Green roof

Last updated

Green roof at the British Horse Society headquarters British Horse Society Head Quarters and Green Roof.jpg
Green roof at the British Horse Society headquarters

A green roof or living roof is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage and irrigation systems. [1] Container gardens on roofs, where plants are maintained in pots, are not generally considered to be true green roofs, although this is debated. Rooftop ponds are another form of green roofs which are used to treat greywater. [2] Vegetation, soil, drainage layer, roof barrier and irrigation system constitute the green roof. [3]

Contents

Green roofs serve several purposes for a building, such as absorbing rainwater, providing insulation, creating a habitat for wildlife, [4] and decreasing stress of the people around the roof by providing a more aesthetically pleasing landscape, and helping to lower urban air temperatures and mitigate the heat island effect. [5] Green roofs are suitable for retrofit or redevelopment projects as well as new buildings and can be installed on small garages or larger industrial, commercial and municipal buildings. [1] They effectively use the natural functions of plants to filter water and treat air in urban and suburban landscapes. [6] There are two types of green roof: intensive roofs, which are thicker, with a minimum depth of 12.8 cm (5+1⁄16 in), and can support a wider variety of plants but are heavier and require more maintenance, and extensive roofs, which are shallow, ranging in depth from 2 to 12.7 cm (13⁄16 to 5 in), lighter than intensive green roofs, and require minimal maintenance. [7]

The term green roof may also be used to indicate roofs that use some form of green technology, such as a cool roof, a roof with solar thermal collectors or photovoltaic panels. Green roofs are also referred to as eco-roofs, oikosteges, vegetated roofs, living roofs, greenroofs and VCPH [8] (Horizontal Vegetated Complex Partitions)

Environmental benefits

Thermal reduction and energy conservation

Model of layers and components used in some green roof systems Construction sample of a green roof system.jpg
Model of layers and components used in some green roof systems

Green roofs improve and reduce energy consumption. [9] They can reduce heating by adding mass and thermal resistance value, and can reduce the heat island effect by increasing evapotranspiration. [10] A 2005 study by Brad Bass of the University of Toronto showed that green roofs can also reduce heat loss and energy consumption in winter conditions. [11] [12] A modeling study found that adding green roofs to 50 percent of the available surfaces in downtown Toronto would cool the entire city by 0.1 to 0.8 °C (0.2 to 1.4 °F). [13]

Through evaporative cooling, a green roof reduces cooling loads on a building by fifty to ninety percent, [14] especially if it is glassed-in so as to act as a terrarium and passive solar heat reservoir.

A concentration of green roofs in an urban area can even reduce the city's average temperatures during the summer, combating the urban heat island effect. [15] Traditional building materials soak up the sun's radiation and re-emit it as heat, making cities at least 4 °C (7.2 °F) hotter than surrounding areas. On Chicago's City Hall, by contrast, which features a green roof, roof temperatures on a hot day are typically 1.4–4.4 °C (2.5–7.9 °F) cooler than they are on traditionally roofed buildings nearby. [16] Green roofs are becoming common in Chicago, as well as in Atlanta, Portland, and other United States cities, where their use is encouraged by regulations to combat the urban heat-island effect. Green roofs are a type of low impact development. [17] In the case of Chicago, the city has passed codes offering incentives to builders who put green roofs on their buildings. The Chicago City Hall green roof is one of the earliest and most well-known examples of green roofs in the United States; it was planted as an experiment to determine the effects a green roof would have on the microclimate of the roof. Following this and other studies, it has now been estimated that if all the roofs in a major city were greened, urban temperatures could be reduced by as much as 7 °C (13 °F). [18]

Water management

A green roof being used on a bike rack to keep bikes dry. Green roof bike rack.jpg
A green roof being used on a bike rack to keep bikes dry.

Green roofs can reduce stormwater runoff [19] [20] via water-wise gardening techniques. Green roofs play a significant role in retrofitting the Low Impact Development (LID) practices in urban areas. [21] A study presented at the Green Roofs for Healthy Cities Conference in June 2004, cited by the EPA, found water runoff was reduced by over 75% during rainstorms. [22] Water is stored by the roof's substrate and then taken up by the plants, from which it is returned to the atmosphere through transpiration and evaporation.

Green roofs decrease the total amount of runoff and slow the rate of runoff from the roof. It has been found that they can retain up to 75% of rainwater, gradually releasing it back into the atmosphere via condensation and transpiration, while retaining pollutants in their soil. [22] Many green roofs are installed to comply with local regulations and government fees, often regarding stormwater runoff management. [23] In areas with combined sewer-stormwater systems, heavy storms can overload the wastewater system and cause it to flood, dumping raw sewage into the local waterways. Often, phosphorus and nitrogen are in this category of environmentally harmful substances even though they are stimulating to the growth of plant life and agriculture. When these substances are added to a system, it can create mass biological activity since they are considered limiting factors of plant growth and by adding more of them to a system, it allows for more plant growth. [24]

Ecological benefits

Green roofs create natural habitat as part of an urban wilderness. [25] Even in high-rise urban settings as tall as 19 stories, it has been found that green roofs can attract beneficial insects, birds, bees and butterflies. A recent list of the bee species recorded from green roofs (worldwide) highlights both the diversity of species, but also the (expected) bias towards small ground-nesting species (Hofmann and Renner, 2017). Rooftop greenery complements wild areas by providing stepping stones for songbirds, migratory birds and other wildlife facing shortages of natural habitat. Bats have also been reported to be more active over green roofs due to the foraging opportunities these roofs provide. [26] Research at the Javits Center green roof in New York, NY, has shown a correlation between higher numbers of certain insects on the roof, particularly moths, with an increased amount of bat foraging activity.

Green roofs also serve as a green wall, filtering pollutants and carbon dioxide out of the air, helping to lower rates of diseases such as asthma. [27] They can also filter pollutants and heavy metals out of rainwater.

Carbon sequestration

An additional environmental benefit of a green roof is the ability to sequester carbon. Carbon is the main component of plant matter and is naturally absorbed by plant tissue. The carbon is stored in the plant tissue and the soil substrate through plant litter and root exudates. [28] A study on green roofs in Michigan and Maryland found the above ground biomass and below ground substrate stored on average between 168 g C m−2 and 107 g C m−2 . Variations occurred among the different species of plant used. Substrate carbon content averaged 913 g C m−2 and after the subtraction of the original carbon content the total sequestration was 378 g C m−2. [29] The sequestration can be improved by changing plant species, increasing substrate depth, substrate composition, and management practices. In a study done in Michigan above ground sequestration ranged from 64 g C m−2 to 239 g C m−2 for S. acre and S album. [29] Also, by increasing the substrate depth would allow for more area of carbon storage and diversify the types of plants with greater potential of carbon storage. The direct carbon sequestration techniques and methods can be measured and accounted for. Green roofs also indirectly reduce CO2 given off by power plants through their ability to insulate buildings. [28] Buildings in the US account for 38% of the total carbon dioxide emissions. [30] A model supported by the U.S. Department of Energy found a 2 percent reduction in electricity consumption and 9-11% reduction in natural gas when implementing green roofs.

Other

Costs and financial benefits

Roof garden which highlights a roof that uses garden boxes which can be a more economical solution for a green roof Rooftop farm at the Essex (65787p).jpg
Roof garden which highlights a roof that uses garden boxes which can be a more economical solution for a green roof

A properly designed and installed extensive green-roof system can cost $108–$248/m2 ($10–$23/sq ft) while an intensive green roof costs $355–$2,368/m2 ($33–$220/sq ft) However, since most of the materials used to build the green roof can be salvaged, it is estimated that the cost of replacing a green roof is generally one third of the initial installation costs. [32]

With the initial cost of installing a green roof in mind, there are many financial benefits that accompany green roofing.

Disadvantages

The addition of a green roof to an existing structure led to this collapse at the City University of Hong Kong. City University of Hong Kong Hu Fa Kuang Sports Centre roof collapses site on 21st May 2016.jpg
The addition of a green roof to an existing structure led to this collapse at the City University of Hong Kong.

The main disadvantage of green roofs is that the initial cost of installing a green roof can be double that of a normal roof. [40] Depending on what kind of green roof it is, the maintenance costs could be higher, but some types of green roof have little or no ongoing cost. Some kinds of green roofs also place higher demands on the waterproofing system of the structure, both because water is retained on the roof and due to the possibility of roots penetrating the waterproof membrane. Another disadvantage is that the wildlife they attract may include pest insects which could easily infiltrate a residential building through open windows.

