For many years, façade greening was primarily seen as an aesthetic tool. However, whilst green walls still undoubtedly meet that requirement, modern systems deliver a great deal more. Over recent years, as part of a broadly based academic research project in Berlin, scientists have been able to demonstrate that professionally designed green walls also deliver considerable ecological and economic benefits.
Large-area greening has been shown to significantly and measurably contribute to passive building cooling during the warm periods of a year, with a number of features contributing to this. Green walls provide natural shading to a building surface which prevents overheating during the summer months (in winter, when most plants have shed their leaves, solar radiation is able to reach the external building walls and warm them when the sun is shining). This climate-control effect is based on ‘evaporative chilling’, whereby green walls expend more than 80% of solar irradiation to evaporate water. By contrast, sealed surfaces convert more than 90% of solar irradiation into heat, which means that on hot days, to ensure a pleasant ambient temperature, this heat must be extracted with energy – and cost-intensive artificial air conditioning methods. Both these effects can be measured on buildings and converted into kilowatt-hours, and energy costs. If rainwater is then collected to irrigate the plants, a further positive ecological and economic benefit can be achieved.
Apart from the contribution that green walls provide to the cooling of buildings, there is another aspect to be considered. Due to the evaporation capability of climber plants, green walls heat up much less than conventional façades when they are exposed to intense sunlight and so reflect much less thermal energy to the environment. Particularly in densely populated areas (inner cities, commercial and industrial zones), they can therefore help curtail temperature peaks and perceptibly improve urban climates.
To fully tap into the ecological and economic potential of green walls, early-phase planning is essential. Ideally, this should begin in the architectural draft phase. For many years, Jakob has partnered clients, architects and designers in planning and implementing green wall projects – as can be seen in numerous project examples in many countries throughout the world. With its Green Solutions range, the company has developed a diverse portfolio of training structures that accommodate the different requirements of climber plants and at the same time guarantee that the training components are robustly and permanently anchored in place. The training structures in the Green Solutions range fulfill both functional and design requirements and can be used on virtually any building type. Needless to say, the development of project-defined special solutions is part of the all-encompassing Jakob service package.