Flat roof of a private house roofing roof. Do-it-yourself house with a flat roof - design options

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

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

The situation is complicated by the fact that the surface of roofing materials has a rough structure, which does not allow moisture and snow to slide off freely. Therefore, 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 makes it necessary to place roofing materials flat roof in layers, one above the other, forming a so-called “pie”. If you look at its cross-sectional structure, you can see the following layers:

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

Roof installation for unheated buildings

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

They are installed at an angle of 3 degrees, which is 30 mm for each linear meter beam length. Then a base of unedged boards, 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 step by step with an overlap of 10-15 cm and fixed wooden slats or steel strips every 60-70 cm in the direction of the drain, so as not to block the path of flowing moisture. Flat roof unheated room can be easily installed with your own hands, even by one worker without the help of assistants.

Roof installation for heated structures

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

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

Monolithic concrete roofing

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

Leaning process

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

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

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

Video instructions

Flat roofs are in demand in modular construction. Among the advantages of this method are the affordable cost and high speed of construction of housing, as well as the possibility of gradually increasing its area

Architects and developers are attracted to these unusual buildings, where you can equip an observation deck or even set up a real hanging garden. Of course, in practice everything turns out to be more complicated than in theory.

Designing a flat roof raises many questions regarding its cost, choice of materials for insulation and waterproofing, organization of water flow, maintenance, etc. Finding answers to them is not so easy. The fact is that domestic contracting companies working in the field of cottage and rooftops are well familiar with the most popular design - pitched, but, as a rule, they have no experience in constructing flat roofs, which are designed completely differently.

Flat roof cost

What immediately attracts attention is the fact that the area of a flat roof is smaller than a pitched roof, which means that less materials will be required, and the work will be cheaper. However, this statement is only true for regions with a warm climate and low snow load, especially if we are talking about an unused roof. IN middle lane In Russia, to ensure the reliability and durability of a horizontal roof, it is necessary to apply rather expensive engineering solutions.

Beam floor

In principle, when constructing a floor, you can use a combination of beams (wooden, steel) and load-bearing corrugated sheeting. However, experts do not recommend using wooden beams (with the exception of those made of LVL beams with a cross-section of 200 × 100 mm) in regions where the snow cover pressure exceeds 1.2 kPa (about 120 kgf/m2) - that is, in most of the territory of the Russian Federation. A roof covering made of steel I-beams and corrugated sheets with a wave height of 60 mm and a wall thickness of 0.7 mm allows you to cover a span of up to 12 m and can withstand a pressure of at least 6 kPa. But in general, it is less durable than concrete, and is relatively rarely used in individual construction. It makes more sense to use corrugated sheeting as permanent formwork, which, by the way, does not replace the need to build a reinforcement frame.

It turns out that 1 m2 of flat concrete or steel base, bearing capacity which will allow you to withstand the weight of the snow cover, costs 2–2.5 times more than a wooden beam structure of a pitched roof. The difference in the volumetric consumption of insulation is leveled due to the fact that a flat roof requires more expensive high-density material. There is still hope to save on roofing, but modern polymer membranes - the optimal waterproofing for horizontal roofs - are no cheaper (and sometimes much more expensive) flexible tiles. There is no need to install snow guards, but without a roof hatch and drainage system can't get by. If you try to cut costs according to the estimate, you will subsequently have to pay the price of having to repair the roof every 10–15 years.

The durability of a flat roof largely depends on the ability of the load-bearing base to withstand operational loads without significant deformation

Finally, it should be taken into account that flat roofs are appropriate only on houses of modern architecture - with a large glazing area and complex finishing with the latest facade materials. Both will not be cheap at all.

On a solid foundation

As a rule, in low-rise housing construction, the flat roofing is a prefabricated or monolithic reinforced concrete slab. Reinforced concrete slabs (PB, hollow PC, PV, etc.) are capable of covering a span of up to 9 m in length and can withstand a pressure of 8, 9 or 12.5 kPa (this value is indicated by the last digit in the product labeling). They can serve as a “base” for any roofing pies, including those with a top layer of paving slabs or fertile soil. However, to install the structure, it will be necessary to ensure that a truck crane can enter the site (while steel beams and flooring can be easily lifted using winches). The depth of support of the ceiling on the wall depends on the material of the latter - for example, for brick this parameter should be equal to the thickness of the slab. Before proceeding with the installation of the roof, it is important to seal the joints of the elements with mortar and additionally seal them with elastic polymer tape.