The additional mass of the soil substrate and retained water places a large strain on the structural support of a building. This makes it unlikely for intensive green roofs to become widely implemented due to a lack of buildings that are able to support such a large amount of added weight as well as the added cost of reinforcing buildings to be able to support such weight. [41] Some types of green roofs do have more demanding structural standards especially in seismic regions of the world. Some existing buildings cannot be retrofitted with certain kinds of green roofs because of the weight load of the substrate and vegetation exceeds permitted static loading. The weight of a green roof caused the collapse of a large sports hall roof in Hong Kong in 2016. [42] In the wake of the disaster numerous other green roofs around the territory were removed. [43]

Green roofs require significantly more maintenance and maintenance energy compared to a standard roof. Standard maintenance include removing debris, controlling weeds, deadhead trimming, checking moisture levels, and fertilizing. [44] The maintenance energy use for green roofs has many variables including: climate, intensity of rainfall, type of building, type of vegetation, and external coatings. [37] The most significant effect comes from scarce rainfall which will increase the maintenance energy due to the watering required. During a 10-year roof maintenance cycle a house with a green roof requires more retrofit embodied energy than a house with a white roof. The individual components of a green roof have CO2 implications during the manufacturing process have additional implications compared to a conventional roof. [45] The embodied energy for green roof components are 23.6 kg/m2 (5 pounds per square foot)CO2 of green roof. This value is equivalent to 6448 g C m−2 which is significantly greater than 378 g C m−2. [37] Criteria for waste management practices when green roofs reach their end-of-life remain uncodified. [46]

Both sod roofs and LWA-based (Lightweight Aggregates) roofs have been found to have a negative impact on the quality of their resulting runoff. [47]

Types

An intensive and an extensive green roof Intensive extensive green roofs.png
An intensive and an extensive green roof
Section of a Gudbrandsdal type sod roof with elaborate "turf log" Torvtak 2.png
Section of a Gudbrandsdal type sod roof with elaborate "turf log"

Green roofs can be categorized as intensive, semi-intensive, or extensive, depending on the depth of planting medium and the amount of maintenance they need. Extensive green roofs traditionally support 50–120 kg/m2 (10–25 pounds per square foot) of vegetation [48] while intensive roofs support 390–730 kg/m2 (80–150 pounds per square foot) of vegetation. [49] Traditional roof gardens, which require a reasonable depth of soil to grow large plants or conventional lawns, are considered intensive because they are labour-intensive, requiring irrigation, feeding, and other maintenance. Intensive roofs are more park-like with easy access and may include anything from kitchen herbs to shrubs and small trees. [50]

Extensive green roofs, by contrast, are designed to be virtually self-sustaining and should require only a minimum of maintenance, perhaps a once-yearly weeding or an application of slow-release fertiliser to boost growth. Extensive roofs are usually only accessed for maintenance. [50] They can be established on a very thin layer of soil (most use specially formulated composts): even a thin layer of rockwool laid directly onto a watertight roof can support a planting of Sedum species and mosses. Some green roof designs incorporate both intensive and extensive elements. To protect the roof, a waterproofing membrane is often used, which is manufactured to remain watertight in extreme conditions including constant dampness, ponding water, high and low alkaline conditions and exposure to plant roots, fungi and bacterial organisms. [51]

Advances in green roof technology have led to the development of new systems that do not fit into the traditional classification of green roof types. Comprehensive green roofs bring the most advantageous qualities of extensive and intensive green roofs together. Comprehensive green roofs support plant varieties typically seen in intensive green roofs at the depth and weight of an extensive green roof system. [52]

Another important distinction is between pitched green roofs and flat green roofs. Pitched sod roofs, a traditional feature of many Scandinavian buildings, tend to be of a simpler design than flat green roofs. This is because the pitch of the roof reduces the risk of water penetrating through the roof structure, allowing the use of fewer waterproofing and drainage layers.

History

Re-creation of Viking houses in Newfoundland Authentic Viking recreation.jpg
Re-creation of Viking houses in Newfoundland
Sod roofs on 18th-century farm buildings in Heidal, Norway. Heidal.jpg
Sod roofs on 18th-century farm buildings in Heidal, Norway.

In ancient times green roofs consisted of cave-like structures or sod roofs covered with earth and plants commonly used for agriculture, dwelling, and ceremonial purposes. These early shelters provided protection from the elements, good insulation during the winter months, and a cool location in the summer. Unfortunately for modern conveniences, these were neither waterproof nor was there any system to keep out unwanted burrowing wildlife. [53] [ disputed (for: trad birchbark underlayer) – discuss ]

On the green roof of the Mountain Equipment Co-op store in Toronto, Ontario, Canada. MEC's green roof among others.jpg
On the green roof of the Mountain Equipment Co-op store in Toronto, Ontario, Canada.

Modern green roofs, which are made of a system of manufactured layers deliberately placed over roofs to support growing medium and vegetation, are a relatively new phenomenon. However, green roofs or sod roofs in northern Scandinavia have been around for centuries. The modern trend started when green roofs were developed in Germany in the 1960s, and has since spread to many countries. Today, it is estimated that about 10% of all German roofs have been "greened". [34]

A number of European Countries have very active associations promoting green roofs, including Germany, Switzerland, the Netherlands, Norway, Italy, Austria, Hungary, Sweden, the UK, and Greece. [54] Germany was the first country to start developing green roof systems and market them on a large scale. [53] The City of Linz in Austria has been paying developers to install green roofs since 1983, and in Switzerland, it[ clarification needed ] has been a federal law since the late 1990s.[ citation needed ] In the UK, their uptake has been slow, but a number of cities have developed policies to encourage their use, notably London and Sheffield.

Green roofs are also becoming increasingly popular in North America, although they are not as common as in some parts of Europe. Numerous North American cities offer tax incentives to developers who integrate green roofs in their buildings. Toronto and San Francisco legally mandate new buildings to include green roofs. [55] [56]

Rooftop water purification is also being implemented in green roofs. These forms of green roofs are actually treatment ponds built into the rooftops. They are built either from a simple substrate (as being done in Dongtan [57] ) or with plant-based ponds. Plants used include calamus, Menyanthes trifoliata , Mentha aquatica , etc. [58] )

Several studies have been carried out in Germany since the 1970s. Berlin is one of the most important centers of green roof research in Germany. Particularly in the last 10 years, much more research has begun. About ten green roof research centers exist in the US and activities exist in about 40 countries. In a recent study on the impacts of green infrastructure, in particular green roofs in the Greater Manchester area, researchers found that adding green roofs can help keep temperatures down, particularly in urban areas: "adding green roofs to all buildings can have a dramatic effect on maximum surface temperatures, keeping temperatures below the 1961–1990 current form case for all time periods and emissions scenarios. Roof greening makes the biggest difference…where the building proportion is high and the evaporative fraction is low. Thus, the largest difference was made in the town centers". [59]

Brown roofs

Roof planted with dune plants from the shores of Lake Ontario, SUNY-ESF, Syracuse, NY ESF-Gateway-Green-Roof-2014.jpg
Roof planted with dune plants from the shores of Lake Ontario, SUNY-ESF, Syracuse, NY

Industrial brownfield sites can be valuable ecosystems, supporting rare species of plants, animals and invertebrates. Increasingly in demand for redevelopment, these habitats are under threat. "Brown roofs", also known as "biodiverse roofs", [60] can partly mitigate this loss of habitat by covering the flat roofs of new developments with a layer of locally sourced material. Construction techniques for brown roofs are typically similar to those used to create flat green roofs, the main difference being the choice of growing medium (usually locally sourced rubble, gravel, soil, etc...) to meet a specific biodiversity objective. [61] In Switzerland, it is common to use alluvial gravels from the foundations; in London, a mix of brick rubble and some concrete has been used.

The original idea was to allow the roofs to self-colonise with plants, but they are sometimes seeded to increase their biodiversity potential in the short term. Such practices are derided by purists. [62] The roofs are colonised by spiders and insects (many of which are becoming extremely rare in the UK as such sites are developed) and provide a feeding site for insectivorous birds. Laban, a centre for contemporary dance in London, has a brown roof specifically designed to encourage the nationally rare black redstart. [63] A green roof, 160 m (520 ft) above ground level, and claimed to be the highest in the UK and Europe "and probably in the world" to act as nature reserve, is on the Barclays Bank HQ in Canary Wharf. [64] Designed combining the principles of green and brown roofs, it is already home to a range of rare invertebrates.

ASLA Award Green Roof Projects

The new California Academy of Sciences building in San Francisco's Golden Gate Park has a green roof that provides 2.5 acres (10,000 m) of native vegetation designed as a habitat for indigenous species, including the threatened Bay checkerspot butterfly. According to the Academy's fact sheet on the building, the building consumes 30-35% less energy than required by code. CaliforniaAcademyofSciences.jpg
The new California Academy of Sciences building in San Francisco's Golden Gate Park has a green roof that provides 2.5 acres (10,000 m) of native vegetation designed as a habitat for indigenous species, including the threatened Bay checkerspot butterfly. According to the Academy's fact sheet on the building, the building consumes 30–35% less energy than required by code.

Examples by country

Australia

Green roofs have been increasing in popularity in Australia over the past 10 years. Some of the early examples include the Freshwater Place residential tower in Melbourne (2002) with its Level 10 rooftop Half Acre Garden, CH2 building housing the Melbourne City Council (2006) – Australia's first 6-star Green Star Design commercial office building as certified by the Green Building Council of Australia, and Condor Tower (2005) with a 75-square-metre (810-square-foot) lawn on the 4th floor.

