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Attachment B Green Roof Plan
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Log in to see the plans as drawn Landscape Architecture Green Roof Proposal
Urban Design Client
Furniture Design Universal Property Company Establishment
Urban Art Curation Markus Hasler
Project
Level 2, No. 4 First Avenue
050 1314 Hasler Residence, Seaview Terrace
Maroochydore
QLD 4558
Date
24/09/2014
07 5326 1855
[email protected]
Issue
www.jamesbirrelldesignlab.com
A
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Page 2
Introduction
James Birrell Design Lab has been engaged by the client to prepare a report to address the preliminary design
of the green roof for the proposed residential building at Seaview Terrace, Sunshine Beach, Queensland. The
proposed project site is located adjacent to Noosa National Park at the northern end of Sunshine Beach on the
foredune of the coastline.
The topography of the site is sloping with an eastern aspect and comprised of natural foredune heathland and
shrubland vegetative cover.
The aim of the proposed green roof is to replicate a natural foredune environment where the proposed residential
building has a minimal visual and environmental impact on the immediate and surrounding natural environment and
ecosystem.
Green roofs are known to promote proven sustainable concepts with environmental and economic advantages
such as:
Environmental advantages:
• key advantage is collecting and harvesting stormwater:
1. reduces rate of flow from roof through stormwater system, i.e reducing flooding / water pollution.
2. green roof substrate filters water as is passes through, providing cleaner water.
SITE 3. collected water can be used for irrigation.
• minimises surface run-off
• reduces heating effect by using planting materials instead of traditional roof construction methods.
• Increases biodiversity through use of local native plant species
Economic advantages:
• Thermal insulation, reducing heating and cooling costs
• Increase the lifespan of the roof membrane by directly shading and protecting to the roof membrane and
therefore greatly reducing exposure to harsh environmental conditions. This means that the expected lifespan
of the roof is much longer than a traditional roof deck. (Sydney City Council Green Roof Design Resource
Manual)
This report has been prepared to respond to the following items that council have requested information on:
1. Proposed green roof design
2. Character of the site and indicative plant palette
Photo 1 : Locality Plan - Google Earth. 3. Proposed drainage, irrigation and substrate (soil)
0 250
4. Maintenance
5. Stormwater Quality Considerations
6. Alternative roof treatment
7. Case studies
Project Background
Date : 24.09.2014
Hasler Residence, Seaview Terrace A
1000
Page 3
1 Proposed Green Roof Design
Green Roof Proposed Design
The proposed green roof design is as follows and is to be read in conjunction with Figure 1:
1. Waterproof membrane
45
Waterproof membrane to protect substructure from water damage.
2. Root barrier protective layer
Root barrier to protect substructure and waterproof membrane. 8
3. Drainage layer with moisture retention cells
Green roofs are capable of storing rainwater and slowing run off however sufficient drainage is important to eliminate standing water which presents long term
risks to the integrity and success of the green roof. The drainage layer will achieve a balance between storage and drainage of stormwater.
7 3
Moisture protection cells will allow for effective removal of subsurface water while allowing for some water retention for plant growth.
4
5
4. Filter fabric
Filter fabric to provide separation between soil and drainage layer while still allowing water penetration.
2
5. Planting substrate
125mm layer of planting media (Total growing media depth is max. 200mm). 6 1
6. Pre-planted coco - coir planting tray
75mm deep coconut coir planting trays pre-planted with native coastal dune species act as a temporary support structure until the plants establish. Coir trays
break down and form part of the growing media. 8
7. Woven coir mat
Coir matting will prevent soil erosion and provide surface stabilisation.
8. Intercept Drains
A grid of intercept drains / gabions, with socked ag- pipe, will support and contain growing media and pre-planted biodegradable trays. 9
9. Off-form concrete facade - steeper than 45 degrees
Where roof is steeper than 45 degrees an off-form concrete facade is proposed.
Figure 1 - Native Vegetation Green Roof Detail (1:20)
Green Roof Proposal
Date : 24.09.2014
Hasler Residence, Seaview Terrace A
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1 Proposed Green Roof Design
PB
GL.
Figure 2 - Section through Building 1:150
Green Roof Proposal
Date : 24.09.2014
Hasler Residence, Seaview Terrace A
Page 5
2 Character of the Site
Character of the Site
The natural landscape charater of the site according to The Noosa Planning Scheme Policy 2007, is Coastal Beach front wallum or heathland.