The main advantage of membranes based on artificial rubber is that they retain elasticity at low temperatures, that is, they can be installed in winter

Classification of flat roofs

Flat roofs are divided into unused and used. The former visit only for inspection, prevention and repair; For this purpose, a roof hatch is installed, to which an attic ladder leads. The roof in use in cottages most often serves as a terrace, that is, a durable wear-resistant coating must be laid on it, and the load-bearing base is designed for increased loads. A type of exploitation is a roof with landscaping, laid with a turf layer on top of the main heat-waterproofing pie; Usually there are paths and a recreation area on it. A convenient exit to the roof in use should be provided, for example from a vestibule superstructure.

A monolithic reinforced concrete floor is erected from heavy concrete using removable (for example, from OSB boards on jack stands) or permanent (from corrugated sheeting) formwork. It is reinforced with a two- or four-level welded frame made of rods with a diameter of 12 mm. Dimensions monolithic slab are not regulated (unlike prefabricated), which provides the architect with freedom when designing a building; other advantages are the absence of seams, the comparative simplicity of the installation of passage units (chimney, ventilation ducts) and high load-bearing capacity (subject to compliance with technological regulations).

Roof protection from cold and heat

In the low-rise sector, mostly flat roofs without attics are in demand, because the attic requires additional costs and disrupts the architectural proportions of the house. This means that the roof must protect against winter cold and summer heat. At the same time general feature flat roofs is that the heat-insulating layer is located on top of the supporting structure (in pitched roofs it is usually located between the rafters). If you insulate the room from below, the dew point may shift into the thickness of the ceiling, which will lead to a reduction in the service life of the latter.

Mastics should be used primarily on roofs of complex configurations

As for roofing options, there are dozens of them. Suffice it to say that more than 40 “recipes” are given in SP 17.13330.2011 alone. At the same time, companies producing coatings and insulation materials are offering more and more new engineering solutions. However, they are always based on one of two fundamental schemes - traditional or inversion.

TechnoNIKOL roof installation diagrams

“TN-ROOF Terrace”: 1 - ceiling; 2 - vapor barrier; 3–5 - EPPS (including the slope-forming layer); 6 - fiberglass; 7 - LOGICROOF V-GR membrane; 8 - geotextile; 9 - tiles on supports

Traditional design in general outline is as follows: a vapor barrier film (polypropylene, polyethylene, butumen-polymer) is laid on top of the load-bearing base, followed by insulation, for example, mineral wool slabs, which have a compressive strength at ten percent deformation of at least 30 kPa, in one or two layers with a total thickness of 200 mm. Above is a separating layer (for example, made of polyethylene film), along which a reinforced slope-forming screed is poured (a flat roof must be given a slope of 2-3% towards the center or edges to ensure water drainage). The dried screed serves as the basis for a roll or mastic waterproofing coating.

“TN-ROOF Green”: 1 - overlap; 2 - ramp made of expanded clay; 3 - reinforced screed; 4 - bitumen primer; 5 - “Technoelast EPP”; 6 - “Technoelast Green”; 7 - geotextile; 8 - EPPS; 9 - PLANTER GEO membrane; 10 - fertile layer

Other options are also possible. For example, a slope-forming screed can be located at the very bottom of the pie; in this case roofing waterproofing fixed with gravel ballast, paving slabs on supports or special dowels. Some materials, say the “RUF SLOPE” system (Rockwool) or “TechnoNIKOL Slope”, allow you to do without a screed altogether: the slabs have variable thickness, and with their help it is not difficult to create smooth changes in level to ensure water drainage.

An inversion roof is designed differently: in it, insulation resistant to constant exposure to water (usually extruded polystyrene foam - EPS) is placed on top of the waterproofing. At the same time, the latter is reliably protected from mechanical damage and is located in the positive temperature zone (freezing-thawing cycles are destructive for almost any material). It is easy to turn an inversion roof into a usable one, for example, by covering the insulation with a drainage layer of sand and gravel and laying paving slabs. The disadvantages of the design include more complex drainage. However, we need to talk about gutters separately.

