Green Roofs: Grass Roofing Technology

The main task of any roof is to retain heat in the house and protect it from wind, rain, snow, ultraviolet rays and other adverse atmospheric factors. However, the acute shortage of places for construction and environmental problems of megacities led to the fact that additional tasks are assigned to the modern roof. One of the modern fashion trends in modern architecture is the creation of a "green roof", where you can equip a flowering lawn and even grow the necessary vegetables and herbs.

Not all city dwellers have the opportunity to fully relax on a forest clearing or enjoy the mountain air - often there is simply no time for such trips. High-rise buildings, close streets, exhaust fumes of passing cars and hot asphalt have a negative effect on people daily.That is why the owners of private houses and cottages work tirelessly to ensure that their homes are as close as possible to nature - they use environmentally friendly materials in construction and develop flowerbeds, lawns and rockeries.

A very interesting technological solution came to Russia from the Scandinavian countries. - This is a “turf earthen roof,” which is often built on small houses in Norway. This design assumes the following: the roofing material is covered with a clay litter, and it serves as the basis for the formation of a sod layer 10-15 cm thick, where the grass was planted. These houses looked very attractive, but this design requires additional strengthening of the bearing pillars - not only is the soil “cake” rather heavy, during the winter period snow masses were added to it, and not every building could withstand such a load. That is why the sod roofs over time almost ceased to equip. Perhaps this idea would have remained an idea, if today landscape designers did not recall the forgotten Scandinavian traditions.

Now the "green roof" is not uncommon in large cities. Roofs, partially or fully seated with live plants, can be found in shopping complexes, office centers and elite residential high-rises. Not so long ago, the fashion was picked up by the owners of country houses, which began to actively plant trees on the dachas.

Like other types of roofing systems, eco-roofs have similarities with puff pastries, although its components differ in some features of operation. Creating a green roof should guarantee reliability and practicality according to important criteria: foundation strength, good protection against water and reduced heat loss. The roofing “pie” of this type of roof has the following layers:

• base - it can be made of wood or concrete, the most important thing is that it should have a large margin of safety that can bear the weight of the earth and the plants themselves;
• waterproofing layer it is extremely important for reliable protection of the structure from moisture ingress; plants require regular watering, therefore, rather high demands are made on the strength of this layer;

• barrier Mounted above the waterproofing material to prevent the germination of the roots in the main roof of the structure. If it is not installed, the plants will take root in the previous layer and damage it;
• drainage it is used to evenly distribute moisture over the entire surface of the roof, retains part of the water, preventing the plantings from drying out, and removes excess moisture through the drain;
• filter - a layer of geotextiles, which limits the ingress of small particles into the drainage;
• geogrid installed in order to prevent the "scattering" of the earth under the influence of rain and strong wind;
• substrate - directly the soil, which is poured on the geogrid with a layer from 5 to 20 cm; its thickness depends on exactly what you plan to grow: a layer of 5 cm will be enough for ground cover flowers, but for growing vegetables you will need about 20 cm.

Large-scale landscaping is one of the necessary conditions for existence in the furious rhythm of modern cities, built of concrete and glass. At the same time, narrow streets do not allow the flower gardens and flower beds to be set up in cities - as a rule, small areas of parks and squares are allocated for this.That is why the arrangement of the green roof solves a very important task - it allows you to significantly improve the ecological situation and at the same time make the most efficient use of useful areas.

The advantages of this technology include the following factors.

• Strengthening the structure - the plant layer reliably protects the roof from various mechanical damages, temperature fluctuations and the adverse effects of natural phenomena. The roof, covered with a green layer, can be used for more than 20 years. However, let's not forget that this is only true for fortified structures with a large margin of safety.
• Efficient use of rain and storm water - soil can hold more than 30% of precipitation. Thanks to the green roof the probability of flooding is reduced. In addition, water, instead of merging into stormwater runoff, is used to irrigate the surface and contributes to obtaining a good harvest.

• Exceptional thermal insulation performance - The turf layer is considered to be a very suitable material for this purpose; it retains heat in winter, prevents heat from penetrating into the house in summer, and also contributes to efficient air circulation, thereby creating a favorable microclimate in the room.
• Soil absorbs noise welltherefore, the inhabitants of the house can be sure that the sounds of rain or hail will not interfere with them.
• Recreation area organization - an attractive roof can be a harmonious place for family leisure and meeting friends in a comfortable environment.

Despite the obvious advantages, the eco-roof has some drawbacks.

