Case study: A conservative approach to green roof benefit quantification and valuation for public buildings

ABSTRACT

The U.S. federal government is routinely making severe spending cuts in an attempt to correct financial instability resulting from overspending. A more recently surfaced avenue of cost savings that is becoming increasingly popular is the implementation of sustainable design. One method of sustainable design or “green infrastructure” is installing vegetated roofs on top of buildings. Such projects require intensive cost analysis that can be extremely convoluted and difficult to present in a convincing manner. Furthermore, there is minimal guidance or literature that provides a methodology for actually quantifying these financial estimates. This article systematically decomposes decision points and calculations associated with a green roof cost analysis. This hybrid analysis strives to present the inherently specific variables such as region and building size while maintaining the generic representativeness to allow readers to replicate. Specific details are derived from the Southwestern region of the United States and generic values are national averages. A 25-year green roof life cycle is evaluated against a conventional roof to illustrate the economic differences associated with both roof types. This comparison strives to provide the framework for others to follow in their efforts to quantify the economic value of their respective green roof projects.