There are special requirements for thermal insulation for flat roofs. The material must not only have a low thermal conductivity coefficient, but also have good resistance to mechanical loads - both distributed (pressure from the overlying layers of the roofing pie, equipment, snow) and local ones that arise during installation. In addition, it is important that the material has hydrophobic properties and is non-flammable. At the moment, there are several ways to install thermal insulation: using mechanical fasteners, adhesive and loose styling. In addition to traditional two-layer insulation, single-layer installation is becoming an increasingly popular solution. Rockwool offers unique dual-density slabs that consist of a rigid top and lightweight bottom layers, which speeds up work and improves its quality.

Grigory Gromakov

Specialist in development of the “Flat roofing” direction of the ROCKWOOL company

Water drainage on a flat roof

The flat roof is equipped with a parapet (attic) 30–90 cm high, which helps ensure an organized roof; on a roof in use it also serves as a safety fence. At the same time, the design of gutters should be approached very responsibly, because in case of an error, a huge puddle can form above your head, which can also lead to damage to supporting structures.

As a rule, the choice is made in favor of an internal drain. Such a system is less exposed to the atmosphere and is therefore more durable and reliable than an external one. Let's talk in more detail about its main elements.

Water intake funnels are installed on low areas of the roof. As a rule, on roofs with an area of up to 150 m2, two funnels are installed - the main one, connected to the riser, and the emergency one - with water discharged through a hole in the parapet. With an increase in the number of funnels and risers, the reliability of the system increases, but its cost also increases.

For inversion and green roofs, special funnels with drainage rings have been developed to collect moisture from the intermediate layers. Water receivers must be equipped with electric heating based on a self-regulating cable - then they will properly perform their function during alternating thaws and frosts.

Traditional covering with external drainage 1 - ceiling; 2 - slope-forming screed; 3 - vapor barrier; 4, 5 - mineral wool insulation; 6 - waterproofing; 7 - drain

In a new type of system, the so-called siphon-vacuum system, special funnels are used to prevent air from being sucked into the water flow. Thanks to them, the speed of fluid movement in the pipe (and hence the throughput of the latter) increases, which makes it possible to reduce the diameter of the system elements. However, for low-rise buildings, the savings turn out to be insignificant; moreover, such systems require more accurate calculations than gravity systems.

The drain riser is made from sewer pipes- polypropylene, polyvinyl chloride, and it makes sense to use sound-absorbing products, for example RAUPIANO Plus (REHAU), or soundproof the riser, otherwise you will hear the murmur of water for hours. The riser is connected to the funnel using an elastic coupling. When laying pipes, the number of bends and the length of horizontal sections that reduce throughput systems.

A drainage pipe laid in the basement or insulated underground connects the riser to the rainwater drainage system or ensures the discharge of water into a linear drainage tray. In the second case, there is a risk of clogging the outlet with ice, so the riser should be equipped with a “winter” outlet to the domestic sewer (the latter should be equipped with a water seal). The outlet pipe is cleaned through dismountable connection or revision module.

Drawing: Vladimir Grigoriev/Burda Media

Inversion roof covering with internal drainage 1 - screed; 2 - PVC membrane; 3 - EPPS; 4 - funnel with drainage ring; 5 - drainage membrane; 6 - sand; 7 - paving slabs

When choosing the standard size of elements of a traditional gravity system, they proceed from the intensity of rain in a given area, focusing on SP 32.13330.2012.

The external drainage system is more vulnerable than the internal one, and also affects the appearance of facades, but does not require holes in the roof and ceilings and does not eat away usable area Houses. Water is discharged through parapet funnels or pipes embedded in the parapet, under which classic funnels (like on a pitched roof) and down pipes attached to the walls with brackets are installed. When calculating, it is assumed that for each square meter The roof area should be 1–1.5 cm2 of the cross-section of the drainpipes. Elements outdoor system can be made of PVC, steel, copper, zinc-titanium.

For roofs in use, as well as roofs installed in regions with harsh climatic conditions, the inversion circuit is ideal. Since the waterproofing layer is located under the thermal insulation layer, it is protected from mechanical influences, as well as from temperature changes and UV radiation, which significantly extends the service life of the roofing system. Waterproofing materials based on modified bitumen must be laid in at least two layers - this technology is more common, and in addition, it allows you to level out possible errors when fusing the material. One layer is enough for a polymer membrane, and reliability is ensured by automatic welding equipment, which greatly increases the speed of work. In addition, when installing a polymer membrane, an open flame is not used, so the technology is considered safer.

