Green Roof Project

By Daniel Schemer, February 2009

Last summer, plans went underway to test the feasibility of green roof technology on campus.  UMass Dartmouth received a grant from the Leading by Example Program, run by the Massachusetts Executive Office of Energy and Environmental Affairs, in order to fund the project.  Specimens, materials, and locations were accumulated and initial stages began.  By the end of the summer, the project had to be relocated and reevaluated because the chosen academic buildings were not structurally stable to support green roofs.  Lack of student involvement was also a growing concern and staff priorities with other projects required more immediate attention.   The Green Roof Project was postponed until a new location could be established; Remnants of the pilot project can be seen on top of the Violette Research Building and on the roof area outside the Liberal Arts 374 Conferencing Room. 

The Office of Campus and Community Sustainability and Administration never abandoned hope for the green roof project.  New plans have been made to relocate and start a new pilot, but success of the second time around is dependent on interest from students.  “We have no students right now.  We have plans, structure, and resources, but no student interest,” said Tom Paine, Project Coordinator for the Office of Sustainability, who began the project but couldn’t maintain it due to lack of assistance.  Student benefits for participation in the project include work-study and community service hours, as well as a heck of a highlight to include on your resume.

Currently, the designated location for the continuing green roof project is the covered walkway between Foster Administration and the Campus Center.  The Foster/Campus Center walkway was designed to bear the weight of a green roof and already has planter boxes on its sides and down the middle.  A preliminary test demonstration needs to be done in order to measure water run-off.  Currently, the pipes from the walkway carry run-off into the adjacent parking lot.  Hopes are that by April a rain barrel can be connected to the drain spout so that run-off can be periodically measured.  This 6-month measuring period is necessary to learn how extensive rainwater management has to be for the drain spout and how many additional rain barrels need to be installed.  The study will also help ascertain the necessary density and porosity for rooftop vegetation, as wells as identify what substrates will work best.  Students are needed for this measurement period and for the actual installation of the green roof.  After the measuring period, the soonest soil layering and planting vegetation can begin is in the fall.      

The biggest benefit of Green Roofs, also referred to as Eco-Roofs, is they absorb and help reduce water-runoff, an enormous cause of erosion, flooding, and the immobilization of pollutants when left unmanaged.  The vegetation and soil of green roofs, aside from providing much needed floral aesthetics, also act as insulation for buildings, keeping heat in buildings when it is cold and providing coolness in the summer.  This can greatly reduce energy consumption for the campus. 

Varying Green Roofs have different layouts depending on building infrastructure and how extensive they need to be.  A basic green roof begins with a waterproofing membrane system laid over the rooftop surface to prevent leaks and root protrusions.  A drainage layer comes next that removes excess water that hasn’t been retained by the moisture blanket on top. The growing medium on top of the blanket is the topsoil or alternative substrate.  Sedums are commonly used plants for green roofs because they are attractive, low-maintenance, and can survive droughts.  Given the region we inhabit, beach grass is also a strong possibility for this project.

Using real topsoil means high costs, more weight, and the consequences of erosion if washed or blown away.  When the first green roof project started up, cheaper, more sustainable alternatives were researched.  Assistance was provided by the Pennsylvanian State University laboratory facilities in order to learn more about different substrates and the cost and fertility options each provide. Sedimentary substrates (sand, clay, granule, etc.) or recycled materials such as crushed brick or seashells are common for green roofs because they filter water and hold roots in place.  A popular and effective substrate is rock wool, a composite material made from mineral fibers, similar in texture to fiberglass.  Rock wool is light, porous, provides stability, helps germinate seedlings, and aids in water and nutrient absorption.

If you are interested in a fun, new learning experience and want to get involved with the green roof project, contact the Office of Campus and Community Sustainability at (508)910-6484.