Chicago Center for Green Technology, Chicago, IL
Completion Date: Spring 2002
Former Network Contractor
The Chicago Center for Green Technology green roof is more than 10 years old and one of the oldest Roofmeadow installations to date. An un-irrigated Roofmeadow Type II with 3.25 inches of media, the green roof is surrounded by solar panels. The LEED certified building is one of the finest examples I’ve seen of green building in the city of Chicago. The green roof moderates the temperature on the roof and helps the solar panels to function more efficiently.
The roof was originally planted with a mix of sedum cuttings and herbaceous perennial seeds including Achillea, Anthemis, and Salvia species. Planted as an experiment to study which species would survive in a thin green roof system with very little maintenance activity, on an exposed roof, all of the perennial species seed germinated and the cuttings rooted in within the first two years.
Today I surveyed the roof and recognized that biodiversity has significantly decreased since the establishment of the green roof. This didn’t trouble me since I also observed that the roof has 95 percent plant coverage which prevents wind scour and erosion of the green roof media. Green roof media not only supports plant roots by holding onto storm water it also filters runoff that does drain from the roof.
There are two distinct media materials on this roof; a growth media produced from coal ash and a volcanic drainage media. The Sedum album has preferentially colonized the volcanic media.
At this time of year the Allium schoenoprasum is in full bloom and dominates the roof with its purple ball like flowers.
—Sedum reflexum ‘Blue Spruce’
—Sedum spurium ‘Fuldaglut’
—Sedum spurium ‘John Creech’
—Sedum spurium ‘Variegatum’
Roofmeadow Network Contractor Greg Raymond of Ecogardens, LLC was on the roof with me today.
This is what it’s like up on this roof: