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Design Tips for Green Roofs and Vertical Greening in Schools
Environment and Conservation fund Sharing Session cum Exhibition
of Environmental Education and Community Action (EE & CA)
Projects (General and Minor Works Projects)
6 June 2012
Kathy Ng 伍 芷 筠
Head of Greening and Landscape Office
Greening, Landscape and Tree Management Section
Development Bureau
發展局 綠化、園境及樹木管理組
綠化及園境辦事處綠化及園境辦事處
Development Bureau, HKSAR Government ©Cumberland Presbyterian
Church Yao Dao Primary School
Source: SP Ng
ytchowText BoxCopyright Notices: For the copyright of this
presentation, please read the Important Notice in Greening website
(www.greening.gov.hk). Besides, the copyrights of third party's
photographs and diagrams rest with the sources as specified. If you
wish to use or reproduce these photographs and diagrams for any
purpose, please seek the permission of the copyright owners
directly.
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Benefit of Green Roof and Vertical Greening
• Environmental benefit– Contribute to the amelioration of
the urban heat island effect– Vegetation and soil can take
up
some gaseous and particulate air pollutants to make air
clean
– Noise mitigation: soil layers and plants absorb sound
energy
– Improve stormwater quality to reduce water pollution for
receiving water bodies
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• Economic Benefit– Reduce air-conditioning energy
cost from green roof cooling effect– Reducing sun exposure
for
building surface to extend roof life – Green roof can protect
the roof top
material, especially the thermal insulation layer and the
waterproofing membrane
Benefit of Green Roof and Vertical Greening
SAVE $$SAVE $$
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Benefit of Green Roof and Vertical Greening
• Education value– Green roof attract wildlife and bring
biodiversity to school for students to experience
– Student can learn the knowledge of Eco-system from observation
for the relationship among creatures
– Learn 3-R concept from using different recycle materials and
making organic fertilizer from waste food / irrigation from waste
water
– Organic farm for students to experience plant growing
process
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Benefit of Green Roof and Vertical Greening
• Academic and health benefits– More open spaces can
encourage
students to join outdoor activities to bring improvement in
health and physical fitness
– Students tend to be more attentive in class, work harder, and
better in academic performance
– Less attention deficit disorder (ADD)and play truant
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Considerations
Technical Feasibility Funding
ObjectivesMaintenance
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Considerations – School objectives
– Recreational / leisure space for students
– Outdoor classroom – hands-on experience
– Living classroom for monitoring studies from observation /
experiment
– Education value– Amenity value
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Considerations – Technical feasibility
• Usable Area– A large clear flat roof >200m2 is
preferred– Not heavily shade by adjacent
buildings– Rectangular and simple shape
is preferred– No limitation – design to suit the
siteSource: Ng Yuk Secondary School
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Considerations – Technical feasibility
• Structural Loading– Choice of Intensive /
Extensive Green Roof– Soil depth– Consult structural
engineer/ check drawings– Min. of 3kPa of load-bearing
capacity is recommended (300kg/m2)
– Loading data should be obtained
(Source: Urbis Limited)
IntensiveAMENTITY PLANTING
TOPSOIL (300-1500mm)
FILTER LAYER
DRAINAGE AGGREGATE (100mm)
PROTECTIVE SCREED (30mm)
WATERPROOFING
STRUCTURAL DECK
ExtensiveLOW MAINTENANCE GROUNDCOVER
LIGHTWEIGHT SOIL (80-150mm)
FILTER LAYER
DRAINAGE LAYER (30mm)
PROTECTIVE LAYER BOARD (5mm)
WATERPROOFING
STRUCTURAL DECK
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Considerations – Technical feasibility
• Accessibility & Safety– Access should be easy and
safe without obstacle– Evacuation for emergency– Universal
accessibility – Parapet wall - building
regulations and safety requirement
– Robust railing / fence for safe use
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Considerations – Technical feasibility
• Waterproofing / Drainage / Irrigation– Rectifying water
leakage if any– Waterproof membrane
installation– Surface drainage channel and
pipes should be able to drain water efficiently
– roof surface should slope > 1.5%for water flow to the
drain
– Water supply for irrigation/ rain water retention
– Manual / auto irrigation
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Considerations – Funding
• Budget for construction and maintenance– Intensive / extensive
green roof– Recycle material for simple
green roof– Students - resources– Out source to competent
contractor for design and construction
– Plant selection– Irrigation system installation
Source: Ng Yuk Secondary School
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Considerations – Maintenance
– Mowing - turf– Removing weeds– plant health care/ pest/
disease control– Fertilizer – when app
when appropriate/ nutrient fixing plants/ organic fertiliser
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Typical School Green Roof
More possibilities!!More possibilities!!
