Flat roof options. The device of a flat roof and the technology of creating a roofing pie. Inversion roofing: reverse pie

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 homes in a modern style. High consumption material, a 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, the installation of a do-it-yourself flat roof must meet the strict requirements of building codes for waterproofing, slope and construction technology.

The structure of the roofing pie

The need for a high level of protection from moisture forces the roofing materials of a flat roof to be placed 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:

1. Flat base made of concrete slabs or profiled metal sheets. It provides rigidity to the structure, bears the weight of the roofing pie, transferring it to the load-bearing partitions and, ultimately, to the foundation. The base of the roof in use must be as rigid as possible.
2. 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.
3. 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.
4. 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 have resistance to temperature changes, elasticity, and a long service life.

Types of roofing and nuances of their installation

The construction of a flat roof is determined by the design and nature of its use. IN individual species, requiring a special approach during construction, the following are distinguished:

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 of beam length. Then a base of unedged boards, securing them with nails or 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 in stages with an overlap of 10-15 cm and fixed with 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. Flat roof 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 are building a private house with a flat roof, which they plan to connect to a 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:

Deflection 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.

Video instruction

A flat roof is a common architectural solution in civil, industrial and private construction. The construction of a flat roof has its own characteristics, but the main principle is that the waterproofing layer should 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 from rolled or bituminous 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 the functional characteristics of the roof. Vary following types roofs:

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 of the outer covering of the roof 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 leveling. It is difficult to pour concrete into a layer of 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 roof slope is towards the water intake funnels (if there are internal drainage), or towards the water intake gutters external system catchment, which should 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 of 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 is cut adjacent to vertical design. 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 traditional 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: high price and simple installation.

More practical non-exploited roofs are made using modern materials. Waterproofing made from PVC membrane 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 liquid material, which is applied on top of a rigid, even thermal insulation layer. The mastic is made on the basis of elastic, hydrophobic polyurethane resins. In the open air, after a certain time after being applied in an even layer, it polymerizes, forming 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 equipping 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 of the area. 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. Paving slabs are used as the outer layer. Such a roof can withstand high loads, including being used 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 parts for flat roofing 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 flat covering houses are 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:

1. In most cases, a flat roof is equipped as a green recreation area.
2. Saving material, because the area of ​​​​the flat coating less area pitched with the same architectural basis.
3. 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.
4. Maintaining flat roofs is not an extreme mountaineering activity, but rather a routine procedure.
5. 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 most importantly, if you want your flat roof to provide reliable protection, it must be installed correctly 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 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 the installation of a flat roof is an integrated approach, which consists in determining the type of coating 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, and installing technological units coverings (junctions to parapets and pipes, drains, corners, superstructures, etc.) and making 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:

1. Breakdown of waterproofing by strong gusts of wind.
2. Loss of the bearing capacity of the base due to electrochemical corrosion in the “wrong screw + corrugated sheet” system.
3. A clogged or frozen funnel, causing the roof to fill with moisture and cause 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 load-bearing slab, made of monolith, reinforced concrete or metal profiled sheet. On top it is covered with a vapor barrier material that 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 more high 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:

1. Low thermal conductivity and water absorption.
2. Fire safety.
3. High vapor permeability.
4. 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. Ventilation accessories are necessary elements of a modern roof. 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 the 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.

With this task the best way This is done 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 of 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 at the highest points of the roof plane at the joints thermal insulation boards together. It is advisable to install aerators at the same time as the roof itself. Otherwise, the cost of installing ventilation increases significantly.

Components for a flat roof a large number of. 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 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.

Another important element of the roof is gutters, which “carry away” moisture and snow along a given route. On a flat roof, an internal drainage system is most often installed. Special drainage funnels or fittings located on the roof surface effectively drain water during heavy rainfalls, eliminating flooding of the roof. 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 drainage is 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 simple and highly profitable option 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. The minimum number of structural elements can dull 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 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 traders hoist them over one-story extensions, garages, household buildings. For an independent craftsman, a flat roof over a barn or shed - great option practice as a roofer.

Briefly about the design of a flat roof

It is customary to call roofs flat, the only conventional 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.
• A finishing coating that gives the structure 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 construction 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 coverings, the finishing roof is 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, a flat roof is not needed truss structure. 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. For fastening systems with PVC coated use the adhesive, mechanical or ballast method. Self-leveling roofs They are applied according to their name; the descendants of the roofing material are fused or glued.

Unlike pitched counterparts, flat systems do not have sheathing that creates ventilation ducts for washing insulation 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 organization is planned usable space over 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, there are effective means to combat it - fire retardants.

Rolled coverings in flat systems with a wooden base then serve only as waterproofing, on top of which plank or parquet flooring is installed. If a flat roof is being erected over a brick or concrete box, it is wiser to lay a reinforced concrete floor for an object in use or a corrugated sheet for an object that is not in use.