• Heavy weight - drainage and soil give a load of about 50 kg per square meter. meter, this leads to a significant increase in pressure on the ceiling of the building.
• High price - Green roof equipment involves the use of only environmentally friendly materials, and they are quite expensive. Therefore, green roof equipment is much more expensive than conventional arrangement.
• The complexity of mounting technology - the construction of eco-roofs and the corresponding increase in pressure on the supports requires the compilation of a design project created by accurate calculations of the permissible parameters of the load on the floor.It is impossible to accomplish this without having the skills of such planning, therefore it is required to seek help from specialists.

Please note that experts do not recommend re-equipment of the existing roof into a greenSince the old foundation and existing floors can simply not withstand significant additional load.

Depending on the usage parameters, eco-roofs emit intensive and extensive types of landscaping.

Such structures are created on the roofs of the cattle type with an angle of inclination of no more than 45 degrees. Features of the layout of these buildings are such that they do not provide for access to the roof. Accordingly, it can not be properly operated. At the same time, undersized perennials are used for landscaping roofs, which pull back the coating, create a decorative appearance and at the same time protect the roof from mechanical effects and precipitation. For planting used unpretentious plants that do not require special care and abundant watering - for full growth and development they have enough natural rainfall.

Extensive roofing provides several options for landscaping.

1. Low plant cover - while the height of the soil does not exceed 6 cm, the land is planted with drought-resistant ground cover plants of several species, so you can achieve continuous flowering from May to October. This is the easiest and easiest way to gardening;
2. Green roof - the roof is designed as a lawn, often for this purpose use rolled types of coatings.

It assumes the arrangement of eco-cover on flat surfaces that can be used by the inhabitants of the building. Such buildings have access to the roof, are equipped with a parapet that protects against possible falls, and special paths for comfortable movement. Here you can grow not only a grassy lawn, but also plant large bushes and even fruit trees. Of course, this design requires special attention during the construction and operation. This garden needs the same care as the ground gardens and flower beds.

Green roofs can be created absolutely in any climatic region.In itself, the device of such a roof with his own hands is not difficult, but time consuming.

Eco-sheeting layers are as follows:

• base;
• vapor barrier;
• insulation;
• waterproofing;

• protective layer;
• drainage system;
• filter;
• priming;
• plants.

The easiest way to complete the arrangement of the eco-cover is to use a turf as a topcoat. If the roof is straight or its angle of inclination does not exceed 10 degrees, the seeds can be planted directly into the ground. If the slopes are steeper, then during the rainy season and melting snows such an unpleasant phenomenon as a landslide may occur. So that the soil does not “slide down”, layers of soil are placed between special barriers.

A very important part of the green roof is the installation of a drainage system. It is very important to understand the relevance of proper drainage: once the water cannot penetrate into the house, therefore, it needs to find a way out at some other place, otherwise it will remain in the roof and will simply sour.This will lead to rotting of the roots and death of the plants.

Geotextiles are used as the main drainage, as well as sand or small crushed stone. Additionally equip the drainage system.

As a rule, use one of the options.

• Drainage plates - plastic panels of profiled type, which are attached to each other and mounted on the entire surface of the roof. The mechanism of action is as follows: water accumulates in the "blades" of the panels, and if it is excessive, it flows into the plates located below. Thus, the water cascading downward, and then drains into the drain pipe.
• Drainage mats have a similar principle of action, but faster to install. In addition, mats contribute to the strengthening of waterproofing. This method is not good for all types of roofing - it does not apply to flat and overly steep roofs.
• Drainage boxes - drainage flat roof involves the use of special systems that contribute to the forced removal of moisture from the roof, as a result of water falls into the funnel. and from there to the storm sewer system.

In conclusion, we give some recommendations on the choice of plants suitable for planting on the roof. So that flowers and herbs will not wither in the very first cold winter and not wither in the hot summer, it is necessary to give preference to unpretentious representatives of the flora, optimally if they meet the following requirements:

• small root system, growing horizontally - cereal and moss are suitable for this parameter;
• frost resistance - flowers should be free to tolerate frosts, typical of most regions of Russia in the cold season;
• drought-resistant - It is desirable to choose plants in such a way that they have enough natural watering (natural precipitation).

Remember that the climatic zone of our country is not characterized by exotic plants, they require serious care, abundant watering and the addition of bait. Therefore, planting such flowers as an eco-cover is only possible if you are ready for the extra effort and time needed to maintain the attractive appearance of your roof. And of course, in this case there are additional requirements for waterproofing coating.

• Traditional sod roofs in Norway looked very impressive. Today, this technology has received a second life. Green roofs are actively settling in many European suburbs.
• You can often find eco-blood in megacities - they adorn shopping and business centers, multi-storey residential buildings.
• Roofs can be decorated with flowers and even trees.

How to green the roof yourself, see the next video.