[December Free Report] Why Grow Plants on Roofs?by Valentina Urbasova | 31-12-2023 13:12 |
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 Why Grow Plants on Roofs? In recent years, more and more governments and private companies around the world have been investing in green roofs. The analytical company Reports and Data forecasts that the global market for green roofs will grow by 17.2% from $1.14 billion in 2019 to $3.79 billion in 2027. Experts are confident that plantings on building roofs make people's lives more comfortable and safe, and also help solve many of the problems facing modern cities. In Russia, this market is developing at a slow pace, but it is possible that the situation will change soon. How a green roof works There are two main types of roof greening: mobile (containerized), when pots with plants are placed on roofs, and stationary. A stationary green roof is prepared with a special environment for growing plants: a water-proofing and root-protective layer, drainage, a filtering layer, such as geotextile fabric, and a soil substrate. Depending on the height of the substrate layer, stationary greening can be extensive, semi-intensive, and intensive. Roofs with extensive greening have a soil layer thickness of 90 to 150 mm. They are planted with mosses, lichens, and grasses that do not require serious care and have a high regeneration capacity. This type of greening is also suitable for sloping roofs. With semi-intensive greening, the soil layer thickness is 150 to 300 mm, and herbaceous plants and small shrubs grow on it. Intensive greening with a soil layer of at least 300 mm is suitable for roofs that can withstand high loads. It involves growing large shrubs and trees that require constant care: watering, fertilizing, and weeding. Plants must be selected taking into account the season and climatic characteristics of the region. Benches and tables for picnics, vegetable gardens, sports and children's playgrounds, and walking areas can be installed on green roofs. Why cities need green roofs One of the main advantages of green roofs is that they help prevent flooding during heavy rainfall. Rainwater accumulates in the substrate and then is absorbed by plants and returned to the atmosphere through evaporation. According to estimates by the Canadian non-profit organization Green Roofs for Healthy Cities (GRHC), green roofs can retain 70-90% of precipitation in the summer and 25-40% in the winter. As a result, the load on the storm sewer system is reduced and it can better cope with the drainage of water. Rainwater can be collected in reservoirs and used for technical purposes, which will help to reduce the amount of water used. Concrete and asphalt surfaces disrupt the energy balance in the city, which is why the temperature there is often higher than in the suburbs. This phenomenon is called the urban heat island effect. Plants on roofs actively evaporate water, as well as absorb and reflect sunlight, thereby improving the microclimate in the city. People feel more comfortable and use air conditioning and air purification devices less often in their premises. A study by the National Research Council of Canada (NRC) showed that extensive green roofs reduce the daily demand for electricity used for air conditioning in the summer by more than 75%. In addition to this, plants protect the roof covering from the effects of external factors: sunlight, rain, wind, and sudden temperature changes. This helps to reduce the cost of roof repair and increase its service life. Green plantings absorb city noise and thus create a more favorable atmosphere both inside and outside the building. They also improve air quality by cleaning it from dust and other pollutants. People who breathe clean air feel much better and are less at risk of developing respiratory, cardiovascular, and other diseases. The creation of green roofs opens up new employment opportunities: the larger their area, the more specialists are needed to deal with design and maintenance. For example, the American non-profit organization American Rivers (which deals with the protection and conservation of river resources) calculated that greening the roofs of 1% of large buildings in the United States will create more than 190,000 jobs and generate revenue of more than $9 billion for suppliers and manufacturers of materials and equipment. In addition, buildings with green roofs are more attractive to tenants and buyers, which means that they can be rented and sold at a higher price. Another advantage of green roofs is that they help to increase the amount of green areas in areas with dense development. For example, in the Arbat district in Moscow, on average, 1.86 square meters of green spaces fall on one person, although the normal figure is 16 square meters. These