Green Roof Research
WESTON, using the GreenGrid system, is helping to meet North America’s demands for sustainable building and roofing solutions today, in order to meet tomorrow’s environmental challenges. Research and development at GreenGrid isn’t just “mixing plant varieties”; it’s providing new and innovative ways to protect building assets and bring the right solution to address a resource efficiency problem.
Bringing successful vegetative green roof systems to market requires the creativity, expertise, and ingenuity of a truly integrated team of professionals including horticulturists, scientists and engineers, roofing experts, and building specialists. It takes a TEAM backed by a fully integrated sustainable services provider and world leader in the environmental industry. Development of new technologies is considered fundamental in meeting the future demands of the vegetative green roofing industry.
WESTON partners with a very select group of professional organizations to aid us in achieving our R&D goals. Combining our internal scientific and engineering expertise with outside organizations fosters fresh thinking on technical issues and helps us more easily solve complex problems for the benefit of our clients. A summary of some of the research with which we’ve been directly involved is presented below. Also be sure to check out the research in this downloads section. The broad effectiveness of green roof systems in multiple study areas is presented, and many of them included the GreenGrid system.
GreenGrid Live Temperature Data Test Site – Beloit, WI
A key benefit to the GreenGrid vegetative green roof systems is its ability to provide a thermal barrier to the roof surface resulting in potential energy savings and extended rooftop durability. This is achieved by reduced heat transfer through the roof structure capitalizing on the plants ability to cool the surrounding air by shading and the evapotranspiration effect. Relatively little actual data has been collected and made available to quantify the temperature reduction benefit of green roofs. GreenGrid has been monitoring the temperature reduction effect of GreenGrid continuously for nearly 10 years on a test roof located in the Midwest. Thermal sensors have been placed on both the GreenGrid green roof and an adjacent conventional roof (Black EPDM and white TPO) to measure and compare temperature data. Data recorders continuously measure and record (every 15 minutes) a vertical temperature profile on each roof. This GreenGrid rooftop temperature data represents some of the most comprehensive collected in the U.S. to date and is made available to the public for research and design work.
Niagara College – Canada
WESTON been supporting Niagara College’s School of Horticulture on a multi-year research program to evaluate irrigation technologies and plant propagation in green roofs through a study introducing native plant species into GreenGrid modules. This is truly a collaborative research effort with multiple stakeholders including Dramm Corporation (Dramm of Canada) and St. Williams Nursery & Ecology Centre. The purpose of this study is centered on two concepts—the introduction of native plant species in vegetative green roofs as a way of promoting environmental sustainability and biodiversity through an emphasis on using native plants and seeds, and how irrigation techniques and practices affect the growth of these native plants within the GreenGrid modules. Results from this study will address mechanics, designs, and planting of GreenGrid and improve efficiency and effectiveness of the irrigation systems prior to market introduction.
Georgia Tech Research Institute
Georgia Tech, WESTON, and Mule-Hide Products have partnered to study and evaluate the thermal properties of vegetative green roofs and their positive effect on the building envelope in order to demonstrably reduce the carbon footprint and operating cost of buildings and their occupants. This partnership with GTRI provides an avenue of collaboration with a high-quality university research laboratory known for conducting cutting-edge technology development. This study allows WESTON to conduct advanced research on some of the more difficult green roof questions including quantifying vegetative green roof thermal performance and solar photovoltaic/vegetative green roof interactions.
University of Florida
WESTON and the University of Florida’s Department of Civil and Coastal Engineering are partnering to address the tough challenges associated with high wind effects on modular vegetative green roof systems. Performance characteristics of plant materials, GreenGrid modular trays, and media are being evaluated when subject to hurricane wind and rain forces to develop a better understanding of the structural (wind uplift) capacity of the system. This is being done through experimental testing of planted modules in large-scale research wind generators.
University of Connecticut
Through a collaboration with UCONN Ph. D. candidate Bruce Gregoire, research has been conducted on a GreenGrid installation on a highly visible plaza at the University of Connecticut to determine the annual storm water management properties of an extensive vegetative green roof in the New England climate. In addition to confirming the water holding capacity of the system, tests are also being performed to qualify and quantify GreenGrid’s capacity as a sink for heavy metals. The results are positive and will continue to develop as research expands.
University of Vermont
The University of Vermont is hosting a study regarding the effects of varying the growing medium blend and plant type to determine survivability of different plants in different growing medium. The experimental plant list was derived using a team of Weston and UVM horticulturalists that assessed each plant based on light requirements, soil moisture requirements, drought tolerance, potential invasiveness, local origin, and acidity-tolerance, among others. The objective of this study is to determine which plants thrive in which growing medium type to create a lush, functional vegetative green roof and potentially expand the list of plants and corresponding growing medium blend which are best suited for vegetative green roofs.
ConEdison installed 10,680 square feet of the extensive GreenGrid system in 2008 at their Long Island City Learning Center. This GreenGrid roof was set up as a test plot to better quantify the potential energy savings benefits of vegetative green roof systems. It also has the added benefit of providing attractive, green views from adjacent office areas. Columbia University is working closely with ConEd to monitor the long term thermal and energy performance of this GreenGrid installation. Their researchers concluded that this GreenGrid installation has an effective R-value of R-100 in the summer and R-7 in the winter, demonstrating the effectiveness of improving building thermal performance, particularly during summer months. Interestingly, this owner has also found that since installation was complete, the frequency at which they have to change air intake filters has been reduced significantly.