May 21st, Peggy Notebeart Museum - Chicago

This four years green roof is composed of different thicknesses of media. From 5 inches to 18 inches.
The part is planted with a nice tree, a Quercus imbricaria. It was very healthy when I saw it today. As you can see on the photo above, this tree gives to the roof a really interesting shape and structure. I like it!

As the Sanitation District green roof, in Cincinnati, this roof has an educational purpose. A lot of children from Chicago's schools come and learn about green roofs.
I was very happy to see a wet area with a pond and a water feature. Like that, Iris can easily grow and gives an original touch to the roof.

Unfortunately, the maintenance is very low and plenty of weeds live there. In my opinion this is not so bad. The roof has a perfect biodiversity and it's perfectly included into the surrounded landscape. From an engineering point of view, weeds can damage roof layers and the building structure (weeds can be very aggressive and have strong roots). So, a minimum of maintenance is required.