Green Roofs: aesthetic and funtional

Simon Schreier, Department of Plant and Environmental Science

The problem: land cover change

Aerial view of Clemson University (Google Maps: www.maps.google.com)

The problem: storm water runoff

Inundated green space, University of Wisconson, Madison

The problem: heating and cooling

Total energy expenditures, Clemson University (Facilities Department)

The solution!

Green roofs! Green roofs galore!

The benefits

• • •

Reduce runoff

– Castelon et al. 2010

Provide habitat

– Dvorak and Volder 2010

Cool and insulate

– Carpenter and Kaluvakolanu 2011 Runoff comparison of green and conventional roof Heat flow across green and conventional roofs

Approach

Consider the roof like a degraded habitat that has cross the abiotic threshold ≈

Reference habitat

Two approaches 1) Find natural habitat most similar in structure 2) Experimentally determine community assemblages on a variety of substrates Compromise Set up a number of test pots using a variety of growth media. Allow some to be colonized naturally, plant others with presumptive successful vegetation

Construction

1) Retrofit roof for waterproofing 2) Permeable later for drainage 3) Growth media (~10 cm) 4) Plants

Remote sensors -soil saturation -water flow -heat flow

Monitoring

Information processing -Real-time analysis -comparison with pre- retrofit data -determine efficiency -Adjustment and maintenance of species composition and physical characteristics

Costs

Component Costs Cost Factors

Design & Specifications Project Administration & Site Review Re-roofing with root-repelling membrane Green Roof System (drainage, filtering, paving, growing medium)

$ 10.00 - $15.00 / ft 2 $ 5.00 - $10.00 / ft 2

Plants Installation and Labor Maintenance Irrigation System

5 - 10 % (of total roofing cost) 2.5 - 5 % of total roofing cost $ 1.00 - $3.00 / ft 2 $ 3.00 - $8.00 / ft 2 $ 1.25 - $2.00 / ft 2 $ 2.00 - $4.00 / ft 2 The size/complexity of the project and the number/type of consultants needed.

The size/complexity of the project and the number/type of consultants needed.

The type of existing roof, type of new roof system, and roof accessibility.

Growing medium (type and depth), pavers (size and type), and square footage of the green roof (project size).

Season of installation, type of plants, and size of seeds being planted.

Equipment necessary to move materials on to the roof (E.g. crane, if rented is: $ 4,000.00 /day), project size, design, and planting methods.

Project size, installation schedule, irrigation system, and plants (type and size) used.

Since extensive roofs require little irrigation (E.g. sprinkler system or drip system), this component is optional.

Total cost per square foot… Usable roof area, assuming 5% of total campus area is usable… $25-$48 1,100,000

Cost to green all roofs... $28 to $52 million

Benefits

• • • • • • $1 to $2.1 million annual savings 10% to 20 % overall decrease in energy usage Unique habitat Less fragmentation Runoff management Less stress on infrastructure

Thanks

• • • • Dr. Eidson Dr. David Kavanaugh, California Academy of Sciences Dr. Melissa Riley Everyone who trusted me to drive a van

References

Bogena, H.R., M. Herbst, J.A. Hulsman, U. Rosenbaum, and A Weuthen. "Potential of Wireless Sensor Networks for Measuring Soil Water Content Variability." Vadose Zone Journal. 9.4 (2010): 1002-1013. Print.

Carpenter, Donald, and Preethi Kaluvakolanu. "Effect of Roof Surface Type on Storm Water Runoff from Full-Scale Roofs in a Temperate Climate." Journal of Irrigation and Drainage Engineering. 137.3 (2011): 161-169. Print.

Castleton, H.F., V. Stovin, S.B.M. Beck, and J.B. Davison. "Green roofs; building energy savings and the potential for retrofit." Energy and Buildings. 42.10 (2010): 1582 1591.

Clemson University. “Energy Consumption and Costs.” Department of University Facilities (2010): Web. 7 Apr 2011. http://www.clemson.edu/facilities/energy awareness/consumption.html

Dvorak, Bruce, and Atrid Volder. "Green roof vegetation for North American ecoregions: A literature review." Landscape and Urban Planning. 96.4 (2010): 197-213. Print.

Fioretti, R. , A. Palla, L.G. Lanza, and P. Principi. "Green roof energy and water related performance."Building and Environment. 45.8 (2010): 1890-1904. Print.

In-Hea, Kim, Huh Keun-Young, Shin Hyeon-Cheol, and Park Nam-Chang. "Assessment of Plant Growth and Soil Properties of Extensive Green Roof System." Korean Journal of Horticultural Science and Technology. 28.6 (2010): 1057-1065. Print.

Kavanaugh, David. "Introducing rare lepidoptera to the roof." Message to Simon Schreier. April 1, 2011. E-mail.

Latz, Karen. "Green Roof Installation." School of Freshwater Sciences. University of Wisconsin, 2005. Web. 7 Apr 2011.

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Liang, Han-Hsi, and Kuo-Tsang Huang. "Study on rooftop outdoor thermal environment and slab insulation performance of grass planted roof." International Journal of Physical Sciences. 6.1 (2011): 65-73. Print.

Lundholm, Jeremy, Maclvor Scott, Zachary MacDougall, and Ranalli Melissa. "Plant Species and Functional Group Combinations Affect Green Roof Ecosystem Functions." PLoS ONE. 5.3 (2010): no pages given. Print.

Maclvor, Scott, and Jeremy Lundholm. "Performance evaluation of native plants suited to extensive green roof conditions in a maritime climate." Ecological Engineering. 37.3 (2011): 407-417. Print.

National Research Council. Urban Stormwater Management in the United States. Washington D.C.: The National Academies Press, 2008. Print.

Oberndorfer, Erica, Jeremy Lundholm, Brad Bass, Reid Coffman, and Hitesh Doshi. "Green roofs as urban ecosystems: Ecological structures, functions, and services." Bioscience. 57.10 (2007): 823-833. Print.

Peck, Stephen, and Monica Kuhn. "Design Guidelines for Green Roofs." Ontario Association of Architects (2003): Web. 7 Apr 2011. .

Thuring, Christine, Robert Berghage, and David Beattie. "Green Roof Plant Responses to Different Substrate Types and Depths under Various Drought Conditions." HortTechnology. 20.2 (2010): 395-401. Print United States Energy Information Administration.Commercial Buildings Electricity Consumption by End Use. Washington D.C.: The National Academies Press, 2007. Print.

Questions?