Since 2008, city councils and influential business groups in Australia have become active promoting the benefits of green roofs. "The Blueprint to Green Roof Melbourne" is one program being run[ when? ] by the Committee for Melbourne. [66] In 2010, the largest Australian green roof project was announced. The Victorian Desalination Project [67] will have a "living tapestry" of 98,000 Australian indigenous plants over a roof area spanning more than 26,000 m2 (280,000 square feet). The roof will form part of the desalination plant's sophisticated roof system, designed to blend the building into the landscape, and provide acoustic protection, corrosion resistance, thermal control, and reduced maintenance.

Movable Tillandsia plant screen Tillandsia Plant screen.jpg
Movable Tillandsia plant screen

In June 2014 ecological artist Lloyd Godman, with structural engineer Stuart Jones and environmental scientist Grant Harris collaborated to install an experiment using Tillandsia plants in extreme outdoor conditions at levels 92, 91, 65 and 56 on Eureka Tower in Melbourne, Australia. The selected air plants are extremely light, and are able to grow with no soil or watering system, and the plants have been checked at regular intervals since their installation and are still growing and flowering. One species; Tillandsia bergeri, has grown from a single shoot to several thriving colonies.

The project is now titled Tillandsia SWARM and has been expanded to include many other buildings across Australia, including Federation Square, National Gallery of Victoria and Essendon Airport. [68] Godman has also experimented with Tillandsia plant screens that can be moved across skylights to create shade in summer and to allow in sun during winter. Temperature readings taken on a 40 °C day in summer revealed that the surface temperature on the roof had reached 84 °C, while the shadows cast by the plants had reduced the surface temperature on the roof to 51 °C.

Canada

The green roof on top of the Canadian War Museum in Ottawa looks like a wheatfield, with the towers of Canada's Parliament visible in the distance Wheatfield in Ottawa.jpg
The green roof on top of the Canadian War Museum in Ottawa looks like a wheatfield, with the towers of Canada's Parliament visible in the distance

The city of Toronto approved a by-law in May 2009 [69] mandating green roofs on residential and industrial buildings. There is criticism from Green Roofs for Healthy Cities that the new laws are not stringent enough, since they will only apply to residential building that are a minimum of six stories high. By 31 January 2011, industrial buildings were required to render 10% or 2,000 m2 (22,000 sq ft) of their roofs green. [70] Toronto City Hall's Podium roof was renovated to include a 3,000 m2 (32,000 square feet) rooftop garden, the largest publicly accessible roof in the city. The green roof was opened to the public in June 2010. [71] Many green roofs in Canada also use sustainable rainwater harvesting practices.

In 2008, the Vancouver Convention Centre installed a 2.4-hectare (6-acre) living roof of indigenous plants and grasses on its West building, making it the largest green roof in Canada. [72] The new Canadian War Museum in Ottawa, opened in 2005, also features a grass-covered roof.

During the renovation of the Hamilton City Hall in Hamilton, Ontario that spanned from 2007 to 2010, many efforts were taken to enhance the environmentally friendly nature of the structure, which included the addition of a grass-covered roof. [73]

Simon Fraser University's Burnaby campus contains a substantial number of green roofs. [74]

Canada's first LEED Platinum V4 Home in Wakefield QC, EcoHome's Edelweiss House, [75] has a living Green Roof which is sloped at 12 degrees.

Costa Rica

Living green roofs have been built and grown at Saint Michael's Sustainable Community since 2012. Native plants, mostly flowers chosen for the environment, maximum shade and mass provide a colorful and functional living roof. The community has the largest number of green roofs in the country.

Egypt

In Egypt, soil-less agriculture is used to grow plants on the roofs of buildings. No soil is placed directly on the roof itself, thus eliminating the need for an insulating layer; instead, plants are grown on wooden tables. Vegetables and fruit are the most popular candidates, providing a fresh, healthy source of food that is free from pesticides. [76]

A more advanced method, (aquaponics), being used experimentally in Egypt, is farming fish next to plants in a closed cycle. This allows the plants to benefit from the ammonia excreted by the fish, helping the plants to grow better and at the same time eliminating the need for changing the water for the fish, because the plants help to keep it clean by absorbing the ammonia. The fish also get some nutrients from the roots of the plants.

Finland

In Finland, green roofs are still scarce. Some experimental green roofs have been built in big cities. However, the capital city of Helsinki has published guidelines for enhancing the building of green roofs in the city. There is on-going research on the topic as the conditions in the southern Europe are very different from those in the north and knowledge acquired there can't be directly applied to colder climates. The fifth dimension – Green roofs and walls in urban areas -research program aims to produce high-level scientific and broadly applicable knowledge on optimal green roof and -wall solutions in Finland.

France

Green roof planted with native species at L'Historial de la Vendee, a new museum in western France Green Roof at Vendee Historial, les Lucs.jpg
Green roof planted with native species at L'Historial de la Vendée, a new museum in western France

In France, an 8,000 m2 (86,000 square feet) extensive, cable-supported green roof has been created on the International School in Lyon. [77] Another huge green roof of roughly 8,000 m2 (86,000 square feet) has been incorporated into the new museum L'Historial de la Vendée which opened in June 2006 at Les Lucs-sur-Boulogne.

Germany

Long-held green roof traditions started in the early industrialization period more than 100 years ago exist in Germany. In the 1970s, green roof technology was elevated to the next level. Serious storm-water issues made cities think about innovative solutions, preferably with living plants. Modern green roof technology with high performance, lightweight materials were used to grow hardy vegetation even on roofs that can hardly support any additional load. In the 1980s modern green roof technology was common knowledge in Germany while it was practically unknown in any other country in the world. In Stuttgart, with one of the most innovative Department of Parks and Recreation and with the world's oldest horticultural Universities, modern green roof technology was perfected and implemented on a large scale. By the early 2000s, Germany had laws mandating that many metropolitan areas have green roofs. [78]

With the first green roof industry boom in Germany there were quality issues recorded. The FLL formed a committee that is focused on modern green roof technology. FLL stands for Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau e.V. (German Landscape Research, Development and Construction Society). The FLL is an independent non-profit organization. It was founded in 1975 by eight professional organizations for "the improvement of environmental conditions through the advancement and dissemination of plant research and its planned applications". The FLL green roof working group is only one of 40 committees which have published a long list of guidelines and labor instructions. Some of these guidelines also available in English including the German FLL-Guideline for the Planning, Execution and Upkeep of Green-Roof Sites. The results of the research and synthesis done by FLL members are constantly updated and promulgated utilizing the same principles which govern the compilation of DIN standards and are published as either guiding principles or labor instructions.

The current Green Roof Guideline was published in 2011. [79] Today most elements of the German FLL are part of standards and guidelines around the world (FM Global, ASTM, NRCA, SPRI etc.).

Fachvereinigung Bauwerksbegrünung (FBB) was founded in 1990 as the second green roof association after DDV (Deutscher Dachgaertner Verband) in 1985. FBB was founded as an open forum for manufacturers and planners, merchants and operators in 1990. The organization was born from the then-visionary idea of understanding the relationship between nature and constructions not as oppositional, but as an opportunity. Both the green roofing and conventional roofing industries are equally represented. The FBB has developed to become an innovative lobbying group with a strong market presence, internationally known through its cooperation with other European associations. Today, approximately 100 member companies use the multifaceted services offered by FBB, which offers a greater degree of market expertise and competitiveness. "Kompetenz im Markt".

Today, about 10,000,000 m2 (110,000,000 square feet) of new green roofs are being constructed each year. According latest studies about 3⁄4 of these are extensive; the last 1⁄4 are roof gardens. The cities with the most green roofs in Germany are Berlin and Stuttgart. Surveys about the status of regulation are done by the FBB. Nearly one third of all German cities have regulations to support green-roof and rain-water technology. Green-roof research institutions are located in several cities as including Hannover, Berlin, Geisenheim and Neubrandenburg.

Germany is the country with the most green roofs in the world as well as the country with the most advanced knowledge in modern green roof technology. [80] Green roofs in Germany are part of the 2 –3 years apprentice educations system of landscaping professionals.

Greece

The oikostegi, a green roof on the Treasury building in Athens The Treasury - Syntagma.jpg
The oikostegi, a green roof on the Treasury building in Athens

The Greek Ministry of Finance has now installed a green roof on the Treasury in Constitution Square in Athens. [81] The so-called "oikostegi" (Greek – oiko, pronounced [ˈiko] , meaning building-ecological, and stegi, pronounced staygee, meaning roof-abode-shelter) was inaugurated in September 2008. Studies of the thermodynamics of the roof in September 2008 concluded that the thermal performance of the building was significantly affected by the installation. [82] In further studies, in August 2009, energy savings of 50% were observed for air conditioning in the floor directly below the installation. The ten-floor building has a total floor space of 1.4 hectares (3.5 acres). The oikostegi covers 650 sq ft (60 square metres), equalling 52% of the roof space and 8% of the total floor space. Despite this, energy savings totalling €5,630 per annum were recorded, which translates to a 9% saving in air conditioning and a 4% saving in heating bills for the whole building. [83] An additional observation and conclusion of the study was that the thermodynamic performance of the oikostegi had improved as biomass was added over the 12 months between the first and second study. This suggests that further improvements will be observed as the biomass increases still further. The study also stated that while measurements were being made by thermal cameras, a plethora of beneficial insects were observed on the roof, such as butterflies, honey bees and ladybirds. Obviously this was not the case before installation. Finally, the study suggested that both the micro-climate and biodiversity of Constitution Square, in Athens, Greece had been improved by the oikostegi.

