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Do-it-yourself flat roof installation. Flat roof for a private house: is it worth it or not? Flat roof on metal beams

When building a house, the final, but no less important process is the roofing of the roof, often called by architects the “fifth facade”. Pitched roofs are considered to be a classic option for private houses, but recently their flat counterparts have begun to gain more and more popularity. And the whole secret is that the device flat roof has a lot of advantages.

Flat roof Houses

This type of roof is widely applicable in both industrial and private construction. The main difference between flat roofs and pitched "brothers" is the use of piece and sheet roofing materials. The device of a flat roof involves the use of materials that can form a continuous carpet. These include polymer, bitumen and bitumen-polymer materials, as well as mastics. In order for any temperature fluctuations and mechanical deformations to which the base of the roof is subject to be perceived well enough, such a carpet must be highly elastic. The basis for it can serve as load-bearing plates, screeds, as well as the surface of thermal insulation. All layers stacked on top of each other represent the so-called flat roof pie.

Exploited and non-exploited flat roofs

The use of operated roofs is advisable on those buildings that provide for frequent access to the roof of people or the presence of any heavy objects on it. The design of this type of flat roof has its own peculiarity, consisting in the need to lay a rigid base or a special screed on the waterproofing layer. This is necessary so that the roof structure can withstand any load, often unevenly distributed over the surface. A rigid base in this case will help maintain the integrity of the waterproofing carpet and will not allow it to be pressed through.

Unlike operated roofs, for non-operated roofs there is no need to lay a rigid base on the waterproofing. In this case, soft insulation is used. The use of such roofs is appropriate when maintenance during the operational period is not required, that is, there is no pressure on the roof surface. But even if there is a need to maintain such a roof, the issue can be resolved with the help of special ladders or walkways that will help to evenly distribute the pressure exerted on the roof surface.

The device of a flat roof of an unexploited type will cost an order of magnitude cheaper than in operation, but its service life will be much lower. Therefore, the choice of roofing should be approached carefully after weighing all the pros and cons.

Other types of flat roofs

Depending on the design features, distinguish the following types of flat roofs:

  • classical;
  • inversion;
  • ventilated.

The traditional option is considered to be a classic flat roof, which has another name - a soft roof. Its base is a carrier plate, on the vapor barrier layer of which a heat-insulating material is applied (in most cases, mineral wool plates are used). Thermal insulation, in turn, is protected from the effects of precipitation by a waterproofing carpet, which is based on rolled bitumen-containing materials.


The device of a flat roof of an inversion type differs from the previous one in that the insulating layer is located above the waterproofing carpet, and not below it. This feature makes it possible to protect the waterproofing from the harmful effects of ultraviolet radiation, freeze and thaw cycles, abrupt changes temperature regime, as well as mechanical damage, which can significantly increase the service life of the inverted roof. This design can be used as an operated flat roof. For example, you can plant grass on it and break flower beds, put a small amount of furniture, or just sunbathe.

Moisture that accumulates in floor slabs and insulation is the main cause of the formation of "bubbles", which subsequently lead to leaks and even ruptures of the roofing carpet. And, unfortunately, removing this cause completely is almost impossible. In the West, this issue is easily solved using the so-called "ventilated roofs". Flat roof units of this type provide for partial fixing of the first layer of the carpet to the roof with glue, or laying on mechanical fasteners. As a result, an air gap is formed between the base and the roof, which eliminates excessive water vapor pressure. It communicates with the outside air through the junctions along the contour of the roof, or through special exhaust deflectors.

Foundation preparation

In order for the end result to be a high-quality and durable roof, it is initially necessary to think over a plan for a flat roof, the drawing will also be an excellent help in installation work. In most cases, the following main units of a flat roof are distinguished: a supporting structure, which can be a monolith, a supporting concrete slab or a corrugated floor, layers of steam, heat and waterproofing and a slope-forming layer designed to drain water.

The first step in flat roofing is the preparation of the foundation. Reinforced concrete slab, corrugated steel sheet, or a solid wood covering most often act as a bearing covering for this type of roof.

If the reinforced concrete base has an uneven surface, it is necessary to create a leveling screed from sandy asphalt concrete or cement-sand mortar. The thickness of the screed will depend on the type of base: for concrete - 10-15 mm; on rigid insulation boards -15-25 mm; on soft insulation boards - 25-30 mm.

