Construction and installation of a typical flat roof: a thorough overview of technological subtleties. Flat roof installation: coating technology

Flat roofs, their types and designs can be classified:

According to the purpose of the surface. Can be exploited or unexploited.
By installation method roofing pie. It can be traditional and inversion.
By type of construction. It can be attic or non-attic.
Ventilated and non-ventilated structures are distinguished separately.

Operable roof

A usable flat roof can be used as a parking lot, helipad, tennis court, swimming pool, green roof or just a terrace. In any case, it is necessary to calculate the possible load on the roof.

Load from operation (weight of a person, car, water in a swimming pool, etc.).

In some cases, the roof is subjected to a pressure of 20 tons per square meter.

Also, due to the design of a flat roof, it is highly susceptible to ultraviolet rays.

Together, these factors mean that the choice building materials For such a roof you need to approach it with special care.

The structure of the roofing pie of the roof in use is as follows:

Reinforced concrete floor slab.
Sloping layer. Made from slag, concrete, expanded clay, wedge-shaped mineral insulation and other similar materials. The top is secured with a concrete screed. Slope angle up to 3%. Necessary for high-quality drainage of water in the required direction. Sloping is always installed in front of the waterproofing to ensure water flow through it.
Leveling concrete screed .
Waterproofing. Made from bitumen, polymer, PVC materials and sealants. Roofing felt is often used, laid in two layers, and it is important that the joints of the upper and lower rows do not coincide.
Thermal insulation. Keeps the room warm in winter and cool in summer. Requires a careful approach to calculating thickness. In case of an error, condensation may form inside the room. If not an inversion type of roofing is used, but a traditional one, the insulation must be resistant to steam. If on the contrary, there must be resistance to water absorption.
Drainage layer. Considering technology flat roof, water should flow over the surface into drainage trays. But in other cases, moisture can get into the joints between tiles used as finishing paving elements, or be absorbed into the ground when using a green roof. To prevent the elements of the roofing pie from getting wet, a drainage layer is installed that drains water in the right direction.
Then everything depends on the type of roof being used. If this green roof– lay geotextiles that will prevent plant roots from destroying the roofing pie. If it is a roof terrace, or a parking lot, behind the drainage layer there is a concrete screed under the tiles or other finishing material.

Please note that when using traditional roofing, the order of the elements of the roofing pie changes. A vapor barrier is laid over the slope-forming layer, then insulation, and only then waterproofing.

The advantages and disadvantages of this method are discussed below.

Unused roof

An unused flat roof is distinguished by its efficiency. It is not designed to withstand any loads other than snow. This allows for a less careful approach to the selection of building materials.

The structure of a roofing pie of this type of roof is as follows:

Reinforced concrete floor slab. Instead, it is allowed to use profiled sheets with a high wave height, such as N-153 and N-158.
Slope formation layer.
Vapor barrier.
Thermal insulation.
Waterproofing.
Ballast layer of gravel. The thickness of such a layer should be from 10 to 20 centimeters. Necessary to protect waterproofing from exposure to ultraviolet rays and prevent fires.

Once again, we draw your attention to the fact that the layers of steam, heat and waterproofing can change places depending on the type of roof used.

Traditional roof

The traditional type of flat roofing has been used for a very long time. In this case, the roofing pie will look like this:

Slope formation layer.
Vapor barrier. Necessary to protect the insulation from steam emanating from the room. Otherwise, even in the case of one percent moistening of the thermal insulation layer, a significant increase in thermal conductivity occurs. Made from specialized vapor barrier membranes and films.
Thermal insulation. Almost all types of insulation can be used, even with a low percentage of moisture resistance.
Further on traditional drawing A layer of waterproofing should be laid on a flat roof. Please note that it must be of high quality, since it is absolutely not protected from temperature changes.

The advantages of a traditional roof are that it guarantees protection of the thermal insulation layer from getting wet. Firstly, this allows you to use the entire range of roof insulation materials. Secondly, the insulation will not lose its thermal conductivity characteristics, which means that a comfortable temperature regime will always be maintained in the room.

At the same time, this flat roof design compromises waterproofing. It is maximally susceptible to temperature changes, which leads to its accelerated aging. Also, the insulation does not protect the waterproofing from external force loads, which again negatively affects its service life. In general, this type of roofing is less durable and requires fairly frequent repair work.

Inversion roof

It is a more progressive type of flat roof device. It assumes the installation of the following roofing pie:

Reinforced concrete floor slab or corrugated sheet.
Slope formation layer.
Leveling concrete screed.
Primer for waterproofing, for better adhesion. During this process, the screed is carefully inspected for cracks and water bubbles. The cracks are covered with solution, water bubbles are removed.
Waterproofing.
Thermal insulation.
Next is either a drainage or ballast layer, depending on whether the roof will be used or not.

Inversion roofing has the following advantages:

Protection of waterproofing film from temperature changes. As a result, this extends the service life of the film in particular, and the service life of the roof in general.
The insulation redistributes force loads across the waterproofing in such a way that this does not affect it.
Extruded polystyrene foam, which is usually used as thermal insulation for this type of roofing, is cheaper than mineral wool used for traditional roofing.
The inversion design of a flat roof allows for more repairs, if it is necessary to replace or add insulation.

There are also disadvantages, which include:

It is permissible to use insulation materials only with closed cells to prevent them from getting excessively wet.
The need to install more complex design gutters.

Attic roof

The technology for installing a flat roof with an attic implies the possibility of using two types:

The attic roof is a lightweight superstructure, and attic floor acts as the main supporting structure.
The attic floor and the attic roof are independent of each other and are able to withstand force loads equally well.

The advantages of a roof with an attic are:

Possibility of constant monitoring of the tightness of the waterproofing layer.
The ability to regularly monitor the condition of the insulation.
The insulation can be laid after the roof has been installed.
The attic itself performs thermal insulation functions.

The disadvantages include:

Impossibility of mechanical snow removal, provided that the attic roof is used as a light superstructure. Instead, the attic is blown with hot, dry air, which ensures that the snow from above melts and gradually melts away.
This type of roof is more expensive.

Roofless roof

More popular is the roofless roof. She:

It costs less than an attic.
Easier to install.
Provides snow melting by conducting heat from the room.

