There are plenty of reasons for green roofs in urban spaces. First and foremost, the city’s appearance and quality of life improve significantly. Residents and employees are provided with additional green areas for sports and leisure activities. Rooftop gardens protect homes and offices from snow, rain and heat, and contribute strongly to energy efficiency by delivering a natural building envelope. Costs for sewers and retention reservoirs are reduced and fewer rainwater drainage fees save money. Local flora and fauna profit from a larger habitat and, last but not least, there is the option to combine green roofing with photovoltaic or solar thermal systems.
Green roofs large and small
Green roofing can come in many forms: moss-based green roofs can be self-sufficient with only the help of rainwater. Moss is especially suitable for installation on preexisting buildings, as moss requires only a thin layer of soil to grow. However, many modern roofs are designed to carry entire green landscapes complete with small ponds and groves. The most prominent example for such an ambitious gardening project is the St. Pauli Bunker on Feldstrasse. Plans for an elaborate network of green areas on top of the grey ramparts were ratified in 2017.
Subsidised green roofs in Hamburg
When it comes to green roofs, Hamburg has taken a leading role among major German and European cities: no less than 70% of all suitable rooftops are to be topped with vegetation. The City of Hamburg began to implement its policy on green roofs already in 2015, when the Hamburg Ministry for Urban Development and Environment allocated EUR 3 million to encourage green roof construction on both new and renovated buildings in Hamburg.
The green roof project, along with other eco-friendly construction measures, is meant to help the city adjust to population growth and climate change. To this end, green roofing measures for residential and non-residential buildings are subsidised with up to EUR 100,000 via the Hamburg IFB bank. You can apply for the funds if you voluntarily plan to install at least 20 sqm of green roofing with a soil layer of at least 8 cm in depth. Speak to the IFB before commissioning your building project, as retroactive funding won’t be granted.
More information in both English and German is available here.