If the roof slope is less than 15%, then first the screed is placed on the grooves and only then on the slopes. In the case of a slope of more than 15%, the actions are performed in the reverse order: first, the slopes are leveled, then they proceed to work with grooves and valleys.

Any elements protruding above the roof, whether chimneys or parapet walls are processed with plaster to a height of 25 cm. Special rails are installed on top of the plastered surface, which serve to fix the roll-type carpet. The roof screed is primed with roofing mastics in order to increase the quality of adhesion of the base to the rolled carpet.

Before priming the base, it must be thoroughly cleaned of contaminants and dried well.

Preparation of roofing soft materials


The roof plan of a flat roof must necessarily include preparatory work roofing materials for their further use.

When using rolled materials, they must first be carefully examined for the presence of various kinds of defects: bumps, cracks, oil stains. And then during the day they are kept rolled out or turned inside out.

Mastic for a roof can perform two functions at once. It can be used as self material, providing a seamless coating, for repair work. And also it is applicable as an adhesive agent for connecting rolled materials with the base. Bituminous mastics can be used both hot and cold.

The use of mastic as an independent roofing material

The composition of a flat roof may or may not include roll materials, it can be done with just one application of mastic. She represents liquid material, based on pure elastic, hydrophobic polyurethane resins. And as a result of its application to a flat roof, when exposed to air humidity, it polymerizes and turns into a rubber-like continuous membrane, which has excellent protective and waterproofing properties.

For a flat roof, mastic, as a roofing material, has a lot of obvious advantages: it is safe and reliable, has high resistance to ultraviolet rays, precipitation and various microorganisms, has high adhesion to any building surface, and besides, it does not change its volume during polymerization . The ease of use of this material is also captivating - it can be applied either manually, with a brush or roller, or by airless spraying.

Roof covering with roll materials

Thinking through the plan of the roof of a flat roof, an important point is the choice of the roofing material itself. Roll materials can be called the most suitable in their properties. Laying of rolled panels for soft roofing is carried out on overlapping slopes. If the roof slope is more than 5%, the overlap should be 70 mm in the inner layers of the carpet, and 100 mm in the outer layers. In the case of a slope of less than 5%, the width of the overlap in any layer is 100 mm or more. Laying of roll strips is carried out strictly in one direction.

If, during gluing, the panel deflected to the side, you should try to move it without peeling it off. If the result turns out to be ineffective, then the glued part of the panel should be cut off and pasted with an overlap of 100 mm.

Roll sheets are laid in layers, and in case of their fastening on cold mastic, it is necessary to observe a 12-hour interval between the sticker of each layer.

Thermal insulation in soft roofs

Considering the device of a flat roof, its insulation can be performed in one of the following ways: external or internal. Ease of installation external thermal insulation makes this method more common. In addition, with the help of this method, both a building under construction and one already in operation can be insulated.


Flat roof - thermal insulation

Flat roofs have a design that provides for two options for thermal insulation, depending on the number of layers: single-layer and two-layer. The choice of thermal insulation is influenced by thermal calculation and strength requirements for roof structure. For laying on the top of the supporting structure of heat-insulating boards, the principle of "seams apart" is used. With a two-layer coating, the joints of the lower and upper plates must also run "in a row". In those places where the plates of thermal insulation are adjacent to walls, parapets and lanterns, thermal insulating transitional ledges are created. To fix the thermal insulation, use one of the following methods:

  • mechanical. The corrugated board is fastened with self-tapping screws, the reinforced concrete base - with plastic dowels with a core;
  • adhesive;
  • with the help of ballast, which is used as pebbles or paving slabs;
  • based.

The main mistakes of installing a flat roof

Installation errors can lead to the formation of so-called "cold bridges", which can be window and door openings, concrete building elements or dowels, with which the plates are attached to the wall. Such "cold bridges" can create heat loss of up to 50%, in addition, they can cause condensation and subsequently mold.

The most common reason for the formation of "cold bridges" is the use of fixing dowels with a metal nail. This phenomenon can be avoided by using roofing works flat stone wool roof. This is due to the fact that there will be enough glue for its fastening, but the use of dowels in this case is also possible, since a plastic rod is provided for the cotton wool.

