The choice of roofing material is a responsible decision, and there is no place for trifles. And if to a roof made of metal or your heart, as they say, does not lie, and the soul requires something unusual and extraordinary, you should pay attention to the so-called " ". And FORUMHOUSE users will help you find out all its secrets.
Green Roof is...
The most widespread "green roof" was in the Scandinavian countries, and its history goes back more than one century. What is a "green roof", and why, despite the fact that the most modern roofing materials are available to us, is it still in demand?
Forum user Novel(nickname on the forum roofing systems )
Novel:
- Speaking in essence, the "green roof" is a set of measures and solutions that allow you to recreate a piece of nature or an ornamental garden on the roof of your house.
microwave:
– "Green Roof" is the roof of a building, on which a layer of fertile soil is placed, in which flowers, vegetables, grass, etc. are planted. The roof turns into a garden, a garden, a meadow area, a clearing for relaxation. It is pleasant to have a picnic on it, sunbathe, relax in the shade of the leaves of a tree, enjoy the smell of flowers, practically without looking up from the workplace and without leaving the building.
And the idea of green roofs is becoming more and more popular.
Green spaces help to reduce the flow of water flowing from the roofs during heavy rains. Water lingers in the soil for several hours and does not pour out in a stormy stream from gutters: a layer of soil 5-10 cm thick absorbs 75% of rainfall. And the vegetation of "green roofs" purifies rainwater from harmful impurities contained in it.
Plowman:
- The sod roof complements the protection of the house from rain, wind and cold. After all, the grass delays the snow cover, and the snow is a heat insulator. And the grass winters normally, like on a lawn. Only the lawn is heated by the heat and, in turn, your home.
Excursion into history
Before moving on to the technology of installing a "green roof", let's remember how such roofs were created in those days when there were no modern building materials.
Novel:
- "Green roof" came to us from Scandinavia, where from the 18th century to this day it has served local population as roofing. And earlier, when there was only stone and houses were built from logs, birch bark was used for waterproofing, because. it does not rot or decay. It was laid over the ceilings, then drainage was paved from stones of various fractions, then a layer of turf with grass was laid.
np28alex:
– For example, grass roofing has been used in Norway since ancient times. Such roofs with birch bark stood for 50 or more years without repair.
Norwegian houses have a roof slope of 22 or 27 degrees - these are the "corners of the earth heap", gentle enough so that the earth no longer crumbles.
An article about how it is customary to build houses in Norway is available .
But it turns out that such roofs are used not only in Norway.
Karluk:
- In Central Asia, in the villages, grassy soil still replaces the roof on many roofs. It saves heat well in winter, and in summer it is cool in adobe or adobe houses under such a roof.
In addition, on the roof of the building, in addition to the standard lawn, you can arrange a rock garden with a mini-fountain, a flower bed, a garden with dwarf trees and shrubs, or you can simply plant any plants.
"Green roof". Modern approach
"Green Roof" is not only an aesthetic design, but also a thermostat that prevents buildings from overheating in summer and works as a heater in the upper part of the building in winter. A waterproofing roofing lasts under a layer of soil several times longer than with an open type of roof.
Novel:
– Waterproofing under the "green roof" is carried out mainly with roofing waterproofing membranes. And before the system of professional drainage for the roof was developed, it was carried out with the help of loose fillers, but the weight of the roof at the same time per 1 sq. m was colossal.
Now the main weight of the roof is a layer of soil, all other materials weigh less than a kilogram per square meter. The main advantages of the "green roof" include the following factors:
- "Green Roof" is an excellent thermostat, which means we save on roof insulation.
- "Green Roof" is UV protection and extends the life of waterproofing.
- Modern underground drainage systems store water inside the "green roof" pie, reducing the amount of water needed to cover the roof.
- Modern geomats will allow you to create any hills and slopes when designing landscape design, and the area of \u200b\u200bthe "green roof" compensates for the territory occupied by nature for building a house.
- The quality of the materials used in the construction of the "green roof" will allow not repairing it for about 50 years.
And the process of installing such a roof can be divided into several important stages:
- The basis for the "green roof" is a monolithic ceiling with a sufficient margin of safety. Mineral wool boards are laid on top of it.
The basis for the "green roof" must be strong enough, since the weight of such a roof starts from 250 kg per square meter. In addition, the moisture-saturated section of the roof becomes even heavier.
- The insulation is laid in two layers with an overlap, but, given that the soil layer is also a heater, mineral wool boards can be reduced in cross section. Alternatively, the bottom layer is 50 mm, the top layer is 40 mm.
