Table of Contents
It is natural to surround aspiration of the person itself with green plantings — it is dictated by the need of organism to breathe clean air, to admire live plants, it gives forces and works better than any synthetic antidepressant.
The majority of the modern cities from height of bird’s flight look not in the best way: these are black roofs of high-rise buildings and black asphalt of roads. It is more and more parks and gardens in the central regions of megalopolises are forced out by parking of transport, new shops, booths, and only owners of owner-occupied dwellings and seasonal dachas have opportunity as much as possible to plant trees and shrubs in surrounding space.
Along with green lawns, rock gardens, artificial ponds more and more people show desire to plant trees and shrubs in the rooftop or country construction. It is the remarkable idea and, fortunately, feasible. Having elementary skills of economic works, great desire and availability of support group, it is possible to change exterior of construction, having given it exclusivity and unusual attractiveness to territorial exterior. Green roofs receive the increasing popularity and they are obliged to these not only order of the day, the green lawn on roof is also fine opportunity to save on expensive roofing materials without damage of esthetic attractiveness of the building. By means of green lawn on roof it is possible to change significantly even the ordinary-looking shed, having made of it the economic room esthetic and pleasant to look.
In what roof it is possible to plant trees and shrubs?
Any strong roof can be used as basis for roofing lawn. Having correctly calculated loading it is possible to create the thorough or facilitated type of additional gardening of the site due to placement of lawn on roof. For a start it is possible to experiment with roof of the shed or doghouse and if you will manage to implement successfully the idea of gardening on small object, to realize it on roof of the summer kitchen, at home, of garage, arbors. Both the flat, and gable roof suits for arrangement of lawn.
It is not necessary to be afraid that the lawn will break covering, on the contrary, competently built lawn with obligatory waterproofing will become guarantee of long duration of operation of roof, it will not be affected by natural rainfall, frost and direct sunshine. Besides, the enclosed space will receive additional heat insulation. In lodge with green to roof is much warmer in the winter and more cool in the hot summer.
Of course, on easy roof it is possible to arrange only grass and flowers which roots are not buried to the earth. But on roof of capital garage with steel concrete overlapping it is possible to create the whole garden, there bravely it is possible to fill soil 400 – 1000 mm thick and to put not only bushes and big flowers, but also small decorative trees between which to lay stony footpath.
What is represented itself by green roof?
In fact, the green roof in section looks as the multilayer pie consisting from:
- wooden blank;
- waterproofing course;
- root barrier;
- heat insulations;
- live plants and elements of decor.
It is necessary to make the decision on the device of green lawn on construction roof, first of all, having made calculations and having defined endurance of design of the roof, walls and the base. Perhaps to be necessary for you consultation of the specialist. For its receiving it is possible to address to the construction or expert company.
Construction of roof lawn
For cultivation of green plantings it is possible to use the construction capable to maintain loading from 50 to 100 kg/sq.m. For comparison: on average in the winter roofs should maintain loading to 75 kg/sq.m therefore the building has to have the considerable margin of safety as the green lawn in winter time will be in addition weighted by snow cover.
As basis under lawn the hardwood, thick plywood can be used. It is not recommended to use material of type of plates of RSD as they can undergo considerable deformation at hit of moisture on them. It is possible to use continuous cloth or to make furring of wooden parts. By means of the timber frame construction intended for arrangement of green roof it is possible to change building format, it can be made at any angle.
The majority of roofs have bias more than 200 therefore it is recommended to use geogrid. This additional layer will prevent possible slipping of lawn, especially if it is going to do the facilitated lawn option. The geogrid is the monolithic polyethylene construction consisting of the tapes 1.5 mm thick connected among themselves. The geogrid is easy, but very strong, it is widely applied in construction, the design keeps within on geolayer (the filter between soil and drainage).
The qualitative waterproofing – necessary basis of any roof lawn, it is intended for prevention of permission of building constructions. One business when rain streams and melt water quickly flow down from roof, without bringing it notable damage and absolutely another when the constant humidity of the earth of lawn can negatively influence building construction. All plants need watering, for lack of enough rainfall the roof lawn will need to be humidified with artificial watering. Correctly chosen and arranged waterproofing not only will prevent hit on moisture roof from watering, but also will become additional board roof design.
For the device of waterproofing course it is possible to use special polyethylene membranes, liquid rubber or dense polyethylene. Whenever possible, it is necessary to exclude availability of seams if seams cannot be avoided, then it is necessary to pressurize them carefully. The waterproofing has to be well fixed and is not mobile concerning roof. The barrier layer keeps within on waterproofing, it is necessary for prevention of damage of waterproofing by roots of plants, over time roots will go deep into the earth. On sale there is waterproofing in which the anti-root barrier is already provided. If you have got normal isolation, then it is necessary to lay plastic film in addition.
