The green roof is an innovative technology that allows you to transform even the grayest building, increasing the efficiency of engineering solutions. It is noteworthy that such structures were in demand even in the Stone Age during the construction of yurts, dugouts and huts. Today, such a roof is a complex system, which should be built according to a certain technology, taking into account the design features of the building itself.
What does it consist of?
The green roof is a whole system consisting of several components:
- anti-root layer, which is laid on the waterproofing layer. Its task is to protect the roof from root sprouting;
- protective moisture-accumulating layer: it is needed to protect the waterproofing from mechanical damage and the accumulation of additional moisture;
- drainage-accumulating layer: its purpose is to accumulate the optimum amount of moisture, which is sufficient to maintain the vital activity of planted plants and regulate the outflow of excess water;
- filter layer: with its help, water is filtered, during which the fine particles of the substrate do not fall into the drainage-storage element and protect the entire system from siltation;
- a layer of soil-substrate, where planting is carried out;
- plant layer, that is, directly planted plants - sedum, lawn, perennials, trees or small bushes.
As we can see, the construction of the green roof is not easy, and therefore it is necessary to take into account every little detail when erecting it.
Ecological Pros
Roof landscaping is used today in many countries, including Russia. The popularity of such systems is explained by their versatility: they can be built in any climate where there is vegetative soil cover. In addition, this solution plays an important role from an environmental point of view:
- The climate is improving. Due to the green roof, the air is humidified, as a result of which natural coolness is ensured. Particularly noticeable positive effect of the green roof in office premises.
- The air is cleaned, and dust and harmful substances are absorbed: the green roof used most often has a large green area, and the vegetation on the roof absorbs about 20% of dust from the air, trapping and absorbing nitrates and other toxins.
- Noise insulation is increased: a vegetable roof covering helps to improve sound insulation, which is especially important if a building with an exploited roof is erected near airports and other structures with a high noise level.
- Part of the green spaces is compensated: as a rule, when erecting buildings, the site is cleared of trees, shrubs, and the green roof is the ability to compensate for at least part of the plantings.
- When creating the system, recycled materials are used: the drainage system is created from rubber, polyethylene, polystyrene foam, which guarantees the ecological safety of the structure.
And what does the financial aspect say?
The green roof, of course, is one of the expensive systems, but experts say that it is still profitable to erect it. Why? Let's try to figure out:
1. The cost of reconstruction of the roofing system becomes lower. The plant layer allows you to protect the roof from ultraviolet rays, temperature differences. Accordingly, landscaping significantly increases the service life of roof waterproofing up to 40 years.
2. Thermal insulation is getting better. Due to landscaping, good heat-shielding properties are provided throughout the year of operation of the roofing system, which makes it possible to reduce the cost of heating the room.
3 . Moisture is well retained. The effect of moisture retention is manifested in the fact that the green roof is able to retain up to 90% of the moisture that is formed due to rainfall. Some of the moisture evaporates, some are absorbed by plants, and some go into drains. This design reduces the cost of installing pipelines and drainage systems.
Design and construction features
Green exploited roofs can be erected in any climate zone. This is possible due to the fact that plants that are resistant to moisture, temperature changes in a particular region are used. The landscaping system can be implemented on any flat roof at any stage of the construction process. Green roofing - roof construction technology using bitumen or polymer waterproofing against the roots. According to technology, the roof supporting structure must be resistant to additional load. The installation of the landscaping system itself is very simple and quick, and the main requirement is the maximum angle of its inclination at 25 0 C.
Extensive roofing
Today it is possible to make an exploited roof of two types - extensive and intensive. To begin, consider the features of the extensive system. It involves the use of only grass cover evenly distributed on a thin layer of soil. The remaining plants are simply planted in separate containers with a mixture of soil. The green roof is obtained due to lawn grass and drought-resistant plants, and it needs to be watered only during the period of planting growth. Caring for such systems involves periodic weed cleaning and grass cutting. The soil mixture is a mixture of gravel, expanded clay, sand and organic substances, which are collected in a certain ratio.
Extensive system options
Extensive roof gardening is ideal for standard roof structures. You can make the roof of a building beautiful due to different system options:
- Low-growing vegetation with a substrate height of 60 mm. This is the easiest and cheapest option to use. To increase the flowering time of the cover, about 7 plant species can be planted.
- To give the roof a personality, you can plant it with drought-tolerant perennials that will delight you with their beauty until late autumn.
- The pitched green roof looks no less beautiful. The photo shows that such landscaping is very original. But there are nuances, from a structural point of view: for any slope, you need to consider reducing the load on the supports, parapets and overhangs of the roof, and protect the substrate from erosion. In accordance with the slope of the roof, plants should be selected.
Intensive landscaping
Intense green roofing is a coating in which low plants are combined with shrubs and trees. Moreover, the planting height can reach 4 m with a fertile layer of more than 1 m and a drainage layer of more than 20 cm. In addition to the original appearance, this design serves to retain heat and prevent overheating of the internal space. The soil layer on the roof is able to smooth out temperature fluctuations, protect it from sunlight. Similar systems are being built by many companies in Moscow, for example, Green Roof LLC, which is engaged in complex roofing works of any degree of complexity.
Intensive system features
In the most standard version, the key component of an intensive roof is a special drainage membrane that removes moisture along the roof slope and retains some of it. The purpose of this membrane is to prevent plant roots from growing into the roof. The pitched green roof of this type cannot be filled with garden soil, as it will be poorly drained, too heavy for the roof and has no nutritional value.
The pitched green inversion roof cannot be filled with ordinary garden soil. Plain earth on an inverse green roof is poorly drained, heavy enough for a roof, and not nutritious for plant growth. The optimal substrate for a green roof is a mixture of 60-70% of medium-sized brick chips, perlite, vermiculite or expanded clay and 40-30% of good compost.
How to choose a substrate?
In addition to the Green Roofing company (Moscow), a variety of companies offer greening services for flat and pitched roofs. And it is very important that the substrate formulation is correctly selected. It consists of compost, old leaves, wood feed in small and large pieces, perlite, expanded clay, coconut fiber. The thickness of the substrate should be 40 mm, not less, and if the roof is inverse, then the thickness should be not less than 80 mm.
The vegetation cover of the green roof is built on the basis of alpine alpine plants of sedum, moss, wildflowers and lawn grass (or rolled lawns). Moreover, on the surface of the roof you can create whole plant compositions.