FunnyChild:
- In a cold climate, care must be taken not to ensure that there is as much insulation as possible, for example, XPS (if it is an inverted roof), but that there is not too much of it. If you overdo it, a thin soil layer on the roof can become supercooled, and the plants will freeze.
For the middle strip above the heated room, the optimal thickness of the XPS is 100 mm.
- Waterproofing is carried out with a PVC roofing membrane.
One of the important components of the "green roof" is a reinforced PVC roofing membrane. A roofing membrane is a waterproofing coating designed for waterproofing flat roofs. Compared with euroroofing material, it has about a great resource of durability and reliability, and that is why it is recommended to use it in green roofing systems that are not available for scheduled and ongoing roof repairs.
- Drainage-accumulative system reduces the number of waterings in half.
Bulk materials served as the first drainages: gravel, expanded clay, separated by geotextile as a filter, which, in turn, increased the thickness of the pie and many times increased the weight of the roof by 1 sq.m.
Novel:
- Not superfluous in the "green roof" will be materials such as geomats for strengthening slopes, and geogrids, which are used when filling soil and creating slopes, hills and other landscape design quirks.
You can learn how to make a drainage system on the site. .
Next, plants are planted on the finished roof. Earth layer thickness should be at least 100 mm, but in general itis determined by the capacity of the supporting structures of the building and the characteristics of the root system of plants.
Novel:
– For greening the roof, there are a large number of ground covers - the so-called carpet plants. These are sedums of various colors and sizes. Unlike a standard lawn, they require virtually no maintenance.
You can also create a simplified "pie" of the roof.
- 1 layer - euroruberoid.
- 2 layer - waterproofing from geotextile.
- 3 layer - coarse sand.
And then light and nutritious soil is laid.
But the following points should be taken into account:
1. The slope of the roof slope for moisture drainage should be 20-28 degrees, then it will not be necessary to lay drainage. If the soil layer is about 20 cm, then the load on the roof will be about 7-15 kg per sq.m. Along the edge, you will have to fix the side that holds the soil.
2. Plants are selected the most unpretentious and winter-hardy. They do not require additional watering and generally no maintenance. The roof can not be corrected for 2-3 seasons.
Rooftop plants such as dandelion, mantle, knotweed, plantain, sagebrush are remarkable in their natural simplicity. They correspond to the natural style and are most suitable for our climatic conditions.
Also, to complete the picture, the experience of building such a roof according to the recipe of our northern neighbors is interesting.
np28alex:
- In Norway, they take the same land that was taken out during the foundation work. They do not sow anything, and what is around grows on the roof. And in order to get a stable turf, you need a layer of earth of at least 10 cm.
But even centuries-old experience should not be blindly copied, because. it is necessary to take into account the specifics of our climatic conditions.
FunnyChild:
- In Norway, the climate is warm, humid and foggy, due to the proximity of the Gulf Stream, and it has very little in common with ours, Moscow. And the classic Norwegian roof consists of several layers of birch bark, collected in a certain period (immediately after the end of sap flow) and only from high-quality trees no more than 40 years old. And this is not counting the many tons of soil that need to be thrown up.
You can often hear the opinion that a "green roof", like that, is a very expensive solution and it has a lot of limitations.
Aleksej2000:
- I once considered a "green roof" as an option for a future home. And so I read a lot about her. But in the end I refused because, it seems to me, of many restrictions. For example:
- The large weight of the roof leads to an increase in the cost of the truss system.
- The slope of the roof cannot be made steep, and because of this it is impossible to use the attic.
This means that you will have to increase either the area or the height of the house.
- The roof requires annual maintenance.
Novel:
– Regarding the weight of the roof: at this stage, the main weight is a minimum 100 mm layer of wet earth and plants, the weight of waterproofing and drainage with a filter of 0.5 kg per square meter. That is, the entire structure weighs half a kilogram before backfilling the soil, and heavy bulk drainage is no longer used for greening the roof.
The slope of the roof can be absolutely anything, even a vertical surface can be planted with greenery. To obtain a pitched roof, we use the same technology, we only add a special geomat and anti-erosion mat.
Novel:
– Maintenance of such a roof is rather a hobby or pleasure. By the way, due to the presence of water-collecting storage drainage, it is possible to water the "green roof" three times less often than an ordinary flower bed, and in order not to take care of the plants, you can plant such ground covers as the so-called mat plants, they, like moss, do not require care, and if put drip irrigation, then this is generally beauty.
How to independently plant grass on the roof, users will tell our forum. All information about the "green roof" can be obtained. In this video, you will learn how to choose modern roofing materials. And this video clearly tells about the so-called "living fence"
green roof- one of the most ancient varieties of roofs. People built similar structures in the Stone Age. The roofs of the oldest buildings (dugouts, huts, yurts) in Scandinavia and Siberia were covered in the same way: several layers of birch bark (at least six) were laid with the outer layer down over the flooring of hewn half-logs or poles. The birch bark was covered with a layer of turf (about 8 cm).The first layer was laid down with grass to protect the birch bark from the humic acids contained in the soil.