Dmitry Mikhailidi

Head of the Engineering and Technical Center of the Technical Directorate of the TechnoNIKOL Corporation

Roof landscaping

Since ancient times, turf-covered roofs have been used in countries with moderately cold and humid climates, and the green carpet performed the main moisture-protective function in them.

As part of the modern concept of a green roof, a layer of fertile soil with plants is needed to give unusual features to the appearance of the building, decorate the terrace roof and extend the life of the coating by protecting it from ultraviolet rays. In addition, it absorbs rainwater, unloading the gutters, dampens the sound of rain, protects the rooms on the upper floor from overheating in the summer and reduces heat loss in the winter. It is believed that landscaping almost doubles the life of a roof. Its disadvantages include an increase in loads on the supporting structures of the building and an increase in construction costs. In addition, a green carpet needs care, the intensity of which depends on the selected plant species. If you do not pay due attention to the plants, they will freeze and die from drought.

To green the roof, you should lay on top of the main waterproofing layer (in an inversion scheme - on top of the insulation) an additional cake made of materials that will ensure protection of the waterproofing layer from roots, filtration and drainage of rainwater. For these purposes, special films, dense geotextiles, gravel bedding or drainage and moisture storage membranes made of high-density polyethylene, for example PLANTER GEO or Delta-Floraxx, are used.

Then a mixture of minerals and fertilizers is poured - the so-called soil substrate. You can prepare it yourself by adding fine expanded clay (5–15%), sand (about 20%) and fertilizers to a light soil mixture of neutral peat. As for plants, the easiest way is to limit yourself to meadow forbs and drought-resistant ground covers - sedum, herbaceous carnation, thyme. They do not need to organize an irrigation system, and the thickness of the soil layer can be only 6–12 cm (this type of roof is called extensive). If you plan to walk on the roof among ornamental shrubs, you will have to provide irrigation and increase the soil thickness to 20–40 cm. Such a roof is called intensive, it creates a significant additional load on the ceiling, therefore it must be provided for at the design stage of the building.

The terrace design provides convenient communication between the living quarters of the cottage and the operated roof, which serves as a resting place

Rolled materials based on modified bitumen, as a rule, are fused with a gas burner, but it is difficult to prevent small flaws that can cause leakage (if there is no second layer)

Rolled PVC membranes , for example, Sikaplan WP, Logicroof, Ecoplast are strong and durable (up to 30 years without repair) and do not support combustion. However, they require a professional approach to installation (the joints of the strips must be carefully welded with hot air) and are relatively expensive - from 320 rubles. for 1 m2. It is important to consider that this material does not tolerate contact with bitumen.

Rolled membranes made of ethylene-propylene rubber (EPDM) and thermoplastic polyolefins (TPO) , for example Firestone RubberGard, Logicroof P-RP, retain elasticity at low temperatures. Note that EPDM membranes are highly flammable (class G4) and are designed mainly for use in the construction of an in-use roof, where the waterproofing is covered with tiles, gravel or soil. EPDM and TPO membranes cost 1.3–1.5 times more than polyvinyl chloride membranes (mostly imported products).

Polymer-bitumen mastics They allow you to create a seamless coating, but they can only be applied to a durable, non-cracking base - a floor slab or a carefully reinforced screed, and this process is quite long and labor-intensive. The service life of a two-layer coating with a thickness of 5 mm is about 20 years, the price is from 120 rubles. for 1 m2. In practice, mastics are used mainly for roof repairs and gluing rolled materials.

Polymer and cement-polymer self-leveling waterproofing , say Aquascud, Osmolastic, Osmoflex, is highly elastic
and UV resistance. To improve performance, materials are used in combination with special primers and lining films, reinforced with mineral fiber (all components are supplied as a set unified system). The estimated service life of the coating is more than 50 years; price - from 700 rub. for 1 m2.

Flat roof: a pragmatist's view

Advantages	Flaws
Eliminates snow avalanches and reduces the risk of falling ice.	Requires significant costs to construct a foundation with high load-bearing capacity.
Provides convenient access to chimneys, ventilation risers, antennas; Compared to pitched ones, it is easier to maintain and repair.	It is more susceptible to atmospheric factors than pitched, so durability is guaranteed only if expensive materials are used.
Can serve as a recreation area or terrace.	Requires increased attention to the arrangement and condition of the drainage system (especially with internal drainage).
Slightly less susceptible to wind loads than pitched.
Allows you to implement the principle of step-by-step modular construction(to make an extension to a house with a pitched roof, you need to solve a difficult architectural and design problem).