Iceland

Sod roof Church at Hof, Iceland Church at Hof.jpg
Sod roof Church at Hof, Iceland

Sod roofs are frequently found on traditional farmhouses and farm buildings in Iceland. [84]

Malaysia

Bus stops in Kuala Lumpur were fitted with green roofs in 2019. [85]

Poland

Several cities in Poland have implemented policies and incentives to encourage the installation of green roofs, including Warsaw, Krakow, and Wroclaw. These policies have helped to increase the adoption of green roofs in the country, particularly in urban areas, where they are seen as an important tool for mitigating the environmental impacts of urbanization and improving the quality of life for city residents. The University of Warsaw green roof is one of the most impressive and well-known examples of green roofs in Poland. It covers an area of approximately 10,000 square meters and includes over 30,000 plants from more than 70 different species. [86]

Singapore

Green roof at Singapore Botanic Gardens GreenRoof-SingaporeBotanicGardens.jpg
Green roof at Singapore Botanic Gardens

Singapore installed a green roof on a bus in 2019 as part of an experiment led by researchers at the National University of Singapore. [85] Green roofs on bus stops in Singapore were found to reduce ambient temperatures by up to 2C. [87]

Switzerland

Switzerland has one of Europe's oldest green roofs, created in 1914 at the Moos lake water-treatment plant, Wollishofen, Zürich. Its filter tanks have 30,000 m2 (320,000 square feet) of flat concrete roofs. To keep the interior cool and prevent bacterial growth in the filtration beds, a drainage layer of gravel and a 15-centimetre (5.9-inch) layer of soil was spread over the roofs, which had been waterproofed with asphalt. A meadow developed from seeds already present in the soil; it is now a haven for many plant species, some of which are now otherwise extinct in the district, most notably 6,000 Orchis morio (green-winged orchid). More recent Swiss examples can be found at Klinikum 1 and Klinikum 2, the Cantonal Hospitals of Basel, and the Sihlpost platform at Zürich's main railway station.

Sweden

What is claimed [88] to be the world's first green roof botanical garden was set up in Augustenborg, Malmö in May 1999. The International Green Roof Institute (IGRI) opened to the public in April 2001 as a research station and educational facility. (It has since been renamed the Scandinavian Green Roof Institute (SGRI), in view of the increasing number of similar organisations around the world.) Green roofs are well-established in Malmö: the Augustenborg housing development near the SGRI botanical garden incorporates green roofs and extensive landscaping of streams, ponds, and soak-ways between the buildings to deal with storm water run-off.

The new Bo01 urban residential development (in the Västra Hamnen (Western Harbour) close to the foot of the Turning Torso office and apartment block, designed by Santiago Calatrava) is built on the site of old shipyards and industrial areas, and incorporates many green roofs.

In 2012, the shopping mall Emporia with its 27,000-square-metre (290,000-square-foot) roof garden, was opened. The size of the roof garden is approximately equivalent to 4 soccer fields, which makes it one of the biggest green roof parks in Europe that is accessible to the public.

United Kingdom

The Sky Garden Wildflower Roof topping the Kanes Salad Factory, Evesham Sky Garden Kanes Foods Green Roof.JPG
The Sky Garden Wildflower Roof topping the Kanes Salad Factory, Evesham

In 2003 English Nature concluded that 'in the UK policy makers have largely ignored green roofs'. [89] However, British examples can be found with increasing frequency. The Kensington Roof Gardens are a notable early roof garden which was built above the former Derry & Toms department store in Kensington, London in 1938. [90] More recent examples can be found at the University of Nottingham Jubilee Campus, and in London at Sainsbury's Millennium Store in Greenwich, the Horniman Museum and at Canary Wharf. The Ethelred Estate, close to the River Thames in central London, is the British capital's largest roof-greening project to date. Toxteth in Liverpool is also a candidate for a major roof-greening project.

In the United Kingdom, intensive green roofs are sometimes used in built-up city areas where residents and workers often do not have access to gardens or local parks. Extensive green roofs are sometimes used to blend buildings into rural surroundings, for example by Rolls-Royce Motor Cars, who has one of the biggest green roofs in Europe (covering more than 32,000 m2 (340,000 square feet) on their factory at Goodwood, West Sussex. [91]

The University of Sheffield has created a Green Roof Centre of Excellence and conducted research, particularly in a UK context, into green roofs. [92] Nigel Dunnett of Sheffield University published a UK-centric book about green roofing in 2004 (updated 2008). [93]

Fort Dunlop has the largest green roof in the UK since its redevelopment between 2004 and 2006.

The UK also has one of the most innovative food preparation facilities in Europe, the Kanes salad factory in Evesham. [94] It is topped with a wildflower roof featuring nearly 90 species of wildflower and natural grasses. The seed mix was prepared in consultation with leading ecologists to try to minimise the impact on the local environment. [95] The pre-grown wildflower blanket sits on top of a standing seam roof and is combined with solar panels to create an eco-friendly finish to the entire factory. [96] The development also won the 2013 National Federation of Roofing Contractors Sustainable Roof Award for Green Roofing. [97] [98]

United States

An intensive roof garden in New York City Green City.jpg
An intensive roof garden in New York City
Roof garden in New York Roof garden 3 (4694438648).jpg
Roof garden in New York
Green roof of Chicago City Hall 20080708 Chicago City Hall Green Roof.JPG
Green roof of Chicago City Hall
A modern green roof at California Academy of Sciences CalifAcadSciRoof 0820.JPG
A modern green roof at California Academy of Sciences

One of the largest expanses of extensive green roof is to be found in the US, at Ford Motor Company's River Rouge Plant, Dearborn, Michigan, where 450,000 square feet (42,000 m2) of assembly plant roofs are covered with sedum and other plants, designed by William McDonough; the $18 million assembly avoids the need of what otherwise would be $50 million worth of mechanical treatment facilities on site. Built over Millennium Park Garage, Chicago's 24.5-acre (9.9 ha) Millennium Park is considered one of the largest intensive green roofs. [100] Other well-known American examples include Chicago's City Hall and the former Gap headquarters, now the headquarters of YouTube, in San Bruno, CA. The U.S. military has two major green roofs in the Washington, D.C. area: the U.S. Coast Guard headquarters (550,000 square feet or 51,000 square metres) and the Pentagon (180,000 square feet or 17,000 square metres).[ citation needed ]

An early green-roofed building (completed in 1971) is the 358,000-square-foot (33,300 m2) Weyerhaeuser Corporate Headquarters building in Federal Way, Washington. Its 5-story office roof system comprises a series of stepped terraces covered in greenery. From the air, the building blends into the landscape.

The largest green roof in New York City was installed in midtown Manhattan atop the United States Postal Service's Morgan Processing and Distribution Center. Construction on the 109,000-square-foot (10,100 m2) project began in September 2008, and was finished and dedicated in July 2009. Covered in native vegetation and having an expected lifetime of fifty years, this green roof will not only save the USPS approximately $30,000 a year in heating and cooling costs, but will also significantly reduce the amount of storm water contaminants entering the municipal water system. [101] [102] In 2001, atop Chicago City Hall, the 38,800-square-foot (3,600 m2) roof gardens were completed, serving as a pilot project to assess the impact green roofs would have on the heat island effect in urban areas, rainwater runoff, and the effectiveness of differing types of green roofs and plant species for Chicago's climate. Although the rooftop is not normally accessible to the public, it is visually accessible from 33 taller buildings in the area. The garden consists of 20,000 plants of more than 150 species, including shrubs, vines and two trees. The green roof design team was headed by the Chicago area firm Conservation Design Forum in conjunction with noted "green" architect William McDonough. With an abundance of flowering plants on the rooftop, beekeepers harvest approximately 200 pounds (90 kg) of honey each year from hives installed on the rooftop. Tours of the green roof are by special arrangement only. Chicago City Hall Green Roof won merit design award of the American Society of Landscape Architecture (ASLA) competition in 2002.

