In the city, the monotony of steel and concrete is cold and hard, and the bustling and noisy and noisy of traffic: every building is covered with the same, lifeless waterproof roof, like a man-made desert, only the dry asphalt surface is felt. , huge temperature differences and dirty air.
But if you step onto the roof of New York’s Museum of Modern Art, you’ll find yourself in a green space floating in the air, not a “wasteland” of asphalt. There are trees and shrubs such as roses, hydrangea, coleus, and Fufang vine, which are interspersed with flowers and plants. The garden is inlaid with cobblestone paths, and a number of wooden lounge chairs are placed in it. The real money can be seen step by step, the plants are lush, and the stream is meandering, which makes people feel the beauty of nature.
A roof garden is an open-air garden built on top of a building. It is the perfect combination of architectural technology and garden art. Although it is still a new concept in urban construction on a global scale, it has a long history dating back to 2000 BC. At that time, in the ancient city of Ur in the lower reaches of the Euphrates River (now Iraq), a majestic Assyrian ancient temple tower, or “Great Temple Tower”, was built, which includes layers of flower beds with plants, Steps and some temples at the top, this tower is called the birthplace of the roof garden by later generations. In the early 1920s, when excavating the site of this building, the famous British archaeologist Lund, Sir Woolley found that there were traces of large trees planted on the 3rd floor of the tower, but because it was planted on the tower, it was not. On the “top”, it cannot be regarded as a roof garden in the strict sense. What is really called the roof garden should be the “hanging garden” that appeared in New Babylon after the ancient Assyrian temple tower in 1500. As one of the seven wonders of the world, the garden was built in the 6th century BC on the outskirts of what is now Baghdad, Iraq. It was ordered by the new Babylonian king Nebuchadnezzar for his wife. The total height of this garden is 50 meters. It is a stepped platform made on the two-story roof, and plants are planted on the platform. The overall appearance is like hanging in the air, so it is called the Hanging Garden. It is actually a garden building complex built on artificial earth and stone, with both living and entertainment functions.
In Tsarist Russia, roof gardens were considered a luxury for the nobility. In the 17th century, the Kremlin built a large two-story roof garden. The 1,000-square-meter roof garden is built on a vaulted colonnade at the same height as the main building, with two suspended platforms that extend almost over the Moskva River. The top-floor garden is surrounded by stone walls and has a 93-square-meter pool that draws water from the Moskva River. The roof garden on the ground floor was built on the roof of the stone building in 1681 and has an area of 600 square meters and also has a pool. Peter the Great formed a toy fleet here in his childhood and cultivated his interest in sailing.
Norwegians have long since adopted the method of planting turf on their roofs to survive the long winters. Planting with soil cover can also thicken the insulation layer of the roof. Of course, this requires the roof to have sufficient load-bearing capacity and a good drainage system. In the mid-19th century, turf roofs were widely used and had a great impact. In the plains where trees are scarce, the buildings are mostly made of brick and wood. Planting grass on the roof can not only prevent the loss of the roof soil layer, but also form a temperature isolation layer. Therefore, the local people set up roof lawns, not for decoration, but for practical purposes. Throughout Norway’s southern border, even some wood-framed buildings use turf roofs. With the development of heating facilities, sod roofs are gradually reduced.
In recent decades, Germany and Japan have conducted in-depth research on roof greening and developed a complete set of technologies. In Tokyo, the government even stipulates that factories, apartment buildings, office buildings and various other buildings must have a certain percentage of roof gardens as long as the roof area exceeds 1,000 square meters. In Germany, since the mid-1980s, since green organizations first joined the local government, bills on the promotion of roof gardens have been implemented one by one. At first, government departments required green roofs in certain building areas as compensation for nature, first in light industrial areas, then in office buildings, apartment buildings and related buildings. When the construction of roof gardens was first included in local building codes, many officials worried whether developers would really accept it, because roof gardens would increase the cost of construction and make developers choose other cities to build projects. But then it turned out that rooftop gardens were not that expensive and their many benefits boosted the developer’s reputation, making them popular. At the same time, the German government has made the promotion of roof gardens more popular by reducing tax rates, directly or indirectly subsidizing roof greening and additional financial support. At present, as the world’s largest roof garden penetration rate, Germany has the most advanced technology and the world’s largest roof garden market.
Going from an empty, single roof to a green garden is not just for aesthetics. According to experts, from the perspective of environmental protection, the roof garden has the functions of heat insulation, air purification, noise blocking and dust absorption, thereby reducing the urban heat island effect. The oxygen released by photosynthesis per 1.5 square meters of plants in the roof garden can meet the annual consumption of ordinary people. It can also reduce noise, purify the air, and form a layer of “filter screen” in the air, 1 square meter of plants can remove 0.2 kg of suspended particles in the air every year. From an economic point of view, designing the unused roof area as a roof garden, especially as a public entertainment place, can not only make full use of the valuable space, but also reduce the cost of land acquisition. In hot summer, when the temperature reaches 30cc, the temperature of the roof without greenery can reach 40°C to 50°C, while the base 10cm of the roof garden is only 20°C; in winter, the green roof protects the building like a warm cover, reducing Heat dissipation, thereby prolonging the life of the building and saving people the cost of heating. In addition, the roof garden reduces roof leakage by storing water, which not only reduces the pressure of urban drainage, but also reduces municipal management costs.
Knowing the many advantages of a rooftop garden, you will feel that it is not a luxury at all, but a necessity of the city. I believe that in the near future, we will enjoy a leisure time in close contact with the sky in the green roofs of major cities around the world. Are you ready for a rooftop walk?
