highways as well as a connection to farmland will differentiate this master-planned city. It will combine all the convenient amenities of living in a city (like shops, offices, culture and activities) with the healthy qualities of living in the country.
Also in 2013, the European Union published " Building a Green Infrastructure for Europe ", a document promoting the inclusion of Green Infrastructure in developments and planning across Europe, explainign how it can meet a range of EU policies and advocating the multifunctional nature of good quality Green Infrastructure.