Heat loss can also be avoided when using a two-layer insulation. But in this case, the top layer must be laid in such a way that the joints between the bottom plates are covered by the top insulation.

Use large format slabs - this will reduce the total number of joints.

In addition, errors can be identified initially, you just need to draw up a competent and clear plan for a flat roof.

Do you want the roof of your house to perform not only its main function of protection from atmospheric precipitation? Do you want to turn it into a beautiful garden, recreation area or outdoor sports ground? Then ideal option for you is a flat roof roof!

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Increasingly recently, flat roofs are used in the design of industrial and public buildings: the technology of their construction has undergone significant changes as a result of the emergence of new roofing materials.

They differ from pitched roofs in that they do not use sheet and piece roofs when arranging flat roofs. roofing materials. When they are created, a carpet is laid from rolled products. Apply mastics, bitumen-polymer, bituminous and polymeric materials. As a result of the work performed, the carpet on a flat roof should be sufficiently elastic in order to withstand mechanical and thermal loads. As the basis for the roofing material, concrete slabs, screeds and heat-insulated surfaces are used.

What are flat roofs

When a flat roof is created, its device depends on whether its surface will be used or not.

Operated roof . It is equipped on buildings so that people can regularly be on it or to place various items (see photo). To withstand the increased load, which can be unevenly distributed over the surface, a special screed is made on the waterproofing layer or a rigid base is laid.


Unexploited roof . To create it, laying a reliable and durable foundation is not required, since the load on the surface of such a roof is minimal. For preventive maintenance or current repair specially designed bridges or ladders are used, which, when moving along them, distribute the load on the surface evenly. The construction of an unexploited roof will be cheaper, but its service life is less than.


Inverted roof . Such a "roof-upside down" can be exploited. On it, a heat-insulating layer is laid on top of the waterproofing and, thus, protects it from negative impact ultraviolet and temperature changes. It should be noted that not any heat-insulating material is able to cope with the assigned function, but only one that does not absorb water, extruded polystyrene foam is most often used.

Ventilated roof . Its first layer is partially glued to the base or special clamps are used, this is done to prevent the formation of air bubbles due to the fact that moisture can accumulate in the insulation layer. These bubbles sometimes cause deformation and damage to the roofing mat, resulting in leaks (detailed: "").

Before proceeding with repair work on a flat roof, it is necessary to find out which type it belongs to. The procedure for taking measures to eliminate defects and leaks depends on this, and it will also be necessary or not to use special equipment that ensures the safety of being on the roof.

Foundation preparation procedure

In the section, the device of a flat roof consists of a bearing coating and a base, on which layers of hydro-, steam- and thermal insulation are laid in a certain order. Most often, the bearing coating is a reinforced concrete slab, steel profiled sheet, much less often a coating of wood materials is used.

If the reinforced concrete base has defects, a cement-sand screed is made, after which the surface becomes even.


Depending on the material on top of which the screed is made, its thickness differs:

  • if it is concrete, then the layer is from 10 to 15 millimeters;
  • when rigid insulation boards are used - 15-25 millimeters;
  • in the presence of non-rigid heat-insulating materials - 25-30 millimeters.

When a flat roof device provides for a slope of no more than 15 percent, the screed is performed primarily on the grooves, and then only on the slopes. If the slope exceeds 15 percent, the procedure for creating a screed is reversed - first the slopes are leveled, and only then they are engaged in the arrangement of valleys and grooves.

On flat roofs modern houses there are always protruding elements - chimney pipes, parapet walls, ventilation shafts, etc. They should be plastered at least 25 cm high. To the upper edge of the plastered surface, slats are mounted for fastening the rolled carpet. In order to improve adhesion between the carpet and the base, the screed is cleaned of debris, dried and primed with roofing mastics.

Roof coating technology


Mastic, after being applied to the surface of a flat roof, as a result of contact with moisture contained in the air, polymerizes and eventually forms a membrane similar in characteristics to rubber, due to which it has good waterproofing and protective performance (more: ""). Liquid sealants provide the coating with reliability, resistance to precipitation, UV radiation, harmful microorganisms, etc. They are easy to use, they can be applied to a flat roof with a roller or brush, both on the reinforced concrete surface of the slabs and on the cement-sand screed.