Modern green roofing has retained some of the features of those ancient structures.
Benefits of using green roofs
From a pragmatic point of view, the installation of a green roof allows significant savings during the heating season. Sometimes maintaining the temperature is sufficient, since the entire roofing cake and soil layer perfectly retain heat in the interior.
In addition, the green roof gives the building a beautiful aesthetic appearance and is a source of oxygen. There is a kind of compensation for the vegetation layer lost during the construction. According to scientific data, 150 square meters of green roof is enough to provide the necessary oxygen for 100 people for a whole year.
The engineering and economic benefits of a green roof include:
- a significant increase in the operational life of the structure: providing natural protection from sudden temperature fluctuations, exposure to ultraviolet radiation, mechanical damage - as a result, significant financial savings that would have had to be spent on the construction of a conventional roof;
- passive heat saving - is provided due to the excellent heat-insulating qualities of a green roof and consists in saving energy in winter and preventing overheating of the roof in the hot season;
- water saving - achieved through the absorption of rainwater;
- excellent sound insulation: a green roof reduces the degree of reflection of sound waves from the roof surface and significantly increases the level of sound insulation;
- there is no need to create special operating conditions - hence, additional financial investments;
- makes it possible to obtain an additional recreation area;
- during a fire, it eliminates the likelihood of a rapid spread of flame along the roofing surface;
- it becomes possible to place different types of communications (water supply, electricity, ventilation, automatic irrigation) during installation and after it;
- differs in simplicity of carrying out installation works;
- creates local accessibility to waterproofing;
- prevents slipping of the soil layer;
- creates an anti-root air gap to protect the waterproofing from root penetration;
- It can be said without exaggeration that this technology has been tested for centuries.
Benefits from an environmental point of view:
- green roof is an additional source of oxygen;
- neutralizes harmful gases and dust in the environment through their absorption;
- regulates the level of air humidity;
- allows you to create a natural green area;
- accumulates rain water;
- makes it possible to obtain new living spaces for flora and fauna: on this type of roof you can plant several dozen species of plants and breed small animals, even keep bee hives or provide a habitat for rare species of birds, lizards, insects;
- prevents the release of volatile toxic substances from roofing materials based on bitumen;
- green roof is absolutely universal and can be arranged in any corner of the planet where there is a soil vegetative cover.
Social and image advantages
- gives the building an attractive appearance;
- provides a high rating during certification according to green standards.
Types of structures
Green roofs are of two types:
1. extensive- for their creation, only a grass cover evenly distributed over a thin soil layer is used. This type of roof is mostly unexploited, with limited access for people. The green surface does not need special care.
For this type of roof, mainly lawn grass and plants are used, adapted to the conditions of lack of moisture, as well as ground cover, which perfectly tolerate not only drought, but also sudden changes in temperature: saxifrage, sedum.
Other types of plants are planted in separate containers with a soil mixture.
Such a roof should be watered only during the growth of grasses and plants.
After they are accepted, the need for watering disappears, and all care comes down to periodic cutting of grass and cleaning of weeds.
The composition of the soil mixture includes gravel, organic compounds, expanded clay, peat, sand, mixed in the required proportions.
The layer thickness should be 5-15 cm.
The main advantages of an extensive green roof are:
- ease of maintenance and care;
- no need for watering;
- unpretentiousness of planted plants;
- light weight;
- low cost.
2. Intensive green roof is a full-fledged garden created on the roof of the house. Landscaping of this type of roof involves planting not only various varieties of plants and flowers, but also shrubs and even small trees. You can create a fairly complex system that needs careful maintenance and should be watered regularly.
The thickness of the soil layer can reach 60 cm, which leads to the imposition of certain weight restrictions on the main (bearing) structure.
In the case of the installation of an intensive variety of green roofs, it is necessary to make a construction calculation in advance, even before the start of installation work.
Special requirements are also imposed on the soil: since irrigated plants will be planted in it, which are highly demanding on the composition of the soil, it must be enriched with organic compounds. Planting ornamental trees and shrubs requires a powerful layer of substrate. Features of this type of roofing are:
- the possibility of creating a unique and rather complex ecological system;
- the need for a special watering and care system;
- increased content requirements;
- the need for preliminary drafting of the project, taking into account the recommendations of professional designers and landscape designers;
- the need for qualified builders with relevant work experience.
