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Grantee Research Project Results

Grantee Research Project Results

The Value Of Steep, Green Roof Technology to Sustainable Cold Climate Communities

EPA Grant Number: SU834762
Title: The Value Of Steep, Green Roof Technology to Sustainable Cold Climate Communities
Investigators: Westphal, Joanne M
Institution: Michigan State University
EPA Project Officer: Nolt-Helms, Cynthia
Project Period: August 15, 2010 through August 14, 2011
Project Amount: $10,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2010)
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Built Environment



Widespread green roof application to a variety of pitched roof structures could have a significant impact in reducing the amount to total impermeable area (TIA) in urban, suburban, and exurban neighborhoods. The goal of this research is to answer fundamental questions relating to the performance of extensive green roof systems (designed primarily for flat roof application), when applied to more conventional pitched roof systems. Three types of data will be generated: microclimate changes in ambient temperature and relative humidity on an existing pitched roof study site equipped with an extensive green roof system and monitoring equipment; the structural requirements of residential buildings to maintain building integrity when adapted with green roof systems (standard of measure: weight per square foot, including structural components, green roof product & snow load); and performance standards needed in manufactured extensive green roof systems if community-wide adoption is to occur and contribute to overall public and environmental health.


The proposed research will involve field study and data collection efforts focused on the performance of a manufactured, sedum-dominated, extensive green roof system produced by Xeroflor North America Inc; this system currently has widespread application for use on predominantly flat (1-10%) sloped roofs (most commercial & institutional buildings) in Europe and North America. In this study, however, the team will examine the performance of the same manufactured product when placed on an extremely steep (43 degrees) sloped structure. The purpose is to document changes in the functional dynamics of the system as it becomes tilted, and to use that data to develop an improved green roof product that maintains or enhances its performance capabilities when placed on roof systems with slopes greater than 30%. (The most common roof pitch for residential structures of Northern U.S. states is 4/12 or 33% slope).

Expected Results:

With the knowledge gained from this preliminary study, we plan to built a modified extensive green roof product that addresses both the opportunities and limitations of current extensive manufactured green roof products. The results of our tests will be shared with building contractors, public officials, and consumers through conference proceedings and juried papers. We believe that the consequence of the data will result in improved manufactured green roof products for wider application to pitched, residential and outbuilding structures in cold climate environments.

Supplemental Keywords:

Pitched roofs, cold climates, green roof design, community sustainability,

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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