The site is exposed to coastal on shore winds and salt spray and combined with low fertility of the sand and its inability to hold moisture creates a harsh
environment for plants.
A typical coastal environment consists of:
1 Ocean
2 Beach / Sand
3 Incipient dune (newly formed dune stablised with grasses and creepers)
4 Fore dune - Heath and Shrublands
5 Hind dune
6 Foothills
7 Rainforest Gully
Site Position
Photo 2: Foredune Heathland Vegetation Character
6
4 5
7
3
1 2
Figure 3 - Typical Coastal Environment Cross Section
Coastal Vegetation
“Soils are generally deep, sandy, freely drained, and leached of nutrients. As vegetation establishes on the bare sand, organic matter from the vegetation and
associated fauna is incorporated into the soil.” p. 3 Coastal Ecology 1998
There are three zones of vegetation in a coastal environment:
1. Incipient dune (strand line zone) vegetation consists of colonising herbs and grasses such as Spinifex sericeus, Carpobrotus glaucescens, Ipomoea
brasiliensis and Scaevola calendulacea.
2. Foredune zone vegetation consists of shrubs and groundcovers plants (Heathland) and scattered multi-stemmed trees such as Pandanus species or
Casuarina equesetifolia. The vegetation in the foredune zone is essential for dune stability and erosion protection. The seaward side of the foredune is
generally stabilised by mat forming groundcovers and grasses such as Lomandra and Dianella species. Hibbertia, Gahnia, Boronia, Banksia, Baekea and
Xanthorrea are species also endemic to the foredune zone.
3. Hind dune vegetation consists of open forest or woodland. Photo 3: Sunshine Beach Coastline (image courtesy of www.visitnoosa.com)
Green Roof Proposal
Date : 24.09.2014
Hasler Residence, Seaview Terrace A
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2 Indicative Plant Palette
Indicative Plant Palette
The plant species shown are per Noosa Planning Scheme Policy 2007 and are indicative of the species naturally occurring on and adjacent to the site . Actual species may
vary depending on seed availability and germination success rates. See Plant Supply, below.
Plant Selection
The indicative plant palette has been selected based on the following properties:
Austromyrtus dulcis Bauera capitata Banksia prostrate species 1. Local native species from incipient and fore-dune vegetation zones which are hardened to the sites climate and exposure to harsh coastal conditions and climatic
variability of South East Queensland seasons.
2. Creeping growth habits to assist with surface stabilisation and greening of steeper sections of the roof.
3. Low water and fertiliser requirements.
4. Compact shrub and groundcover species with the ability to grow in 200mm depth of growing substrate.
5. Species listed by the Noosa Planning Scheme.
Plant Supply
Carpobrotus glaucescens Crinum pedunculatum Ricinocarpus pinifolius prostrate Seed Collection
It is recommended that native seed be collected from the site from 2 years prior to any clearing carried out for construction. Seed will need to be collected periodically to
allow for seasonal variation in flowering of different species.
There are numerous benefits to sourcing seed endemic to the site, such as:
1. improved plant success rates
2. broader palette of species will potentially be available which will increase biodiversity and mimic natural plant vegetation character more closely (nursery plant stock can
be limited)
3. plants have greater resistance to pest and disease
4. introducing plants grown from seed from outside the ecosystem can reduce genetic integrity of naturally occurring species and strains.
Helichrysum sp. Hibbertia scandens Pultenaea maritima
Growing Contract
The collected seed can be grown on by a local specialist native nursery under contract to provide the specified pre-planted coco-coir trays and/or tube stock to be installed/
planted on the roof when appropriate.
The seed collection and growing contract will need to be organised in the early stages of project development.
Ipomoea pes caprae Scaevola calendulacea Xanthorrhoea johnsonii
Green Roof Proposal
Date : 24.09.2014
Hasler Residence, Seaview Terrace A
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3 Proposed Drainage, Irrigation and Substrate (Soil)
Drainage
Green roofs are capable of storing rainwater and slowing water run off however sufficient drainage is important to eliminate standing water / water-
logging which presents long term risks to the integrity and success of the green roof.. Roof drainage will consist of the following:
• A drainage layer, located beneath substrate, consisting of moisture retention cells to help achieve a balance between storage and drainage of
stormwater.
• A grid of intercept drains or rock gabions to assist with surface runoff and provide linear holding points to support drainage and substrate layers.
• Drainage / downpipes are proposed behind off form concrete facade areas to assist with drainage at steeper sections of the roof where substrate
moisture content levels will be higher.