Roof covering with roll materials

The device of flat roofs allows the use of rolled materials, the strips of which are overlapped, and in the same direction:


If during the process of sticking the panel deviated from its location, you should try to return it to its place without peeling off the material. But if it is impossible to move, the glued piece is cut off and the panel is glued again, observing a 10-centimeter overlap.

It is necessary to determine the design of the roof at the design stage of the building. If you have chosen a flat option, it is very important to represent all the positive and negative aspects of the operation of a building with such a roof. The choice of the type of roof also depends on the use of special materials and technological methods in construction.

Flat roof device

Not always a flat type of roof evoked positive emotions among builders. This was due to some prejudices in the construction and operation of a flat roof - lack of aesthetics, uneconomical, fragility.

Recently, there has been a trend to revive the popularity of flat roof structures, a significant role in this was played by new construction technologies and innovative materials.

A flat roof made of modern materials reliably protects the house and looks beautiful

Roof device flat type can be represented as a multi-tiered "pie" with several layers:

  1. Reliable foundation. Most often, this role is played by a reinforced concrete slab or a metal profile structure.
  2. Vapor barrier coating. The most popular bitumen or roll materials.
  3. Thermal insulation layer. Mineral wool, expanded clay, expanded polystyrene, cement screed - the main components used by builders for thermal insulation.
  4. Waterproofing. There are a lot of materials to protect the roof from moisture (bitumen-based mastics, PVC membranes, compositions for liquid fusing, etc.), the choice depends on the material and production capabilities of the developer.

The listed order of layers is not mandatory, it can be different in different flat roof structures.

All elements of the roof must be of high quality, a flaw in at least one of them can lead to problems in the normal operation of the roof.

Pros and cons of a flat roof

A flat roof, despite its apparent simplicity, has a number of useful features that attract builders. Such designs also have disadvantages that must be taken into account.

Advantages of flat roofs


Photo gallery: flat roof operating options

Modern technologies allow you to plant grass on the roof and arrange a playground exactly like on earth. You can get to such a cafe by elevator. Only a flat roof can be decorated so beautifully and modernly. On the roof, you can place a table, benches, a hammock and enjoy your vacation. without leaving home - you can only dream about it

Disadvantages of a flat roof structure

No roof is perfect. There are significant disadvantages of a flat roof:

  • instability to snowfalls (with heavy snowfall, the likelihood of a roof break increases, with abundant spring thawing, leaks are possible);
  • the need to build additional drains for water;
  • increased requirements for the state of hydro- and thermal insulation of the roof.

If internal drains are made on the surface of flat structures, then they require constant monitoring of their condition (it is necessary to clean debris, eliminate freezing, etc.).

Types of flat roofs

There are two main types of flat roofs:


The structural differences between the two types of flat roofs are in the order in which the layers are laid. In an unused roof, the top layer is waterproofing, which quickly collapses under the influence of various natural factors - the sun, wind, precipitation, etc. This option is not suitable for the active use of the roof.

The inversion roof is “packed” differently. The sequence of layers here is as follows: concrete, waterproofing, thermal insulation, protective coating. The last layer is often made of drainage or geotextile. Such durable structures are in demand among designers who want to make the most of the entire roof space.

Holding concerts, building car parks, summer cafes and studios implies a high degree of load, so builders put additional reinforced materials between the insulating layers.

flat roof slope

A flat roof does not have to be completely flat, minimum slope must be foreseen. Otherwise, sewage disposal will be difficult, moisture from precipitation will accumulate on the roof and contribute to its rapid destruction.

In the absence of a slope, stagnant zones with negative aspects may appear:

  • accumulation of moisture;
  • germination of seeds carried by the wind;
  • lichen formation.

To prevent this from happening, a slope of one to four degrees should be made on a flat roof. With such a difference in the levels of melt and waste water will not linger on the surface, which will extend the service life roofing.

Work to create a slope on a flat roof is called slope.

achieve desired slope on a flat surface, you can use different materials:

  1. Backfill components (expanded clay, perlite, etc.).
  2. different layers of insulation.
  3. Lightweight mixtures of concrete on various bases (polymers, bulk materials, etc.).