The 14,000 square feet (1,300 m2) of outdoor space on the seventh floor of Zeckendorf Towers, formerly an undistinguished rooftop filled with potted plants, make up the largest residential green roof in New York. [103] [104] [105] The roof was transformed in 2010 as part of Mayor Michael Bloomberg's NYC Green Infrastructure campaign, and supposedly serves to capture some of the rain that falls on it rather than letting it run off and contribute to flooding in the adjacent Union Square subway station. [103]

Some cost can also be attributed to maintenance. Extensive green roofs have low maintenance requirements but they are generally not maintenance free. German research has quantified the need to remove unwanted seedlings to approximately 6 seconds/m2/year. [106] Maintenance of green roofs often includes fertilization to increase flowering and succulent plant cover. If aesthetics are not an issue, fertilization and maintenance are generally not needed. Extensive green roofs should only be fertilized with controlled-release fertilizers in order to avoid pollution of the storm water. Conventional fertilizers should never be used on extensive vegetated roofs. [107] [108] German studies have approximated the nutrient requirement of vegetated roofs to 5 gN/m2. It is also important to use a substrate that does not contain too many available nutrients. The FLL guidelines specify maximum-allowable nutrient content of substrates. [109]

One of the oldest American green roofs in existence is atop the Rockefeller Center in Manhattan, built in 1936. This roof was primarily an aesthetic undertaking for the enjoyment of the center's workers, and remains to this day, having been refurbished in 1986. [110]

With the passage of Denver's Green Roof Initiative [111] in the November 2017 elections, effective January 2018, new buildings or existing buildings meeting the initiative's thresholds are required to have rooftop gardens, optionally combined with solar photovoltaic panels. [112] [113]

Seattle is another city in which green roofs have been used on an increasing basis. This phenomenon is in large part due to efforts on behalf of the city to encourage green roofs through new and improved building codes. In 2006, the Seattle Green Factor program was approved. [114] The program rewards the incorporation of landscaping in new building developments in an attempt to reduce stormwater runoff and associated pollution, stabilize temperatures, and create habitats for birds and insects. [115] These changes were expanded in 2009 to recognize the specific stormwater benefits of green roofs, and to reward developers who used them accordingly. [114] [116]

By 2010, Seattle was home to approximately 8.25 acres (3.34 hectares) of green roofs. [117] Despite initial hiccups in the city stemming from weeds, lack of irrigation during dry summer months, and a need for continuous replanting, the project has continued to succeed as understanding around the best soils and plants and the need for monitoring and upkeep has increased. [114] A 2010 survey of the green roofs in Seattle acknowledged that while the initial costs of implementing a green roof may deter businesses or homeowners, it is likely that green roofs actually preserve the roofing material and cut costs in the long run. [118] In light of the success in Seattle, other cities such as Portland, Chicago, and Washington, D.C. have all made efforts to develop their own Green Factor programs. [116]

The Seattle City Hall has led the way by implementing a green roof project that has involved the planting of more than 22,000 pots of sedum, fescue, and grass. [119] The City hopes that the project can reduce the annual stormwater runoff for the building by 50 to 75 percent, which will in turn reduce damage to local watershed areas that provide habitats for native species such as salmon. [119] The historic Union Stables building has used green roofs alongside other efficiency based changes to reduce stormwater runoff and decrease the building's energy use by 70 percent. [120] The Park Place building in Seattle's downtown provides a leading example of the use of landscaping to recapture rain water with the hopes of cutting back spending on utilities. [120]

Washington, D.C.

Washington, D.C., started implementing incentives for green roofs within their city at the beginning of the 21st century. In 2003, the Chesapeake Bay Foundation introduced a “green roof demonstration project” in combination with the D.C. Water and Sewer Authority. [121] This program issued grants to several pilot green roofs, which would assist with the cost of construction for the building owner. From this project the city began to understand how beneficial these roofs could be and more programs were implemented over the years. In 2007, the Riversmart Rewards Program introduced a RiverSmart Rooftops Green Roof Rebate Program that would lend a $3 per square foot subsidy to potential green roof projects within the District. This culminated to assist 12 projects that year. [121] A year later, the subsidy was raised to $5, incentivizing even more developers to use this program within their design. There is also possibility through the RiverSmart Rewards program for “residents and property owners to receive a significant discount on their water utility fees” if they install approved stormwater management features. [122] In 2016, a rebate of $10-$15 per square feet was introduced, “promoting the voluntary installation of green roofs for the purpose of reducing stormwater runoff and pollutants”. [123] $10 per square foot rebates were set for installation within a combined sewer system. $15 per square foot rebates were set for installation within a municipal storm sewer system. The greatest aspect of this incentivized project is the lack of restriction of building type that qualifies. There is no size cap on properties that qualify whether it’s residential, commercial or institutional. [123] In 2016 there was a total of 2.3 million square feet of green roofing within the district. As of 2020, there is 5.1 million square feet of green roofing. [124]

See also

Related Research Articles

Energy-efficient landscaping is a type of landscaping designed for the purpose of conserving energy. There is a distinction between the embedded energy of materials and constructing the landscape, and the energy consumed by the maintenance and operations of a landscape.

<span class="mw-page-title-main">Infrastructure</span> Facilities and systems serving society

Infrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and private physical structures such as roads, railways, bridges, airports, public transit systems, tunnels, water supply, sewers, electrical grids, and telecommunications. In general, infrastructure has been defined as "the physical components of interrelated systems providing commodities and services essential to enable, sustain, or enhance societal living conditions" and maintain the surrounding environment.

<span class="mw-page-title-main">Stormwater</span> Water that originates during precipitation events and snow/ice melt

Stormwater, also written storm water, is water that originates from precipitation (storm), including heavy rain and meltwater from hail and snow. Stormwater can soak into the soil (infiltrate) and become groundwater, be stored on depressed land surface in ponds and puddles, evaporate back into the atmosphere, or contribute to surface runoff. Most runoff is conveyed directly as surface water to nearby streams, rivers or other large water bodies without treatment.

<span class="mw-page-title-main">Roof garden</span> Planted area on the top covering of a building

A roof garden is a garden on the roof of a building. Besides the decorative benefit, roof plantings may provide food, temperature control, hydrological benefits, architectural enhancement, habitats or corridors for wildlife, recreational opportunities, and in large scale it may even have ecological benefits. The practice of cultivating food on the rooftop of buildings is sometimes referred to as rooftop farming. Rooftop farming is usually done using green roof, hydroponics, aeroponics or air-dynaponics systems or container gardens.

<span class="mw-page-title-main">Storm drain</span> Infrastructure for draining excess rain and ground water from impervious surfaces

A storm drain, storm sewer, highway drain, surface water drain/sewer, or stormwater drain is infrastructure designed to drain excess rain and ground water from impervious surfaces such as paved streets, car parks, parking lots, footpaths, sidewalks, and roofs. Storm drains vary in design from small residential dry wells to large municipal systems.

<span class="mw-page-title-main">Green wall</span> Wall or vertical structure covered by living vegetation and growth substrate

A green wall is a vertical built structure intentionally covered by vegetation. Green walls include a vertically applied growth medium such as soil, substitute substrate, or hydroculture felt; as well as an integrated hydration and fertigation delivery system. They are also referred to as living walls or vertical gardens, and widely associated with the delivery of many beneficial ecosystem services.

A blue roof is a roof of a building that is designed explicitly to provide initial temporary water storage and then gradual release of stored water, typically rainfall. Blue roofs are constructed on flat or low sloped roofs in urban communities where flooding is a risk due to a lack of permeable surfaces for water to infiltrate, or seep back into the ground.

<span class="mw-page-title-main">Rainwater harvesting</span> Accumulation of rainwater for reuse

Rainwater harvesting (RWH) is the collection and storage of rain, rather than allowing it to run off. Rainwater is collected from a roof-like surface and redirected to a tank, cistern, deep pit, aquifer, or a reservoir with percolation, so that it seeps down and restores the ground water. Rainwater harvesting differs from stormwater harvesting as the runoff is typically collected from roofs and other area surfaces for storage and subsequent reuse. Its uses include watering gardens, livestock, irrigation, domestic use with proper treatment, and domestic heating. The harvested water can also be used for long-term storage or groundwater recharge.

<span class="mw-page-title-main">Flat roof</span> Type of roof

A flat roof is a roof which is almost level in contrast to the many types of sloped roofs. The slope of a roof is properly known as its pitch and flat roofs have up to approximately 10°. Flat roofs are an ancient form mostly used in arid climates and allow the roof space to be used as a living space or a living roof. Flat roofs, or "low-slope" roofs, are also commonly found on commercial buildings throughout the world. The U.S.-based National Roofing Contractors Association defines a low-slope roof as having a slope of 3 in 12 (1:4) or less.

<span class="mw-page-title-main">Bioswale</span> Landscape elements designed to manage surface runoff water

Bioswales are channels designed to concentrate and convey stormwater runoff while removing debris and pollution. Bioswales can also be beneficial in recharging groundwater.

<span class="mw-page-title-main">Combined sewer</span> Sewage collection system of pipes and tunnels designed to also collect surface runoff

A combined sewer is a type of gravity sewer with a system of pipes, tunnels, pump stations etc. to transport sewage and urban runoff together to a sewage treatment plant or disposal site. This means that during rain events, the sewage gets diluted, resulting in higher flowrates at the treatment site. Uncontaminated stormwater simply dilutes sewage, but runoff may dissolve or suspend virtually anything it contacts on roofs, streets, and storage yards. As rainfall travels over roofs and the ground, it may pick up various contaminants including soil particles and other sediment, heavy metals, organic compounds, animal waste, and oil and grease. Combined sewers may also receive dry weather drainage from landscape irrigation, construction dewatering, and washing buildings and sidewalks.

