Minimizing costs and increasing the speed of work have long been current trends in the field of construction. The frantic pace of life and production processes forces developers to choose those designs that allow them to deliver the project as quickly as possible, cheaper. Therefore, for multi-storey residential buildings of standard construction, industrial facilities, office buildings, a flat roof based on rolled waterproofing materials is increasingly being chosen.
A flat roof that replaced the intricate structures of a gable, three-slope and hip roof, completely utilitarian. Its roof cake protects the building from moisture penetration and maintains optimal temperature regime inside.
Technology application of modern roofing roll materials and installation methods guarantee the highest level waterproofing and thermal insulation. Under what conditions and for what design is it appropriate flat roof, we will tell in this article.
Performance and Benefits
The name "flat" has a figurative meaning, because even though such a flat roofing cake does not have slopes, there is still a slight slope in it. After all, completely flat, even structures will not allow melt water and rain to drain into the designated places.
Without even a small slope of 2-3 degrees, excess moisture accumulates on the roof, forms puddles, and provokes leaks. Unlike other varieties, the technology of mounting a flat roof from rolled materials has the following advantages:
- Economy. Comparing the construction costs of even the simplest gable structure and a flat one, it is obvious that the pitched options lose in terms of saving material resources. On this cost item, you can save up to half of the money included in the estimate for the construction of the roof through the use of inexpensive roll materials.
- Speed and ease of installation. Due to the lack of need for rafter system, flat roofing works are carried out very quickly, despite their large area requiring overlap. In addition, the workers performing the installation may not be highly qualified.
- High degree of protection against wind and precipitation. This point is especially important for the construction of high-rise buildings. Imagine a skyscraper from two pitched roof th, the picture that pops up in the imagination will surely cause laughter. But, not taking into account the appearance of such a roof, its installation is impossible due to insecurity. The higher the overlapped structures, the stronger the wind load on it, the more gently sloping their roof should be.
- Rational use of space. The flat multi-layer cake of the exploited roof makes it possible to compensate for the entire area occupied by the building. Since it can be equipped with a parking lot, a swimming pool, a recreation area, a cafe, even a garden or install solar panels. While there is not enough living space in megacities, everyone square meter available space should be used as efficiently as possible.
Flat roof device
A structure in the form of layers of rolled materials is called a roofing pie. This cake consists of layers of three types:
- Base. Depending on the way the roof is used, either concrete plates, or sheets of profiled metal. The main purpose of this layer is to stiffen the structure. Since one of the features of a flat roof is that it can be used not only for the temporary location of people, but even for parking cars or arranging a pool.
- Screed. Its task is to set the slope of the roof surface so that melt and rain water can be channeled into it. To do this, use a concrete mixture or a cement-sand mortar. In roofs under construction, it is advised to lay a slope of 2-3 degrees, in restored or repaired - 1 degree.
- Waterproofing. A layer that prevents the penetration of moisture into the roofing cake. For its manufacture, bitumen, polymer and bitumen-polymer roll materials are used.
Important! The nature of the use makes adjustments to the structure of the roofing pie, adding special layers, but the base, screed and rolled waterproofing materials are present in any type of flat roof device.
Types by nature of use
The design of a flat roof, depending on how it will be used, is significantly different. There are the following types:
Simple operated roof
roofing cake operated flat roof
If the building project provides for the installation of an operated flat roof, a drawing is drawn up that reflects the sequence of layers of the pie. They are usually placed in the following order:
- Reinforced concrete base;
- Concrete screed;
- Waterproofing film or membrane in the form of a roll material;
- Drainage metal grate;
- thermal insulation material;
- Sand-cement mortar;
- Terrace cover.
As thermal insulation, extruded polystyrene foam or mineral wool in the form of solid slabs is used. Most often, an exploited flat roof is covered with paving slabs intended for paths and parking lots.
The main disadvantage of this arrangement method is that the insulation is located quite close to the surface, which can cause it to deform, sag, get wet, and therefore lose more than 50% of its peat insulating properties.
Inverted operated roof
Before the invention of membrane elastic materials, builders noted a significant drawback with a simple exploited roof - the rapid wear of the waterproofing layer, which was made from rolled bitumen derivatives based on cardboard.
