Chicago City Hall Green Roof

As part of an EPA study and initiative to combat the urban heat island effect and to improve urban air quality, Mayor Richard M. Daley and the City of Chicago began construction of a 38,800 square foot (total roof area) semi-extensive greenroof in April 2000. It was completed at the end of 2001 at a cost $2.5 million, funded by a settlement with ComEd. The 20,300 square foot City Hall rooftop garden features over 20,000 herbaceous plants of more than 150 varieties, rainwater retention, and a supplemental irrigation system. It is estimated that the greenroof saves $5,000 a year on utility bills.