If creating a full-fledged green roof seems difficult or expensive to you, it may be worth considering the option of greening the roof with seasonal potted plants or planting outdoor plants in tubs. Currently, such an opportunity is provided by many companies specializing in complex gardening, including our partners - FreshPlants.ru phytodesign studio.
The main elements of a green roof
The main elements of an extensive type of green roof are:
- plant layer;
- a layer of soil substrate;
- filter element;
- drainage system;
- waterproofing layer;
- thermal insulation material.
Intensive (or inverse) green roofing has a distinctive feature: in its roofing pie, the waterproofing layer is located under the heat-insulating material, due to which the waterproofing is always in positive temperature conditions and is reliably protected from mechanical damage.
The depth of the soil substrate is determined by the specific type of green roof.
In the case of an extensive variety, it should be in the range from 5 to 15 cm, and with an intensive roof, from 20 to 60 cm.
The filter layer in most cases is geotextile. Its purpose is to prevent soil particles from clogging the drainage system. You can use thermo-riveted material, the peculiarity of the arrangement of the fibers of which guarantees operation throughout the entire operation with virtually no clogging.
The drainage system provides appropriate conditions for vegetation growth. It is based on high-strength rolled materials made of high-pressure polystyrene or perforated polyethylene. In some cases, plain perforated polystyrene can be used or the surface can be covered with gravel.
Excess water is removed using asbestos or corrugated pipes with slots.
One of the best thermal insulation materials is foam glass. Its use makes the green roof completely safe in terms of ecology, since the material is completely neutral. Its other advantages are resistance to plant root pressure and non-hygroscopicity.
You can also use more traditional materials: basalt wool or extruded polystyrene foam.
It can be on a synthetic or bituminous basis. An incorrectly selected membrane or a violation of the rules for its installation can lead to problems with the entire system in the future.
If there is a need for additional protection of all supporting structures, copper or aluminum foil can be laid over the waterproofing membrane.
Features of designing and creating a modern inverse green roof
The main component of an inverted green roof is a special drainage membrane equipped with pimples. It performs a dual function:
- Carries excess moisture down the roof slope towards the drainage layer.
- The presence of recesses in the material makes it possible to retain a certain amount of water, which is required for plant growth.
- The dense structure of the membrane creates an obstacle for plant roots.
There are certain types of membranes that have an additional filter layer - geotextile: it simultaneously retains a certain amount of moisture and prevents the filling of recesses with soil.
In case of insufficient strength of the drainage membrane, it is necessary to use an additional layer to prevent the germination of plant roots.
With an extensive variety of landscaping (i.e. without maintenance and irrigation), the estimated weight of the roof varies in the range of 60-150 kg per sq.m. A possible snow load of 180 kg is added to it. This requires a rafter system with beams measuring 50x200 mm and a rafter step of up to 35 cm.
When creating an inverted green roof with a slope angle of more than 20 degrees, transverse stops are required to prevent the soil layer from sliding off the roof surface. Antiseptic-impregnated boards, T-shaped plastic profiles, XPS strips, etc. are used as the material for the stops. They are laid with a distance of 60 cm.
For optimal drainage, a gravel-based drainage gap is laid along the edges of the roof, the width of which should be 30 cm.
As a rule, green roofing is arranged on roofs with an angle of inclination up to 45 degrees. In some cases, the maximum allowable value is 51 degrees - in this case, it is necessary to use a firmly fixed geogrid.
The ideal angle for a green inverted roof is an angle of 5 degrees (or 8%)
When constructing a pitched inverted green roof, you cannot use ordinary garden soil. It is too heavy, does not drain well, and does not provide the plants with the necessary nutrients for good growth and development.
The best substrate for a green roof is a mixture of perlite, medium-sized brick chips (60-70%), expanded clay or vermiculite, and quality compost.
Some rules for green roofing
In connection with the creation of an additional load on the supporting structures, it is better to design a green roof in advance.
When installing a green roof on an already erected building, it is necessary to make all the calculations, taking into account the possible increase in load.
If a green roof is being installed on an existing building, calculations must be made taking into account the possible increase in pressure.
At large angles of inclination, the use of additional elements is required to prevent the roofing cake from slipping.
One of the most vulnerable places is the junction with a vertical surface. This problem is relevant in the case of other types of roof structures. You can prevent leakage by lifting a layer of waterproofing material along the interface.
When installing an extensive variety of green roofing, it is necessary to take into account the illumination of the sun. The lack of sunlight has a very negative effect on the condition of the main planted plants.
In the case of intensive roofs, this issue is not so important due to the wide variety of plants used.
Another important point is the need to treat the roofing PVC waterproofing membrane with anti-root preparations, thanks to which the roots of plants will grow parallel to it, without penetrating inside.