Since he was at the top of the pie, his condition quickly deteriorates due to exposure to temperature changes, UV rays, and mechanical damage. The way out of this situation was the invention of an inverted flat roof, the arrangement of the layers of which is different.
It looks like someone turned a roofing pie upside down. Waterproofing from rolled materials, bitumen or bitumen-polymer material is laid on concrete slabs.
This is followed by a layer of moisture-resistant insulation, extruded polystyrene foam covered with geotextile is ideal. The top layer necessary for protection is made by pouring gravel. This technology and placement of rolled materials has three advantages:
- The waterproofing layer of the roof, securely hidden in the thickness of the roofing pie, lasts longer, as it is not exposed to external influences.
- Condensation does not form on the insulation located in the upper part of the roof, it does not get wet, it retains high thermal insulation qualities for 20-25 years.
- Close to the surface of the slabs of the thermal insulation layer, it makes it easy to replace them and repair the roof.
green roof
This type of exploitable roof turns the top of the building into a blooming oasis, with lawns, flower beds or small beds with kitchen greens and vegetables. In conditions of high gas pollution of cities, green roof not only decoration, but a means of their recovery and relaxation.
The peculiarity of this type of roof is that a layer of geotextile is laid over the insulation to hold the soil layer and the earth itself, which is subsequently sown with a grassy lawn mixture. It is important to choose high-quality, reliable waterproofing and moisture-resistant insulation, for example, polystyrene foam.
Ventilated roof
The invention of a ventilated roof solves the problems of moisture accumulation in the thickness of the roofing pie. It penetrates there in various ways: it settles in the form of condensate on the insulation, accumulates in concrete screed, remains in the layers of the old roof. The breathable roof gives excess water an outlet - aerators, installed at the rate of 1 piece per 50 square meters. m.
Ventilated roof
Advantages of ventilated roofs:
- Installation does not require removal of the previous roofing.
- Aerators guarantee effective evaporation of moisture, and a new layer of screed-decomposer effectively channels it through the drainage system.
- A method, the application of which is possible both during repair and during the initial installation of the roof
flat roofs different types opens up many opportunities for the implementation of bold design projects. This is the future of housing construction, modern technology for the careful use of free space, because the arrangement on the roofs of greenhouses, gardens, accommodation solar panels make the life of urban residents more convenient and comfortable.
Video instruction
Flat roofing is one of the easiest and most convenient installation methods.
Therefore, the construction of a flat roof is quite often involved in the construction of residential buildings and industrial-type buildings.
The article discusses the functions, advantages and disadvantages of a flat roof according to wooden beams, stages of its installation (destruction, creation of a drain and a roofing pie, installation of parapets).
Depending on the type of roofing, the flat roof device is divided into 4 separate types:
- exploited;
- unexploited;
- inversion;
- traditional.
Positive and negative points
The device of a flat roof in frame houses on wooden beams is gaining more and more popularity every year.
The installation technology of such an exploited roof is so simple that even a non-professional can cope with this task with a small amount of construction work.
Even though it is called flat, it is still not horizontal.
When recreating it, a small technological bias is still very important - for 1 m of length it is 1.5-2.5%, provided that it is an exploited space.
In all other cases, this slope, according to SNiP, must be at least 3-10%.
If we are talking about the service life of the coating (corrugated board) on frame house, then it directly depends on the professionalism of the builders who were involved in its construction.
But at the same time, an important role is played by the choice of materials, the properties of which must correspond not only to the terrain, but also to other parameters.
In regions with moderate rainfall, corrugated roofs are most often constructed. Laying corrugated board on a flat roof is carried out directly on the floor beams.
It is important that the technology of installation and installation of flat roofs is observed, since any deviations from the specified standards, when using low-quality materials, can cause a decrease in the life of not only the roof, but the building itself as a whole.
Advantages:
- The device of a flat exploited roof based on rolled materials is considered an example of simplicity and minimalism, from an architectural point of view:
- Smaller area, and therefore savings in materials;
- Long service life of a roof from a professional flooring;
- Simple mounting technology and device flat cover from corrugated board;
- Convenience during professional examinations and repair of the exploited roof of a house from corrugated board;
- The possibility of using this site for a cafe or a green lawn;
- Stability of roll materials under any weather conditions.