The overlap of a flat roof does not always serve as the basis for its installation. 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. The structure of the roofing pie of attic roofs is similar, but the layers can 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 presence of an 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 formation, and as a result extends the life cycle of 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. It is better for an independent craftsman to give preference to roofs with an attic, if their construction is not excluded by the design decision.

Subtleties of water drainage

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

Optimal type drainage system determine climatic conditions 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 internal circuit Water is transported through slopes or inclined pipes to water intake points in the center of the roofs. Drainpipes, transporting water to the sewer, 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 the construction of the old roof and the construction of the 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 by wooden bases are specified structurally, but if they are absent 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 over a 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 this method is valid only for wooden options, and for roofs on a concrete base or corrugated sheet it is unacceptable.

The ventilation system for roofing pies on concrete and corrugated sheets depends on the type and characteristics 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 bituminous and bituminous polymer materials It is mandatory to install wind 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 suburban area. 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 it to the sides wooden slats with a triangular section or a regular plinth. These are fillets necessary to drain water from the edges of the roof.
• We treat all wooden elements 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 according to 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 a gas burner. They are glued to mastics or using the back adhesive side, fixed mechanically, laid loosely and loaded with ballast.

Video for DIYers

This video collection will help you reinforce 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:

And for me, a flat roof - 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 damage to the structure.

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

If previously flat roofs were made only on urban multi-storey buildings and were associated with constant leaks, today the situation has changed radically. These structures are used not only during construction multi-storey buildings, but also during the construction of prestigious private houses according to exclusive projects. Such changes became possible thanks to the emergence of completely new building materials and technologies.

Flat roofs are one of the many types of roofing, which has both positive and negative sides. The advantages of such roofs include the following characteristics.

1. Saving building materials and speed of construction. The effect is achieved through physical savings - the area of ​​a flat roof is much smaller than a gable roof. In addition, for this design there is no need to manufacture a complex rafter system with various purlins, supports, crossbars, mauerlats, etc. A small number of roof elements makes it possible to construct flat roofs independently without the involvement of expensive professional specialists.
   True, for this you should have initial skills in performing roofing works, understand modern technologies and materials. Otherwise, attempts to reduce estimated cost structures can cause large additional costs for unplanned repairs. And not only the roof itself, but also the interior of the buildings.

   

2. Possibility to use the roof as an exploitable one. On flat roofs you can equip winter gardens, places for recreation, flower beds, small areas for sports, etc. But in these cases, the roofs have a very complex structure and require a professional approach to all construction work.

   

3. Flat roofs make installation and periodic maintenance easier. Maintenance various engineering equipment: air conditioning and ventilation systems, solar panels, antennas, etc.

   

Unfortunately, such people have architectural structures and disadvantages.

We have listed the real advantages and disadvantages; each developer should carefully analyze them before making a final decision.

Types of flat roofs in private houses

Thanks to new materials and technologies, designers have been able to create several types of flat roofs with unique performance characteristics.

Flat roof type	Brief description of technical and operational characteristics
	The most commonly used, simplest and cheapest type of roof. It is most often found on commercial buildings; it is rarely installed on private houses.
	A very prestigious roof allows you to use the area to increase the comfort of living in the building. The construction of such roofs requires high-quality materials and special technologies. The roof in use is often inverted.
	It differs from the usual one in the arrangement of layers of the roofing cake. Waterproofing is done directly on the supporting base; this feature protects the coating from mechanical damage. Geotextiles, extruded polystyrene foam, another layer of geotextiles and a ballast layer are laid on top of the waterproofing. Geotextiles allow water to flow to the drainage system, and ballast prevents layers from being undermined by strong gusts of wind.

Important. The cost of flat roofs varies widely; some options can be several times more expensive than gable roofs.

Roofing pie device

All flat roofs in residential buildings must be insulated; the structures consist of several layers. Each of them performs its own function and is critical for the roof.

Base

Can be reinforced concrete or wood.

Professional builders prefer reinforced concrete slabs, but not all houses can use them. The slabs are mounted only on brick or concrete facade walls; such elements are not used for wooden or frame buildings.

Vapor barrier

Prices for vapor barrier materials

Vapor barrier material

It is used only in two cases: the base of a flat roof is wooden and mineral wool is used as insulation.

But such options are rare; most often the base is made from concrete slab, and durable extruded polystyrene is used for insulation. Both of these materials are not only resistant to steam, but also do not react to direct contact with water. Accordingly, when constructing roofs made of such materials, vapor protection is not required.

Insulation

There are two types of insulation that can be used in the construction of flat roofs.

1. Mineral wool or glass wool. On flat roofs, only pressed types are used, rolled in their technical parameters do not meet existing requirements.

