Green roofs are touted as an environmental technology for urban areas due to their many benefits (Lundholm et al. 2008). Although the design and the benefits have been reported in many reports and articles, they are reviewed here for those who are unfamiliar with this technology. Green roofs, or more formally, green roof infrastructure, is a technology that allows for the growth of vegetation on a roof while protecting the building envelope from leakage and root penetration. A green roof is more than a layer of soil piled on the roof, planted in the way that you might plant a garden. The technology consists of multiple layers that include the plants and growing medium or substrate, but also a drainage layer for storing water that was not used by the plants and a waterproof, root-repellent membrane (Figure 1).