In this case, the root system of plants will be located parallel to it, without penetrating inside.
FINDINGS:
- Green roofing is one of the oldest types of roof structures.
- The main advantages of a green roof: the possibility of significant savings, environmental safety, beautiful appearance, passive heat saving.
- There are two types of green roofs: extensive and intensive.
- The roofing cake of the extensive variety consists of six layers.
- A feature of the intensive type is the location of the thermal insulation above the waterproofing.
- The main element of an inverted green roof is a special drainage system.
- With a significant slope angle, it is necessary to use a geogrid.
- Ordinary soil is not suitable for creating a soil layer: special mixtures are used for this purpose.
- Since the green roof has an additional load on the supporting structures, its design has its own characteristics.
- The waterproofing membrane must be impregnated with anti-root preparations to prevent the penetration of plant roots.
Read more about the stage of waterproofing when creating a green roof in the video.
Using the roof for planting is considered know-how in landscape design. But this is far from true. Green roofing has long been a well-known roofing material in Central Asia and Scandinavian countries, which effectively protects the house from overheating in the heat, and retains heat well in winter.
The idea is based on the use of the roof area to place a layer of soil on it with various plants.
The arrangement of such a green roof allows you to create not only vegetable beds and plant flowers, but even equip your own small garden. An artificial meadow of yarrow, lavender, echinacea and sage looks very beautiful on it. In addition to aesthetic pleasure, such a roof will emit a pleasant aroma.
Features of operation and installation of a roofing pie
For long-term operation of a green roof, you will need to make a roofing pie in accordance with its purpose. Usually, the choice of material with the required characteristics is made by the designer, taking into account the total weight of the structure, solar radiation, and water loads. A properly executed technological process guarantees the service life of such a green coating from 30 to 50 years.
In addition to the appropriate technology for laying materials, the pie requires attention to the fertile layer of the earth. A properly selected assortment of plants is of great importance, since the depth of the roots should be less than the thickness of the soil. To extend the life of the roof and its individual elements, it may be necessary to apply anti-root protection. It can be made from non-woven geotextiles or some types of polymer-bitumen membrane. If you plan to plant plants with a developed root system, it is better in this case to use special flower beds and tubs for them.
Consists of the following layers:
- floor slab;
- waterproofing carpet;
- thermal insulation layer;
- profiled drainage membrane;
- filter layer;
- the soil.
To create a green roof, the main supporting structure must be made of reinforced concrete slabs or monolithic reinforced concrete.
The formation of the slope and direction of water drainage from the surface provides this layer. And for a good flow of water, you need to properly plan its angle of inclination. Typically, this value ranges from 0.5 ... 3%. The slope-forming layer can be made as a bearing base or created as an additional layer of expanded clay, slag or foam concrete.
Waterproofing and thermal insulation layer
The use of bituminous and polymeric membranes, as well as sealants, helps to prevent the penetration of water into the building. The main requirements that are put forward to these materials are: service life from 20 to 50 years, increased tensile strength and other types of loads.
It should be noted that steam accumulates under the waterproofing layer, which causes the structure to become wet and fungus to form. To avoid these troubles, the installation of droppers or wind vanes to remove condensate from under the waterproofing will help.
In addition to the above layers, the cake also requires good thermal insulation. The function of this layer is to keep warm in winter and cool in summer. The type of material and thickness of the coating are calculated by specialists who must take into account the operating conditions of the coating, climatic features and the location of the house. If errors are made in the calculations, the material will get wet, which will lead to the appearance of moisture inside the room. In addition, such a coating will lead to a holistic violation of the entire roofing pie.
Drainage layer and drainage system
The purpose of this coating is to drain water and prevent its stagnation. In addition to engineering purposes, the drainage system plays a significant role in the existence of vegetation. Therefore, this layer consists of perforated drainage and special pipes.
In this case, high-strength roll materials are used. In the process of their production, perforated polystyrene or high-density polyethylene with spike-like growths is used. When arranging a territory where this problem is not so significant, you can use perforated polystyrene slabs or simply cover the area with gravel, expanded clay or gran-slag.
This complex should provide high-quality removal of rainfall, melted snow and water used to irrigate vegetation on the roof. For this, drain funnels should be provided during the design. A feature of their installation is a uniform arrangement, without strong differences between the crest and the funnel itself. In this case, the area, slope, type of soil and type of vegetation should be taken into account.
A green roof requires the use of multi-level funnels that provide water flow not only from the roof surface, but also from the drainage layer. The axis of the funnel is mounted at a distance of at least 600 mm from the parapet, the funnels are attached to the supporting base of the roof, connected through expansion joints with the main risers. The connection of the funnel with the waterproofing mat is provided by a removable or non-removable flange or an integrated connecting apron combined with the waterproofing mat. Gravel filling up to 250 mm wide is made around the water intake funnel.
