Comparison of Conventional Roof and Green Roof Design

Student Classification


Faculty Mentor

Niroj Aryal, Natural Resources and Environ Design, Paula Faulkner, Agricultural Education


Biological Engineering

Document Type


Publication Date

Spring 4-2021


A green roof is a building rooftop covered with vegetation to compensate for the vegetation removed during the building's construction, a sustainable alternative to conventional roofs. With its plants, green roofs act as a sponge regarding its rainwater retention, reducing the amount of excess water that would run off the surface of a conventional roof. This project is to design a green roof at NC A&T State University for research and education. The green roof's ecological, social, and environmental benefits, in comparison to conventional roofs, include water runoff reduction, easing of heat intensity among urban communities, and conserving energy. Additionally, the green roof bestows a more aesthetically-pleasing environment. The study objective is two folds: 1) Review current literature in green roof research to produce an objective, and 2) Design a green roof to evaluate the objective identified in (1). The experiment will be conducted on a developed roof-like structure located on the campus of North Carolina A&T State University. The design consists of a waterproofing membrane, drainage layer, filter geotextile, lightweight growth media, and vegetative cover plants. The magnitude and timing of peak runoff and total runoff volume will be compared between conventional and green roofs. Green roofs are expected to yield lower runoff volume, lower peak runoff rate, lower flooding risk, and better water quality than conventional roofs. Countries associated with the Feed the Future campaign can use the low-cost technology.

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