Important conditions:
- High strength, which is very important during periods of heavy snowfall, when it is under pressure from snow and ice. This indicator must be taken into account when the roof is in operation;
- The use of materials when constructing a flat roof of a private house, which are able to withstand severe frosts and hot sunlight;
- The roof must be heat-insulated and fireproof, according to SNiP.
Operated and non-operated types of coatings
The technology of the device of a flat exploited roof implies the wear resistance and strength of rolled materials.
Due to this, it is able to be homogeneous even with fairly strong uneven and long-term loads.
Such a roof is suitable for walking on it, like a corrugated roof.
Non-exploited corrugated roofing is less wear-resistant, due to the lack of a rigid base in it.
But at the same time, a corrugated roof is more durable and does not need special care.
The device of operated flat roofs today is carried out using the following materials:
- Use of roll materials;
- The use of polymer membranes;
- Use of asphalt and bituminous mastics;
- Application of materials with liquid rubber.
The device of a flat exploited roof made of corrugated sheets differs in the design of a roofing pie from any other roof.
A vapor barrier is laid on top of the ramp.
To date, several subspecies are known:
- directed;
- membrane;
- bulk.
Flat roof mounting scheme using different materials consists of the following steps:
- Vapor barrier with glassine, polyethylene film, roofing material;
- Warming with mineral wool, expanded clay, polystyrene;
- Gravel spreading device;
- The device of a bulk cement-sand or asphalt concrete screed;
- Priming screed;
- Device roll roofing from polymeric membranes;
- Installation of overhang and parapet from steel sheets;
- External drainage system;
- Installation of funnels for water drainage.
How is a flat roof slope created?
The formation of stagnant zones, thawing and freezing, the appearance of vegetation adversely affects the roof, reducing its service life.
The decompression device helps to combat these phenomena. SNiP, regulating their device, contribute to the flow of water to the funnels from the parapet, even with damage to the roof.
There are several ways to create a slope on the exploited roof of a house:
- With backfill heaters;
- On heat-insulating plates;
- With the help of concrete mixtures.
The most economical option for flat roofing on wooden beams is the use of wedge-shaped styrofoam slabs.
This method is considered the least laborious, in contrast to the demolition using a cement-sand screed. The most optimal is the creation of a slope with a slope of 1.7-2%.
All construction and repair work is carried out strictly in accordance with the requirements of SNiP, therefore soft roofing is no exception.
For construction companies, SNiP are the rules that guide the performance of work. Only in this case the coating will be durable and strong.
To work with each of the rolled roofing materials, there are standard flow sheets that describe detailed diagram flat roof construction process.
When creating a typical map, the requirements of SNiP for roofing must be taken into account.
So, when installing a flat roof of a house from rolled materials, SNiP II-26-76 is considered the main regulatory document.
In addition, the provisions of SNiP 3.04.01-87 are used, with a description of finishing and heat-insulating coatings, as well as requirements governing labor safety when performing such work.
Drainage system on a flat roof
The device of an internal drain on flat roofs of the house helps to eliminate moisture. by the most the best option is the organization of internal drainage.
To do this, the funnels are evenly distributed over the surface of the roof, carrying out the removal of water flows during heavy snowfalls and showers, preventing flooding. This is the main function of the drain.
The system of internal drainage and slopes is an indicator of roof care.
This suggests that it is important to inspect funnels, cleaning them of dirt, leaves, and also repair or replace them in a timely manner.
The device of an internal drain and slope is a sanitary standard, the miscalculations of which are carried out specifically for each individual case.
Initially, many people believe that the device of an internal drain and slope is not so important for residential buildings, however, a large functional load is assigned to it.
SNiP provides for the mandatory presence of an internal drain to protect structures from adverse effects.
It is important to perform the internal drainage device correctly, since if even small mistakes are made, there may be problems later.
At the time of drawing up the construction project, it is important to plan for the presence of a drain.
