Life-cycle cost-benefit analysis of extensive vegetated roof systems assesses the benefits and costs of green roofs from a pilot study in Athens, Georgia, including private and social benefits. The public benefits identified were avoided best management practice costs, energy savings, and air quality, and the private benefits identified were stormwater utility fee credits, building energy savings, and air quality. The costs identified in the study included lifetime construction and maintenance. The study revealed that green roofs were 10-14% more expensive than conventional counterparts, and therefore, recommended that a broader range of positive social benefits be included in the analysis in order to outweigh the higher construction costs and encourage the construction of green roofs.