2
6
Irrigation Considerations
5 Irrigation will need to be controlled and respond to plant growth, substrate moisture content and climatic conditions.
3 4
5 Drip and tube irrigation, buried in the substrate, is proposed for the following reasons:
• water is directed only to plant roots;
• less water is lost by drift and evaporation;
• buried pipework is not visible and more efficient than surface pipes; and
• weeds are less likely to germinate if substrate surface is kept dry.
(Dunnett N and Kingsbury N. 2008. p. 98.)
7 Irrigation is required during the first few years until planting has established. Following establishment irrigation requirements will be reduced and only
required strategically during periods of drought to maintain plant growth.
1
It is important to note that sloping green roofs produce significant variability in moisture content of the substrate where substrate is typically a dryer
medium at the top of the slope and moist and the base which will be an important factor in the irrigation design and water dispersion as well as
drainage provisions.
Figure 4 - Roof Drainage Concept (Level 3)
Growing substrate
Legend
1. Hardstand / pavements Native coastal plant species typically prefer sandy soils low in nutrients, with a low pH (3.5-6.5) and a constant supply of moisture. The ideal substrate
2. Pool is moderately fertile to maintain a constant plant coverage yearlong. Overly fertile soils encourage competition which may result in uneven coverage.
3. Proposed intercept drains
4. Proposed off form concrete roof sections with down pipes. (where roof pitch is too steep to support planting) Soil composition for coastal species generally need to be open, free-draining and consider the following properties:
5. Drain outlets - into existing vegetation -particle size
6. Roof extent (approx.) -water holding capacity
7. Site boundary -air filled porosity
-nutrient reserves
Note: Actual substrate composition to be specificed by soil scientist during design development phase of the project.
Green Roof Proposal
Date : 24.09.2014
Hasler Residence, Seaview Terrace A
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4 Maintenance
Task Frequency Frequency Maintenance Requirements
Establishment Period (2- 5yrs) Post Establishment
Item / Maintenance Objective All green roofs require higher levels of maintenance in the first 2-5 years of establishment until colonization has occurred and the vegetation has
Maintenance check point: Flood roof to check for any leaks / One off.: After waterproof membrane n/a stabilized. Based on existing exemplary green roof projects, green roofs are not set and forget. It takes time to get plants, irrigation and maintenance
weaknesses in the membrane. has been installed - prior to installing right and adjustments will be inevitable.
remaining components.
1. Irrigation Ensure automatic irrigation is suffi- 2-3 x per week during dry periods As required during extended dry Once plants are installed on the roof regular monitoring of all components and plants is essential.
cient to maintain substrate moisture (June - Dec) (varies according to rain- periods ( approx. June - Nov)
levels for optimum plant growth. fall / temperatures )
“Extensive green roofs require maintenance for first 2 years to ensure vegetation has stabilised and there are no competing weeds. Beyond the first 2
2. General maintenance (i.e Pruning / Maintain substrate levels, especially 2 x per year Minimal - as required
years, maintenance is minimal and may only be required once or twice annually.” Green Roof Design Resource Manual. p. 3.1
weeding) on sloping areas and top dress
where needed.
Remove weeds by hand. The maintenance contractor must be clear about the maintenance objectives and their capacity to complete this with the available resources. The
Prune shrubs and grasses to main- proposed design must be fully evaluated in terms of the maintenance it will entail.
tain dense leafy form.
Remove waste plant material.
A key challenge for maintaining the green roof is ensuring that plants are getting enough water for the desired level of growth, while also avoiding water
3. Pest control Inspect for signs of pest or disease 4 x per year (quarterly) Minimal - as required
logging in the soil. Table 1 shows the annual rainfall for the Noosa area where dry periods extend from June through to November.
and treat only as required.
4. Fertilising / Monitoring of plant Apply slow release complete fertilis- 2 x per year (6 monthly) At the be- Minimal - as required Refer to Figure 5 for a preliminary maintenance regime.
nutrition er to ensure adequate nutrient levels ginning of Spring prior to high rainfall
for plants, in accordance with soil period and 6 months later.
scientiest recommendations.
Maintain a log of fertiliser additions Fertilising
and records of pH levels before and
after fertilising.