Mounting
First of all, for laying a waterproofing layer in a green roof pie, it will be necessary to bring the main coating to the required standard. If the design does not provide for a slope, then the best option would be a claydite-concrete carpet with a reinforced cement-sand screed arranged over it. In such screeds, there should be temperature-shrinkage joints up to 10 mm, which divide it into sections of 6x6 m. They are installed strictly according to the project in low places with mechanical fastening to the building structure. Next, the base is checked for cracks and irregularities. If required, it is necessary to seal with a cement-sand mortar.
Scheme of installation of a green roof.
To ensure good adhesion of the roll material to the main layer of the green roof, the entire surface is treated with a primer using a brush or roller. And only after the entire surface has completely dried, the installation of a waterproofing coating begins. The waterproofing of a roofing pie can be improved by applying a welded reinforced material to places where water intake funnels, engineering equipment, and antenna extensions are installed. The laying of the roll material begins with the lowered places of the roof. With a slope of more than 15%, it is done along, and less than 15% - perpendicular or along the slope. The overlap of rolls during coating should be about 150 mm. For interconnection, a bitumen-polymer binder mass is used.
The second layer in the waterproofing is an anti-root film, which is laid over the entire surface with an overlap of 150 mm. At the locations of the drainage funnels, the film is cut along the diameter of the drain. In the process of laying, the panels should not have wrinkles, folds and waviness. To do this, all work is carried out with soft brushes and rolled with rollers. Particular attention is paid to the edges on which the connection technology is repeated several times.
Assumes the presence of a thermal insulation layer. Since it has direct contact with water, the insulation should be used with low water absorption. These include extruded polystyrene foam or foamed glass. Having a closed cell structure, they practically do not absorb water (less than 0.5%) and therefore are quite effective throughout the entire service life. Plates made of extruded polystyrene in inverted roofs are laid in one layer and connected to each other in a groove (dowels).
Next, a drainage layer is laid in the green roof pie. It consists of a filter element and a drainage core. As the latter, both natural materials (expanded clay, slag) and artificial (drainage mats or profiled membranes) are used. The filtration layer is intended for the passage of water into the drainage cavity, but at the same time does not allow it to silt. In addition, it prevents clogging of the drainage and prevents it from mixing with the soil. Made from thermally bonded fabric.
If a green roof is installed on an existing structure, calculations must be made taking into account possible pressure increases.
If the cake has a drainage substrate made of natural material, then they will need to cover the entire surface of the roof. As for laying artificial drainage, it has its own characteristics. The drainage mats will need to be sawn with a wide, fine-toothed saw before being installed. For the funnel, a hole for the drain is cut out of the appropriate size. Next, you will need to install inspection wells, dividing corners and other structural elements.
A filtering membrane is laid over the core of the drainage layer with an overlap of at least 200 mm. It will need to be brought out above the vegetation layer by 100 mm. In places where various structural elements are installed, the filter coating is brought out to the level of landscaping.
The final stage
The intensive type includes a full-fledged garden, which consists of coniferous and deciduous trees, the height of which reaches 4 meters, and shrubs. The fertile soil layer must be at least 1 meter. In this case, the building structure must be designed for a mass of 150 ... 750 kg / m². As for the exterior type of landscaping, in this case only the grass cover is planted, and large plants are placed in special containers. The soil layer is not more than 600 mm. Such light landscaping can be placed even on pitched roofs.
Sometimes the design of the territory requires the presence of pedestrian zones. The arrangement of such paths excludes the use of concrete. In this case, the laying of the coating should be carried out using sand or gravel, which are the basis for this coating. The use of this type of material will ensure the outflow of water to the drainage layer and prevent the appearance of puddles and ice. In some cases, it makes sense to carry out gravel filling along parapets near flammable structural elements and objects. It is separated by metal L-profiles with perforations. The installation of such separators is carried out even on the drainage layer.
Building their dwellings, mankind has made a grass roof since ancient times. In some cases, this type of roof is called earthen. This type of roof does not present any difficulty and the construction scheme is not difficult.
There is, however, one indispensable condition: the weight of such a roof is large enough, so the roof rafters must be as reliable as possible. If structures are built from logs, beams, gun carriages, then a grassy, heavy roof is even preferable - with its additional weight, the building being erected will go through the shrinkage process much faster. Also, the crowns will close much tighter.
You can divide the varieties of grass roofing into the following types:
- Turf.
Reed.
Shingled (wooden).
Slate.
Tiled.
Copper.
How to make a grass roof
Let's highlight the main components of a grass roof.
