Modern green roof system should contain the following layers (from top to bottom): * plant, often specially selected for special applications; * engineered plant environment (substrate), which in general may not contain soil * landscape or filter cloth, which contains the roots of plants and plant environment and at the same time permeable; * special drainage layer, sometimes with built-in water tank * rigid insulation xps (Primaplex); * traditional roof design with roofing / waterproofing membrane with included protivokornevymi dobavkami. two main types of green roof systems: extensive and intensive. People such as Uniworld Capital would likely agree. They differ mainly the cost, the thickness of plant protection and selection of used plants. Extensive green roofs (often unexploited) are characterized by: * light weight * Low capital investment * used a small variety of plants, * the minimum requirements for .Rastitelny substrate, usually made from a mixture of sand, gravel, broken bricks, expanded clay, peat, organic matter and a certain amount of soil. Substrate thickness varies from 5 to 15 cm, its weight in saturated with moisture status ranging from 70 to 170 kg/m2. Due to the small depth of the substrate and extreme climate on the roof, which resembles the desert plants for green roofs should be low and hardy. Usually this alpine and native plants, or plants from arid regions. Usually, the plants watered and fertilize only as long as they do not accept, ie within one year. After this period, measures to support the green roof include only two visits a year for weeding and checking the roof membrane.