Each of these solutions has its own characteristics in relation to the slope. The use of backfill materials during long-term operation of the roof does not give a clear angle of inclination. Loose materials can slide off the roof, move, which leads to a change in slope. It is difficult to achieve a smooth height difference if using expanded clay large sizes(more than 20 mm).


 Accurately leveling an inclined surface with expanded clay is quite difficult.

Lightweight concrete masses are devoid of such disadvantages, but they are quite heavy, not every roof structure provides for such additional weight. These materials cannot be used in cases where the building has already been built and its design is not designed for a large load on the frame and foundation.

Modern industry produces materials that help create the necessary and smooth slope on a flat roof. The polymer base of these mixtures makes them plastic, which is a big plus in the construction of flat roofs.

There are other possibilities for creating a slope on a flat roof:

  • installation of metal profile structures covered with flat slate;
  • construction of a crate (rarely used due to the cost and impossibility of creating small slopes);
  • installation of wedge-shaped heat-insulating plates.

The last of these methods is gaining popularity among builders, because this method of ramping has its advantages:

  • simple installation. Plates for thermal insulation are already cut at a certain angle. Their installation does not require any special skills, it is enough just to lay the wedge-shaped slabs on a flat surface of a flat roof to get required slope.
  • light weight. During construction works You don't have to use any lifts. Moreover, insignificant total weight insulation boards will not affect the performance of the roof in the future.
  • Independence from external conditions. Laying wedge-shaped thermal insulation can be done in any weather.

Video: flat roof flattening

Insulation and drainage for flat roofs

To avoid a quick failure of a flat roof, you should take care of its proper insulation and drainage.

Drainage

A drain on a flat roof is mounted outside or inside the building. The choice of water drainage method depends on climatic conditions:


Video: installation of a receiving funnel on a flat roof

Warming

The thermal insulation of a flat roof is carried out differently than the insulation of pitched surfaces.

This process includes two important moments- vapor barrier and thermal insulation. Depending on the type of roof (classical or inversion), the order of the layers changes.

Used as thermal insulation:

  • mineral wool;
  • Styrofoam;
  • polyurethane foam;
  • ecological cotton wool;
  • foam concrete.

A good vapor barrier can be provided by a polypropylene film and a build-up mass with a bitumen base.

Photo gallery: flat roof insulation

Flat roofs can be insulated in a well-known way - by filling expanded clay Large surfaces are easier and faster to insulate with mineral wool For the insulation of flat roofs, they are increasingly used modern materials, for example, extruded polystyrene foam Foam glass provides not only thermal insulation, but also an excellent soundproofing effect Foam concrete is poured automatically using a pump and a flexible hose, so you can handle this work alone

Flat roof ventilation

To begin with, let's denote the negative points that will arise on a flat roof without ventilation. Roof flat design, devoid of ventilation will be “loaded” with condensate. Natural physical processes will lead to the fact that warm air, rising up, will not settle on the elements of the attic (as on pitched roof), but on a reinforced concrete base. The result of such adverse processes will be the appearance of fungus and mold on the ceiling.

In the future, steam and heat insulation, other roofing elements will suffer. To prevent this from happening, it is necessary to equip deflectors and aerators on the roof. Their installation is provided at the design stage of the building.


 Devices to ensure unhindered air circulation are provided at the design stage of the roof

The inflow and outlet of air is carried out due to different pressures outside and inside the building. A flat roof will "breathe" if devices for artificial ventilation. This will help to keep the layers of hydro- and thermal insulation from destruction, relieve the spread air bubbles and swelling of the roofing material.

Flat roof covering materials

As roofing materials for flat roofs are used:

  • mastics;
  • polymeric membranes;
  • roll materials on a bitumen basis.

They provide good waterproofing and excellent resistance to mechanical stress and temperature extremes.

Bituminous materials

The basis of many roll coatings is oxidized or modified bitumen. Ruberoid, stekloizol, rubemast, euroroofing material are the main types of bituminous materials used on a flat roof.

