Facade greening
Facade greening is a form of building greening and means planned and at least controlled vegetation of suitable or specially prepared facades with plants.
Use
The facade greening serves the protection and the individual external design of a building as well as the improvement of the built environment under ecological aspects. In particular, building physics, air hygiene and urban ecological effects have been scientifically investigated since about the last third of the 20th century. The results so far - obtained from the occasional existing greenery - confirm positive effects that have long been assumed. However, in each case in a rather modest quantity. In 2012, however, it was determined by simulation at the Karlsruhe Institute of Technology (KIT) that facade greening in particular can bring about considerable improvements in urban air and urban climate (up to 30%). This result agrees noticeably better with the perceived positive effect of green facades, which residents and neighbors of green houses often report. This confirms the suspicion that the above So far, measurements have not been able to adequately determine the overall effect of facade greening. A comprehensive assessment of the positive effects reveals numerous reasons for these greening methods. There is no technical system that can develop comparably diverse and appropriate positive effects. The expected effects include shading and the associated cooling, filtering and binding of dust and air pollutants, contribution to biodiversity, retention of water from rapid seepage, mitigation of extreme temperatures as well as noise, radiation and weather protection.
The identification of house residents with facade greening is high according to studies by the Geographical Institute of the University of Cologne . This results in a corresponding importance in the context of improving the living environment and urban development. However, this also results from the fact that the majority of city dwellers regret the lack of green in their city.
Types of greening
Up until now , greening facades was usually done with climbing plants - possibly also with espalier trees. In the meantime, methods based on direct facade vegetation are increasingly establishing themselves. For this purpose, the facades are designed as vegetation areas. A distinction is therefore currently made in specialist circles between wall-bound and ground-bound facade greening - depending on where the facade growth sprouts or roots. There are various mixed forms between the ground-based (classic) and wall-based facade greening, e.g. B. Façade vegetation from planters arranged in layers.
Ground-based (classic) greening
The classic facade greening with climbing plants can be done by direct vegetation with self-climbing climbing plants or with so-called scaffolding climbing plants. In Germany, the “Guideline for the Planning, Execution and Maintenance of Facade Greening with Climbing Plants” (FLL eV, Bonn, 2000) claims to represent the current state of the art for such measures. A revised version is currently being prepared.
The climbing plants - both self-climbers and scaffold-climbing plants - specialize in rapid height growth. They grow on a base (e.g. rocks, tree trunks) or around or in a support (mostly wood, but also dead wood). In addition, they form only minimal trunks that only fulfill supply tasks, and thus gain advantages in the competition for light and solar radiation. Climbing plants do not have the ability to support themselves. This aspect is increasingly important for facade greening with climbing plants, as modern facades often have very limited surfaces.
Self-climbing plants
Self-climbers, suitable for direct vegetation on buildings, develop organs of attachment. As a rule, these are adherent roots (e.g. ivy , climbing hydrangea , trumpet winds ). Adhesive disks are very specially adapted tendrils of Parthenocissus species / varieties, i.e. of the wild wine. Only its adhesive disc-forming varieties are self-climbing.
There are many opinions and prejudices about the compatibility of self-climbing vegetation on facades. These are partly based on historical observations on ivy-covered structures. In addition, there have been long-term positive and negative experiences. The latter result in the mostly completely undifferentiated “general reservation” against any facade greening, which can still be found with (predominantly older) house owners.
The analysis of historical damage reports is only of limited use due to technical progress. The majority of modern facades have different technical requirements (cladding, coating, etc.) than historical walls and plasters. A rough, currently useful rule of thumb for the suitability of self-climbing for facade greening could be: "Only hard, difficult to remove, vertically loadable and joint-free and crack-free facade surfaces should be greened with self-climbing". Wild wine that forms adhesive discs has lower requirements than species that form adhesive roots.
Scaffolding climbing plants
The scaffold climbing plants are divided into climbing plants (wrapping around), climbing plants (form "grasping organs" = tendrils) and spreading climbers (spreading and hooking each other) according to their climbing strategy. These climbing techniques result in basic demands on scaffolding that such climbing plants need for facade greening. These constructions are called comprehensive climbing aids in specialist circles . Strictly speaking, the colloquial terms "climbing aids", "climbing grids" etc. only apply to climbing aids that meet the requirements of climbing plants.
Wall-mounted systems
In addition to the aforementioned systems, non-ground systems are also establishing themselves on the market. These cassette systems are not directly connected to the ground and require separate irrigation. This boom was founded by the French botanist Patrick Blanc , who developed the first system in this direction over many years.
The system structure influences the physical effects of the building. Usually it corresponds to a curtain-type, rear-ventilated facade (VHF).
The approaches for the substructures are diverse. From fleece-lined bags to structures made of plastic, filled with rock wool as a water reservoir, to aluminum cassettes filled with substrate, there is a multitude of different, functioning systems. What all non-ground-based systems have in common is that they are quite complex in terms of the initial costs for material and assembly. Irrigation and nutrient supply as well as maintenance are usually expensive.
Modules can be used flexibly. Curtain-type facade baskets keep heat radiation away from the building. The evaporative cooling of the irrigation water also offers a certain cooling effect.
maintenance
Every facade greening requires a certain amount of maintenance in the long term. The care for the growth of the plants goes over to the maintenance care, which is often limited to the cutting free of facade openings. The respective effort is largely determined by the height of the facade greening. It can be reduced by selecting the right plants and adapting the greening technique.
Choice of plants
Primarily, the requirements of plants in terms of light, soil and (small) climate must be taken into account. In addition, the climbing technique of the plants and species-specific properties such as weight, shoot diameter, height and orientation are important. Evergreen facade vegetation is particularly advantageous on walls that are exposed to precipitation and on walls that are permanently shaded anyway, as they can worsen the energy balance of facades exposed to the sun in the winter months.
Evergreen climbing plants
Besides the well-known ivy, there are few evergreen climbing plants in the Central European climate.
Depending on the location, some species of the 5 to 10 meter high, looping Akebia in Central Europe keep their leaves through the winter until almost spring.
Picture gallery
Wall in Mexico City
Parking garage in Mannheim
House in Giessen
Lavishly green wall
Britomart Transport Center in Auckland
literature
- Federal Agency for Nature Conservation (BfN) (Hrsg.): Roof and facade greening - new habitats in the settlement area. Facts, arguments and recommendations. Bonn 2019, ISBN 978-3-89624-276-1 (PDF, 3.6 MB)
- Rita Gunkel: Façade greening . Ulmer, 2004, ISBN 3-8001-4237-6 .
- Manfred Köhler: Facade and roof greening . Ulmer, 1993, ISBN 3-8001-5064-6 .
- Ralf Röger , Tobias Chilla, Alexander Stephan, Ulrich Radtke: Façade greening as an instrument for sustainable urban development - legal issues and perspectives. In: Journal for Environmental Law. 2002, ISSN 0943-383X , pp. 249-257.
- Nicole Pfoser, Nathalie Jenner and others: Green building energy. Potentials and interactions. Final report research project Zukunft Bau. Bonn 2014, ISBN 978-3-940122-46-9 . (free download)
Web links
Individual evidence
- ↑ Press release from August 2012.
- ↑ FLL eV: RWA facade greening , accessed on February 1, 2014.
- ↑ Akebie , In: Fassadengruen.de
- ↑ Akebia quinata - Akebie, blue cucumber wine , twining climbing plants, light, medium-high, evergreen, early flowering. In: Fassadengrünung-polygrün.de. Accessed April 2020