Making a roofing cake
The installation conditions of the operated roof provide for the mandatory presence of a roofing pie, as it prevents heat loss. Protecting the roof from overheating is also one of the functions of the roof threshold.
The device of a roofing cake for a flat roof implies the presence of such layers:
- base;
- steam insulation;
- insulation;
- hydroprotection.
Each of the elements of the roofing pie performs its function. If the work on creating a roofing pie was performed in violation of the instructions, then the entire system will not function correctly. As a result, the work will have to be completely redone.
During the creation of a roofing pie, the following points are performed:
- steam isolation;
- creating a crate;
- insulation installation;
- work with waterproofing;
- ventilation system.
Subject to all the requirements for the construction of a roofing pie, you can be sure of a positive result the work carried out.
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Increasingly recently, flat roofs are used in the design of industrial and public buildings: the technology of their construction has undergone significant changes as a result of the emergence of new roofing materials.
They differ from pitched roofs in that they do not use sheet and piece roofing materials when arranging flat roofs. When they are created, a carpet is laid from rolled products. Apply mastics, bitumen-polymer, bituminous and polymer materials. As a result of the work performed, the carpet on a flat roof should be elastic enough to withstand mechanical and thermal loads. As a basis for roofing material concrete slabs, screeds and heat-insulated surfaces are used.
What are flat roofs
When a flat roof is created, its device depends on whether its surface will be used or not.
Operated roof . It is equipped on buildings so that people can regularly be on it or to place various items (see photo). To withstand the increased load, which can be unevenly distributed over the surface, a special screed is made on the waterproofing layer or a rigid base is laid.
Unexploited roof . To create it, laying a reliable and durable foundation is not required, since the load on the surface of such a roof is minimal. For preventive maintenance or current repair specially designed bridges or ladders are used, which, when moving along them, distribute the load on the surface evenly. The construction of an unexploited roof will be cheaper, but its service life is less than.
Inverted roof . Such a "roof-upside down" can be exploited. On it, a heat-insulating layer is laid on top of the waterproofing and, thus, protects it from the negative effects of ultraviolet radiation and temperature changes. It should be noted that not any heat-insulating material is able to cope with the assigned function, but only one that does not absorb water, extruded polystyrene foam is most often used.
Ventilated roof . Its first layer is partially glued to the base or special clamps are used, this is done to prevent the formation of air bubbles due to the fact that moisture can accumulate in the insulation layer. These bubbles sometimes cause deformation and damage to the roofing mat, resulting in leaks (detailed: "").
Before proceeding with repair work on a flat roof, it is necessary to find out which type it belongs to. The procedure for taking measures to eliminate defects and leaks depends on this, and it will also be necessary or not to use special equipment that ensures the safety of being on the roof.
Foundation preparation procedure
In the section, the device of a flat roof consists of a bearing coating and a base, on which layers of hydro-, steam- and thermal insulation are laid in a certain order. Most often, the bearing coating is a reinforced concrete slab, steel profiled sheet, much less often a coating of wood materials is used.
If the reinforced concrete base has defects, a cement-sand screed is made, after which the surface becomes even.
Depending on the material on top of which the screed is made, its thickness differs:
- if it is concrete, then the layer is from 10 to 15 millimeters;
- when rigid insulation boards are used - 15-25 millimeters;
- in the presence of non-rigid heat-insulating materials - 25-30 millimeters.
When a flat roof device provides for a slope of no more than 15 percent, the screed is performed primarily on the grooves, and then only on the slopes. If the slope exceeds 15 percent, the procedure for creating a screed is reversed - first the slopes are leveled, and only then they are engaged in the arrangement of valleys and grooves.
On the flat roofs of modern houses there are always protruding elements - chimney pipes, parapet walls, ventilation shafts, etc. They should be plastered at least 25 cm high. To the upper edge of the plastered surface, slats are mounted for fastening the rolled carpet. In order to improve adhesion between the carpet and the base, the screed is cleaned of debris, dried and primed with roofing mastics.
