Next Level Landscape for a Greener City Centre
is a green roof ?
are these already working ?
is it right for Manchester ?
WHAT IS A GREEN ROOF ?
There are many different types of green roofs, each bring their own unique benefits. They come at varying degrees of cost and maintenance, and each can be tailored to fit the appropriate roof top. They can also be combined to create a more complex roof system. Just as natural landscapes are a composition of varying habitats and ecosystems, the role of green roofs is to contribute to a wider cityscape of living green infrastructure.
B ROW N
P RO D U C T I V E
B LU E
BIODIVERSE R E C R E AT I O N
BIODIVERSE B LU E
P RO D U C T I V E
T YPES OF GREEN ROOF BLUE Rainwater drains through the surface treatment (usually gravel) and is temporarily stored on the roof, helping in reducing the risk of street level flooding.
BLUE - FEATURE This blue roof will store rain water on the surface creating a water feature that comes and goes with the rain fall. Whilst helping to reduce the risk of flooding, it also creates temporary habitats for wildlife.
AMENITY The main purpose is to provide usable space for the public. This could include a public roof top cafe or a small private terraces.
WILDFLOWERS Higher maintenance roof which comprises of a diverse mix of wildflower species, can be seeded or pre-grown on mats. Creates a more diverse habitat that will attract a larger variety of wildlife.
SEDUM Low maintenance roof which, comprised of a mix of sedum plants suitable for rooftops, can be installed as pre-grown mats or plugs.
BROWN This roof mimics the surrounding environment that has been built upon in order to reduce the ecological impact. The surface is comprised of a mix of recycled crushed bricks, organic materials, log piles and boulders. The roof if left to self seed.
PRODUCTIVE A productive roof can be anything from a large rooftop farm which, grows crops and keeps live stock, to a small herb garden or allotment. Itâ€™s main purpose is food production.
WHY BUILD GREEN ROOFS ? Wa t e r s t o ra g e a n d re l e a s e •
There are many benefits to installing green roofs. Some are localised benefits that can be witnessed in the short term, others can be seen benefiting the larger community and can help achieve long term improvements.
Reduces risk of flash flooding by slowing water run off. Absorbs and filters rainwater, minimising contaminated run off Water stored can used reused in the building
Counters the urban heat island effect â€˘
Green roofs reflect more sunlight than conventional roofs and cool air temperature through evapotranspiration Helps to insulate the buildings internal temperature
Improves air quality â€˘ â€˘
Planted surfaces help to filter dust and pollutants in the air Plants absorb CO2
Increases biodiversity • • •
Green roofs can provide habitats for local wildlife They help in replacing otherwise lost groundbase habitats due to urbanisation Different types of green roofs support different habitats and species, including endangered wildlife and plants
WHERE ARE THESE ALREADY WORKING ?
Cityâ€™s across the world are increasingly promoting the establishment of green roofs, either through policy requirements for new developments or financial subsidies for retrofit projects. Through these initiatives the ability of green roof spaces to repay financial investment, over and above the environmental benefits, has been demonstrated.
SUCCESSFUL GREEN ROOFS ? Green roofs can pay back the investment required to create them in the following ways: • • • • • •
extend the lifespan of waterproofing and underlying materials reduce stormwater runoff increase property values reduce sound reflection and transmission improve thermal insulation reducing the need for cooling/heating allow commercial use of roofspace
Amsterdam launched a green roof incentive programme in 2009 offering direct subsidies to building owners to install green roofs (up to 50% of the installation costs to a maximum value of €50/m2). It has been demonstrated that the return on the investment in these projects occurs within 2 and 6 years. The quickest return on investment was seen with those green roofs that provided a degree of access, despite the higher implementation costs. These examples opened up a broader range of income streams, over and above lifetime efficiency savings. www.moss.amsterdam
As part of its overall strategy to become a carbon neutral city by 2025, Copenhagen has implemented a policy in 2010 that requires all new buildings with roof slopes of less than 30 degrees to have green roofs. Today the City of Copenhagen is estimated to have over 40 green roofs. The National Archives buildingâ€™s green roof, in Copenhagen, spans 7,200m2. It is accessible to the public and is planted with over 40 different species creating a biodiverse landscape that supports local wildlife. It is estimated that around 60-70% of the precipitation that falls on this area is retained annually, and hence does not impact on the drainage system.
N e w Yo r k
The City of New York and New York State passed legislation in 2008 to provide a 1 year tax abatement of $4.50 per square foot (up to $100,000 or the buildingâ€™s tax liability, whichever is less). To be eligible the roof must meet certain criteria such as; at least 50% of the total roof area must be a green roof. The renovation of the Javits Center included the installation of a new green roof spanning 6.75 acres (2.73 hectares), making it the second largest green roof in the USA. Sensors have been installed all over the building to monitor efficiency, revealing a 26% reduction in energy consumption since the renovations were completed. It also collects up to 6.8 million gallons (25.7m litres) of water annually.
WHY IS IT RIGHT FOR MANCHESTER ?
Not for the first time in its history Manchester is growing at a dramatic rate. The industrial revolution left a legacy of strong built character but has not blessed the City Centre with an abundance of green space. As we move through this next period of growth, demands upon existing space intensifies. We must make smarter use of investment to deliver an attractive and sustainable urban environment with increased amenity.
WHO BENEFITS ?
The positive impact of large scale green roof installations would not only be beneficial for building owners but also the wider public. For example, city wide reduction in storm water run off would reduce the strain on the cityâ€™s sewer system and the risk of large scale flooding. Devolution of issues, such as healthcare spending, also provides an increased incentive to tackle the impact of poor air quality to limit its long-term health and financial impacts.
Increased property value
Increased roof longevity
Air cleaning quality
Improves energy efficiency
Reduced flooding risk
Creates habitat for wildlife
Reduced heat island effect
The Local Community
MAKING IT HAPPEN ? OPEN are working with a range of developers and Architects across Manchester and the UK to promote the delivery of green roof solutions, making effective use of elevated spaces and roofscapes to enrich the natural environment within city centres.
Swan House Location: Manchester Client: Cable Swan Ltd. Design Team: Simpson Haugh, Curtins, GVA HOW, G&T, OPEN Green roof types: Biodiverse wildflower roof Accessible amenity terrace Living green wall
Dantzic Street Location: Manchester Client: Leftfield Investment Holdings Design Team: Simpson Haugh, Hydrock, Paul Butler Associates, Savills, Fabrik (to planning), OPEN (post-planning), visual by Our Studio Green roof types: Biodiverse wildflower roofs Accessible amenity terraces
Excelsior Works Location: Manchester Client: Mulbury City Design Team: Tim Groom Architects, Ramboll, UTH, Deloitte, OPEN Green roof types: Accessible amenity terrace
River Street Location: Manchester Client: Downing Students Design Team: Simpson Haugh, AJP, Desco, Deloitte, OPEN, visual by Our Studio Green roof types: Biodiverse wildflower roof
Belgrade Plaza Location: Coventry Client: Downing Students Design Team: Simpson Haugh, AJP, Desco, Fabrik (to planning), OPEN (postplanning), visual by Our Studio Green roof types: Biodiverse wildflower roof
St James Location: Edinburgh Client: TH Real Estates Design Team: Allan Murray Architects/ BDP, OPEN Green roof types: Accessible amenity terraces
Location: Glasgow Client: Inhabit Design Team: CDA/Richard Murphy Architects, OPEN Green roof types: Accessible amenity terraces
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Next Level Landscape for a Greener City Centre