A roofless flat roof also has a significant disadvantage:

There is no way to timely detect a violation of the waterproofing layer. This damage appears as a wet spot on the ceiling, making it impossible to determine the exact location of the leak.

Ventilated and non-ventilated roof

Roof ventilation is arranged between the insulation and the waterproofing layer. Thus, constant air circulation is achieved, which ensures constant dryness of the insulation. Used with the traditional type of roofing pie.

When installing ventilation, it is important to adhere to the following recommendations:

Height vent at least 1/30 of the width of the building.
The diameter of the hole is at least 1/150 of the total roof area.
Air inlets should be located lower than the outlets.
The holes are evenly distributed across the width of the entire building.

In turn, a non-ventilated roof does not require the creation additional elements roofs of flat roofs. But this somewhat shortens the service life of the thermal insulation material.

Flat roof - common architectural solution in civil, industrial and private construction. The construction of a flat roof has its own characteristics, but main principle is that the waterproofing layer must be a continuous carpet with certain technical characteristics. The design of roofing structures must be carried out in accordance with current SNiP.

Roofing pie structure

If you look at the structure in cross-section, this type roofing is a multilayer structure, which includes:

The base of a flat roof can be reinforced concrete slab ceilings, or metal profile construction. Depending on the type of base, the material for the remaining components of the roofing cake and methods of its installation are selected.

The vapor barrier layer is made of roll or bitumen materials. It prevents the penetration of moisture from the premises into the thermal insulation layer of the roof structure.

A wide range of materials are used as insulation for flat roofs, including:

mineral wool;
expanded clay gravel;
polystyrene foam boards;
cement-sand screed.

The waterproofing layer is traditionally made from roll materials on a bitumen basis. Special mastics or a PVC membrane can also be used.

A waterproofing carpet must have a certain elasticity in order to withstand mechanical deformations of the base and temperature changes.

The structure of the pie depends on functional features roofs. The following types of roofing differ:

Flat roof slope

According to SNiP, when installing a flat roof structure, it is necessary to provide for its slope of 1-4°. This design of flat roofs avoids the accumulation of water on the surface of the covering. It is not only prolonged stagnation of water in certain areas that is dangerous for waterproofing. Severe deformation and destruction outer covering roof damage is a consequence of repeated repetition of the process of freezing and thawing of accumulated moisture. Can be used to slope the roof various materials. The choice depends on their technical characteristics and installation features.

Lightweight concrete with loose polymer filler (in particular, extruded polystyrene) is one of the popular materials. It is quite easy to install, and the resulting structure is highly durable. But the use of this material for leveling should be considered at the building design stage, since the significant weight of the concrete used increases the load on the floor, walls and foundation of the building.

Has similar characteristics lightweight concrete with perlite or expanded clay filler. This material is cheaper, but its weight is even greater, and the resulting roofing cake is less durable.

The installation of a flat roof can be carried out using monolithic insulation, allowing for slope. In this case, it is mounted on the prepared surface sheet material(mineral wool, expanded clay sheets, etc.). Fastening can be done with strong, tenacious glue, which prevents the sheets from moving over time. Dowels with a plastic spacer can also be used - it is advisable to exclude metal contact with the base of the roof so that the roofing cake does not have cold bridges.

The most labor-intensive is the installation of a roof using bulk materials for deflection. Difficult to pour concrete layer bulk insulation(expanded clay or perlite), observing the required angle of inclination of the roof plane, since the granules can move.

An effective, but expensive option for degrading is laying foam concrete followed by applying a layer of fiber-reinforced concrete. A cake with such a heat-insulating layer is designed for long-term use. This technology requires the involvement of experienced specialists.

In accordance with SNiP, the slope of the roof is made towards the water intake funnels (if there is an internal drainage system), or towards the water intake gutters of the external drainage system, which must be mounted under the roofing carpet or on external wall building.

Roofing units

To ensure that the roofing pie is reliably protected from external influences, Special attention should be given to the places where it adjoins building structures– parapets, walls, pipes, external parts ventilation systems etc. There are various nodes of a flat roof, first of all, this is the node:

adjacencies;
overhang;
passage through the roof.

The units are installed on a reinforced concrete base in places where the roofing pie meets the vertical structure with a cut. Manufacturers of roofing materials often develop their own systems, which may have certain design features.

The unit must ensure the tightness of the joint and its thermal protection, therefore the installation of the units should be treated with the utmost care.

Installation of an unused flat roof

The most common design is the traditional one. soft roof. In cross-section, it consists of a load-bearing base slab, a vapor barrier layer, thermal insulation made of sheet mineral wool and a waterproofing carpet made of rolled bitumen-containing material. The advantages of this design include low cost and simple installation.

More practical non-exploited roofs are made using modern materials. PVC membrane waterproofing is very popular. Its installation can be carried out in any season, since the membrane is resistant to low and high temperatures. In addition, if the thermal insulation layer has managed to accumulate moisture during the installation process, the membrane allows it to evaporate. At the same time, the material has high water-repellent properties. In the process of installing the panels into a single whole, special welding equipment without an open flame is used.

Covering an unused flat roof can be done using mastic. This is a liquid material that is applied on top of a rigid, even thermal insulation layer. The mastic is made on the basis of elastic, hydrophobic polyurethane resins. Outdoors, after a certain time after application even layer, it polymerizes to form a continuous rubber-like membrane. The installation of such waterproofing allows you to reliably protect the roofing pie from moisture penetration.

A popular technology is the use of built-up waterproofing. This affordable option in terms of price and quality ratio - the durability of such a roof is from 25 years. A bitumen-polymer material based on a fabric that is not subject to rotting creates a super-strong waterproofing layer. Using this material it is possible to install serviceable roofs.

Construction of a serviceable roof

This flat roof design is much more expensive to install, but makes it possible to profitably use additional space. Today this type of roofing is widely in demand for equipment sports grounds, green areas, cafes, parking lots, etc. Installation of a reinforced roof is also necessary if heavy objects, including equipment, are to be installed on the roof. In accordance with SNiP, the roofing structure must withstand uneven high loads, that is, not deform in limited areas. The section of a flat roof in use differs from the usual one in the presence of a rigid base or a special screed on top of the waterproofing layer. This coating prevents the waterproofing carpet from being pushed through with its subsequent destruction.