   

   The advantages of mineral wool are absolute resistance to open fire and environmental friendliness. She doesn’t have any more advantages, but she does have quite a few long list disadvantages: high cost, low mechanical strength, hygroscopicity, dependence of thermal conductivity on relative humidity, wind blowability. Additional disadvantages include the difficulty of installation: you need to work only in good weather and in protective clothing.

   

2. Polymer insulation. This category includes expanded polystyrene, polystyrene foam and other materials made on the basis of polymers. These insulation materials have two common disadvantages: they release harmful chemical compounds into the air and are inferior to mineral wool in terms of fire resistance. But such shortcomings in this case very conditional for two reasons. The first is that for insulation on the roof, the amount of chemical compounds released does not matter; they do not enter living quarters. Second, modern achievements of innovative technologies have made it possible to produce polymer insulation With high performance resistance to open fire and release of chemical compounds permitted by sanitary standards.

   

Insulation can be installed in two ways.




Currently, architects in most cases prefer the second option for insulating a flat roof, keep this in mind. But practitioners advise installing insulation from inside the premises. Each developer must make his own decision.

Prices for thermal insulation materials

Thermal insulation materials

Practical recommendations for arranging a flat roof on a frame house

As an example, we will take the option of arranging a flat roof on a wooden frame house. These buildings are very popular among many developers; they are quickly assembled, are relatively inexpensive and provide residents with a modern level of comfort.

How to make floors

For the ceiling you need to use I-beams; ordinary ones are not suitable due to very high loads. If you increase significantly linear dimensions ordinary beams, then their own weight will play a noticeable role in the calculations of the acting forces, and this is extremely undesirable for all structural loaded elements.





Important. If the house is large, then it is much more profitable to order short beams and splice them on site. Due to this method, the process of transporting and installing structures is simplified. During installation ceiling beams you need to make a slight slope for the water to drain.

Video - Wooden floor

What to make waterproofing from

Prices for PVC membranes for roofing

PVC membrane for roofing

For sealing, it is recommended to use a modern high-quality membrane that is protected from the harmful effects of ultraviolet rays. The membrane thickness is at least 1.5 mm, the service life of such coatings is more than thirty years. Membranes must retain their original properties at temperatures of -30° and below. It must be borne in mind that situations may arise when in winter it is necessary to remove snow from the roof; the waterproofing must withstand mechanical forces and not be damaged.



How to install a funnel for receiving water

The diameter of the funnel must correspond to the roof area and the maximum water flow. The data is available in comparative tables and is attached to the instructions for using the elements. If for some reason there is no such instruction, then you need to consult with the seller.





The funnel is installed at the lowest point of the roof. The roof plane is divided into several sectors and each has a slight slope towards the drain. To prevent ice from accumulating in the funnel in winter, it is recommended to connect the system electric heating. Heating functions temporarily and only during the period when the temperature changes from positive to negative several times a day.



How to properly lay a waterproof membrane

The joints are boiled with a construction hairdryer and additionally filled with a special two-component glue. You should start from the very bottom edge, the width of the overlaps is at least 10 cm. To increase the strength of the fastening, each strip of the membrane is separately fixed with special fasteners, and the wide washers are then closed.



Along the perimeter of the parapet, the membrane is also screwed with washers of large diameter, the distance between them is approximately 20–30 cm.



How to drain water from a roof

Experienced builders do not recommend attempting to install external gutters and pipes on flat roofs to drain water to the ground. The best option is to run plastic pipes through interior spaces. Installation of the system should be done immediately after assembling the frame of the house; the pipes are hidden during the cladding of the internal walls. Due to this installation location, the possibility of freezing is completely eliminated, and the reliability of the system is significantly increased.



The best way to process OSB boards

There are many options, efficiency depends not only on the materials used, but also on the professionalism of the master. But practice shows that, all things being equal, bitumen mastics have the greatest reliability. Surfaces must be coated at least twice, this guarantees the tightness of the coating for a long period of time. Of course, the top membrane must also be of high quality and correctly installed.

A flat roof in a private house provides many different possibilities. With such a simple design, you can save on roofing materials and labor, and installation is carried out in less than short term. It is also easier to place on its surface various systems: antennas, hoods, solar panels and others. In addition to all this, additional space can be used by arranging a garden, recreation area or greenhouse on it.

However, despite the cheaper installation, many nuances must be taken into account so that such a roof does not become a “headache” for the home owner.

Flat roof design

A flat roof, like any other, must fully perform all its functions: protection from water and its drainage and thermal insulation. In addition, it must have sufficient strength to withstand external loads.

This is what determines the structure of the roofing pie, which consists of the following mandatory elements.

