New Heat Mitigation and Water Retention Concepts to
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New Heat Mitigation and Water Retention Concepts to Expand Green Roofing Demand Greening Rooftops for Sustainable Communities June 4, 2009 Atlanta, GA James L. Hoff, DBA Research Director
A New-Old Concept Ballasted Roofs
Ballasted Roofs Simple 3 3
Ballasted Roofs Economical
Ballasted Roofs Protection Albo Corporation, West Bend, WI Ballasted Roof Installed in 1980
Ballasted Roofs Easily Recycled 1 3 2 Windrow & Sweep 4 6 5 Grind Source: EPDM Roofing Association Chop Cut & Stack Sieve & Package Recycle
Ballasted Roofs Historic Benefits 7 • Economical Low Initial Cost • Durable Low Life Cycle Cost • Recyclable Low Environmental Impact 7
Ballasted Roofs Emerging Benefits • Heat Island Mitigation • Storm Water Retention
Ballasted Roofs Heat Island Mitigation Envelop Systems Research Apparatus Oak Ridge National Laboratories
Ballasted Roofs Heat Island Mitigation Black EPDM Light Ballast (10#) Med. Ballast (17#) OF Heavy Ballast (21#) White TPO Concrete Paver Painted Paver 1 Painted Paver 2 Hour Average Roof Membrane Temperature By Hour Source: Desjarlais, Petrie & Atchley, 2008
Ballasted Roofs Heat Island Mitigation Black EPDM BTU / (H X Sq. Ft. ) Light Ballast (10#) Med. Ballast (17#) Heavy Ballast (21#) White TPO Concrete Paver Painted Paver 1 Painted Paver 2 Hour Average Heat Flux By Hour Source: Desjarlais, Petrie & Atchley, 2008
Ballasted Roofs Heat Island Mitigation 12 Now Recognized By… • California Title 24 (Min. 21 # / sq. ft. ) • Chicago Energy Code (Min. 15# / sq. ft. ) 12
Ballasted Roofs Storm Water Retention Mat Option Interlocking Tray Option Source: Carlisle Construction Products Source: Green. Grid® Eco. Ballast ® Systems
Storm Water Retention Mat Option Ballasted Water. Retaining Roof Smooth Stone Ballast (2” to 4”) Moisture. Retention Mats (1 or 2) Extensive Green Roof 14 Planting Medium ( 2” to 6”) Moisture. Retention Mats (1 or 2) Drainage Board Protection Mat Roof Membrane Roof Insulation Roof Deck 14
Storm Water Retention Interlocking Tray Option Modular Ballasted Water-Retaining Roof Smooth Stone Ballast (2” to 4”) Interlocking Tray Modular Extensive Green Roof Interlocking Tray Planting Medium ( 2” to 6”) Protection Mat Roof Membrane Roof Insulation Roof Deck
Ballasted Roofs Water Retention Testing Water Retention Test Apparatus Architectural Testing, Inc. York, PA
Ballasted Roofs Water Retention Testing Single Retention Mat Double Retention Mat 1” / Hour 22. 4% 37. 8% 2” / Hour 6. 2% 11. 5% 4” / Hour 5. 9% 5. 6% Rain Event Percent Water Retention: Three Hours After Simulated Rain Event Source: Architectural Testing, Inc. , 2008
The Opportunity Integrating Green & Ballasted Roofs Installed Cost ($US / Sq. Ft. ) Annual Sales (Millions of Sq. Ft. ) Green Roof Ballasted Roof
The Future Hybrid Green / Ballasted Roofs Ballasted Areas Retain Storm Water Reduce Summer Temperatures and Add Wind, Fire & Traffic Resistance Vegetated Areas Reduce Summer Temperatures and Retain, Transpire and Cleanse Storm Water Tapered Roof Design Directs Storm Water
Hybrid Green / Ballasted Roofs Future Research • Green / ballasted storm water testing and modeling 20 • Hybrid systems energy modeling • Economic analysis to optimize benefit / return 20
New Heat Mitigation and Water Retention Concepts to Expand Green Roofing Demand Greening Rooftops for Sustainable Communities June 4, 2009 Atlanta, GA James L. Hoff, DBA Research Director