In modern cities, less and less space is given to gardens, parks and other green areas. Construction is actively developing, modern skyscrapers are growing like mushrooms in megacities. There is no room for trees and flowers.
In this regard, the idea of greening the roofs of city houses is being actively considered and implemented all over the world. Many experts are confident that this allows not only creating cozy green corners in cities, but also improving the overall ecological stop. It’s not for nothing that trees are called the “lungs” of our planet..
The history of roof gardens
One of the most famous gardens, which were located 25 meters above the ground, are the legendary “Hanging Gardens of Babylon”. The gardens were planted in 600 BC. in Babylon by order of King Nebuchadnezzar II. It was truly an outstanding structure and an achievement of the ancient “landscape designers” that delighted the people of Babylon for over two centuries. “Hanging Gardens of Babylon” are rightfully included in the list of the famous seven wonders of the world.
However, these are not the first such green spaces. Archaeologists managed to find evidence that back in 2113 BC. ancient Sumerians planted trees on terraces of high towers – ziggurats.
There are also very old hanging gardens that still delight people. For example, on the territory of Northern Italy on the Isola Bella island in the palace that once belonged to Cardinal Borromeo, there is an incredibly beautiful hanging garden, the creation of which dates back to the end of the 16th century.
As for Russia, the first experiments with planting trees on the roofs of buildings began in the 17th century. At that time, the hanging gardens, which were called “horse”, were the decoration of the terraces of the Moscow Kremlin.
In 1623, two large hanging gardens appeared in Moscow – the Upper and the Lower. The upper garden was located on the vaults of the Reserve Palace, which descended to the foot of the Kremlin Hill; it was laid by the gardener Nazar Ivanov. According to historians, this garden had a total area of about 2.6 thousand square meters. m. The Lower Garden was created at the Taynitsky Gate. Its area was noticeably smaller – about 1.5 thousand square meters. m.
Hanging Gardens of Babylon, Iran
In the 17th century, “riding gardens” became a typical type of urban garden in Russia. For their time, they were no less a “miracle” for our country than the world famous Babylonian gardens.
In Moscow, the “red” (from the word beautiful) gardens of the boyars Ordyn-Nashchokins and Golitsins were known, which were planted on the roof and the level of the upper floors of their estates. These gardens combined both aesthetic beauty and practical benefits: tall trees delighted the owners with a shade that protected the house from the summer sun. In addition, there were many fruit trees in the garden, which were complemented by exotic and incredibly beautiful flowers, as well as fragrant and healing herbs..
In the 18th century, the architect V.V. Rastrelli used the hanging gardens to decorate the Winter Palace in St. Petersburg. In the Small Hermitage, on the stone vaults of the palace stables, a small hanging garden was built, which was stretched along two galleries – Romanovskaya and Petrovskaya. Similar gardens were planted in Tsarskoe Selo.
In Europe, the massive construction of roof gardens began in the mid-19th century. This was facilitated by the emergence of new building materials. In 1867, a model of a garden created on the roof of the house of the famous German inventor and builder Karl Rabitz, presented at the World Exhibition in Paris, became a sensation. Then all the newspapers wrote that this was a new word in architecture and that such green decorations for city houses must definitely find practical application in the future..
The architects didn’t mind. And in many European countries, including Russia, roofs of houses began to be decorated with gardens. For example, in 1908, a garden with a fountain and a rose garden appeared on the roof of the Merchant Club on Malaya Dmitrovka (now the building of the Lenkom Theater). The first Moscow “skyscraper” – a ten-storey residential building in Bolshoy Gnezdnikovsky lane, built by the architect E.R. Nirnzee, was not ignored either. On the flat roof of this house, a special pavilion was arranged, surrounded by a large number of plants..
Heroes of the film “Office Romance” on the roof of the Nirnzee house
At the beginning of the twentieth century, the projects of the American architect F.L. Wright, as well as his French colleague Le Corbusier, who were convinced that the city of the future could not do without roof-gardens, became famous. So, in Chicago in 1914, Wright designed and built a restaurant with open roof terraces. Among the huge number of rooftop greening projects implemented by Le Corbusier, there is even a whole green city: the Frenchman created a grandiose ensemble of gardens on the roofs of administrative buildings in the Indian city of Chandigarh.
Architect Ralph Hancock in the 30s of the twentieth century in London on the roof of a six-story department store, created a whole garden complex called “Derry and Toms” (Derry and Toms). The construction of this garden cost about 25 thousand pounds. It is noteworthy that there are still three thematic gardens on the roof of this building: Spanish (created in the Moorish style), historical Victorian (created in the Tudor style) and landscape, also called English (it contains more than 100 types of trees).
In Russia, the construction of buildings with a flat roof began in the 1920s, thanks to the constructivist architects G. Barkhin, I. Leonidov, the Vesnin brothers and some others. At the same time, several buildings were built, on the roofs of which special observation platforms with gardens and even children’s playgrounds were equipped..
Unfortunately, the Great Patriotic War made its own adjustments to the development of European and Soviet architecture, the design of houses with roof gardens stopped for many years. It resumed only by the end of the 20th century..
Modern greening of roofs in megacities – the fight for clean air
Germany is currently the world leader in rooftop landscaping and air gardening. Here, not only architects and designers are actively engaged in the development of this area, but also scientists are creating new roofing to facilitate this task..
