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Green Roof Retrofit: Building Urban Resilience

Green Roof Retrofit: Building Urban Resilience

Sara J. Wilkinson (Editor), Tim Dixon (Editor)

ISBN: 978-1-119-05560-0

Jun 2016

288 pages

$96.99

Description

A deep understanding of the implications of green roof retrofit is required amongst students and practitioners to make the decisions and take the actions needed to mitigate climate changes. Green Roof Retrofit: building urban resilience illustrates the processes undertaken to develop this new knowledge and thereby embed a deeper level of understanding in readers.Illustrative case studies and exemplars are drawn from countries outside of the core researched areas to demonstrate the application of the knowledge more broadly. Examples are used from the Americas (North and South and Canada), Oceania, Asia and other European countries.The book describes the multiple criteria which inform decision making and how this provides a way forward for making better decisions about green roof retrofit in different countries and climates.

Notes on Editors x

Notes on Contributors xi

Foreword xiv

Acknowledgements xvi

Chapter 1 Building Resilience in Urban Settlements Through Green Roof Retrofit 1

1.0 Introduction 1

1.1 Background and Context: Green Infrastructure 2

1.1.1 Green Roofs 4

1.2 Extensive and Intensive Systems 5

1.3 Valuing Green Infrastructure and Wider Economic Benefits 5

1.4 Measures of Greenness in Cities and the Growing Market for Green Roofs 7

1.5 A Growing Global Market for Green Roofs 7

1.6 Overview of the Structure of the Book 8

1.7 Conclusion 12

References 12

Chapter 2 Technical and Engineering Issues in Green Roof Retrofit 14

2.0 Introduction 14

2.1 Technical and Engineering Considerations 15

2.2 Roof Structure and Covering Typologies 15

2.2.1 Pitched Roof Structures 15

2.2.2 Pitched Roof Coverings 16

2.2.3 Flat Roof Structures 18

2.2.4 Flat Roof Coverings 19

2.2.5 Other Roof Designs 20

2.2.6 Green Roof Modular Systems 20

2.3 Available Space 21

2.4 Structural Capacity 21

2.5 Waterproof Membranes and Insulation 23

2.6 Drainage 24

2.7 Heritage 24

2.8 Green Roof Access 24

2.8.1 Access for Maintenance 25

2.8.2 Temporary or Permanent Access Strategies 25

2.8.3 Maintenance Frequency 26

2.9 Other Issues 26

2.10 How to Determine Which Green Roof Type is Best Suited to Different Structures 26

2.11 Illustrative Case Studies 27

2.11.1 Australia – Surry Hills Library and Beare Park, Sydney 27

2.11.2 Brazil 30

2.11.3 1214 Queen St West, Toronto, Ontario, Canada 33

2.11.4 107 Cheapside, London, UK 34

2.12 Conclusions 35

References 36

Chapter 3 Green Roof Retrofit and the Urban Heat Island 37

3.0 Introduction 37

3.1 Defining the Urban Heat Island 37

3.1.1 UHI Impacts on Environment, Society and Economy 39

3.2 Microclimatic Effects of Rooftop Greening 40

3.3 Green Roof Cooling Mechanisms 43

3.4 Green Roof Retrofit for UHI Mitigation – Defining the Boundaries 45

3.4.1 Roof Availability and Suitability 45

3.4.2 Design Considerations – Intensive Versus Extensive 46

3.5 Green Roof Retrofit for UHI Mitigation – Developing the Model 47

3.5.1 Overview of Methods 47

3.5.2 Modelling Roof Availability and Suitability 48

3.5.3 Modelling Thermal Performance 49

3.6 Model Implementation – Evaluating Sydney’s Surface and Canopy]Layer Heat Islands 50

3.7 Green Roof Retrofit for UHI Mitigation – Model Implementation 55

3.8 Conclusions – Where to from Here? 57

3.8.1 Limitations of the Research and Opportunities for Further Work 58

References 59

Chapter 4 Thermal Performance of Green Roof Retrofit 62

4.0 Introduction 62

4.1 Green Roof Retrofit and Thermal Performance 63

4.2 Research Methodology 67

4.3 Case study: Rio de Janeiro and Sydney 68

4.3.1 Rio de Janeiro Case Study 69

4.3.2 Sydney Case Study 74

4.3.3 Evaluation of Rio de Janeiro and Sydney Cases 78

4.4 Conclusions 80

References 82

Chapter 5 Stormwater Attenuation and Green Roof Retrofit 85

5.0 Introduction 85

5.1 The Problem of Pluvial Flooding 86

5.2 Specifications for Stormwater Roofs and Issues for Retrofit 88

5.2.1 Technical and Physical Issues in Retrofit 88

5.2.2 Estimating Runoff Reduction 89

5.3 Modelling for City]Scale Stormwater Attenuation 90

5.3.1 Melbourne, Australia 92

5.3.2 Newcastle]upon]Tyne, UK CBD Database 95

5.3.3 Melbourne and Newcastle Runoff Estimation 97

5.4 Assessment of Retrofit at a Building Scale 99

5.4.1 Portland Ecoroof Programme 101

5.5 Conclusions – Where to Next? 102

References 103