<span class="mw-page-title-main">Rain garden</span> Runoff reducing landscaping method

Rain gardens, also called bioretention facilities, are one of a variety of practices designed to increase rain runoff reabsorption by the soil. They can also be used to treat polluted stormwater runoff. Rain gardens are designed landscape sites that reduce the flow rate, total quantity, and pollutant load of runoff from impervious urban areas like roofs, driveways, walkways, parking lots, and compacted lawn areas. Rain gardens rely on plants and natural or engineered soil medium to retain stormwater and increase the lag time of infiltration, while remediating and filtering pollutants carried by urban runoff. Rain gardens provide a method to reuse and optimize any rain that falls, reducing or avoiding the need for additional irrigation. A benefit of planting rain gardens is the consequential decrease in ambient air and water temperature, a mitigation that is especially effective in urban areas containing an abundance of impervious surfaces that absorb heat in a phenomenon known as the heat-island effect.

<span class="mw-page-title-main">Sustainable drainage system</span> Designed to reduce the potential impact of development

Sustainable drainage systems are a collection of water management practices that aim to align modern drainage systems with natural water processes and are part of a larger green infrastructure strategy. SuDS efforts make urban drainage systems more compatible with components of the natural water cycle such as storm surge overflows, soil percolation, and bio-filtration. These efforts hope to mitigate the effect human development has had or may have on the natural water cycle, particularly surface runoff and water pollution trends.

<span class="mw-page-title-main">Retrofitting</span> Addition of new technology or features to older systems

Retrofitting is the addition of new technology or features to older systems. Retrofits can happen for a number of reasons, for example with big capital expenditures like naval vessels, military equipment or manufacturing plants, businesses or governments may retrofit in order to reduce the need to replace a system entirely. Other retrofits may be due to changing codes or requirements, such as seismic retrofit which are designed strengthening older buildings in order to make them earthquake resistant.

<span class="mw-page-title-main">Green infrastructure</span> Sustainable and resilient infrastructure

Green infrastructure or blue-green infrastructure refers to a network that provides the “ingredients” for solving urban and climatic challenges by building with nature. The main components of this approach include stormwater management, climate adaptation, the reduction of heat stress, increasing biodiversity, food production, better air quality, sustainable energy production, clean water, and healthy soils, as well as more human centered functions, such as increased quality of life through recreation and the provision of shade and shelter in and around towns and cities. Green infrastructure also serves to provide an ecological framework for social, economic, and environmental health of the surroundings. More recently scholars and activists have also called for green infrastructure that promotes social inclusion and equity rather than reinforcing pre-existing structures of unequal access to nature-based services.

<span class="mw-page-title-main">Urban runoff</span> Surface runoff of water caused by urbanization

Urban runoff is surface runoff of rainwater, landscape irrigation, and car washing created by urbanization. Impervious surfaces are constructed during land development. During rain, storms, and other precipitation events, these surfaces, along with rooftops, carry polluted stormwater to storm drains, instead of allowing the water to percolate through soil. This causes lowering of the water table and flooding since the amount of water that remains on the surface is greater. Most municipal storm sewer systems discharge untreated stormwater to streams, rivers, and bays. This excess water can also make its way into people's properties through basement backups and seepage through building wall and floors.

Building-integrated agriculture (BIA) is the practice of locating high-performance hydroponic greenhouse farming systems on and in mixed-use buildings to exploit synergies between the built environment and agriculture.

A subtropical climate vegetated roof is a type of green building practice that employs a planted soil media installed above a waterproof roof deck to obtain environmental benefits and address sustainability concerns, similar to traditional green roofs located in northern continental United States. Soil media, plant palettes, and green roof systems that can adapt to the adverse weather conditions and physical characteristics of the humid, subtropical regions of the United States are utilized in the construction and design of subtropical climate vegetated roofs.

<span class="mw-page-title-main">Business Instructional Facility</span> Academics in Illinois , United States

The Gies College of Business Instructional Facility (BIF) is a state-of-the-art business facility designed by Pelli Clarke Pelli Architects located on the Champaign campus at the University of Illinois Urbana–Champaign (UIUC).

A runoff footprint is the total surface runoff that a site produces over the course of a year. According to the United States Environmental Protection Agency (EPA) stormwater is "rainwater and melted snow that runs off streets, lawns, and other sites". Urbanized areas with high concentrations of impervious surfaces like buildings, roads, and driveways produce large volumes of runoff which can lead to flooding, sewer overflows, and poor water quality. Since soil in urban areas can be compacted and have a low infiltration rate, the surface runoff estimated in a runoff footprint is not just from impervious surfaces, but also pervious areas including yards. The total runoff is a measure of the site’s contribution to stormwater issues in an area, especially in urban areas with sewer overflows. Completing a runoff footprint for a site allows a property owner to understand what areas on his or her site are producing the most runoff and what scenarios of stormwater green solutions like rain barrels and rain gardens are most effective in mitigating this runoff and its costs to the community.