Features of inversion coating

The structure of an inversion roof is fundamentally different from other types of roofs. When arranging it, first of all, a waterproofing layer is mounted on the base. In cross-section, the roofing pie looks like this: base slab, waterproofing, insulation, drainage layer, geotextile. This design allows you to protect the waterproofing material from the destructive effects of ultraviolet radiation, temperature changes, and mechanical damage. Geotextiles, in turn, provide protection for the insulation. Used as an outer layer paving slabs. Such a roof can withstand high loads, including use as a parking lot.

It is required to approach the installation of the waterproofing layer as carefully as possible, since in order to correct errors it will be necessary to open the ballast layers.

The installation of a traditional roofing structure can be done independently, but for the installation of flat roofs using modern materials and technologies, it is recommended to involve specialists who have the necessary equipment.

Flat roof installation: design and components

The device of a flat roof and its design. The main components and composition of the roofing pie in section. SNiP for the structure and slope of flat roofs

Flat roof installation

Many people associate a flat roof with urban high-rise buildings. And very few people draw in their imagination Vacation home with a flat roof, which combines saving precious space and the possibility of creating luxurious places to relax on the roof.

Flat roof pie.

In the age of modern building materials and new technologies, it is possible to successfully build private houses with a flat roof, without fear of the surprises of our unpredictable climate. But the full extent of pleasure from a flat roof can only be experienced when the builders and the customer himself listen carefully to the advice of a specialist in installation technology and the selection of the necessary components of the roof structure. Only under such conditions will a flat roof serve for a long time for more than one generation of the inhabitants of the house, without requiring additional costs.

What are the advantages of flat roof designs?

Until recently various designs and the parts for installing a flat roof were either very expensive or not reliable and functional enough, which did not at all benefit the popularization of roofs of this type, especially for private developers.

However, life experience proves that, being under the influence of stereotypes, we are too biased towards many problems, as a result of which we do not always judge things objectively. The main thing is from many existing options choose the most adequate and correct one to avoid mistakes.

According to architects, buildings in the spirit of constructivism, which brings a minimum of details and simplicity of design, are now becoming fashionable again. As a consequence, in better side The attitude of customers towards flat roofing is changing. In Europe, the design of flat roofing houses is called fashionable architectural feature project. A house with a roof without slopes looks more modern.

Flat roof installation diagram.

Until recently, a flat roof was a complete taboo for most consumers. According to some, it was simply tasteless, others were afraid of heavy precipitation in the form of snow, and still others believed that a flat roof was an undertaking that required prohibitive financial costs. Nevertheless, experts cite a lot of obvious advantages for buildings with this design:

In most cases, a flat roof is equipped as a green recreation area.
Saving material, because the area of the flat coating less area pitched with the same architectural basis.
Laying a flat roof is much more convenient than a pitched roof - it is easier to install the covering under your feet rather than in an unsafe position at a high altitude.
Maintaining flat roofs is not an extreme mountaineering activity, but rather a routine procedure.
Plus, the design of flat roofs makes it possible to get additional area without increasing the outline of the structure.

By the way, in developed countries, the possibility of using a flat roof is most relevant in megacities. Here, the problem of ecology has increasingly come to the fore, and therefore raising elements of gardens, parks, vegetable gardens and lawns from the ground to the clouds has become a very popular thing. And the most important thing is that if you want your flat roof to be reliable protection, it must be properly installed using durable modern building materials.

Components of a flat roof

Typically, a flat roof is based on a load-bearing base (it can be a reinforced concrete slab or profiled a metal sheet), on which heat-insulating material is laid over a vapor barrier layer, which is protected from precipitation by a waterproofing layer.

Scheme of an inversion flat roof.

It is characteristic that all components of the roofing “pie” are of equal importance, and if at least one of them is unsuitable, the entire structure will be damaged. The basis for installing a flat roof is A complex approach, which consists in determining the type of coverage and implementing the best constructive solution when considering all operational and technological properties, such as fire resistance, water resistance, ease of maintenance, labor costs during installation, aesthetic qualities, etc.

Specialists pay special attention to sealing seams, choosing fastening methods and elements, arranging technological components of the coating (junctions to parapets and pipes, drains, corners, superstructures, etc.) and performing through holes. And it goes without saying that the operation of the roof will not depend on any damaging factors if the various components of the structure are made of impact-resistant and weather-resistant materials that are resistant to corrosion processes and exposure to UV rays. Exclusion of at least one detail from common system is fraught with the most undesirable consequences.

Depending on the type of waterproofing, it can be glued, mechanically secured, or loosely laid. Much attention should be paid to the quality of fasteners and the method of their installation, especially for materials that are laid to the base of the roof with mechanical fastening.

If the rules for laying roofing are neglected, the following undesirable consequences may occur:

Breakdown of waterproofing by strong gusts of wind.
A loss bearing capacity foundations due to electrochemical corrosion in the “incorrect screw + corrugated sheet” system.
A clogged or frozen funnel, causing the roof to fill with moisture and leaks.

The roofing “pie” consists of the following layers (from bottom to top):

Insulation of a flat roof

Types of flat roof insulation: one, two and three layers.

The base of a flat roof is a load-bearing slab made of monolith, reinforced concrete or corrugated metal sheet. On top it is covered with a vapor barrier material, which protects the insulation from water vapor, thus preventing it from swelling from getting wet and ensuring the preservation of all properties. After this, thermal insulation is installed on the roof, which, in turn, is covered with a waterproofing carpet to protect it from precipitation.

For a flat roof, there are one- and two-layer thermal insulation systems. Nowadays, a two-layer system is more often used in construction. It works like this: the bottom layer, 70-200 mm thick, is assigned the main function of thermal insulation, while the top layer, which is 30-50 mm, is responsible for the redistribution of mechanical loads. Despite the smaller thickness, the second layer is more durable and has a higher density. This distribution of flat roof covering layers makes it possible to significantly reduce its weight and, thereby, the load on the floors. The insulation must meet the following requirements:

Low thermal conductivity and water absorption.
Fire safety.
High vapor permeability.
Compressive and peel strength of layers.

Drainage device

Diagram of a drainage system on a flat roof.

