There has been much talk and show of Green roofs which have long been in use in Europe but is now starting to filter to the United States. May it be a building or house, a green roof is the way for it has a lot of added benefits such as a cooler living space and even a nice harvest of your favorite crops from your own rooftop. The system works with the integration of several technologies that represent the different layers that makes the system possible. The roof of course is made of concrete in order to support the weight of the system which has the added bonus of being stronger than traditional roofing systems. The first layer next to the cement roof is a vapor barrier that prevents moisture from penetrating into the concrete and flooding your home. Thermal insulation is then placed on top to further insulate the system, preventing heat and cooling loss through the cement roof deck. A waterproofing membrane that also has water repellant properties is used to allow water to properly be shed from the desired slope preventing wet spots and allowing even moisture distribution. It is then topped by coarse grade material which allows water to drain through above which is a filter medium that prevents soil from washing away into the lower layers. The growing medium which is simply soil or substitute materials that allow plants to grow which can range from four to six inches. The bed is then ready for planting.
The choice of plants that would be best suited for your green roof would be plants that have medium height and try to avoid trees and hardy shrubs which can penetrate all the protective layers. When plants have had a chance to propagate, a healthy green environment can be achieved with little effort and maintenance. It would also be a good idea to have plenty of water for the roof is usually the hottest part of the property due to the increased exposure and height. Vegetables and other herbs can also be grown giving you a nice and clean source of your favorite herbs at short notice. So go green and keep it green.