Our study trip participants have been quite surprised to learn that green roofs are actually very easy to construct! They require only a waterproof bottom membrane, a drainage layer, and a thin substrate of soil or other material for the plants to grow in. Because the green layer protects the waterproof membrane from the damaging effects of UV rays and the daily heating and cooling cycles, the membrane can actually be LESS substantial than on a more traditional roof. Recent studies have also shown that a properly construcuted green roof can last up to 75 years, with minimal maintenance. (photo by Mark Brumbaugh, Brumbaugh & Associates)