When installing roofs, it is very important to ensure the free escape of wet vapors from the roof covering. Necessary elements ventilation accessories are modern roofing accessories. As a result of human activity, water vapor is continuously generated inside the building. Due to the convective process and diffusion, it rises upward and, when cooled, condenses in the space under the roof. This process is especially intense in winter time. It negatively affects roof elements - both wooden and metal. If too much condensation accumulates, wet spots form on the ceiling and mold develops. In addition, moisture accumulating in thermal insulation material, reduces its properties, which leads to increased costs for heating the room. To avoid such situations, you need to take care of the proper removal of moisture from the outside of the building.

This task is best accomplished by special roofing components - a roof fan, otherwise called an aerator. The aerator consists of pipes different diameters made of plastic or metal, which are covered with umbrella-shaped caps.

The operation of the aerator is based on the pressure difference caused by the flow air masses. Its design allows moisture vapor to be removed from under the roofing without damaging the latter.

On flat roofs, aerators are placed evenly over the entire surface in the most high points roof plane at the junction of thermal insulation boards with each other. It is advisable to install aerators at the same time as the roof itself. Otherwise, the cost of installing ventilation increases significantly.

There are a large number of components for installing a flat roof. The need for their use is determined by the design of the roof. For example, in Western countries, much attention is paid to equipping roofs with natural smoke removal devices, which enable people to safely leave the building in the event of a fire.

The reliability of the roof also depends on its slope. There are no completely flat roofs, because to drain water you need, albeit a very small, slope. For a flat roof it is measured as a percentage.

It is not advisable to install roofs with a slope of less than 2 percent. The most the best option is a slope of 2.5 percent. In this case, the structure is freed from water in a short time, providing more comfortable conditions for the functioning of the roofing material. With a good slope, even a small defect in roofing will be insignificant.

One more important element roofs are gutters that “carry away” moisture and snow along a given route. On a flat roof, an internal drainage system is most often installed. Special located on the roof surface drainage funnels or fittings effectively drain water during heavy rainfalls, eliminating roof flooding. Their location and quantity must be determined taking into account the design rules for these structures and construction requirements for the design of drains and sewerage systems for buildings. The required number of funnels on the roof depends on its operating conditions, architecture and amount of precipitation. The funnel comes with a special filter that protects the drain from foreign objects getting into it. To prevent the water in the drain from freezing, the mouths of the funnels are equipped with special thermal cables, which guarantees rapid drainage of water at any time of the year.

External drainage is more often used as drainage from a flat roof in private houses, because the internal one is more suitable for installing flat roofs of large industrial buildings. External drain usually performed using overflow windows, which are installed in the parapet along with roof storm drains. Ideally, self-regulating thermal cables should be used in this case, since the storm inlet and overflow window, by virtue of their design, winter period susceptible to icing.

When choosing a drainage system, due attention should be paid to the choice of structural material. For example, products made of PVC (polyvinyl chloride) are less susceptible to icing than metal ones.

Flat roof design

The flat roof design is a simple and very profitable option for home improvement. It is easy to maintain and opens up a lot of new possibilities.

Design and installation of a typical flat roof: a thorough overview of technological details

The apparent simplicity of a flat roof often misleads novice home builders. The elementary configuration gives rise to thoughts about the efficiency and low cost of construction. Minimum number structural elements is capable of dulling the vigilance of independent performers who are ignorant of the intricacies of the roofing business. In reality, installing a flat roof requires scrupulous adherence to the rules unique to it, guaranteeing the flawless operation of the structure and long-term operation.

Specifics of flat roofs

Flat roofs are a separate category of roofing structures that do not require the construction of a rafter frame. Purely visually, it is a ceiling that rests directly on the walls of the building. Due to the absence of slopes, a flat roof does not upset the windage that occurs under the influence of gusty winds. However, its configuration does not contribute to the rapid removal of snow deposits from the surface.

The load from the snow is not transferred to the rafters, as in standard pitched systems, but presses directly on the walls of the building. Therefore, it is strongly recommended to equip houses with flat roofs in regions with insignificant amounts of winter precipitation and high wind loads.

In regions and districts of the fatherland located in middle lane and further north, flat roofs are used mainly in industrial construction. Private owners install them over one-story extensions, garages, and household buildings. For an independent craftsman, a flat roof over a shed or shed is an excellent option to practice as a roofer.

Briefly about the design of a flat roof

It is customary to call roofs flat, the only conditional slope of which is located to the horizon at an angle from 0º to 1.5º, or otherwise up to 2.5%. However, a number of technical sources call systems with a slope of up to 5º flat, a percentage value of up to 8.7%. Even roof structures have a slight slope, creating a clearly horizontal impression. It is formed to drain wastewater to drainage points or to an overhang.

Regardless of the steepness, the layers of a flat roof are arranged in a strictly defined order:

Vapor barrier covering the base. It is necessary to protect the insulation from the penetration of household fumes.
Insulation laid in one or two tiers. Required to prevent leakage of heat waves through the upper ceiling, used exclusively in insulated systems.
A screed created when the thermal insulation is insufficiently rigid or when there are no slopes for drainage.
Waterproofing that protects the insulation and ceiling from the destructive effects of atmospheric water. It is laid with a continuous waterproofing carpet.
Finish coating, giving the building an aesthetic appearance.

The brands of waterproofing materials currently supplied to the market successfully perform the functions of finishing roofing. These include numerous rolled and mastic bitumen, bitumen-polymer, and polymer varieties. Most of them are laid in one layer.

Due to the slight slope of flat roofs, the use of piece materials in the arrangement is contraindicated, because multiple joints between elements create the risk of leaks. It is undesirable to use large sheet metal due to the harmful effects on the material of water stagnating on a flat surface during periods of heavy rain and snowmelt.

When using old, well-known roofing felt types of roll coatings finishing roof arranged in 4 or more layers, the lower of which play the role of waterproofing. A mastic or emulsion self-leveling roof is constructed in a similar way: the emulsion or mastic is applied in five or more layers, alternating pasty or creamy material with layers of fiberglass or polyester.

To lay and fix the above elements of the roofing pie of a flat roof, a rafter structure is not required. They are laid directly on the base, which can be a ceiling, a screed created on top of it, or the upper plane of the attic structure. To fasten PVC-coated systems, adhesive, mechanical or ballast methods are used. Self-leveling roofs are applied according to their name, the descendants of roofing material are fused or glued.