First of all, absolutely any vegetation can be used for laying. But still better hardwood.
Next, a dense layer of earth (peat, turf) is laid, waterproofing is possible if necessary. Also, you can not do without a heater. Do not forget about drainage - it is permissible to use gravel or crushed stone as it.
Please note that the geogrid is used with a large roof slope. It makes sense to cover the drainage layer of crushed stone with a layer of geotextile.
Consider an eco-friendly way of laying a grass roof.
The construction of a grass roof is similar in most cases. This is a supporting truss structure and a crate made of unedged boards, on top of which turf was laid.
Instead of the waterproofing that is widely used today from rolled bitumen or other materials, a layer of birch bark was laid on the crate, on top of which turf was laid in two layers or the soil mixture was poured for sowing it with grass seeds.
However, before touching on the technology of laying bark and turf, it should be noted that the own weight of a green roof is about 250 kg/m2. This means that the shear load (especially on roofs with steeper slopes) can move all the grass down. To avoid this, fences were an indispensable constructive element of green roofs. Their function was traditionally performed by sod-protecting beams or boards laid along overhangs - the so-called sod holders.
At the same time, when creating a grass carpet, the construction of the roof had to ensure unhindered runoff of rainwater from the roof slopes. To do this, it was necessary not only to choose the right shape of the sod holders, but also to properly attach them to the crate.
Strips of birch bark were laid overlapping each other. In the overhang zone they were laid in 5…8 layers. At the same time, the strips released from under the fencing beam and put on it were laid with the outer side up. This was done in order to ensure effective water drainage and protect the sod holder and the end parts of the batten boards from moisture. In addition, the bark, laid with the outer side up, is an important decorative element of a green roof.
To increase the life of the roof, the rest of the bark was laid with the outer side down, since the inner side of the bark provides more effective protection of the batten from the mixture of sigumic acids contained in the soil.
To protect the turf laid on the sides of the pediment from wind and water erosion, natural stones were laid on the edges of the pediment. Later, gabled wind elements, which were used as logs, began to be used for this. They were laid so that the ends protruded above the ridge. Connected logs crosswise. And since the logs had the same thickness as the turf holders, together they formed a kind of wooden frame for the entire roof.
In another version, a windboard was used to protect the turf from erosion. They fastened it with wooden pins, and covered it with birch bark from moisture. Sometimes, instead of bark, a horizontally laid covering board was used.
One of the important elements of traditional grass roofs is a wooden gutter, which was made from boards connected to each other on screws at right angles or hollowed out from a tree trunk.
The weak point of grass roofs is openings (in particular for chimneys). To avoid water runoff along the walls of the pipe into the house, stone slabs protruding beyond the pipe were immured into its masonry.
At the same time, sheets of birch bark were placed under these slabs, diverting the flow of water to the roof. Stone slabs on the side of the slopes were arranged in steps, which contributed to a more efficient removal of rain or melt water from the pipe walls.
As a fencing element, a log is used here, supported by a thrust hook fixed under the crate. In this case, the hook, cut into the log of the upper crown, is fixed under the crate, and the round timber itself lies completely on the birch bark. So that water does not accumulate on the roof, slots are made in the sod holder for its drain.
Round timber, in turn, is also lined with birch bark. Despite the presence of such moisture protection, the sod holder still needed to be periodically replaced with a new one.
For example, when attaching a thrust hook over a crate, a space is formed between the birch bark and the sod holder, which ensures effective water drainage. And when fastening the enclosing element with the help of a dowel, special slots were provided in the sod holder for water drainage.
The solution is also interesting, when the fencing beam is attached to the side, with an indent of 5 cm from the edge of the overhang, which also ensures a quick runoff of water.
In all these cases, the sod holders are protected by birch bark. The overhang zone itself is covered with bark in several layers.
You can also apply the option of fastening the fencing beam using a powerful dowel, cut into the end part of the rafter. This method of fastening was used for roofs with hanging rafters protruding from the overhang by about 12 cm.
Often, in order to save wood, instead of logs or beams, boards 3 ... 4 cm thick and 12 ... 16 cm wide were used to protect the grass cover, depending on the thickness of the green roof.
To ensure water runoff, holes or cuts 3 × 3 cm in size were made on the lower edge of the board every 20 cm. On the side of contact with the turf, they were expanded, giving the shape of a funnel. Sometimes boards were installed without drain holes. In this case, they were fastened so that they protruded 2 ... 3 cm beyond the overhangs. For this, as a rule, persistent steel corners were used, which were screwed to the crate with screws.
norwegian roofs with a lawn instead of tiles - a byword for all neighboring peoples. Ironic Swedes have long drawn Norwegians with grass on their heads instead of hair. Charming lawn roofs today have become the same symbols of a country popular with tourists, like fjords, trolls and salmon.
grass roofs appeared in Norway and the Faroe Islands in ancient times. It was convenient and economical: the building material was at hand, such roofs did not require special care, they served for a long time, and even helped to disguise themselves from enemies.
