The green roof and its ecological benefits
The green roof is an ecological solution to fight against stress and pollution in big cities. Also called green roof, its concept has existed for millennia. The principle is simple: it consists of covering a flat or sloping roof with a substrate and vegetation.
A green roofing system is a set of materials and plants placed on a roof
This urban vegetation system is relatively easy to set up. In addition, besides the aesthetic aspect, it helps the protection of biodiversity and the purification of the air.
Green roof terrace
Urban agriculture is booming not only for consumption reasons but also because of its ecological benefits: the reduction of rainwater runoff and the size of heat islands.
Take into consideration
Before proceeding with the installation of a garden on the roof, the following facts must be taken into account:
- In large cities access to buildings is sometimes limited and narrow
- The height of the building must be taken into account for logistics
- Wind and drafts can be a drying factor
- The weight of the vegetation system is limited
Components of the green roof
The green roof consists of different layers: support carrier, thermal insulation, sealing complex, vegetation complex.
Green roofing scheme
It must be able to withstand the weight of the installation (to the mass of the various components of the revegetation system, the water stored in the system and the weight of the plants). It is recommended that the support support is concrete slab, steel tray or wood panels.
It is acceptable that the roof is sloped. On the other hand slopes of up to 100% require special study.
Planting on an inclined roof
The revegetation complex
By planting complex is understood all the materials for the growth of plants. They provide the drainage function by promoting the evacuation of excess water and the anchoring and nutrition function of the plants.
The choice of the type of draining layer (which directs the rainwater to the rain outlet or to the external gutters) depends on the slope of the roof, the strength of the supporting structure and the thickness and thickness of the roof. nature of the substrate.
In addition to the ecological image they can give, green roofs have many real advantages
In order to prevent clogging of the drainage layer by particles of the culture substrate, it is sometimes necessary to add a geotextile filter which retains the fine particles from the soil and allows the water to drain. In this way the attachment support for plant roots is guaranteed.
Actually it's a contemporary building
The culture substrate
The professionals of green roofs prefer to use specific substrates. They are light, resistant to corosion, retaining water and consist of a mixture of volcanic rocks, light stone aggregates and absorbent foamed materials, organic components such as peat, bark compost and others. The thickness of the substrate can vary: 2 cm for the pre-vegetated rolls, from 12 to 15 cm if one intends to grow a larger variety of plants.
A recreational area that relieves the overcrowded natural environment
The vegetal layer
The vegetation layer is chosen according to the climate of the region, the slope of the roof, the thickness of the substrate and sunshine. On a roof we privilege herbs, perennials, alpine plants. We choose between a plantation of extensive, semi-extensive or intensive type.
The integration of a green roof is possible for already existing constructions but with certain precautions
It is vegetation installed on culture complexes 6 to 15 cm thick. The plants need to be watered only in case of prolonged drought.
Semi-intensive plantations or light gardens approach traditional gardens (with flowers, shrubs, climbing plants etc.). The plants survive on a thin culture complex (from 15 cm). Regular watering is obligatory.
Intensive planting can even include trees. In this case it is carried out on culture complexes of a depth up to 1 meter. This type of planting normally has a significant weight.
Being a form of return of nature, the vegetable roof makes it possible to recover a part of the lost surface. Regarding the sustainability of the building and the comfort of its inhabitants, the choice of green roof has a lot of advantages. For example, the roof of the building is well protected from heat, sunlight and bad weather. In addition, the green roof is a good acoustic insulation because it absorbs sound waves and helps to reduce the noise of the urban environment.
Evapotranspiration caused by rooftop gardens raises the humidity of the air
All this persuaded you that the installation of a plantation on the roof is a good idea? If you want to know more about the theme, go to the article on the methods of create a green roof yourself .
Green roofs give cities a new aesthetic value