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Greenroofs
Greenroofs are vegetated roof covers, with growing media and plants taking the place of bare membrane, shingles, tiles or other roofing materials. The primary reason for greenroofs in cities is for stormwater retention (delay in runoff) and reduction of stormwater volume entering piped drainage infrastructure.
In many cities around the world greenroofs are also used to:
- improve runoff quality (especially where acid rain, high dust/traffic volumes or Cu/Zn (copper/zinc) roof features)
- modify city temperatures and reflectance leading to increased energy efficiency of building
- create or enhance biodiversity: habitat for plants, insects, and birds.
Waitakere Civic Centre extensive greenroof planted winter 2006, photo November 2006.
Lower photo - a cafe & conference centre in North Auckland countryside - a greenroof used as recreational lawn
(R. Simcock)
The number of layers and the layer placement vary from system to system and greenroof type. However, all greenroofs at least include a single to multi-ply waterproofing layer, drainage, growing media and the plants. Grasses, trees and shrubs may be used, though various species of sedum are most commonly used in many greenroof applications (note: sedums are weeds in some New Zealand environments). In New Zealand both exotic and native species can be used.
A cross-section through a typical greenroof showing the various layers. This diagram is for an extensive greenroof (thin). Vege garden types are 'intensive' and may be up to 500 mm plus depth.
Commonly, the roof function or objective of the roof space determines the design – is it just an ecological cover or is it intended for human recreation, vegetable gardening, etc.? The limiting factors for greenroofs include: the roof loading capacity or maximum dead and live weight loads, determined by a structural engineer; the slope of the roof, and perhaps the client’s budget. More...... (NB: this link will take you to another site)
Greenroofs on public toliets at Maori Bay, Auckland Regional Park (R. Simcock)
Eden Valley roof garden provides recreational space (R. Simcock)
Environment Canterbury office block roof garden with native fescue and poa tussock grasses and broadleaf (Griselinia) hedges, Christchurch (ECan)
Kawakawa’s Hundertwasser extensive greenroof
New research
- Greenroofs in New Zealand - article in Soil Horizons March 2006
- Greenroofs - article/interview in Terra firma 2008
Recent Publications
Landcare Research. 2006.
Poster on greenroofs.
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Auckland Regional Council sponsored roof at Auckland University.
Landcare Research. 2006. Waitakere greenroof . Urbis magazine.
Simcock R, Whitelaw L. 2006. Indigenous New Zealand greenroofs: a Waitakere case study and possible planning incentives. RNZIH Conference.
Recent Presentations
Simcock R 2008.
A tale of three extensive greenroofs: developing resilient local substrates and plants
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Paper presented at 2nd Annual Greenroofs Australia Conference, Brisbane 18-20 June 2008
Links
New Zealand
Green roofs have a role in urban agriculture - Article in "The Australian" on greenroofs
- Sixth Annual International Greening Rooftops for Sustainable Communities Conference, Awards & Trade Show April 30, May 1 and 2, 2008, Baltimore, Maryland, USA
- World Green Roofs Congress 17-18 Sept 2008, London, UK
- Coming soon – Green roofs for Sustainable Cities (New Zealand), a not-for-profit group aiming to educate and promote greenroofs.
- Greenroofs in New Zealand
- Greenroof design, construction
and maintenance (ARC Chapter 12 TP 10
) - TVNZ news item and video clip on green roofs. "Green roofs hailed stormwater solution" Oct 7 2006.
International
- The Sheffield 'Green Roof Centre'
'The Sheffield 'Green Roof Centre' leads the UK, with Sheffield City last year requiring greenroofs to be installed on large buildings to aid control of stormwater runoff. The site has free download including a FAQ fact sheet and DIY home greenroof factsheet, and some great case studies that include two school projects. I particularly like the DIY Gallery pages pages where you can see, and submit your own, 'home greenroof' - from bird boxes to sheds.
- Green buildings
This is an article showing the main cities where the 30% increase in greenroof area over the last year has occurred: Chicago
- Greenroofs.com
A clearinghouse of information to promote green roof interest and development. Includes the history, technical details, international and North American projects and case studies, and a comprehensive annotated bibliography of green roofs literature. - The International Greenroof Association
The International Greenroof Association – greenroof case studies from all over the world. - Living roofs.org
An independent United Kingdom resource for greenroof information. - Green Roofs for Health Cities Network
The Green Roofs for Health Cities Network was established in 1999 with the mission to develop the greenroof industry infrastructure in North America. GRHC conducts research on the benefits of greenroofs, educates industry stakeholders and the public, and works with policy makers to create public incentives for the adoption of greenroofs. - Greenroofs Australia
Urban Agriculture and Greenroofs for Healthy Australian Cities host site. - Roofscapes Inc.
The Roofscapes Inc. homepage includes information about their services, examples of green roof projects and the benefits of using green roofs in order to reduce runoff volume, increase insulation, and increase the aesthetic value of projects. - Low Impact Development Urban Design Tools
- USEPA - Green infrastructure
Contact
 | Robyn Simcock Email  |
Landcare Research | |
Phone: 09 574 4100 | |
| Details: Robyn Simcock |