Verticalization of green spaces is an adequate way to increase vegetated surfaces with many ecological services in urban environments. Free standing living walls serve as adaptation measures for the urban heat island effect. Furthermore they create space with high amenity value and (potentially) high biodiversity and reduce noise emissions. They are suitable to re-use run-off water and evapotranspirate highly. On the contrary, with extensive vegetation they sustain also longer periods of drought.

Basic information

Type: 
Retrofitting + Creation

Performance

Evapotranspiration 2 2
Shading 2 none
Reflection (Albedo) none
Water Conveyance none
Water Infiltration none
Water Retention none
Water Storage none
Water Reuse none
Water Filtering none
Water Bio-remediation none
Deposition 1
Bio-filtration 1
Habitat Provision 2
Connectivity 1
Beauty / Appearance 2
Usability / Functionality 1
Social Interaction 1
Role of Nature / Mode of Action: 
Natural soil with vegetation cover (perennials and shrubs/trees) is the model for living walls. Vertical layering of soil with plants growing on vertical surface as well as on top of the wall. Depending on the thickness of the living wall (approx. 40 cm) as well as the height normal soil functions can evolve, with filtering along the passage through the soil. Evaporation from vertical soil is one major effect. Transpiration from vegetation depends on plant selection, exposition and level of irrigation.
Technical & Design Parameters: 
Vertical layering of soil/substrate which is stored in metal cages with supporting elements to create walls of up to 4 m. Fabric (organic or un organic) is used to prevent the substrate / soil from eroding from the cages. Fairly heavy construction which rests on a simple strip foundation. Living wall needs to be constructed in two segments (minimum) that form a right angle in order to stabilize the living wall. Very flexible with regard to plant selection, as long as irrigation and fertilizer can be managed accordingly.
Conditions for Implementation: 
Because of the thickness of the living wall there is hardly any problem with central European frost periods. Underground needs to be loadable in order to support the wall. Little risk of fire because of constant irrigation.
Benefits & Limitations: 
Benefits: Living walls provide direct shelter from the sun and depending on the vegetation indirect shelter (e.g. tree wall with trees growing from the wall). High evapotranspiration of vegetation also helps to decrease heat island effect. - Beneficial for selected species if respective plants are used. - Noise reduction - Surface water can be used for irrigation of living wall. Potential limitations/disservices: - Irrigation is needed (summer and winter) but it should not rely on drinking water. - Supporting underground is needed. - Free standing living wall may act as a barrier for pedestrian movement.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 730052 Topic: SCC-2-2016-2017: Smart Cities and Communities Nature based solutions