Roof coating technology
Mastic, after being applied to the surface of a flat roof, as a result of contact with moisture contained in the air, polymerizes and eventually forms a membrane similar in characteristics to rubber, due to which it has good waterproofing and protective performance (more: ""). Liquid sealants provide the coating with reliability, resistance to precipitation, UV radiation, harmful microorganisms, etc. They are easy to use, they can be applied to a flat roof with a roller or brush, both on the reinforced concrete surface of the slabs and on the cement-sand screed.
Roof covering with roll materials
The device of flat roofs allows the use of rolled materials, the strips of which are overlapped, and in the same direction:
If during the process of gluing the panel deviated from its location, it must be tried to return to its place without peeling off the material. But if it is impossible to move, the glued piece is cut off and the panel is glued again, observing a 10-centimeter overlap.
The device of a flat roof, carried out using modern methods and materials, has allowed this type of roof to become an integral part of the architecture of buildings for various purposes. And if, until recently, flat roofs were mainly industrial and agricultural buildings, now they are an attribute of many residential, administrative buildings, and even country cottages. And the main thing is that time "works for them", reliably confirming that flat roofs in all their qualities are no worse than the good old pitched roofs.
Flat roofs have been steadily gaining popularity in recent years. With a small amount of construction work, for example, during the construction of a barn, outbuildings, a garage, even a non-professional can easily cope with such a design. Of course, although this type of roof is considered flat, it is not horizontal. Required condition long-term operation of such a structure - the presence of a minimum technological slope, which should be about 1.5-2.5% per 1 m of length, provided that the exploited space is built on the roof. In other situations, the technological bias should be about 3-10%. Sometimes structures with a slope of 10-20% are classified as flat, which is not true. Such coatings are already referred to as pitched, only consisting of one slope.
A flat roof is a minimum of details and simplicity of construction
The period of trouble-free operation of a flat roof is directly related to the professionalism of the builders involved in the construction of the structure. For a high-quality coating, it is necessary to competently approach the issue of choosing a roofing material, the properties of which must correspond to certain parameters.
It's important to know! Even small violations, deviations from the technology of a flat roof, not to mention obvious errors and shortcomings, or the use of low-quality building materials can cause a significant reduction in the life of not only the coating itself, but the entire building as a whole.
Flat roof device
Advantages flat design:
- flat roof - an example of simplicity and minimalism, fashionable now, according to architects;
- economy of materials used due to its smaller surface area;
- long service life;
- simplicity and security of implementation installation work;
- convenience of preventive inspections of the roof and repair work on it;
- flat roof - additional free space, for example, for a cafe or a green lawn;
- no problems when servicing chimneys, television antennas, ventilation ducts;
- resistance to high wind loads.
The green lawn on the roof is so cute!
If the device of a flat roof is made competently and efficiently, there are no shortcomings in its operation. In the case of unprofessional installation, defects are possible, which will come to light on the very first rainy autumn or snowy winter.
Flat roof construction: we study the basic requirements
- The high strength of the roof is especially important during the snow season, when it is forced to withstand the pressure of thick layers of snow and ice. This indicator is also important in cases where a flat roof is exploitable.
- The roof must be a reliable barrier to water during rain and snowmelt and have a slope.
- The construction of a flat roof must not react to the effects of bitter frost and scorching sunlight, to the influence of changes in ambient temperature and hail strikes the size of egg.
- The roof should perfectly perform a heat-insulating function.
- All materials used must be fireproof.
A flat roof always accumulates much more snow in winter than a pitched roof.
Classification of flat roofs and features of the roofing plan
All flat roofs, depending on the functions they perform, can be divided into two groups:
- An unused roof, which is an ordinary element of a building structure and performs the functions of a roof.
- An exploitable roof, which is also used as an additional usable area. If this is the roof of the house, then a pool or lawn can be organized on it. And if this is the roof of some kind of underground structure, then a parking lot, a cafe, a park, etc. can be located at the top. One thing is clear that such a flat roof will experience completely different loads than an unexploited one.
Operated roof with a cozy terrace
Depending on the features of the installation and the materials used, two types of roofs are also distinguished. In accordance with this, a flat roof cake in each case will have its own characteristics:
traditional method
The traditional way, in which the topmost layer is waterproofing. It is she who in this case is subjected to thermal, physical and mechanical loads.