The drainage is necessary for the normal growth of plants, it is necessary for regulation of amount of water and excludes its stagnation in case of excessive watering. The excessive moisture content can be serious threat to green lawn therefore in addition to drainage it is necessary to provide water drain from inclined and flat roof. This question needs to be thought over for blueprint stage of roof lawn. The haydite of average and large fraction, drainage grids reminding basts can be material for the device of drainage.
The filter between drainage and fertile soil prevents contamination and consolidation of drainage and keeps functionality of system as contamination of drainage layer leads to loss of its properties. As the filter it is recommended to use special geolayer.
The composition of the ground and its thickness are chosen depending on what plants are supposed to be planted on green roof. The soil has to be easy, porous, steady against consolidation. Shall enter soil substrate: humus, peat, sand, small haydite. If the green roof consists of small plants, then sufficient will be to roof soil 50 mm thick. If landing of bushes is planned, the layer of the earth about 1 meter thick is necessary.
What plants suit for green roof?
Choosing plants and bushes for green roof it is necessary to provide that they will be exposed to direct sunshine (radiation), winds, frost. High speed of the rain flow which is flowing down on inclined roof can damage roots of plants therefore it is necessary to choose plantings with well developing root system.
Care of plants on roof will be problematic therefore it is better to choose long-term. Over time they form dense green carpet that will interfere with germination of weeds which seeds will be brought on roof by wind. It is recommended to plant at the same time several kinds of herbs, it will allow to be defined what survival from plants better and, further, to sow this look all surface of lawn.
Care of green roof
As care of the lawn located on roof is difficult, it is necessary to automate it as much as possible. For a start it is necessary to bring enough slowly soluble fertilizers of long action in soil. It will allow not to disturb at stage of survival of plant and once again not to subject roof to additional loading from curb weight. Having watered too it is desirable to make automated, it is possible to lay easy polypropylene watering water supply system by means of which it is possible to water plants on lawn surface, having opened only the crane located in the available place. As soft soil is applied to roof lawns, there is no need to loosen it. Leaving has to come down further to watering, weeding and fertilizing of plants.
In many respects it is possible to simplify care of grass roof, using the unpretentious plants steady against drought, frosts and sharp temperature differences. Those plants are sedums, yarrow, phloxes, hand bells and some other. The live roof from such plants adds to the building height of 25 – 30 cm, it blossoms not brightly, but, practically, the whole summer is long.
The grass bevel on roofing lawn, usually, is not made, and at winter the dried-up plants remain on the places. It allows to avoid violation of the developed ecological balance and loss by heat insulation roof. It is enough to remove accurately rake dry grass from roof in the spring.
Advantages of grass roof
Roofing lawns attract judges of beauty of the surrounding nature and adherents of healthy lifestyle thanks to the fact that:
- it is one more opportunity to add purity and natural vegetation to surrounding space, to thereby improve ecology;
- that rational decision to occupy the empty space;
- the grass roof is fireproof;
- the problem of rational use of rain waters is solved, the roofing lawn is capable to absorb and acquire to 80% of rainfall which is dropping out on its square, including melt waters.
Besides, the grass roof allows to reduce costs on heating of the building in the winter and cooling with summer as the roofing lawn is excellent heat insulator. Thanks to the additional isolating layer, sound insulation of the building and safety of building constructions considerably raises.
Grass roofs were known to mankind long ago, to take, for example, the well-known gardens, but the Berlin bricklayer of Carl Rabitz has designated them as full-fledged roofs. In the middle of the 19th century it has covered roof of own house with garden from live plants. He was so inventive that has made of the roof not only lawn where flowers and beautiful herbs, but also full-fledged kitchen garden on which beds have sung vegetables grew. The house was big and on the rest of roof of Carl has organized the place for meetings with friends. The invited guests with pleasure visited roofing garden, they enjoyed opportunity to stay in environment of vegetation and to survey the city from height.
Having gained recognition in the country, Carl Rabitz has been invited to Paris for demonstration of the invention at agricultural exhibition. The French public has been fascinated by live roof, and such type of arrangement of roof began to be applied by the European architects widely. Soon the mode has extended to grass roofs worldwide, the possibility of such original gardening in big cities is especially relevant. Today it is already impossible to surprise with the gardens arranged on roofs of skyscrapers. Thus the mankind tries to compensate lack of the environment of daily environment.