References

  1. 1 2 Rodriguez Droguett, Barbara (2011). Sustainability assessment of green infrastructure practices for stormwater management: A comparative emergy analysis (Thesis). ProQuest   900864997.
  2. ↑ Özyavuz, Murat, B. Karakaya, and D. G. Ertin. "The Effects of Green Roofs on Urban Ecosystems." GreenAge Symposium 2015.
  3. ↑ EPA (2017) Green Roofs. U.S. EPA. Available from: http://www.epa.gov/heatisland/strategies/greenroofs.html
  4. ↑ "Benefits of Green Roofs". www.greenroof.hrt.msu.edu. Archived from the original on 4 July 2018. Retrieved 1 November 2018.
  5. ↑ Vandermeulen, Valerie; Verspecht, Ann; Vermeire, Bert; Van Huylenbroeck, Guido; Gellynck, Xavier (November 2011). "The use of economic valuation to create public support for green infrastructure investments in urban areas". Landscape and Urban Planning. 103 (2): 198–206. Bibcode:2011LUrbP.103..198V. doi:10.1016/j.landurbplan.2011.07.010.
  6. ↑ "System Overview : Planted Roof : GSA Sustainable Facilities Tool". sftool.gov.
  7. ↑ Volder, Astrid; Dvorak, Bruce (February 2014). "Event size, substrate water content and vegetation affect storm water retention efficiency of an un-irrigated extensive green roof system in Central Texas". Sustainable Cities and Society. 10: 59–64. Bibcode:2014SusCS..10...59V. doi:10.1016/j.scs.2013.05.005.
  8. ↑ "Aurélien P. JEAN". Archived from the original on 24 August 2011. Retrieved 19 May 2011.
  9. ↑ Li, W. (2013). A scenario planning approach for school green roofs to achieve stormwater management benefits: A case study of Brier’s Mill Run Subwatershed
  10. ↑ Santamouris, M. (2014). Cooling the cities – A review of reflective and green roof mitigation technologies to fight heat island and improve comfort in urban environments. Solar Energy, 103(Supplement C), 682–703.
  11. ↑ "University of Toronto – News@UofT – Green roofs in winter: Hot design for a cold climate". 17 November 2005. Archived from the original on 11 April 2008. Retrieved 10 June 2008.
  12. ↑ Niachou, A; Papakonstantinou, K; Santamouris, M; Tsangrassoulis, A; Mihalakakou, G (September 2001). "Analysis of the green roof thermal properties and investigation of its energy performance". Energy and Buildings. 33 (7): 719–729. Bibcode:2001EneBu..33..719N. doi:10.1016/s0378-7788(01)00062-7. ISSN   0378-7788.
  13. ↑ Reducing Urban Heat Islands: Compendium of Strategies, Green Roofs. Available from:https://www.epa.gov/heat-islands
  14. ↑ "Nedlaw Living Roofs - Living Roofs". Archived from the original on 5 January 2010. Retrieved 5 February 2010.
  15. ↑ "Here Comes Urban Heat". Archived from the original on 15 May 2008. Retrieved 10 June 2008.
  16. ↑ "Plant-Covered Roofs Ease Urban Heat". Archived from the original on 30 December 2005. Retrieved 10 June 2008.
  17. ↑ "Urban Waterways" (PDF). Archived from the original (PDF) on 19 July 2006. Retrieved 14 June 2012.
  18. ↑ "Is that a Garden on Your Roof? - Enterprise The Future of Energy - MSNBC.com". Archived from the original on 7 September 2007. Retrieved 10 June 2008.
  19. ↑ "Archived copy" (PDF). Archived from the original (PDF) on 6 July 2011. Retrieved 5 February 2010.{{cite web}}: CS1 maint: archived copy as title (link)
  20. ↑ Shafique, Muhammad; Kim, Reeho; Kyung-Ho, Kwon (March 2018). "Green Roof for Stormwater Management in a Highly Urbanized Area: The Case of Seoul, Korea". Sustainability. 10 (3): 584. doi: 10.3390/su10030584 . ISSN   2071-1050.
  21. ↑ Shafique, Muhammad; Kim, Reeho (20 June 2017). "Retrofitting the Low Impact Development Practices into Developed Urban areas Including Barriers and Potential Solution". Open Geosciences. 9 (1): 20. Bibcode:2017OGeo....9...20S. doi: 10.1515/geo-2017-0020 .
  22. 1 2 U.S. Environmental Protection Agency (2008). "Green Roofs" (PDF). Reducing Urban Heat Islands: Compendium of Strategies (Report). Retrieved 9 June 2017.
  23. ↑ Earth Pledge (2005). Green Roofs : Ecological Design and Construction. Atglen, PA: Schiffer Pub.
  24. ↑ Sharpley, A.N. (September 2003). Agricultural Phosphorus and Eutrophication (PDF).
  25. ↑ "Archived copy" (PDF). Archived from the original (PDF) on 6 July 2011. Retrieved 5 February 2010.{{cite web}}: CS1 maint: archived copy as title (link)
  26. ↑ Partridge, Dustin R.; Parkins, Kaitlyn L.; Elbin, Susan B.; Clark, J. Alan (3 March 2020). "Bat Activity Correlates with Moth Abundance on an Urban Green Roof". Northeastern Naturalist. 27 (1): 77. doi:10.1656/045.027.0107. ISSN   1092-6194.
  27. ↑ "Archived copy" (PDF). Archived from the original (PDF) on 6 July 2011. Retrieved 5 February 2010.{{cite web}}: CS1 maint: archived copy as title (link)
  28. 1 2 Rowe, D. Bradley (August 2011). "Green roofs as a means of pollution abatement". Environmental Pollution. 159 (8–9): 2100–2110. Bibcode:2011EPoll.159.2100R. doi:10.1016/j.envpol.2010.10.029. PMID   21074914.
  29. 1 2 Getter, Kristin L.; Rowe, D. Bradley; Robertson, G. Philip; Cregg, Bert M.; Andresen, Jeffrey A. (October 2009). "Carbon Sequestration Potential of Extensive Green Roofs". Environmental Science & Technology. 43 (19): 7564–7570. Bibcode:2009EnST...43.7564G. doi:10.1021/es901539x. PMID   19848177.
  30. ↑ "Green Building Facts | U.S. Green Building Council". www.usgbc.org. Retrieved 29 February 2016.
  31. ↑ "Green Roofs for Healthy Cities". Greenroofs.org. Retrieved 23 June 2017.
  32. ↑ Sproul, Julian; Wan, Man Pun; Mandel, Benjamin H.; Rosenfeld, Arthur H. (March 2014). "Economic comparison of white, green, and black flat roofs in the United States". Energy and Buildings. 71: 20–27. Bibcode:2014EneBu..71...20S. doi:10.1016/j.enbuild.2013.11.058.
  33. ↑ Carter, Timothy; Keeler, Andrew (May 2008). "Life-cycle cost–benefit analysis of extensive vegetated roof systems". Journal of Environmental Management. 87 (3): 350–363. Bibcode:2008JEnvM..87..350C. doi:10.1016/j.jenvman.2007.01.024. PMID   17368704.
  34. 1 2 "Penn State Green Roof Research: About Green Roofs". Hortweb.cas.psu.edu. Archived from the original on 24 August 2002. Retrieved 10 June 2008.
  35. ↑ Bianchini, Fabricio; Hewage, Kasun (December 2012). "Probabilistic social cost-benefit analysis for green roofs: A lifecycle approach". Building and Environment. 58: 152–162. Bibcode:2012BuEnv..58..152B. doi:10.1016/j.buildenv.2012.07.005.
  36. ↑ "Green Roofs for Healthy Cities - About Green Roofs". Archived from the original on 2 May 2008. Retrieved 10 June 2008.
  37. 1 2 3 Saadatian, Omidreza; Sopian, K.; Salleh, E.; Lim, C.H.; Riffat, Safa; Saadatian, Elham; Toudeshki, Arash; Sulaiman, M.Y. (July 2013). "A review of energy aspects of green roofs". Renewable and Sustainable Energy Reviews. 23: 155–168. Bibcode:2013RSERv..23..155S. doi:10.1016/j.rser.2013.02.022.
  38. ↑ VanWoert, Nicholaus D.; Rowe, D. Bradley; Andresen, Jeffrey A.; Rugh, Clayton L.; Fernandez, R. Thomas; Xiao, Lan (May 2005). "Green Roof Stormwater Retention: Effects of Roof Surface, Slope, and Media Depth". Journal of Environmental Quality. 34 (3): 1036–1044. doi:10.2134/jeq2004.0364. PMID   15888889.
  39. ↑ 'Tax Credits For Green Rooftops In NYC', Environmental Leader, 29 June 2008. Retrieved 10 July 2012.
  40. ↑ Getter, Kristin L.; Rowe, D. Bradley (August 2006). "The Role of Extensive Green Roofs in Sustainable Development". HortScience. 41 (5): 1276–1285. doi: 10.21273/HORTSCI.41.5.1276 .
  41. ↑ Currie, Beth Anne; Bass, Brad (December 2008). "Estimates of air pollution mitigation with green plants and green roofs using the UFORE model". Urban Ecosystems. 11 (4): 409–422. Bibcode:2008UrbEc..11..409C. doi:10.1007/s11252-008-0054-y. S2CID   22157617.
  42. ↑ Cheng, Kris; Cheung, Karen (20 May 2016). "Roof collapses at City University sports centre, three injured". Hong Kong Free Press .
  43. ↑ Tsang, Emily (24 May 2015). "Chinese University of Hong Kong to remove green roofs, Buildings Department issues new guidelines for immediate safety checks". South China Morning Post.
  44. ↑ "Green Roof Maintenance" (PDF). Columbia-green.com. Retrieved 23 June 2017.
  45. ↑ Bozorg Chenani, Sanaz; Lehvävirta, Susanna; Häkkinen, Tarja (March 2015). "Life cycle assessment of layers of green roofs". Journal of Cleaner Production. 90: 153–162. Bibcode:2015JCPro..90..153B. doi:10.1016/j.jclepro.2014.11.070.
  46. ↑ Rizzo, Gianfranco; Cirrincione, Laura; La Gennusa, Maria; Peri, Giorgia; Scaccianoce, Gianluca (4 January 2023). "Green Roofs' End of Life: A Literature Review". Energies. 16 (2): 596. doi: 10.3390/en16020596 . hdl: 10447/586396 . ISSN   1996-1073.
  47. ↑ Teemusk, Alar; Mander, Ülo (November 2011). "The Influence of Green Roofs on Runoff Water Quality: A Case Study from Estonia". Water Resources Management. 25 (14): 3699–3713. Bibcode:2011WatRM..25.3699T. doi:10.1007/s11269-011-9877-z. S2CID   154130342.
  48. ↑ Archived 3 July 2010 at the Wayback Machine
  49. ↑ "Green Roof". Raingardennetwork.com. Archived from the original on 14 October 2012. Retrieved 15 August 2012.
  50. 1 2 "City Green Building – Green Roofs". Seattle Department of Planning and Development. 3 November 2008. Archived from the original on 7 September 2008.
  51. ↑ "Green (Planted) roofs". The Vinyl Roofing Division of the Chemical Fabrics & Film Association. 22 June 2012.