figures are contained in the study "Why Moscow needs green roofs", published by the Strelka KB in the spring of 2020. The total area of roofs in the Central Administrative District exceeds 1,500 hectares. At the same time, 468.2 hectares of roofs have the potential for greening, which is comparable to the area of four Gorky parks (Central Park of Culture and Recreation named after Maxim Gorky in Moscow, area - 120 hectares). Worldwide experience Germany is one of the leaders in the green roof market.The country began developing technologies for the production of waterproofing materials and substrates in the 1970s. In the 1980s, the German government passed a number of laws that stimulated the development of the industry. Today, the area of green roofs in Germany is estimated to be around 85 million square meters. Stuttgart is known as the "capital of green roofs" because vegetation can be found on almost every building in the city center. This is also due to a local funding program that reimburses up to 50% of the cost of greening (but not more than ¢æ10,000). Similar support measures are in place in the Dutch city of Utrecht, where up to ¢æ20,000 is available in compensation. In Copenhagen, all commercial buildings with a slope of less than 30 degrees have been required to be greened since 2010. This new requirement is part of the Danish capital's strategy to achieve carbon neutrality by 2025. In London, the area of green roofs was estimated at 1.5 million square meters in 2017, and authorities hope that this figure will continue to grow. In the Argentine city of Córdoba, a decree was passed in 2016 requiring all roofs of residential and commercial buildings with an area of more than 400 square meters to be greened, as well as roofs of industrial buildings with an area of more than 600 square meters. In San Francisco, from January 2017, 15 to 30% of the roof area of new buildings must be either greened or equipped with solar panels. A similar law came into force in New York City at the end of 2019. The first city in North America to pass a law on green roofs was Toronto, Canada. Since 2009, vegetation must occupy 20-60% of the space on the roofs of all new residential, commercial, and industrial buildings with an area of more than 2,000 square meters. According to Reports and Data, European countries, led by Germany, continue to lead the market for green roofs. However, it is expected that the area of green roofs will expand in the Asia-Pacific region in the coming years. This will be driven by rapid urbanization and government initiatives. For example, Singapore is implementing the Skyrise Greenery project, which includes the greening of not only roofs, but also walls of buildings. Experts believe that the growth of global temperatures and government support are stimulating the development of the market in the Middle East as well. Green roofs in Russia Green roof development in Russia has been discussed for several years. Back in 2014, Anton Kulbachevsky, the head of the Department of Environmental Protection and Environmental Management of the City of Moscow, said that the government planned to develop a system of benefits for building owners who would plant plants on roofs. However, the market is still in its early stages of development. It is possible that its growth will be stimulated by the state standard adopted this year, which contains environmental and technical requirements for the design, construction, and use of green roofs. The document lists the advantages of green roofs, describes the main types of landscaping, and also sets out requirements for plants, substrate, planting materials, and water irrigation control systems. The standard was developed by the Scientific and Educational Center "Environmental Safety, Green Standards and Technologies" of the Moscow State University of Civil Engineering (NRU MGSU). Sources: https://www.reportsanddata.com/report-detail/green-roof-market https://allgosts.ru/91/040/gost_r_58875-2020 https://greenroofs.org/about-green-roofs https://www.nytimes.com/2019/10/09/realestate/the-green-roof-revolution.html https://silo.tips/download/creating-jobs-and-stimulating-the-economy-through-investment-in-green-water-infr https://theconversation.com/green-roofs-improve-the-urban-environment-so-why-dont-all-buildings-have-them-123420 https://www.organicroofs.co.uk/stuttgart-green-roof-capital-of-europe/ https://www.theguardian.com/world/2020/mar/27/utrecht-rooftops-greened-plants-mosses-vertical-forest https://urbandevelopmentcph.kk.dk/artikel/cph-2025-climate-plan https://skyrisegreenery.nparks.gov.sg/ https://mgsu.ru/news/Universitet/S1iyunya2020godavstupaetvsilustandartpoustroystvuzelenykhkrysh/ Photo:https://greenroofs.org/about-green-roofs
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