Owing to their greenery and construction, the green roofs provide retention and storage of an average of 40 liters of rainwater per square meter. This represents between 70 and 80 percent of precipitation. The majority evaporates and is utilized by plants, thus supporting the natural water cycle.
Greening the roof surfaces commences in 2003. Meanwhile, more than 3,500 square meters of roof area on the company's premises in Ispringen have been extensively greened in a multi-layer structure. This includes parts of the administrative buildings and the logistics center.
Extensive greening implies near-natural green areas on roofs which largely preserve and develop by themselves. In addition to architectural benefits such as improving fire protection and proofing roofs against wind and weather, green roofs also play an important role in reducing wastewater. As more and more surfaces are sealed with impermeable, solid concrete, rainwater can no longer seep into the ground, but enters the sewage system directly. Especially during heavy rain, this can repeatedly lead to flooding. A green roof counteracts this, as much of the precipitation is consumed by the plants, which in turn supports the natural water cycle. The remaining precipitation drains off with a time lag, relieving the burden on the sewage systems and reducing the risk of flooding.
A green roof offers additional ecological benefits: the planted roofs are natural air conditioners, as water evaporates during photosynthesis of the plants, which creates a pleasant cooling effect during the day. In contrast, water condenses on the surface of the plants at night, which generates heat. The natural evaporation of water stored in the green roof improves the microclimate, providing both cooling and humidification. This has a particularly positive effect on the adjacent administrative offices. Throughout the year, the plants insulate against cold, heat and wind, thus balancing the temperature. By doing so, they make a considerable contribution to energy savings.
In addition, green roofs filter between 10 and 20 percent of particulate matter from the air and reduce pollutants in the air and precipitation. Green roofs are natural sound absorbers and reduce noise by up to eight decibels.
Another particularly important aspect is the promotion of biodiversity, as green roofs help to replace the habitat for insects and other small animals ruined by building development. If one takes a closer look, one can discover various wild bee species such as bumblebees, wasps and solitary bees, blue butterflies, checkerboard butterflies and other butterflies, ants, ladybugs and spiders on the roofs of Dentaurum ... even the wasp spider, one of the most beautiful spiders native to Germany, has already been spotted on the roofs. In turn, the abundance of insects attracts birds such as wagtails and redstarts.