Design Features for Green Roof and Vertical Greening
Source: C.Y. Jim, School Green Roof, Ng Yuk Secondary School and
Munsang College Primary School
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• Screen off railing, pipes and utility for amenity
Railing and plastic twine to guide climbers to grow
Simple but effective
Design Features for Green Roof and Vertical Greening
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Source: http://www.japanfs.org/
Green Roof Design Tips – Vertical Greening
Source:http://weblogs.baltimoresun.com
Climbers can grow well in planter boxes and climb up to fences /
railings intensively
Plastic bag planters hang on fences can also create vertical
greening in times
Design Features for Green Roof and Vertical Greening• Screen off
railing, pipes and utility for amenity
Plastic bottles hanged in wood frame vertically as planters can
also create an excellent greening effect
Source: Ng Yuk Secondary School
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Planter boxes for climbers to screen off railingsRailings are
screen off by climbers
Higher shrubs to cover the pipe on parapet
wall
Design Features for Green Roof and Vertical Greening
• Screen off railing, pipes and utility for amenity
Railings and parapet walls can be a great elements for vertical
greening
Source: Munsang College Primary School
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All pipes and utilities are exposed as eyesores
Plants can screen off eyesores to enhance to amenity value
Design Features for Green Roof and Vertical Greening
Climber on parapet wall
Shrubs to cover utilities and pipes
• Screen off railing, pipes and utility for amenity
Source: Ng Yuk Secondary School
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Source: Ng Yuk Secondary School
Design Features for Green Roof and Vertical Greening
• Logo / Graphic on Wall
Logos can also be composed by a small pots plugged in vertical
planters
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• Cooling effect with vertical greening as a buffer
– Reduce sun exposure in the evening
Design Features for Green Roof and Vertical Greening
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Design Features for Green Roof and Vertical Greening• Small
garden design concept
Arrange plant carefully with different heights and layers can
create an interesting spaces and enclosure feeling
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• Decks, Pavements, Furniture and Shade area
Wood deck was built as a path and resting area
Design Features for Green Roof and Vertical Greening
Source: The Hong Kong Jockey Club Headquarters
Paving and vertical greening on roof garden
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• Decks, Pavements, Furniture and Shade areaDesign Features for
Green Roof and Vertical Greening
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• Water feature for cooling, irrigation and amenity
Design Features for Green Roof and Vertical Greening
Source: Ng Yuk Secondary School
School green roof with water feature can enhance the cooling
effect for the building and the biodiversity in the roof.
Source: Architectural Services Department
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• Recycle material
Design Features for Green Roof and Vertical Greening
Source: Ng Yuk Secondary School
Plastic bottles and aluminum cans be skillfully used in the
green roof garden as a planting materials
Reuse wasted banners to become the waterproof membrane
Source: Ng Yuk Secondary School
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• Modular System
Design Features for Green Roof and Vertical Greening
- movable planter boxes (modular system) -more flexibility
- easy to install and flexible to adjust and rearrange as
needed
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• Play, Learn, Eat
Collecting food waste
Burial food waste
Food waste decomposing
Organic fertilizers
Design Features for Green Roof and Vertical Greening
Source: Ng Yuk Secondary Shcool
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• Solar energy - integration• Experimental Results:
– PV panel shades and reduces surface and soil temperature of
green roof
– Green roof cools PV panels and increases its power output
– PV-GRS integration generates 8.3% more electricity than PV
alone
– Less evaporation under PV panels
Design Features for Green Roof and Vertical Greening
Source: Ng Yuk Secondary School
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• Plant selections– fragrance
含笑含笑 Banana Shrub (Banana Shrub (MicheliaMichelia figofigo))
九里香九里香 Orange Jasmine (Orange Jasmine (MurrayaMurraya
paniculatapaniculata)) 桂花桂花 KwaiKwai--FahFah((OsmanthusOsmanthus
fragransfragrans))
米仔蘭米仔蘭 Mock Lime Mock Lime ((AglaiaAglaia odorataodorata))
Source: Hong Kong Herbarium & www.hktree.com
Design Features for Green Roof and Vertical Greening
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• Plant selections– Native plants
Design Features for Green Roof and Vertical Greening
Source: Hong Kong Herbarium & www.hktree.com
龍船花龍船花 Chinese Chinese IxoraIxora ((IxoraIxora
chinensischinensis ))假蘋婆假蘋婆 LanceLance--leaved leaved
SterculiaSterculia((SterculiaSterculia lanceolatalanceolata))
珊瑚樹珊瑚樹 Sweet Sweet ViburnumViburnum((ViburnumViburnum
odoratissimumodoratissimum))
石斑木石斑木 Hong Kong Hawthorn Hong Kong Hawthorn
((RhaphiolepisRhaphiolepis indicaindica ))
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Source: http://web.expasy.org/
Design Features for Green Roof and Vertical Greening
破布葉破布葉 MicrocosMicrocos ((MicrocosMicrocos nervosanervosa ))
九層塔九層塔 Basil (Basil (OcimumOcimum basilicumbasilicum))
射干射干 BlackBlack--berry Lily berry Lily ((BelamcandaBelamcanda
chinensischinensis))
薄荷薄荷 Peppermint Peppermint ((MenthaMentha canadensiscanadensis
))
Source: Hong Kong Herbarium & www.hktree.com
• Plant selections– Herbs / Chinese medicinal plants
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Design Features for Green Roof and Vertical Greening
忍冬忍冬 HoneysuckleHoneysuckle ((LoniceraLonicera
japonica)japonica)
大花老鴉嘴大花老鴉嘴 LargeLarge--flowered flowered
ThunbergiaThunbergia((ThunbergiaThunbergia grandifloragrandiflora
))
異葉爬山虎異葉爬山虎 DiverseDiverse--leaved Creeperleaved
Creeper((ParthenocissusParthenocissus dalzieliidalzielii ))
炮仗花炮仗花 FireFire--cracker Vinecracker Vine((PyrostegiaPyrostegia
venustavenusta ))
• Plant selections– Climbers
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Why Green Roof / Vertical Greening?
Thank you!Please visit DEVB’s Greening website for more
information: http://www.greening.gov.hk