Moisture Safety of Green Facades

In Nordic climate, climbers covering facades are conventionally removed, although there is no evidence of the actual impact of the climbers on the moisture performance of facades. Such information is needed to support building design and nature-based solutions for climate change adaptation. This study aimed to find evidence on the performance of green facades from the physical and life-cycle engineering perspectives of buildings by testing double-skin green facades in laboratory and field conditions. First a mature thicket creeper was grown on a steel mesh over 100 days, and it was exposed to rain and dry periods by accelerated weathering equipment in a laboratory. Then the leafless creeper was exposed to rain cycles on a rooftop in natural conditions. The results indicated the high protective capacities of the climber during the leaf season, but even during the winter season (without leaves) protective performance was measured in laboratory and natural conditions. In conclusion, double-skin green facades provide effective protection from wind-driven rain while the distance between the green structure and the load-bearing wall impacts the relative humidity levels, and the drying process of the load-bearing wall. Thus, moisture safety can be improved with a double-skin structure with ventilation and access for maintenance.