ENERGY INDEPENDENCE: Green Roofs – Implementation and Feasibility

1. ENERGY INDEPENDENCE:Green Roofs – Implementation and Feasibility Chris Gardino

2. History of Green Roofs Originated in ancient Mesopotamia Viking sod roofs in Scandinavia Sod roofs in Africa

3. Green Roofs: Generally • Growing medium is part of the roof • Layers of a contemporary green roof Cross Section of a Green Roof

4. Decking • Can be constructed from wood, metal concrete, plastic, gypsum, or composite • Concrete decking will provide the most sound structural support

5. Waterproofing Layer • Very important to make sure that there is an effective seal • There are four different methods of waterproofing - Built up roof - Modified Bitumen roof - Single Ply membrane - Liquid applied membrane

6. Insulation • Proper insulation will promote the energy saving advantages of green roofs • Insulation can either be placed above or below the waterproof membrane

7. Protection and Storage Layer • Must be placed above the waterproof membrane • Usually constructed with PVC or HDPE sheets

8. Drainage Layer • Drainage layer is critical to the health of the plants and the roof system • Drainage systems are very site specific

9. Filter Layer • Root permeable • Basically separates the medium from the drainage layer to avoid clogging • Could be a filter cloth or some other semi-permeable fabric

10. Growing Medium • Green roof plants need to grow in a medium that is porous • Ideal mixture is about 75 to 90 percent inorganic material with the remainder consisting of compost • Depth of medium will vary with the type of roof

11. Extensive Green Roofs • Typically less than 6 inches of soil • Usually not open to public • Low plant diversity • Minimal cost to maintain

12. Intensive Green Roofs • Deeper and more organic soils • Often open to the public • More plant diversity • Higher maintenance costs

13. Semi-Intensive Green Roofs • Between intensive and extensive green roofs regarding maintenance and support capacity • Semi-public purpose

14. Plant Selection • Will be extremely site specific • Generally Green Roof plants will be tougher and less nutrient reliant than plants found in ground gardens • Elevation will carry certain dangers not found on the ground

15. Annuals • Annuals are plants that grow, flower and seed in one season • Should not be dominant in green roofs: used more as an accent

16. Herbaceous Perennials • Herbaceous perennials are some of the most desirable green roof plants • Advantages: aesthetically pleasing, lots of variety • Disadvantages: Most have limited drought tolerance, will require deeper substrate, biomass accumulates as they grow, very few are evergreen

17. Some Well Suited Herbaceous Perennials Phlox Dianthus Campanula Petrorhagia

18. Hardy Succulents • Hardy Succulents are the best suited plants for green roofs • Advantages: can survive drought/ wind/ temperature extremes, store water for extended periods, shallow root systems • Only viable option for certain shallow soil extensive roofs

19. Sedums • Nearly 600 species available • Found in well drained areas • Long life span and self-propagating • Change color with the seasons

20. Other Hearty Succulents Talinum Delosperma Sempervivum

21. Grasses • Grasses can add texture and habitat • Require deeper medium for root systems and larger biomass

22. Herbs • Herbs can be very tolerant once established • May require deeper substrate for less ground cover • Added culinary and olfactory perks

23. Groundcovers • Groundcover plants provide dense soil cover, retard weed growth, and prevent soil erosion • Most of the plants on a green roof should be low density ground covers • Allow for rapid and reliable growth at a reasonable price

24. Accents • Accent plants may not live over five years and will require more care and maintenance • Many of the aforementioned annuals make for viable options as accent plants

25. Natives • Native plants often function in an ecological system which makes their inclusion in green roofs somewhat difficult • Advantages: already adapted to local weather conditions, resistance to local pests etc.

26. Cost!!!! • The cost for implementing a green roof in the United States is about $15-$20/sq ft • The price of a conventional roof runs about $8-$10/sq ft • The price of a green roof is offset by long term cost saving

27. Energy Independence • Heating/cooling energy • Green roofs can reduce heat consumption during the winter months • Green roofs will keep air conditioner use down in the summer months • Will also keep surrounding areas cooler in the summer months

28. Urban Heat Island • Most suburbs and city roofs are made in shades of gray and black which tend to soak up heat and UV • This contributes to the phenomenon known as the ‘urban heat island effect’

29. Urban Heat Island

30. Carbon Dioxide and Other Particulate Matter • Green roofs will naturally absorb excess CO2 through photosynthesis • Green roof plants can also remove harmful or unwanted particulate matter (dust)

31. Water Run-Off • Excess runoff is costly • About 75% of rainwater in urban areas becomes surface runoff • Green roofs can mitigate surface water runoff ABOUT 1.5% OF THE UNITED STATES IS COVERED IN IMPERVIOUS SURFACES: AN AREA ABOUT THE SIZE OF OHIO

32. Other Benefits • Habitat • Aesthetics • Worker Productivity • Sound Insulation

33. Green Roofs and the Law: Incentives and Mandates • Most contemporary legislation relating to green roofs is based upon incentives • Germany offers individuals 15 euros per square meter of green roof • Switzerland requires that 25 percent of new commercial development be greened

34. Domestic Green Roof Incentives • Chicago is at the forefront • Tax incentives • Water run-off credits • Open Space Requirements South Loop Target Store

35. CONCLUSION • Green roofs provide an opportunity to use otherwise wasted space in a way that promotes energy independence • Legislators should follow the lead of European countries in promoting the development of green roofs to offset the loss of open spaces through incentives and mandates