Comparative life cycle analysis for green façades and living wall systems

Greening the building envelope focusing on green façades with vegetation is a good example of a new construction practice. Plants and partly growing materials in case of living wall systems (LWS) have a number of functions that are beneficial, for example: increasing the biodiversity and ecological value, mitigation of urban heat island effect, outdoor and indoor comfort, insulating properties, improvement of air quality and of the social and psychological well being of city dwellers.This paper discusses a comparative life cycle analysis (LCA) situated in The Netherlands for: a conventional built up European brick façade, a façade greened directly, a façade greened indirectly (supported by a steel mesh), a façade covered with a living wall system based on planter boxes and a façade covered with a living wall system based on felt layers. Beside the environmental benefits of the above described greening systems, it is eventually not clear if these systems are sustainable, due to the materials used, maintenance, nutrients and water needed.A LCA is used to analyze the similarity and differences in the environmental impacts in relation with benefits estimated for two climate types for building energy saving (reduction of electrical energy used for building cooling and heating).

► The direct greening system has a small influence on the total environmental burden.
► The indirect greening system analyzed has a high influence.
► The LWS based on planter boxes has not a major footprint due to the materials.
► The LWS based on felt layers has a high environmental burden.
► Greening the building envelope can be a sustainable option.