Unlike their stingy counterparts in flat systems there are no lathing creating ventilation ducts for washing the insulation with air currents. Therefore, the selection of design solutions, materials and their sealed installation should be approached with due respect and focused attention. A ventilated flat roof is only possible when lumber is used in the construction of the ceiling and attic. The latter option is most often used in private construction.

Types of floors used

The construction of flat roofs is carried out on floors made of reinforced concrete, wood and profiled sheets. The choice of material for the ceiling depends on the purpose of the roof structure, the size of the span to be covered, possible operation and ease of maintenance.

One of the significant advantages of a flat roof is the possibility of organizing a used area on it: a place for relaxation, a solarium, a green area, a terrace, etc. Of course, the overlap for such objects should be quite powerful. In addition, in the flat family there are roofs that do not involve incidental use, and therefore do not require a thorough covering.

Depending on the operational criteria, flat roofs are equipped with:

Reinforced concrete floors, if it is planned to organize useful space above a long-span brick or concrete box.
Steel profiled flooring metal beams, if an unused roof is being constructed that covers spans of any size between walls made of brick or other artificial stone.
Wood panel made from boards 40-50mm thick, up to 180mm wide. It is used to cover medium and large spans wooden buildings in case of planned operation.
Wood chipboards and fibreboards according to wooden beams, used to cover small spans of wooden and stone buildings. They are used if an unused roof is being constructed.

Lumber is a leader in the construction of low-rise residential buildings, because... are ahead of concrete and steel competitors in terms of environmental criteria. Note that wood is inferior in fire resistance. True, fire hazard in low-rise housing construction is not recognized as a decisive factor. In addition, to combat it there are effective means- flame retardants.

Roll coverings in flat systems with wooden base Then they serve only as waterproofing, on top of which plank or parquet flooring is laid. If a flat roof is being erected over a brick or concrete box, it is wiser to lay a reinforced concrete floor for the object in use or corrugated sheet for the one not in use.

The overlap of a flat roof does not always serve as the basis for its construction. In some cases, an attic structure is erected above the ceiling, which can be either a canopy over the base with a roofing pie, or the base itself. Roofing pie structure attic roofs similar, but the layers may be located at different levels.

With or without an attic?

The unconditional inclusion of flat roofs in the category of non-attic structures is fundamentally incorrect, although it has strong technical justifications. They may or may not have attics, although they are not formed by installing rafter legs.

Depending on the availability of the attic flat roofing systems are divided into:

Without roofs, the elements of which are structurally combined with the ceiling. They are completely devoid of an attic superstructure, which significantly reduces the budget allocated for their construction.
Attics with an attic superstructure above the ceiling. The minimum height of the superstructure is 80cm. The construction of attic structures for flat roofs is more expensive, but by separating the floor from the roof, the service life of the system increases at least three times.

In addition to the budget cost, one of the advantages of atticless systems is the ability to eliminate mechanical cleaning. The snow will melt due to the heat emanating from the room. Due to spontaneous precipitation, it is not advisable to equip flat roofs without an attic with parapets. It is enough to install railings, which further reduces costs. The disadvantage of the absence of an attic will affect when identifying the causes of leaks, because the condition of the thermal insulation and other layers of the cake cannot be controlled.

The attic is an air chamber between the ceiling and the roof. This is a kind of buffer that compensates for the difference in temperatures outside and inside the premises. The presence of an attic reduces the likelihood of condensation forming, and as a result prolongs life cycle structural elements. Elements of the attic system are always available for observation: the simplicity of inspections is difficult to overestimate.

An undeniable advantage is the possibility of installing insulation after construction, which prevents it from getting wet. The disadvantage of flat roofs with attics is their high cost and the need to regularly clear snow.

Despite the mythical cheapness of atticless systems, this is a very complex structure that requires experience from the builder, careful selection of materials and adherence to technologies for their hermetic connection. For an independent master It is better to give preference to roofs with an attic, if their construction is not excluded by the design decision.

Subtleties of water drainage

Flat roofs must be equipped with drainage systems that all year round are obliged to freely drain water at an operational pace. Systems come in external and internal types.

The optimal type of drainage system is determined by the climatic conditions of the construction area:

External drains are constructed when constructing flat roofs in the southern regions, where icing of drains in external pipes is excluded. According to the external type, water is discharged to pipes located outside along the perimeter of the building or to a gutter attached along the lowest overhang. In the middle zone, only flat roofs of non-residential buildings are equipped with external systems.
Internal drainage systems for atmospheric water when installing flat roofs are built in the middle zone and to the north. In accordance with the internal layout, water along slopes or obliquely installed pipes transported to water intake points in the center of the roofs. Drainpipes transporting water to the sewer system are laid inside the building, but isolated from the premises.

Despite the impressive cost, the construction of an internal drainage is mandatory for temperate and northern latitudes, and in the south its construction is irrational.

Installation of slopes for drainage

If the slope of the flat roof was not provided for during construction old roof and the construction of a new one, it must be created. The roof must be inclined towards the water intake funnels by at least 1-2%, approximately 1º. Those who want to know how to correctly make a slope on a flat roof and what material is best to use to form slopes should adhere to the following recommendations:

Slopes on reinforced concrete slabs are made mainly using a screed, or a screed is combined with preliminary filling of expanded clay or laying slab insulation. On an unused roof, it is enough to lay wedge-shaped mineral wool slabs, produced specifically for forming slopes.
Slopes on corrugated floorings are formed using metal structures or wedge-shaped insulation.
Slopes on wooden bases are specified constructively, but if they are not included in the project, it is possible to use wedge-shaped mineral wool.

Due to their serious weight, screeds are poured only for exploited roofs erected above concrete floor. On a concrete slope, the recommended thickness of the screed is 10-15mm, on rigid insulation panels 15-25mm. For backfill thermal insulation, the screed is poured with a layer of 25-40 mm and used metal mesh for reinforcement.

Nuances of organizing ventilation

Normal ventilation can be done in the only way - by installing battens on the floor beams; similar methods are dictated to us by the construction schemes of pitched structures. It is clear that the above method is only valid for wooden options, and for roofs by concrete base or it is unacceptable to the professional sheet.