Table: characteristics of rolled bituminous materials

Material name What is Average service life Characteristics
positive negative
Ruberoid Cardboard impregnated with bitumen. The material also has a protective layer of backfill - talc, sand, granular expanded clay, etc. 5–10 years Good waterproofing, resistance to atmospheric collisions and mechanical impacts.
Low cost, easy installation.		 Does not withstand temperatures of +50 °C and above. Cracks form on the roofing material even at large minus values.
Rubemast Improved modification of roofing material with a thicker layer of bitumen. 15 years High ductility and resistance to cracking (with temperature extremes and mechanical damage). The need for certain skills when welding this material.
Stekloizol The basis of the material is fiberglass with a bituminous top layer. For protection, there is an additional layer of backing at the top, and a special film at the bottom. 20 years Doesn't rot, doesn't crack. Requires professionalism when laying, bubbles and folds may form, burns through the bituminous coating when the gas burner malfunctions.
Euroruberoid Bitumen supplied with various polymeric additives. Over 20 years All characteristics are an order of magnitude higher than those of any other bitumen materials Assembly skills required.
High price.

Polymer membranes

These materials have become popular relatively recently. The advantage of such flat roof coatings is plasticity, resistance to damage, resistance to temperature extremes, and simple installation. Another big plus of polymer coatings is their production footage. The length of one roll of polymer membrane is from 20 to 60 meters, so it can cover large areas of a flat roof very quickly.


 Polymeric membranes are available in long rolls, so they can quickly cover large areas.

The operating period of roofs with polymer membranes is 30–50 years.

Mastics

The positive aspects in the use of mastic materials are the absence of seams and the integrity of the coating. The service life of such roofs is from three to ten years.

Applying a viscous and viscous mastic to the roof surface is a simple process, this layer becomes solid at normal air temperature. Mastics are also used as an adhesive base for mounting roll materials.

There are cold and hot mastics. The first type does not require additional manipulations during the preparation and installation, in the second case, the mixture will need to be heated to 180 °. It is safer to work with cold mastics, but hot materials set faster.

Flat roof repair

Any roof needs constant inspection, care and repair. On the roof, under the influence of various factors, cuts, damage, breakthroughs, swelling, delamination and other problems can occur that interfere with the normal use of the roof. To eliminate such negative conditions, it is necessary to carry out repair work. They can be current, emergency and capital.

Emergency repair is a forced, unplanned measure, emergency measures to restore the integrity of the roof. Current and capital repairs of a flat roof are provided in advance. The volume of work carried out during current and major repairs differs significantly. Overhaul requires more time and costs, while the area of ​​repaired coatings is also much larger.


 Defects on roofs covered with rolled materials are most often eliminated by gluing patches.

During emergency and scheduled repairs of a flat roof, patches are most often installed on the damaged area. Materials for repair in each case are selected individually. One of the latest "assistants" when updating a flat roof is a self-adhesive tape with a bituminous coating. It is very convenient and effective to use it for roof repair. There is only one limitation: such a tape is not suitable for repairing damage over a large area.

Flat roof repairs are much easier and safer than pitched roofs. The repair time on such a surface is also much less.

Video: flat roof repair technology

Economic nuances of using a flat roof

If you are wondering about economic benefits, then you should consider some points when building a flat roof.

Of course, the construction of a flat type of roof is less expensive, since the cost of building a rafter system is not required. This will also be the case with operation, if repair of the rafter part of the pitched roof is required. In a flat roof, such an expense item is simply absent.

A pitched roof will require more investment also because it is clearly visible, being an integral part of the facade of the building. The materials used in the construction of the upper layers in a flat roof are not always appropriate for a pitched version. They can be simpler, uncomplicated, while on a pitched roof it is better to use not only reliable, but also beautiful finish.

The costs of building, maintaining and repairing a flat roof largely depend on its intended purpose. The cost will be much lower if the roof is not in use.

The construction, maintenance and operation of a flat roof have their own natural features. There are advantages and disadvantages to using flat roofs. Given the purpose of using the building, a flat roof should be mounted with strictly defined materials.

The construction of a gable or hip roof not always rational and expedient, if we are talking about outbuildings, industrial and commercial facilities, and sometimes private houses in a modern style. Large consumption of material, complex rafter system make the construction of these structures economically unprofitable, protracted undertaking. While flat roof projects greatly reduce construction costs, build quickly and are suitable for almost any structure.

