Green Roofs

Green roofs are functional and beautiful.

Green roofs are those topped with a layer of soil and plants designed to absorb and slow down rainwater. These features improve local water quality by retaining and filtering rainwater. They also help to improve air quality, mitigate urban heat islands, increase local biodiversity, and improve building energy efficiency through the additional insulation they provide.  

Green roofs are classified into two categories: extensive and intensive.

  • Extensive green roofs have a shallow layer of substrate in which sedums, grasses, and other shallow-rooted perennials can grow.
  • Intensive green roofs have a deeper layer which allow for deeper-rooted plants. 

Generally, green roofs are installed on commercial scale buildings with large footprints, but they can be on residences. They provide stormwater management, energy benefits, and added green space in dense, urban settings. While stormwater design at the ground level is typically less expensive, green roofs are a viable option for new development or for redevelopment of structurally reinforced buildings. If you are considering a green roof, consult with an expert. 

Campus green roof photo: UI NEWS BUREAU/L. Brian Stauffer