The ventilation system for roofing pies on concrete and corrugated sheets depends on the type and characteristics of the finishing coating. PVC roofing is capable of spontaneously transmitting excess moisture from the insulation to the outside, so there is no need to install ventilation ducts between it and the insulation.

When using bitumen and bitumen-polymer materials, it is mandatory to install weather vanes over the entire area of the flat roof. The spacing of these devices depends on the thickness of the insulation. Vane aerators ensure the removal of moisture from the under-roof space to the outside.

Algorithm for constructing a flat roof

Let's consider the common case of constructing an unused flat roof over an extension on a suburban site. It will be equipped with an external drain. Insulation of the structure is not expected, because climatic conditions and the purpose of the room below do not require thermal insulation.

The sequence of constructing a cold flat roof on wooden beams:

We mark the installation step of the floor beams, for which we will use a board 40-50mm thick. Installation step from 50 to 70cm: choose it based on the actual length of the walls. There should be equal spaces between the beams.
We place the board on its edge, fasten it with nails or corners. The required slope to the lowest overhang is created spontaneously due to the difference in the height of the box walls.
We lay a continuous flooring made of OSB boards, moisture-resistant plywood or other similar material on the beams. There should be a gap of 3-5mm between the plates to compensate for thermal expansion. They are fastened with galvanized self-tapping screws or rough nails.
We install a wind board along the perimeter of the roof, the edge of which rises 5-7 cm above the plane of the future roof so that a small side is formed.
We nail a wooden strip with a triangular cross-section or a regular plinth to the sides. These are fillets necessary to drain water from the edges of the roof.
All wooden elements We treat with antiseptics and fire retardants. After they dry, apply primer.
We lay an additional waterproofing carpet in a strip along the perimeter on top of the fillets. In the case of junctions and pipes passing through the roof, additional waterproofing is applied to the adjacent vertical planes similarly, i.e. on top of the fillets.
We fuse the finishing roofing material selected for installation, heating its back side with a gas burner.

In the case of thermal insulation, a vapor barrier layer is first laid out on the base, the edges of which are placed on the vertical sides. Insulation boards are placed in a kind of pallet formed by the vapor barrier, the thickness of which is calculated in accordance with the requirements of SNiP 02/23/2003. Thermal insulation is attached to the base with self-tapping screws and telescopic devices.

Then waterproofing is laid over the sides and junctions. If one of the latest brands of rolled waterproofing material is chosen for the installation, then it will also be entrusted with the responsibility of the finishing coating.

An impressive range of new polymer-bitumen and polymer coatings laid in one layer, which helps to save the installer’s effort and construction costs. Among them there are materials that are extremely preferable for home craftsmen and do not require the use of gas burner. They are glued to mastics or using the back adhesive side, fixed mechanically, laid loosely and loaded with ballast.

Video for DIYers

A video collection will help you consolidate information about the difficult task of constructing flat roofs:

We hope that the information we presented will help future roofers who decide to practice with their own hands in constructing a not-so-simple design.

There are many conditions for the proper construction of a flat roof, but they must be observed for ideal operation and long service. Information about the intricacies and specifics of constructing a flat roof will help not only determined craftsmen, but also owners of country estates who resort to the services of third-party construction organizations.

Some of the materials for writing this article were taken from here:

But for me, a flat roof is the best option, it is preferable to use a roof slab made of expanded clay concrete grade 100, and also do not forget about thermal and waterproofing. Still, a flat roof is more aesthetically pleasing to me. And the fact that in winter you will need to constantly remove snow, I think that this must be done from any other roof too. But if you consider that the material is concrete and plus protection, then when performing this necessary measure there is no risk of structural damage.

Flat, but still with an insignificant slope of a couple of degrees, or rather. A flat roof to some extent makes it possible to minimize costs. Flat roofing is utilitarian. Temperature insulation and water protection are also excellent. The use of rolled materials creates the possibility of savings, ease and speed of installation, and a good degree of protection from weather conditions.

Installation of a flat roof: design, device, installation, layers, elements

The installation of a flat roof requires strict adherence to the rules for installing elements and a clear arrangement of layers laid when installing rafter-free structures

Still an unusual decoration country cottages– flat roof. It is believed that flat roofs are intended only for urban development or industrial buildings. But that's not true. The roofs of houses in historical neighborhoods are often pitched. And a private house can have a flat roof.

Now we will look at what it is, what are the advantages/cons and how to make a flat roof with your own hands.

Types of flat roof

Structurally, flat roofs are divided into two main types: those on beams and those with a concrete slab at the base.

Flat roofs are never completely flat; there is still a slight angle (within a few degrees). This is necessary for water drainage. Otherwise it will stagnate on the roof.

Most often, internal drains are installed on flat roofs: funnels are mounted in the roof, risers from them pass through interior spaces. Funnels are placed on the lower part of the roof, at the rate of one riser per 150-200 square meters.

The waterproofing around the funnels is reinforced; cable heating is also recommended (so that the water in the riser does not freeze). If the roof is flat without a parapet, and the angle is decent (from 6 degrees) drainage system can be standard external, as for pitched roofs: gutter and pipes.

Roofs are divided according to functionality, roofing structure and type of coating. Here are a few main varieties:

The unused roof is flat. It is built solely for the sake of originality and saving material. Does not require structural reinforcement.

Operable flat roof. It can be used for any purpose, from placing an outdoor swimming pool to constructing a parking lot.

The type of floor depends on the intended purpose: it is obvious that for high expected loads, the base should be a concrete slab. But this does not mean that the entire building must be brick or concrete. For example, a flat roof in a wooden house can also be used. Of course, it cannot be used as a helipad, but setting up a solarium, laying out a garden or putting up a gazebo for tea drinking is fine. Of course, you can’t make a sparse sheathing, only a continuous one.

Traditional roofing. The classic design of the roofing pie: a waterproofing layer on top of the insulation, the base is concrete, for the outflow of water - expanded clay concrete (inclined screed).

Inversion roofing. Here the insulation lies on top of the waterproofing and protects it from damage. The floor can be finished with paving or ceramic tiles, and you can also plant a lawn here. A mandatory requirement for an inversion design is an angle of 3-5 degrees.