A house with a flat roof is reliably protected from increased wind load. However, having no slopes, it cannot quickly divert 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 that does not allow moisture and snow to slide off freely. Therefore, a do-it-yourself flat roof device must comply with the stringent requirements of building codes for waterproofing, ramping and construction technology.

The structure of the roofing pie

The need for a high level of protection against moisture forces the roofing materials of a flat roof to be arranged in layers, one above the other, forming the so-called "pie". If we consider its device in section, we can see the following layers:

  1. Flat base made of concrete slabs or profiled metal sheets. It provides structural rigidity, bears weight roofing cake, passing it to the load-bearing partitions and, as a result, to the foundation. At the exploited roof, the base should be as rigid as possible.
  2. vapor barrier. A layer that is necessary in order to protect a flat roof from the penetration of vapors from internal heated rooms into the thickness of the insulation. Settling on thermal insulation in the form of condensate, water irrevocably reduces its insulating properties by more than two times. As the simplest vapor barrier, polyethylene film or bitumen-based coatings are used.
  3. insulation. For thermal insulation of a flat roof, backfill materials are used, such as expanded clay, perlite, slag, rolled, for example, mineral wool and in the form of plates, in particular expanded polystyrene. By the way, insulation is used not only to regulate the temperature regime, but also to flatten 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 rolled materials for protection from moisture: bitumen, polymer and bitumen-polymer. In addition to high waterproofing qualities, they must be resistant to temperature extremes, elasticity, and long service life.

Types of roofing and the nuances of their installation

The device of a flat roof determines the design and nature of use. The following are distinguished into separate types that require a special approach during construction:


Roof installation for unheated buildings

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

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

Roofing material is used as a waterproofing agent - the most affordable material. It is produced and sold in the form of rolls. Carry out the cutting of the waterproofing, cutting the strips so as to lay them in the direction of the slope of the flat roof.

Strips of roofing material are laid in stages 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. The flat roof of an unheated room is easily mounted by one's own hands, even by one worker without the help of helpers.

Roof installation for heated buildings

If they are building 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 bar with a section of 150x150 mm or more, or a steel I-beam, is used for the manufacture of support beams.

Monolithic concrete roof

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


Decline process

- the device of a small angle of the roof surface for organizing a drain. 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 drain with the help of a ramp into the water-catching funnels, which are located 1 per 25 sq.m or more often. If you make an external drain, then moisture should fall into the gutter. The slope is formed by the following methods:


A flat roof without a proper slope is an unreliable shield between you and the weather. Moisture that has no way out will accumulate on the surface of the roof, provoke the destruction of the roof and leaks.

Video instruction

All city high-rise and industrial building These are houses with flat roofs. Moreover, today many who love modern style in architecture, prefer to have a flat roof in their private homes. It really looks stylish, but, among other things, houses with such a roof are more functional - they can be equipped winter Garden or use the roof as a place to relax in the warm season. Therefore, we immediately proceed to the description of the installation steps and consider in detail its device.

A flat roof is great for those who use it as an open floor.

The subtleties of installation and the design of the roofing "pie"

Installation of a flat roof involves the presence of a roofing "pie". It has high heat-shielding properties that prevent overheating of the attic in summer time and keep warm in winter. In addition, the roofing “pie” is able to prevent the formation of condensate, the insulation will be protected from moisture, and icing and icicles will not appear on the roof. It is important to observe its correct device.

The design of the roofing "pie" involves the presence of several layers:

  • bearing base;
  • vapor barrier layer;
  • multilayer insulation;
  • hydroprotection.

You should start by preparing the foundation. It needs to be leveled, cleaned, cracks in concrete filled with polyurethane sealant, based on a consumption of 180 g per 1 running meter with a joint width of 5 cm and a depth of 0.3 cm. The next step is priming using an epoxy primer. On porous surfaces, you will need 0.2 kg per 1 sq.m, on non-porous surfaces - 0.12 kg. The primer is mixed with a low-speed mixer until a homogeneous mass is obtained, after which it is diluted ½ with water. Apply to the surface with a paint roller or brush. After all of the above, the base surface can be reinforced. For this, a special mastic is applied (14 kg per 1 cubic meter). Before polymerization, a construction bandage is laid on it, and after polymerization, another layer of mastic is laid.