Naturally, those who care about the preservation of traditions, the Norwegians put them on now - grass roofs can be seen on modern hotels and restaurants, on private houses and public transport stops. In other villages, almost half of the roofs sway in the wind with green waves. They say they improve the microclimate, provide reliable heat and waterproofing, and stabilize the temperature in the house.
Many craftsmen do such roofs on their own. The technology is described in detail on the Internet. Several private firms also offer the service in Norway. Although new tools are used in laying grass roofs, it is still based on ancestral technology and a lot of manual labor, which is why such roofs are somewhat more expensive than ondulin ones.
First of all, fit several layers of dry bark. For water resistance, it can be impregnated with sheep fat or blood. Peat, straw, moss are laid on it ...
Many dream of building a cottage with landscaping on the roof a la the Vikings. They say: “Can you imagine, when the roof is mother earth, how will you sleep peacefully?”
The fact is that in the Norwegian roof there is a real biocenosis in its harmonious balance. Moreover, the roof simply must be wet, grass (and even bushes and trees) feeds on this moisture, along with all the microorganisms of living peaty soil. At the same time, it does not require painstaking care only due to the unique features of the Norwegian climate.
Rising up this summer on the famous rock Throne, along the roots of trees, like steps, you can unravel the secret of the Norwegian fauna. For such a thin layer of soil to bear fruit so abundantly, it requires almost daily watering. Humidity and raininess of the Norwegian climate, as you know, is listed in the Guinness Book of Records. Anywhere else on the planet, a grassy roof would quickly dry up and be blown away by the wind.
Where does the rain come from?. The Gulf Stream hits Norway. Warm evaporation, in turn, rests on the mountain range, cools and pours rain (in Bergen, on a sunny day, in general, I opened my umbrella five times!). The water cycle in Norway is the most intensive in the world. From here, they have 80 percent of hydropower and, in general, an excess of energy, which they generously share with Europe. And what is especially valuable, unlike oil, it is a renewable, or rather, inexhaustible resource! Here is such physics.
Therefore, the main feature Norwegian roof is that, for all its functionality, it is also alive, fertile!
In eastern Norway beyond the mountain range, where the climate is drier - and the roofs with grass are an order of magnitude smaller.
Who first saw earthen roofs in Norway, remember the famous English lawn. The fact that it needs to be sheared, watered and rolled for 500 years is all a fairy tale for naive foreigners. Modern lawns have long been rolled out from rolls reinforced with mesh, planted in squares ... A year later, it does not differ from a 500-year-old one.
But nowhere does it say about the main thing - about its composition. And the whole secret is in the peaty base of the soil of the British Isles. That is why there is no wind erosion (like we have), that is why the golf ball rolls like on a pool table. That is why the horse gallops over it without tearing the turf with horseshoes, and that is why only on the grass courts of Wimbledon it is possible to mow the lawn with a height of only 8 millimeters (!) - standard for the legendary Grand Slam tournament.
About the same and with grass roofs. Their creation is justified only in the conditions of the Norwegian climate and Norwegian turf. With us, if the craving for the roots has woken up, it is better to cover the roof with wood chips.
For several centuries roofing in Norway has been carried out using natural ecological materials. Green roofs in this country surprise no one and are traditional. Since ancient times, the peoples of Scandinavia have made roofs from peat, turf, birch bark and other natural environmental materials. 
The descendants of the Vikings, the Norwegians, highly appreciated this method of roofing and managed to keep green roofs on their houses to this day. Almost until the beginning of the 19th century, turf was a universal material used to cover roofs in houses of all classes in Norway. 
Over time, materials such as shingles, slates and other roofing materials have appeared on the market, which have gradually begun to replace Norway's traditional ecological, beautiful and cute grass roofs. The “Advance of Civilization” began in the cities, but eventually reached the countryside.
Enthusiasts saved the green grassy roofs of Norway from complete extinction.
They organized and led a movement aimed at reviving old folk traditions. First, open-air museums, mountain lodges, ... and then green roofs made of grass and flowers again became simply popular and fashionable.
Indeed, in addition to the fact that such a roof roof is simply beautiful and gives aesthetic pleasure, it is quite cheap, durable, stabilizes the temperature in the house, improves the microclimate, providing reliable thermal and waterproofing. Therefore, green roofs have become popular again and at the same time have become a worthy alternative to new building materials.