Roofs can be attic or non-attic. Both types have their advantages: the presence of an attic allows you to place all the necessary communications on it (ventilation pipes, expansion tank heating, etc.), a roofless roof can be made usable.

One of the options for a non-attic design is a flat combined roof: the attic floor is combined with the roof, the lower side is the ceiling in the living room.

note

The design of these roofs differs from simple attics; they cannot be used for use.

When the height of the house is ten meters or higher, as well as on roofs in use, a parapet must be installed. For those in use - no less than 1.2 meters.

If the roof is not in use and the cottage is not high, you can make a flat roof without a parapet or install fencing bars instead, or even do without them.

General structure of a flat roof

It is obvious that roofs used for different purposes will have different structures:

When constructing a swimming pool, pay special attention to waterproofing;

“Green” roofing is also a thorough waterproofing plus soil filling, etc.

The most common covering is flat roofing. It is cheap, simple and high speed installation, excellent waterproofing. The cheapest material that can be used to cover a flat roof is roofing felt.

Disadvantages of rolled materials (and roofing felt in particular) - low durability, low mechanical strength. For “high traffic” roofs, tiles are preferable.

A flat roof made of and a flat roof made of corrugated sheets can only be made in a non-operational version and if there is required slope. When choosing a material, you need to read the instructions for the model: some types of corrugated sheets and metal tiles allow installation on roofs with a slope of less than 11 degrees.

Some brands of corrugated sheets can also be used as a base for an unused roof, instead of plywood or a concrete slab.

There are other coating materials for unused roofs:

Polycarbonate;

Pros and cons of flat roofs

Advantages:

Original look. Flat roofs on cottages are rare.
Possibility of operation.
Flat roof – easy installation and savings on materials. But it depends on how you plan to use the roof. Otherwise, construction will cost even more than an expensive pitched roof made of ceramic tiles.
Laying covering, maintenance, and repairs on a flat roof are easier to perform than on a slope.
Flat roofs are wind-resistant, pitched roofs have windage.

Minuses:

A flat roof leaks more often than a pitched roof. Constant monitoring of the condition of the waterproofing layer is necessary.
The need to clear the roof of snow.
Rolled flat roofing requires more frequent repairs and replacement of the covering than metal profiles, tiles and other pitched ones.

So which roof is better, flat or pitched? Purely a matter of taste.

Building a flat roof

Let's consider the option when a corrugated sheet is used as the base of the roof:

1. Sheets are laid on the beams (rafters). The pitch between the rafters depends on the profile. For example, for load-bearing profiles with a corrugation height of 6-7.5 centimeters (H60, H75), the step between the beams is 3-4 meters.

2. Laying a vapor barrier film. The film is laid with an overlap, the joints must be sealed with mounting tape.

3. Thermal insulation. Mineral wool slabs are usually used for this purpose. Please note that the depressions of the corrugation also need to be filled with insulation.

4. Waterproofing. Polymer film is suitable for this purpose. If the insulation is mineral wool, you can also use built-up waterproofing, because cotton wool is a non-flammable material.

5. Finish coating. You can also use a welded one. The roll is slowly rolled out on the roof, heating it with a burner along its entire length. The deposited coating is pressed against the roof and smoothed.

6. On flat roofs, a fused roofing can be laid in several layers.

In other cases, a flat roof on wooden beams is arranged more traditionally: a solid plywood or OSB sheathing is nailed onto the beams, a roofing pie is laid (vapor barrier + basalt wool), direct the waterproofing layer and roll roofing.

If you are interested in a flat roof with a more complex structure, contact us: we will complete roofing of any complexity quickly and at an affordable price.

This option for arranging the upper part of a building is used, as a rule, in the construction of “high-rise buildings”, as well as various administrative, industrial, warehouse and some other buildings: pavilions, showrooms and the like. Despite the fact that a flat roof has a number of disadvantages, this does not reduce the popularity of such a design, including in private housing construction.

Advantages of flat roofs

Firstly, the installation of a flat roof can be carried out independently, rather than inviting assistants or hiring professionals, as, for example, when constructing a roof with a complex configuration (hipped, etc.). Consequently, you will not have to pay for their work (we are not talking about large areas where it would be problematic to cope alone).

Secondly, the construction of such a roof provides significant savings both in materials (money) and in time (the covering area is much smaller than with a pitched roof). You won’t have to make numerous calculations or order a project (which won’t be cheap), assemble a complex system of rafters, install jibs, extensions, and so on. In addition, there are no restrictions on the choice of type of roofing.

Third, a flat surface is much easier to maintain and repair, which also provides significant savings in the long term.

Fourth, the ability to choose arrangement options. A flat roof can either serve only as a traditional “cover” for a house, or be used (inverted). For example, greenhouses are mounted on it, summer gardens, solariums and the like. Even helipads are being built. This fully compensates for the inconvenience due to the lack of attic space.

Flaws

Increased requirements for waterproofing. Since the roof is located horizontally, water falling in the form of precipitation will stagnate on it. You can use , for example.
Debris will constantly accumulate (for example, fallen leaves), so such a roof will have to be serviced more often.
Lack of attic (attic) space

What to consider

The maximum load that the roof will experience (for truss structure). This means the weight of the frame itself, roofing material, layers of insulation and insulation, as well as possible snow cover. In addition, you need to count on the fact that the roof must withstand the weight of people who will subsequently walk on it.
The purpose of the building and the possibility of further use of the surface (for example, equipping a terrace). Depending on this, the type of overlap is determined.

Work technology

The simplest version of a flat roof is when reinforced concrete slabs are laid (for example, a garage, shed). Everything here is extremely simple. A so-called “layer cake” is arranged on the surface: vapor barrier, if necessary - insulation material, waterproofing layer. For the latter equipment they are most often used roll materials.

Insulation of a reinforced concrete slab can be done by pouring a layer of expanded clay and arranging it on top cement screed. Slag and some other materials are also used.

Traditionally, roofing material is used for waterproofing, which is covered with bitumen mastics. It is necessary to take into account that this material will last no more than 5 years, and then you will have to do repairs. It is more expedient to lay it as a “waterproofing” polymer materials eg membranes. Liquid rubber is also great.

Since the installation of slabs requires the use of special equipment, when independent device A flat roof can be equipped with a simple rafter system made of wood.

