Comparison of Five Green Roof Treatments in Flint Michigan with Freidman’s Two-Way Analysis of Variance by Ranks

Planners and designers are interested in evaluating the metrics and statistical differences between design treatments. This study addresses categories of design treatments for a rooftop at The Sylvester Broome Empowerment Village, located in Flint, Michigan. Five design treatments: flat roof, self-design roof, extensive green roof, semi-intensive green roof, and intensive green roof, were evaluated by 36 variables chosen by the investigators. The Friedman’s Two-way Analysis of Variance by Ranks statistical test was applied to examine significant differences between the five treatments (p ≤ 0.05). The Friedman’s multiple comparison test revealed the treatment of the flat roof performed the poorest. There was no significant difference to demonstrate that the other four design treatments perform better than the other with the exception that the intensive green roof treatment was predicted to be significantly better than self-design rooftop (p ≤ 0.05).

Keywords: landscape architecture, environmental design, sustainability, green architecture.