Roof greening needs to choose very light, high-nutrient planting media to reduce the roof load, and at the same time show a good growth environment for horticultural plants. Greening plants are consistent with the application functions of roof greening. When choosing plants, you need to consider the thickness of the planting medium layer and coordinate the climate and environmental factors together. When designing and conceiving, it is necessary to ensure that plant landscaping is the mainstay, and ecological functions are put first. Ensure that the added load of building a green roof does not exceed the load-bearing capacity of the building structure, and that the external wall waterproof structure can be used safely. Because the roof green area is related to the small green spaces such as parks above, it is necessary to plan carefully to obtain a more ideal artistic effect.
The roof greening load must be able to integrate the effective load generated by the density of all structural layers under water saturation, the gradually increasing load generated by the plant itself, as well as non-large equipment, personnel activities, and natural forces. Based on the allowable cargo capacity of the service platform per unit area, it is necessary to ensure: the allowable cargo capacity of the service platform> the maximum wet weight of a certain thickness of the planting layer + the weight of a certain thickness of drainage chemical substances + the weight of plants + the weight of other chemical substances (building sketches, etc.) . According to the "roof" conditions, that is, according to the load-bearing capacity of the service platform roof, design and conceive different roof greening methods. In order to reduce the load, heavy scenic spots such as pavilions, corridors, flower beds, pools, rockeries, etc. should be designed in load-bearing structures or green roof trays locations with smaller spans. According to the site conditions of the roof greening, the soil layer of the planting layer must have the properties of small bulk density, very light, loose and breathable, water and fertilizer retention, suitable for plant growth, cleaning and environmental protection. Due to the high intensity of sunlight on the roof and the large amount of water evaporation, it is necessary to choose an artificial soil layer that is lighter than the natural original soil, and has better water absorption and water storage, such as a mixture of ceramsite, nutrient humus and organic matter.
Waterproof and drainage
In the design and conception, multiple water-proof equipment should be stopped according to the flat roof structure, and the water-proof and drainage structure should be properly handled. Set up a complete drainage system, in addition to overflow holes, gutters, water outlets, drainage pipes, etc., to meet the needs of daily drainage and flood discharge during heavy rains, and do regular cleaning and dredging work. It is best to form a double-layer waterproofing and drainage system, so as to immediately sweep away the water in the flat roof area.
Because the roof greening project is located on the top of the sky, and is no longer connected to the soil layer of the earth, it is a typical artificial sky, so its habitat is very different from the sky above, which has advantages and disadvantages for plants. Its beneficial elements are: compared with the sky above, the roof has strong light and long light time, which can greatly promote the use of light.