“Fertilising can be a useful method for increasing the rate of spread of pioneer dune-stabilising plants over bare areas”. QLD Govt. Environmental
5. Plant evaluation / renewal to improve Replace dead plants and infill plant As required
Protection Agency. Natural coastal dune systems typically have low levels of plant nutrients however fetiliser applications will be necessary to provide
planting design to maintain dense cover
desirable nutrient levels for establishment of plants once pre-planted trays are installed on the roof.
6. Maintain irrigation system Manually test and inspect irrigation Weekly during dry periods / monthly at
system and make seasonal adjust- other times
ments. Check: Broad leaved herbaceous dune plants such as Ipomoea pes-caprae and Spinifex sericeus require fertiliser containing predominantly nitrogen. A natural
- volume of water delivered slow release fertiliser containing Ammonium nitrate, 34% N, is the preferred form of use for coastal native species. QLD Govt. Environmental Protection
- frequency Agency. Specific product specification and application rates will need to be determined by soil scientist.
- substrate moisture content
Fertiliser levels need to be monitored and altered accordingly to allow for inconsistent growth of plants due to varying shade levels and leaching of
7. Maintain non vegetated zones and Remove vegetation from perimeter 4 x per year 2 x per year
waterproofing zones and around other equipment
nutrients from the substrate during high rainfall periods.
and fixtures.
Inspect flashings over waterproofing
membrane terminations, wall fabric
for damage.
Conduct leak detection of water-
proofing if possible.
8. Maintain drainage Remove dirt, litter and other depos- 4 x per year 2 x per year
its from roof drains and gabion cage
intercept drains to ensure they are
clear and functioning
Figure 5- Preliminary Maintenance Regime
Green Roof Proposal
Date : 24.09.2014
Hasler Residence, Seaview Terrace A
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5 Stormwater Quality Considerations
Rainfall Data
Maintenance Impact on Stormwater Management
The Monthly rainfall is the total of all available Daily rainfall for the month. Observations of Daily rainfall are nominally made at 9 am local clock time and record
the total for the previous 24 hours. Rainfall data has been collected at the nearest station approximately 2km from the site in Noosaville. The maintenance tasks that will impact on stormwater management and water quality are fertilising and pest control. Consideration of timing of
applications, frequencies and rates is important to prevent contamination of stormwater runoff that can pollute nearby water resources.
Fertilising:
Fertilising during the establishment period (2-5 years) should occur prior to the growing seasons and consider months of high rainfall. According to
Table 1, Noosaville Monthly Rainfall, the highest rainfall occurs between the months of December and March, during summer.
Fertilising should occur bi-annually. One application at the beginning of spring, (Sept) during low rainfall and at the start of the growing season. A
second application should be applied approximately 6 months later (March-April) following months of high rainfall to replenish the substrate after
probable leaching of nutrients during the wet season. Post establishment, fertilising can be reduced to respond to plant growth and due to careful
species selection may not even be required.
Use of Pesticides / Herbicides:
It is recommended that weeds are removed by hand to avoid the use of herbicides and reduce contamination of stormwater. If adequate plant cover
is achieve weeding will be minimal.
The use of pesticides should be limited where possible and only organic pesticides used.
The impact of maintenance on stormwater can be minimised using plant species endemic to the site. As previously mentioned plant species
endemic to the site are stronger and more competitive specimens that will provide greater site coverage and therefore reduce weed infestation.
These plant species are also likely to be more resistant to pest and disease reducing the need for the use of chemicals.
Table 1- Noosaville Monthly Rainfall Data by Australian Government Bureau of Meteorology
www.bom.gov.au
Green Roof Proposal
Date : 24.09.2014
Hasler Residence, Seaview Terrace A
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6 Alternative Roof Treatment
Alternative Roof Treatment
The following roof treatment is proposed in the event that the green roof is unsuccessful following an adequate establishment period of a minimum of 2 years
and follwoing unsuccessful remedial works in attempt to rectify issues.
1. Waterproof membrane - maintain 10
Waterproof membrane to protect substructure from water damage. 4
2
3
2. Root barrier protective layer - maintain
Root barrier to protect substructure and waterproof membrane.
3. Drainage layer with moisture retention cells -
Retain moisture retention cells where gravel is to installed. (Upper sections of the roof). Remove drainage layer elsewhere.
4. Filter fabric - 1
Retain moisture retention cells where gravel is to installed. (Upper sections of the roof). Remove drainage layer elsewhere.
11
5. Planting substrate - remove
6. Pre-planted coco - coir planting tray - remove
75mm deep coconut coir planting trays pre-planted with native coastal dune species act as a temporary support structure until the plants establish. Coir trays
break down and form part of the growing media.