  52. ↑ Omni Ecosystems (9 March 2013). "Comprehensive Green Roofs". Archived from the original on 9 December 2013.
  53. 1 2 Breuning, Jörg. "History of Green Roof Technology, Green Walls, Living Walls". Green Roof Technology.
  54. ↑ "European Federation of Green Roof Associations – EFB". Efb-greenroof.eu. Retrieved 25 April 2012.
  55. ↑ "City of Toronto Green Roof Bylaw". City of Toronto. Archived from the original on 26 January 2018. Retrieved 17 December 2017.
  56. ↑ "San Francisco Better Roofs". City of San Francisco Planning Department. Retrieved 17 December 2017.
  57. ↑ "EUKN". Archived from the original on 16 October 2007. Retrieved 14 March 2008.
  58. ↑ "Dakvijvers". Toontoelen.be. Retrieved 23 June 2017.
  59. ↑ Gill, S.E; Handley, J.F; Ennos, A.R; Pauleit, S (13 March 2007). "Adapting Cities for Climate Change: The Role of the Green Infrastructure". Built Environment. 33 (1): 115–133. doi:10.2148/benv.33.1.115.
  60. ↑ "Brown Roofs and Biodiversity (Biodiverse Green Roofs)". Archived from the original on 17 October 2011. Retrieved 10 September 2009.
  61. ↑ "Green Roofs Tree of Knowledge | Browse Materials and Plants Research". Archived from the original on 19 March 2012. Retrieved 25 May 2012.
  62. ↑ "Creating Brown Roof Habitats". Archived from the original on 2 January 2012. Retrieved 13 January 2012.
  63. ↑ "Frontpage". Archived from the original on 5 July 2008. Retrieved 17 July 2008.
  64. ↑ "Wildlife flourishes 32 floors above the Thames". The Guardian.
  65. ↑ "California Academy of Sciences – Newsroom". Archived from the original on 3 April 2008. Retrieved 10 June 2008.
  66. ↑ "Best Remodeling Ideas To Increase Your Home's Value -". Best Remodeling Ideas To Increase Your Home’s Value. Archived from the original on 14 November 2010. Retrieved 2 November 2010.
  67. ↑ "Home". www.aquasure.com.au.
  68. ↑ Dow, Aisha (23 March 2015). "Extreme gardening on the 92nd floor of the Eureka Tower". The Age.
  69. ↑ "Toronto Makes Green Roofs the Law, Approves Controversial Bike Lanes". TreeHugger.
  70. ↑ "Council approves stringent green-roof rules". Globe and Mail. Toronto. 23 August 2012.
  71. ↑ "Toronto City Hall's Podium Green Roof". City of Toronto. Toronto, Ontario, Canada. 27 June 2013.
  72. ↑ "Projects – Vancouver Convention Centre Expansion Project". Greenroofs.com. Retrieved 23 June 2017.
  73. ↑ Ryan McGreal. "City Hall Reno Photo Tour: Part 2". Raise the Hammer. Retrieved 23 June 2017.
  74. ↑ "Green Development". Archived from the original on 7 August 2017. Retrieved 7 August 2017.
  75. ↑ "Canada's first LEED V4 Platinum house". www.ecohome.net.
  76. ↑ "Al-Ahram Weekly | Environment | May your roof be green". Weekly.ahram.org.eg. 8 June 2005. Archived from the original on 3 July 2012. Retrieved 25 April 2012.
  77. ↑ "Chic Sustainability". Greenroofs.com. 14 March 2006. Archived from the original on 3 May 2012. Retrieved 25 April 2012.
  78. ↑ Oberndorfer, Erica; Lundholm, Jeremy; Bass, Brad; Coffman, Reid R.; Doshi, Hitesh; Dunnett, Nigel; Gaffin, Stuart; Köhler, Manfred; Liu, Karen K. Y.; Rowe, Bradley (1 November 2007). "Green Roofs as Urban Ecosystems: Ecological Structures, Functions, and Services". BioScience. 57 (10): 823–833. doi:10.1641/b571005. ISSN   1525-3244.
  79. ↑ "Archived copy". Archived from the original on 4 March 2016. Retrieved 1 March 2015.{{cite web}}: CS1 maint: archived copy as title (link)
  80. ↑ Li, W.C.; Yeung, K.K.A. (1 June 2014). "A comprehensive study of green roof performance from environmental perspective". International Journal of Sustainable Built Environment. 3 (1): 127–134. doi: 10.1016/j.ijsbe.2014.05.001 . ISSN   2212-6090.
  81. ↑ "Διαδικτυακή Πύλη Υπουργείου Οικονομικών – Κεντρική Σελίδα". Mnec.gr. 20 April 2012. Archived from the original on 18 April 2009. Retrieved 25 April 2012.
  82. ↑ "Σχολή Μηχανολόγων Μηχανικών Ε.Μ.Π. – Μέλος ΔΕΠ". Mech.ntua.gr. Archived from the original on 2 May 2012. Retrieved 25 April 2012.
  83. ↑ "Μελέτες". Oikosteges.gr. 24 September 2009. Retrieved 25 April 2012.
  84. ↑ "Greenroofs101: History". Greenroofs.com. Archived from the original on 10 July 2012. Retrieved 15 August 2012.
  85. 1 2 Bailey, Stephanie (3 June 2019). "Green roofs are sprouting up on buses". CNN. Retrieved 24 April 2023.
  86. ↑ "Is the World's Greatest Green Roof in Warsaw, Poland? | Smart Cities Dive". www.smartcitiesdive.com. Retrieved 30 March 2023.
  87. ↑ "Grass roofs on 30 bus stops in S'pore, can lower ambient temperatures by around 2°C". mothership.sg. Retrieved 24 April 2023.
  88. ↑ "Green Roof – Augustenborg's Botanical Roof Garden – History". Greenroof.se. Retrieved 25 April 2012.
  89. ↑ Grant, G., Engleback, L., and Nicholson, B., Green Roofs: their existing status and potential for conserving biodiversity in urban areas [Report No. 498], Publisher: English Nature Reports (2003)
  90. ↑ "London Gardens Online". London Gardens Online. Archived from the original on 18 March 2012. Retrieved 25 April 2012.
  91. ↑ Archived 3 January 2014 at the Wayback Machine
  92. ↑ "Green Roof Research". The Green Roof Centre. Retrieved 12 April 2021.
  93. ↑ Dunnett, N., Kingsbury, N., Planting Green Roofs and Living Walls, Publisher: Timber Press (2004)
  94. ↑ "F Stop Press – Specialists in News and PR in the Midlands". www.fstoppress.com. Archived from the original on 4 March 2016. Retrieved 23 June 2017.
  95. ↑ "Eco Factory « Kanes Foods". kanesfoods.co.uk.
  96. ↑ "Worcestershire garden roof salad factory opens". BBC News. Bbc.co.uk. 5 July 2012.
  97. ↑ "Kanes Foods Wildflower Blanket Green Roof – Gallery – Sky Garden". www.sky-garden.co.uk.
  98. ↑ "The National Federation of Roofing Contractors". The National Federation of Roofing Contractors.
  99. ↑ California (magazine of the University of California Alumni Association), Sept/Oct 2008, cover and pp. 52–53
  100. ↑ Nelson, Bryn (15 April 2008). "Green roofs popping up in big cities – Business – Going Green". NBC News. Archived from the original on 25 December 2013. Retrieved 25 April 2012.
  101. ↑ "USPS News Release: U.S. Postal Service Opens First Green Roof". 22 July 2009. Archived from the original on 31 December 2010. Retrieved 11 February 2011.
  102. ↑ "Green Roof: Morgan Processing and Distribution Center (P&DC)" (PDF). Archived from the original (PDF) on 1 August 2014. Retrieved 3 March 2014.
  103. 1 2 One Union Square East Opens City's Largest Residential Green Roof, Zeckendorf Towers press release of 15 November 2010.
  104. ↑ Zeckendorf Towers Unveils City's Largest Green Roof Archived 20 January 2011 at the Wayback Machine , DNAinfo, 16 November 2010.
  105. ↑ A New Roof That Works for a Living, The New York Times , 23 December 2010.
  106. ↑ Kolb, W.; Schwarz, T. (2002). "Gepflegtes grün auf dem dach". Deutscher Gartenbau (in German). No. 7. pp. 32–34.
  107. ↑ Emilsson, Tobias; Czemiel Berndtsson, Justyna; Mattsson, Jan Erik; Rolf, Kaj (March 2007). "Effect of using conventional and controlled release fertiliser on nutrient runoff from various vegetated roof systems". Ecological Engineering. 29 (3): 260–271. Bibcode:2007EcEng..29..260E. doi:10.1016/j.ecoleng.2006.01.001.
  108. ↑ Berndtsson, J; Emilsson, T; Bengtsson, L (15 February 2006). "The influence of extensive vegetated roofs on runoff water quality". Science of the Total Environment. 355 (1–3): 48–63. Bibcode:2006ScTEn.355...48B. doi:10.1016/j.scitotenv.2005.02.035. PMID   16442432.
  109. ↑ "FLL: Startseite". Fll.de. Retrieved 23 June 2017.
  110. ↑ "Projects – Rockefeller Center Roof Gardens". Greenroofs.com. Retrieved 23 June 2017.
  111. ↑ "Denver's Green Roof Initiative". DenverGov.
  112. ↑ Murray, Jon (6 October 2017). "Initiated Ordinance 300: Denver Green Roof Initiative". The Denver Post.
  113. ↑ Chow, Lorraine (10 November 2017). "Denver Becomes Latest City to Require Green Roofs". EcoWatch. Retrieved 17 November 2017.
  114. 1 2 3 Stiffler, Lisa (23 September 2010). "City of Seattle wants more eco-friendly 'green roofs'". Seattle Post-Intelligencer. Retrieved 16 November 2019.
  115. ↑ "Seattle Green Factor". Seattle.gov. Retrieved 17 November 2019.
  116. 1 2 "Seattle Green Factor". Analysis and Planning: ASLA 2010 Professional Awards. American Society of Landscape Architects. Retrieved 17 November 2019.
  117. ↑ "Green Roof Database and Evaluation". Green Futures Research + Design Lab. University of Washington. Retrieved 17 November 2019.
  118. ↑ McIntosh, Annika. "Green Roofs in Seattle: A Survey of Vegetated Roofs and Rooftop Gardens" (PDF). Seattle.gov. City of Seattle. Retrieved 17 November 2019.
  119. 1 2 "Seattle City Hall". Greenroofs.com. Retrieved 20 November 2019.
  120. 1 2 "Green Roofs + Seattle's Downtown: A Perfect Match". Seattle Business Magazine. Retrieved 20 November 2019.
  121. 1 2 "Washington D.C. Green Roof Program | Adaptation Clearinghouse". www.adaptationclearinghouse.org. Retrieved 4 December 2020.
  122. ↑ Charron, David. "How green roofs can save you lots of green". Washington Post. ISSN   0190-8286 . Retrieved 4 December 2020.
  123. 1 2 "Green Roofs in the District of Columbia | ddoe". doee.dc.gov. Retrieved 4 December 2020.
  124. ↑ "Inventory of Green Roofs | ddoe". doee.dc.gov. Retrieved 4 December 2020.

Further reading

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.