1. Base. This part bears all the main loads. The ceiling must be very durable, but it all depends on whether the roof will be used or not. Most often, the base is a reinforced concrete slab laid on load-bearing walls, less often on non-residential buildings - a layer of profiled sheets.
2. Vapor barrier layer. Performs a protective function, which consists in preserving materials from steam penetrating from inside the room.
3. Thermal insulation. Reduces heat consumption from the house.
4. Waterproofing. A flat roof does not drain away all the water completely, like gable roofs; as a result, high-quality protection is needed from the penetration of room moisture.

For normal moisture removal, a slope is used. Most often, it is a screed that forms angles of inclination along which water can flow into a prepared system of trays for its removal from the roof plane.

Saving on any parts of a flat roof is unacceptable, otherwise it will lead to leaks, freezing and other negative phenomena of a poorly installed roof pie.

Types of Flat Roofs

The presence, order and sequence of individual elements of the roofing pie determine the type of roof. The following types of flat floor structures are distinguished:

• Unexploited. These structures can be seen on multi-story buildings. It is believed that their surface is not intended for use and is designed for short-term stay of people. In this option, on non-residential buildings you can use a profiled sheet as a base.
• Exploited. In this case, it is necessary to have a concrete base capable of withstanding heavy loads. The surfaces can be used as a garden, recreation area or even car parking. In addition to a solid base, it is important to observe the angle of inclination, which should not exceed 3 degrees.

• Inversion. The design involves changing the order of layers of the cake. The waterproofing is placed under the insulation, which allows it to be protected from damage. Quite often this type of roofing is used in the construction of private residential buildings.
• Ventilated. These types of roofing have a ventilation system (built-in aerators) that evaporate excess moisture from the thickness of the roofing pie. Can be combined with other types of roofs.

In addition, the type of roof depends on other factors, for example, whether the room is heated or not.

Installation of a flat roof on different types of buildings

Depending on whether the room will have a heating system or not, the technology for assembling the roof may differ during installation.

Roofs on unheated premises

Typically, unheated buildings are garages, sheds, gazebos, and various pavilions.

• The required slope of 3 degrees, on such buildings is formed by load-bearing beams roofs. The height difference is about 30 millimeters per 1 meter of beam length.
• After laying the beams, a flooring is made that will serve as a base. These can be boards or profiled sheets. They are secured with self-tapping screws or other suitable fasteners.
• If the room is unheated, you may miss a layer such as thermal insulation. Waterproofing material is laid on the base. Roofing felt is used as a waterproof coating. It is spread in overlapping strips (about 150 mm) and additionally fixed with slats, which are placed along the slope of the roof.

This is the simplest version of a flat roof, which can be mounted on a utility unheated room with your own hands at a minimal cost of money and time.

Assembling a flat roof on heated buildings

IN residential buildings With a heating system, the roofing pie of a flat roof will be different. Here you will definitely need a thermal insulation layer, high-quality hydro- and vapor barrier. The presence of the latter is no less important, since water vapor can gradually ruin the entire roofing pie.

• The floor under the base is assembled from wooden beams, which are placed at intervals of 900-1000 mm.
• They are covered with flooring made of boards with a cross-section of 40-50 millimeters. The thickness of the lumber is selected depending on the distance between the beams. The larger it is, the thicker the boards are needed.
• Roofing felt is laid on the flooring, it is cut and straightened in advance. Waterproofing sheets are laid with an overlap of about 100-150 mm.
• The thermal insulation layer can be made using the bulk method. To do this, fill the resulting base with a layer of expanded clay up to 300 mm and level it.
• Next, pour onto the layer of thermal insulation backfill cement-sand screed(minimum thickness 30 mm).
• After the cement has hardened, the surface is covered with bitumen-based soil and covered with a layer of roofing material.

You can also install a more solid roof made of monolithic concrete.

Monolithic concrete flat roof

In this embodiment, a durable concrete base with your own hands.

• An I-beam is used as support beams, which are laid level without forming a slope.
• For pouring, you will need to prepare concrete of a grade not lower than M250; it is prepared in a concrete mixer, maintaining a ratio of 4:1.5:1:1, where the ingredients are crushed stone (20-25mm), cement (m400), water and sand, respectively.
• For pouring, a base is made of boards, which are mounted on the lower flanges of I-beams and covered with roofing felt.
• Fine crushed stone is poured on top of the waterproofing, which is filled with the resulting concrete. The filling must be done at one time, otherwise the structure of the roof will not be the same.
• Next, expanded clay is poured in and a slope is made.

Leaning

Sloping is the formation of slight slopes on the surface of a flat roof, which allows water to be removed from its surface. The drainage system is assembled in two versions: external and internal. That is, the trays can be attached to the end of the roof or on its surface.

If the drainage gutters are located internally, the presence of water collectors is planned in advance, the number of which is calculated as follows - 1 funnel per 25 square meters roof area.