As part of the City of Minneapolis and Hennepin County’s storm water management initiatives, along with the growing awareness of the importance of protecting our rivers, the decision was made to turn a simple waterproofing project into a 5,000 square foot extensive green roof with a 10,000 gallon cistern for irrigation.
The interior court roof work started in 2006 as a 15,000 square foot waterproofing project. This work included the removal of the several layers of roofing and HVAC equipment located on the roof. The project also included the preparation of the first floor level roof (approximately 5,800 square feet) for a future extensive green roof (minimal amount of growing medium with a variety of plants). The waterproofing project and “green roof ready” portion was completed in 2007.
Installation of the irrigation system began the week of May 12, 2008 and the dirt was brought in on May 17. Planting was done June 10 and 12 followed by the final step – the cistern installation on June 28, 2008.
Although the roof will not have public access, a 24-hour live stream webcam is being investigated as a potential avenue for public education regarding green roofs. We believe that installing a green roof on the Minneapolis City Hall and Hennepin County Courthouse will set an example for downtown businesses and give environmental responsibility greater exposure to the general public.
- Green roofs serve as an effective sustainable building practice by reducing storm water runoff,
- improving the quality of water in the storm water system,
- mitigating the effects of the urban heat island effect,
- reintroducing plants to the urban area,
- extending the life of the roof, and
- improving the aesthetics for tenants and the public.