Chapter 6 Biodiversity and Green Roof Retrofit 106

6.0 Introduction 106

6.1 What is Biodiversity? 108

6.2 Green Roofs for Vertebrate Conservation 109

6.3 Green Roofs for Invertebrate Conservation 110

6.4 Conclusions 112

6.4.1 Designing Biodiverse Green Roofs 113

References 115

Chapter 7 Planting Choices for Retrofitted Green Roofs 118

7.0 Introduction 118

7.1 Ecosystem Services Delivery By Green Roofs: The Importance of Plant Choice 120

7.2 Plant Species Choice and Building Cooling/Insulation 120

7.2.1 Plants and Cooling – Basic Principles 120

7.2.2 Plant Species Choice and Summer]Time Surface Cooling 123

7.2.3 Plant Species Choice and Winter]Time Insulation 129

7.3 Plant Species Choice and Stormwater Management 130

7.4 Greater Plant Variety can Enhance Urban Biodiversity 133

7.5 Plant Choices and Particle Pollution Mitigation 134

7.6 New Plant Choices and Adaptation of Current Green Roof Systems 134

7.7 Conclusions and Future Work 135

References 136

Chapter 8 Green Roof Retrofitting and Conservation of Endangered Flora 140

8.0 Introduction 140

8.1 Biodiversity Conservation – a Strategic Overview 141

8.2 A Review of Green Roofs in Habitat Conservation 143

8.3 Knowledge Gaps and Further Research 146

8.3.1 A Research Programme for Conserving Endangered Species on Green Roofs 147

8.3.2 The Endangered Community of the Eastern Suburbs Banksia Scrub 147

8.4 A Model Research Design for Species Conservation 149

8.4.1 Extensive or Intensive Roofs? 149

8.4.2 Research Objectives 150

8.4.3 Guiding Principles for ESBS Regeneration 152

8.4.4 Preparatory Steps 152

8.4.5 Monitoring 153

8.4.6 Expected Outcomes 153

8.5 Conclusions 154

References 154

Chapter 9 Urban Food Production on Retrofitted Rooftops 158

9.0 Introduction 158

9.1 Green Roof Retrofit and Urban Food Production 159

9.2 Stakeholders and Urban Food Production 161

9.3 Contamination and Air]Quality Issues 162

9.3.1 Types of Pollutant 163

9.3.2 Most Urban Soils are Contaminated 164

9.3.3 Do Contaminants Accumulate in Urban Crops? 165

9.3.4 Mitigating Urban Crop Contamination 167

9.3.5 Urban Gardens and Air Quality 169

9.4 The Research Design and Methodology 170

9.4.1 Case Studies 171

9.4.2 Gumal Student Housing 171

9.4.3 Science Roof 173

9.4.4 Vertical Gardens 175

9.4.5 Results and Interpretation 176

9.4.6 Findings 180

9.5 The Carbon Footprint of Food Grown on Demonstration Beds 180

9.6 Potential Reductions in Carbon Footprint 181

9.7 Conclusions 183

References 183

Chapter 10 Social Aspects of Institutional Rooftop Gardens 189

10.0 Introduction and Objectives 189

10.1 Social Aspects, Productivity and Sustainability Potential of Rooftop Gardens 190

10.2 Methodology 193

10.2.1 Comparative Analysis of Eight University Rooftop Garden Case Studies 195

10.2.2 Semi]Structured Interviews with UTS Roof Gardening Club 195

10.2.3 107 Projects Rooftop Garden: A Sensory Ethnography 196

10.3 Main Findings 197

10.3.1 Comparative Analysis of Eight Rooftop Gardens in Universities 197

10.3.2 Qualitative Analysis of UTS Roof Gardening Club Semi]Structured Interviews 198

10.3.3 107 Projects Rooftop Garden, Sydney 205

10.3.4 St Canice Kitchen Garden, Kings Cross, Sydney 208

10.4 Recommendations, Discussions and Conclusions 209

Acknowledgement 212

References 212

Chapter 11 Cool Roof Retrofits as an Alternative to Green Roofs 216

11.0 Introduction 216

11.1 What is a Cool Roof? 216

11.2 Background – How does a Cool Roof Work? 217

11.3 Cool Roof Studies and Measurements 217

11.4 The Experiments 218

11.4.1 Results 219

11.4.2 Other Residential Building Typologies 228

11.4.3 Impact of CRP on PV Energy Generation 231

11.5 Conclusions 232

11.5.1 Negative Impacts of Cool Roofs 232

11.5.2 Green Roofs Versus Cool Roofs 232

11.5.3 Cool Roofs and Retrofits 233

11.5.4 Barriers and Stakeholders 233

Acknowledgements 233

References 234

Chapter 12 Looking to the Future 235

12.0 Introduction 235

12.1 City]level Actions: Basel and Paris 235

12.2 City]level Actions: Requirements or Inducements? 237

12.3 Tools and Information Sources 240

12.4 Green Roofs: The Big Picture of GI and Future Developments 241

12.5 Recognising the Multiple Benefits of Green Roof Retrofit 243

12.6 Overall Conclusions 244

References 245

Appendices 247

Appendix 1: A Checklist for Appraising the Suitability of an Existing Roof for Green Roof Retrofit 247

Appendix 2: Checklist for Designers of Biodiverse Green Roofs 250

Appendix 3: Tools, Information Sources and Mapping/GIS for Green Roofs – Some Examples 253

Index 257