Today's cities are largely built up and sealed. At the same time, buildings that we plan and construct today must still function in 50 years or more under the prevailing climatic conditions and withstand future extreme weather events as well as possible. It is therefore important not only to provide short-term answers to urgent needs, but also to consider these as long-term strategic measures at various scales. In addition to principles such as the sponge city or measures to contain the urban heat island effect, green façades and roofs also contribute to improving the microclimate in the immediate living environment. “Green” architecture has been proven to reduce heat islands in cities, has an insulating effect, binds particulate matter and promotes biodiversity.
High costs and maintenance costs, damage to the building fabric, doubts about the climate effect and even unwanted animal co-inhabitants—the list of prejudices is long. Yet greening buildings offers many advantages. One of the most important is the improvement in air quality. Plants on the façade filter pollutants and dust from the air and thus significantly improve air quality. They absorb carbon dioxide and produce oxygen, which is particularly important in densely populated urban areas.
Another advantage is energy saving. Green façades act as a natural insulating layer that keeps the interior cool in summer and warm in winter. This reduces the energy required for heating and cooling, leading to considerable savings in energy costs. Plants also help to reduce the urban heat island effect as they absorb and reflect less heat than conventional building materials such as concrete or glass.
In addition, façade greening offers protection for the building fabric. They protect the façade from harmful weather influences such as rain, UV radiation and extreme temperature fluctuations, which can extend the service life of the building materials and reduce maintenance costs. Green façades also improve the microclimate by regulating humidity and creating a more pleasant environment. In addition, they can reduce noise levels in urban areas by absorbing sound. From an aesthetic point of view, green façades beautify the cityscape and contribute to the creation of attractive and liveable urban spaces. The sight of plants and green spaces has been proven to have a positive effect on people's mental health and well-being. Finally, façade greening promotes biodiversity by providing a habitat for birds, insects and other small animals.
Overall, façade greening contributes significantly to sustainability and quality of life in urban areas by reducing the impact on the environment, lowering energy costs and promoting the well-being of residents.
In order to maintain and develop resilient climate-effective urban greenery, specialized knowledge of the adaptability of individual species under different conditions is required. Two recent publications by the Federal Institute for Research on Building, Urban Affairs and Spatial Development (BBSR) offer support in this regard.
Under the title “Stadtgrün wirkt!” aspects of plant selection for efficient vegetation for climate adaptation and climate protection in the city are presented.
The publication “Low-Tech-Green Façade Greening” is dedicated to quantifying the costs and benefits of façade greening. The aim of the research and development project is to develop a cost-effective system for the greening of building façades in production and operation and to verify the course of plant growth using dynamic building model simulations in order to provide evidence of thermal insulation in summer.