First of all on the upper parts load-bearing walls supports are laid - Mauerlats. The most commonly used material is timber. It must be taken into account that these structural elements must be rigidly fixed to prevent the possibility of their horizontal displacement.

Therefore, metal pins are first embedded along the entire length of the walls into their upper end surfaces. Their length is calculated so that after installing the mauerlats they rise above the beam by about 5 cm. Threads must be cut at their ends.

If the masonry is old, then a “ribbon” of concrete mortar. After this, in each wooden blank Pre-designed holes with a diameter slightly larger than the cross-section of the metal “fingers” are drilled. First, strips of roofing felt (or similar waterproofing material) are laid on the tape, and then Mauerlats. They are mounted on pins, and a washer is put on top of each and with the help of a nut the beam is securely fixed at the installation site.

Next, the floor beams are laid. It is necessary to take into account that the roof should protrude beyond the dimensions of the house by 50 - 60 cm (the required overhang). This will protect both the walls and the blind area from water flowing from it, as well as from raindrops.
Device load-bearing frame. Depending on the type, it can be either solid (boards, slabs) or cellular (lathing).

Vapor barrier.

Insulation. For flat roofs there is a nuance. The absence of an attic space deprives such a building of “ air cushion" above. Therefore, insulation is carried out both outside and inside. But at the same time, you need to take into account the weight of such material, since it is an additional load on the rafter system.

Waterproofing.

Roofing covering.

Finishing of overhangs.

This is only a general list of necessary activities. The technology for performing work on each item depends on both local conditions and the selected materials.

Any “wood” used in construction must be well dried. The moisture in its structure gradually “leaves” (natural shrinkage of the material), which leads to a change not only in the volume of the workpiece, but also in its deformation (for example, twisting).
Wood has two significant drawbacks: it burns and is susceptible to rotting. Therefore, before using it, all wooden parts of the structure are pre-treated with fire retardants and antiseptics. It is better to spend money on these products than to suffer from frequent repairs later.
When installing mauerlats, you need to constantly monitor their horizontalness using a building level. Otherwise, the roof will be skewed. If necessary, either the tape is leveled or a rigid lining is made under the Mauerlat.
To prevent stagnation of water on the roof, it is advisable to make it with a certain slope (approximately 3 0 - 5 0). As a rule, the decline goes towards the rear side of the building. To do this, the height of the front mauerlats increases, so the floor beams will lie with a slope.

The construction of a gable or hip roof is not always rational and advisable when it comes to outbuildings, industrial and commercial facilities, and sometimes private houses in modern style. High material consumption, complex rafter system make the construction of these structures an economically unprofitable, protracted undertaking. While flat roofing projects significantly reduce construction costs, are quick to build and suitable for almost any structure.

A house with a flat roof is reliably protected from increased wind loads. However, without slopes, it cannot quickly drain rain and melt water from the roof surface.

The situation is complicated by the fact that the surface of roofing materials has a rough structure, which does not allow moisture and snow to slide off freely. Therefore, a do-it-yourself flat roof must meet strict requirements building codes to waterproofing, slope and construction technology.

The structure of the roofing pie

Necessity high level protection from moisture makes it necessary to place roofing materials flat roof in layers, one above the other, forming a so-called “pie”. If you look at its cross-sectional structure, you can see the following layers:

Flat base made of concrete slabs or profiled metal sheets. It provides rigidity to the structure and bears the weight of the roofing pie, transferring it load-bearing partitions and, ultimately, the foundation. The base of the roof in use must be as rigid as possible.
Vapor barrier. A layer that is necessary to protect a flat roof from the penetration of vapors from internal heated rooms into the thickness of the insulation. When water settles on the thermal insulation in the form of condensation, it irreversibly reduces its insulation properties by more than half. The simplest vapor barrier is polyethylene film or bitumen-based coatings.
Insulation. For thermal insulation of a flat roof, backfill materials are used, such as expanded clay, perlite, slag, rolled materials, for example, mineral wool, and in the form of slabs, in particular polystyrene foam. By the way, insulation is used not only to regulate the temperature, but also to tilt a house with a flat roof. The main requirements for insulation are low hygroscopicity and thermal conductivity, light weight.
Waterproofing. A flat roof allows the use of roll materials for covering to protect against moisture: bitumen, polymer and bitumen-polymer. In addition to high waterproofing qualities, they must be resistant to temperature changes, elasticity, for a long time operation.

Types of roofing and nuances of their installation

The construction of a flat roof is determined by the design and nature of its use. Some types that require a special approach during construction include the following:

Roof installation for unheated buildings

If a flat roof is being built with your own hands for an unheated utility room, for example, a barn, gazebo, shed or outbuilding, the slope is organized using support beams.

They are installed at an angle of 3 degrees, which is 30 mm for each linear meter beam length. Then a base of unedged boards is laid on the beams, secured with nails or self-tapping screws.

Roofing felt, the most affordable material, is used as a waterproofing agent. It is produced and sold in roll form. The waterproofing is cut by cutting strips so as to lay them in the direction of the slope of the flat roof.

Strips of roofing felt are laid step by step with an overlap of 10-15 cm and fixed wooden slats or steel strips every 60-70 cm in the direction of the drain, so as not to block the path of flowing moisture. A flat roof of an unheated room can be easily installed with your own hands, even by one worker without the help of helpers.

Roof installation for heated structures

If they build a private house with a flat roof, which they plan to connect to the heating system, then the work takes place in the following order:

To build a house with a flat roof, the length of which exceeds 6 m, a beam with a cross-section of 150x150 mm or more, or a steel I-beam, is used to make support beams.

Monolithic concrete roofing

Another option for building a flat roof with your own hands is to use monolithic concrete. The process looks like this:

Leaning process

– arrangement of a small angle of the roof surface to organize drainage. Before building a house with a flat roof, it is better to decide in advance which drain you will install, internal or external, and make a drawing.

If provided, water should flow into water collection funnels using a slope, which are located 1 per 25 sq.m or more often. If you make an external drain, then moisture should enter the gutter. The slope is formed using the following methods:

A flat roof without proper slope is an unreliable shield between you and bad weather. Moisture that has no outlet will accumulate on the roof surface, causing roof destruction and leaks.