The role of the supporting base can be performed by a reinforced concrete slab, a special reinforced profiled steel sheet or roofing sandwich panels. The required slope is usually achieved by means of a concrete or expanded clay concrete screed. Sometimes expanded polystyrene concrete or slag is laid.
The next layer is a vapor barrier that prevents fumes from the room below from reaching the insulation. As a result, it always stays dry. For vapor barrier, a thick film of polyethylene or polypropylene is used. Its stripes should be perpendicular to the slope of the surface and overlap each other at the joints. Sometimes a bituminous membrane is chosen as a vapor barrier.
With the traditional arrangement of layers, waterproofing becomes the most vulnerable point
Then the thermal insulation material is laid. Mineral basalt wool is usually used, which has good compression resistance, vapor permeability, fire safety and low thermal conductivity. Its first layer (70-200 mm) will act as a heater, and the second (40-50 mm) will act as a load distributor. In general, the thickness of this layer is calculated in accordance with the climatic conditions of the region.
To redistribute pressure, the heat insulator layer is sometimes covered with a cement-sand screed, which is additionally reinforced with a metal mesh to prevent cracking.
And, finally, the finishing layer is waterproofing, which has proven itself well with special liquid mastics that form a rubber-like layer, built-up roofing material and roofing membranes.
Why are the latter good? They have a huge service life, they are able to let steam out. Roofing membranes are easy to install and, subject to technology, form an excellent waterproof coating.
The inversion method, when the thermal insulation layer is located on top of the waterproofing material, which here also performs the function of a vapor barrier. This the best option for the installation of operated roof structures. The cake of a flat roof made in the inversion way will be different depending on what the roof is used for (pool, pedestrian zone, lawn, park, etc.). But in any case, over concrete base a monolithic screed is made to level its surface. The next layer is waterproofing material, which in the future turns out to be reliably protected from the influence of any factors external environment. Then all this is covered with a heat insulator, on top of which, if, for example, the roof will serve as a pedestrian zone, it is laid on the sand-cement mixture paving slabs.
The flat roof of an underground car park can be made using the inversion method
In the design of any building with a flat roof, one of the mandatory items should be the plan of the roof of the flat roof. This is necessary not only to improve the aesthetic qualities of the structure, but also to increase the functional abilities of the future roof structure. Apart from accurate calculation number of all necessary materials the plan includes directly the technology of the work, the scheme of the drainage system, the features of the implementation of the ramping, ventilation and other points.
Horizontal ventilation in flat roofing
During the operation of the roof, damage to the vapor barrier layer is possible, which leads to moisture ingress into the insulation and its freezing in winter time. All this reduces the heat-insulating ability of the material. Therefore, it makes sense to design the roof in such a way that it is ventilated. The flat roof ventilation system is a whole system of aerators (metal or plastic tubes) located under the roofing membrane. The system has access to the roof in the form of umbrellas protected by nets. The best places for aerators are the highest points on the roof.
A ventilated flat roof has a longer service life. Ventilation device
Roof drainage system
An important role in the drainage of water is played by the slope of the roof, which is recommended to be at least 2%. Even a slight slope can prevent the penetration of moisture through possible defects in the roofing.
For flat roof drainage system is of great importance. Its components are receiving funnels and pipes through which water is directed to the sewer, storage tanks or simply to the soil.
Water disposal can be carried out in two ways:
The number of funnels, their diameter and location, the diameter of the pipes should be calculated in accordance with the architectural features of the building, the operating conditions of the roof and the amount of precipitation. The funnels are usually equipped with filters that prevent leaves, small birds, etc. from entering the system.
Metal or PVC funnels and pipes are used as materials for the drainage system. Components made of polyvinyl chloride do not corrode, therefore they are more popular.
Roof funnels can be equipped with electric heating, thanks to which frost does not form on them in winter
The installation of a flat roof, from its design to commissioning, must be carried out by specialists of appropriate qualifications. Knowing only the basics of creating a roof structure without taking into account specific features can lead to errors, the correction of which will require considerable material investments. Therefore, the installation of a flat roof is the prerogative of professionals.