8
7. Woven coir mat - remove
Coir matting will prevent soil erosion and provide surface stabilisation.
8. Intercept Drains - maintain
A grid of intercept drains / gabions will support and contain growing media and pre-planted biodegradable trays. 9
9. Off-form concrete facade - steeper than 45 degrees
Where roof is steeper than 45 degrees an off-form concrete facade is proposed.
10. Gravel infill- install
Install gravel (local quarry rock) in place of planting substrate to upper sections of roof. Nominal size 100mm - 200mm. dia.
11. Timber infill- install Figure 6 - Alternative Roof Treatment Detail (1:20)
Install 200mm x 75mm native HWD timber sleepers in place of planting substrate to mid sections of roof.
Green Roof Proposal
Date : 24.09.2014
Hasler Residence, Seaview Terrace A
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7 Case Studies
1. American Society of Landcape Architects Headquarters, Washington DC - 2005 2. California Academy of Sciences, San Francisco
The American Society of Landscape Architects Headquarters 3,300 square foot green roof garden was designed by Michael Van Valkenburgh Associates in The California Academy of Sciences building, designed by Renzo Piano supports a 2.5 acre green roof with a focus on sustainable design strategies. This case study
collaboration with the Conservation Design Forum. This case study exemplifies the fusion of the environmental with the humane through the employment of ‘the is an example of green roof design for sloped roofs as well as one utilising native plant species for suitably to the harsh conditions of a green roof environment.
waves’ (vegetation) and ‘the grating’ (vegetation/grating) which allows access into the roof without taking area away from the green roof. The grating/vegetation
system covers sixty percent of the accessible surfaces. “Assembling a 197,000-square-foot rooftop to accommodate a living tapestry of native plant species is challenging enough. Add to that the technical problems
posed by the roof’s extreme dips and slopes. How to keep the plants and soil from sliding off? Rana Creek, who worked with Piano to design the roof, developed and
Green roofs can create habitats for flora and fauna through careful composition of growing medium, plants and the manipulation of micro-climatic conditions. Due to patented a solution called the BioTray®. They used 50,000 porous, biodegradable trays made from tree sap and coconut husks as containers for the vegetation.
a sturdy roof structure a deeper growing medium was possible in this example which has the following benefits: These trays line the rooftop like tile, yet enable the roots to grow and interlock, binding the trays together like patchwork.”
- important for the survival of invertebrates
- plants better withstand dry, hot periods due to moisture retention in lower portion of the roof profile “The living roof´s 1.7 million native plants were specially chosen to flourish in Golden Gate Park´s climate. After experimenting with thirty native species, the finalists
- after drought conditions deeper growing media allow for a greater seed bank, that can establish to replenish bare areas of the roof where plants did not survive. were all able to self-propagate. These nine species, located inside and outside of the special exhibit, will thrive with little water, resist the salt spray from ocean air, and
tolerate wind.” http://www.calacademy.org/academy/building/the_living_roof/
Another distinguishing factor of this roof is the varying solar expositions of it’s green surfaces which results in creating different micro-climatic conditions. The varing
expositions and soil depths of the roof create varying moisture regimes that influence the distribution of animals and plants. (Werthmann 2007)
Green Roof Proposal
Date : 24.09.2014
Hasler Residence, Seaview Terrace A
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8 Document References
References
Dunnett, N and Kingsbury, N. 2008. Planting Green Roofs and LIving Walls. Portland: Timber Press, Inc. p. 98.
Heisler, J. Coastal Ecology 1998. p. 3
Leiper, G., Glazebrook, J., Cox, D., Rathie, K. Mangroves to Mountains Revised Edition. 2008. Logan River Branch SGAP Inc. Queensland.
Noosa Council. Noosa Planning Scheme Policy 3. Landscaping Plants and Guidelines. 2007.
Open Space - Urban Public Landscape Design. SendPoints, Lin Gengli, China.
Queensland Government Envrionmental Protection Agency. Leaflet V-05.1 Management guidelines for dune use.
Sydney City Council Green Roof Design Resource Manual. Available from http://CityofSydney.nsw.gov.au. Accessed September 2014.
Werthmann, C. Green Roof - A Case Study, 2007. Princeton Architectural Press, New York.
www.calacademy.org/academy/building/the_living_roof/
www.bom.gov.au
Green Roof Proposal
Date : 24.09.2014
Hasler Residence, Seaview Terrace A