In modern Germany, when designing new buildings, roof greening is one of the prerequisites, without which the project will not be approved. Local specialists even give a 30-year guarantee for gardens that are erected on rooftops. If everything is designed and built taking into account all the requirements, then during the entire warranty period such a roof does not require repair..
There are many examples of greening roofs in Germany – almost all houses in German cities have green lawns or small gardens on their roofs. There is even a tax for homeowners who don’t like rooftop gardens..
Roof Garden of the Medical Center in Germany
Switzerland is following in Germany’s footsteps – in this country, more than 25% of the roofs of city buildings are reserved for gardens and green lawns. In Japan, the authorities are also actively promoting greening roofs: there is a decree to grow trees, lawns and flowers on all flat roofs with an area of more than 100 square meters. m.
The Moscow authorities also decided to keep up with the European countries. At the scientific-practical conference “An Integrated Approach to the Improvement of the City Territory”, which took place in the capital in early April 2012, projects for greening the roofs of Moscow houses were actively discussed. In particular, new developments in the field of modern roofing materials were presented at the conference. According to officials, in the near future, an improvement program may start in Moscow, which will include greening the roofs of residential buildings..
It should be noted that while in the 18th-19th centuries greening of roofs and the creation of hanging gardens was considered exclusively as a decoration and a special element of urban architecture, today special attention is paid to the ecological aspect.
Unfortunately, industrialization negatively affects the quality of life and the state of the atmosphere. In modern megacities, there is very little space left for parks and natural landscaping. Therefore, people began to pay more and more attention to the need to increase the number of living plants. One of the options available was the creation of gardens and green lawns on the roofs of houses, offices and other city buildings..
Residential complex “Forest Spiral” Huntertwasser, Darmstadt, Germany
Scientists claim that a roof garden is a natural regulator of indoor climate. The green roof works like a living “air conditioner”: it protects from the cold in winter and from the heat in summer. It has been proven that the temperature on a green roof fluctuates less sharply: in the range from -15C ° to + 30C °.
Building a roof garden has the following benefits:
- landscaping reduces the cost of air conditioning and heating by a third;
- landscaping protects the roofing from destruction by ultraviolet rays and mechanical damage. In this case, the service life of the coating increases by 2-3 times;
- an additional vegetative layer retains approximately 20% of the harmful substances and dust contained in the air;
- plants produce additional oxygen that we need for breathing, for example, German scientists have proved that the grassy lawn on the roof is only 15 square meters. m. produces oxygen sufficient for breathing of 50 people.
Nowadays, you can plant a garden and plant a lawn on almost any roof and roof covering. However, there are a number of requirements that must be taken into account if you want to design landscaping on the roof of your house..
When creating a green roof, you need to pay attention to the following parameters:
- The stability of the roof and its ability to withstand additional loads. Since the soil, the drainage system, the plants themselves, the decor and other elements necessary for creating a roof garden can weigh quite a lot, the roof must be guaranteed to withstand such a load. If the roof does not meet this requirement, additional work may be required to strengthen it..
- Irrigation system design. It is important to remember here that the microclimate on the roof is very close to the mountain one: wind, solar radiation, sudden temperature fluctuations, a solid foundation with a thin layer of soil. In addition, at the roof surface, the relative humidity is usually 5-10% lower than on the ground, and in summer this figure rises to 20%. As a result, the soil dries out faster and requires regular watering, and, therefore, a water supply system to the roof to supply water. The structure of this system primarily depends on the size of the future garden. The larger the area of the future garden, the more water will be required to water it..
- Removal of moisture remaining after watering. This factor must be taken into account when designing landscaping. Traditionally, special drainage membranes are used to drain excess water. Polymeric membranes are now widely used, but composite versions are also used, which should be laid on top of thermal insulation boards. It is important to take into account the fact that a certain amount of moisture must remain in the soil for the normal growth and development of plants. Therefore, when greening roofs, not just earth is used, but a special substrate lighter than ordinary soil. You can also add small lumps of clay to it, which can first absorb excess moisture, and then gradually give it to the plants..
- Plant root growth. In the process of growth of the plants themselves, their root system also increases. This can cause the garden to lose its original form. In order to inhibit root growth, special materials have been created. Most often, a polymer film with special chemical additives is laid over the waterproofing layer, which prevents the growth of the plant root system. There is one more point that requires special attention – when the coating is displaced or poorly made seams, the waterproofing layer can be damaged and the roots will begin to grow into the roof. As a result, the entire building will be threatened with flooding, as moisture will begin to seep down. It is extremely difficult to eliminate such a leak – it will take a lot of effort and money. To minimize the possibility of such a leak, special materials are used when forming a roof garden, which combine the properties of waterproofing and protection against germination..
- Choice of plants. When choosing plants for roof gardening, preference should be given primarily to unpretentious and hardy crops. As a rule, plants typical for mountain flora are chosen for such projects: dwarf or creeping varieties of shrubs and trees, various lianas and other climbing plants, herbaceous and ground cover plants. Such crops are less whimsical, have a not too developed root system and relatively easily withstand wind and temperature fluctuations..
Of course, many people dream of having a green garden on the roof of their house in a metropolis. But it is necessary to approach the implementation of such projects extremely seriously, since before starting to lay a garden, it is necessary to consult with specialists who can develop technical documentation in accordance with all building codes and standards. Otherwise, you risk getting not a cozy garden, but a headache in the form of constant repair of the current roof..
What are the obstacles and challenges faced in implementing green roofs in megacities?