Any roof needs a vapor barrier. For this, polypropylene and polyethylene films are used, which are fastened with nails or binders or glued. At the same time, it is necessary to maintain a 10 cm gap for ventilation so that steam does not accumulate under the film. The thermal insulation material must adhere tightly to the roof surface, pipes and ventilation units.

Roof insulation and thermal insulation materials

Insulation is responsible for maintaining warmth and comfort in the house. Properly selected thermal insulation materials will not only bring comfort to its walls, but will also significantly save on heating. Therefore, you should always pay attention to such qualities of roof insulation as low thermal conductivity, fire safety, vapor permeability, which is necessary for good ventilation of the room; resistance to moisture and various mechanical damage.

It is very important that the material of which the insulation consists is resistant to point loads. In 80% of cases of damage to roofs, they are the cause of many problems. The main ones are:

  • violation of waterproofing, as a result of which moisture reaches the roofing “pie” and destroys it;
  • causing serious damage during a thaw due to freezing of snow;
  • the appearance of "cold bridges" that increase heat loss.

To protect the roof from such troubles, you need to ensure that everything happens in accordance with all the rules and regulations of construction, and you also need to control the quality of the materials used. One of the most common materials, without which thermal insulation is indispensable, is stone wool. It is very easy to install and withstands temperatures up to 1000°C. In addition, as a roofing thermal insulation material polyurethane foam, foam concrete, foam glass and extruded polystyrene foam are often used. Let's take a closer look at each type of material.

Polyurethane foam (PPU) is highly adaptable and has additional waterproofing properties. However, it cannot be left as a finishing coating, since ultraviolet radiation on the PPU will make it brittle and reduce its service life, insulation is its main purpose. But this material has good maintainability and is easily amenable to local repair. For 1 cubic meter, 60-80 kg of polyurethane foam will be needed. This amount is due to the fact that polyurethane foam is prone to burning, but its use in this particular ratio reduces its combustible qualities. When exposed to direct fire, PPU melts, and when the source of fire is eliminated, it instantly fades.

Foam concrete has a higher coefficient of thermal conductivity in comparison with polyurethane foam, therefore reliable insulation it will turn out if its thickness and material costs are higher, on average, 250 kg per 1 cubic meter. However, this increases the load on the roof above the roof.

Extruded polystyrene foam refers to plate materials for thermal insulation. Warming with its use has become very widespread and is very popular due to the ease of installation. The slabs are tightly laid over the entire surface and glued together, after which the roof is considered to be fully insulated.

Thermal insulation using stone wool implies a laying method identical to the previous one. The difference lies in the material itself. Stone wool slabs usually have two degrees of density. The side with increased density is often marked with a black stripe. This side of the plate should lie up.

Foam glass is laid on a flat, dry surface filled with molten bitumen. Blocks of foam glass are superimposed at some distance from adjacent blocks and move towards them diagonally. To fix the position of the plate and remove excess bitumen from under it, you need to press your foot in the middle. Foam glass is high-strength, resistant to high temperatures and many acids, has low thermal conductivity, which ensures maximum insulation. However, its high cost often makes it less attractive for use as a thermal insulation material.

It can be carried out in many ways, but the most popular of them is bituminous. Let's stop on it. Bituminous mastic stir with a drill with a nozzle for 5 minutes. The first layer is made more liquid than subsequent ones. It is applied with a density of 90-120 g per 1 sq. cm. The next layer of bitumen is applied after the previous one has dried, after about 10-12 hours. The more layers there are, the higher the protection.

Features of a flat roof device

The device of flat roofs divides them into operated, non-operated, inversion and traditional. The device of the inverted roof is different in that the thermal insulation layer is located above the waterproofing, and not below it. This allows you to protect it from ultraviolet radiation, mechanical damage, temperature difference. does not imply additional use roofs, its installation is most affordable. involves the active use of the roof surface (the presence of a sports or helipad, a cafe). In this regard, its device is more expensive than the device of non-exploited roofs, but also more durable.

Despite the fact that the roof is called flat, it still has a slight slope (1-4%). This design allows precipitation to descend on its own. The device of any roof structure must withstand a load of 200 kg per 1 sq.m, its own weight and the weight of the roof covering. Therefore, it is laid on durable reinforced concrete slabs 4-5 cm wide and 40 x 40 cm in size to increase reliability.