Do-it-yourself flat roofs have become popular precisely because of their easy-to-build structure. Let's take a closer look at the process of constructing such a roof.

First step: flat roof house designs

Projects of houses with a flat roof and cottages are not popular enough in moderate climatic zone. Even an impeccable project can be spoiled by poor-quality installation work and the use of low-quality materials.

Unfortunately, in the post-Soviet space innovative technologies and materials appear much later than in other countries.

If you decide to build such a shelter, then it is better to entrust the creation of its design, especially on a residential building, to specialists. There are certain subtleties of installation and operation of such roofs that must be taken into account in the project. Thus, the following processes must be justified:

Cleaning. Indeed, snow and water can accumulate on the roofing surface of a flat roof. If mistakes were made during its design and construction, then all precipitation will gradually begin to flow into the house, and can even significantly damage the ceiling.

Therefore, if you want to build such a roof with your own hands, you need to remember this at the design stage, especially when calculating the slope of the future roof. Even the smallest, visually invisible slope is enough to ensure effective water drainage. It is more difficult for such a roof to cope with winter snow deposits when roofs with the steepest slope, let alone almost flat ones, cannot cope with them. Snow, as a result of alternating thaws and frosts, turns into an ice crust on the roof.

There are 2 ways out of this situation: mechanical cleaning roofing and installation various systems heating and anti-icing, otherwise leaks will appear. Any design developments are calculated and included in the project.

Thermal insulation. A roof with a classic structure, with a pitched system at its base, has a layer of air in the attic, which provides insulation of the house building from above. A do-it-yourself flat roof has virtually no attic and, accordingly, no air gap. Therefore, roofs require additional high-quality insulation and the creation of a thermal insulation layer, which is reflected in the project.
Easy to install. It is easier to build a flat roof with your own hands than a gable, hip, hip or half-hip roof. She doesn't have truss structure, no skates or runs. But this roof requires better installation of the roof covering to avoid leaks.
Application. The flat roof of the house can be used as a terrace, recreation area, sports ground or even a swimming pool. It is enough to equip the sides to ensure the safe stay of people. A modern building materials and technologies make it possible to arrange a lawn on the roofing and plant various plants. This use may be especially in demand in large cities, when it is not possible to create a green area around housing construction. If the shelter is planned to be used not only for its intended purpose, this should be additionally calculated in the project.

Step two: installing a flat roof

Building a flat roof with your own hands is not difficult, so even one builder can handle the roofing of a garage or outbuilding. Technologically, for the construction of such a roof it is assumed that beams made of metal or wood will be used as the main load-bearing element, redistributing the load from the roof structure to the surface of the main walls. The roof must withstand:

load in the form of the entire roof, all its elements and communications placed on it;
the weight of the builder carrying out the inspection or restoration work;
the weight of snow falling on its surface in winter.

When calculating roofing flat design, (especially when calculating its reliability), it is necessary to remember that the load of fallen snow may be too great, since the roof will not have sloped surfaces from which the mass of snow could fall down.

The minimal cost of purchasing building materials makes DIY flat roof construction one of the most inexpensive roofing projects. The basis for arranging such a roof is, as a rule, reinforced concrete. For this, floor slabs or a monolith are used, on top of which all components of the roofing pie are installed. A layer of waterproofing is placed on the concrete, on which, in turn, insulation is laid. The thermal insulation layer is protected by laying another layer of waterproofing on top of it.

Step three: how to make a flat roof with your own hands for different rooms

The technology for constructing a flat roof with your own hands will depend on its further purpose. There are two types of structures for such roofs:

Roofs for unheated housing construction.
Type of roof used for heated buildings.

Roofs over unheated rooms must be made with a slope. Since even a slight slope of the roof will allow you to effectively get rid of moisture resulting from precipitation in the form of snow and rain. The structure of such a roof consists of load-bearing beams, on top of which a continuous boardwalk is placed. Roofing felt (or other flexible roofing building material) is laid on top of the deck in several layers, which serves as waterproofing. Distinctive feature roofs of this type are minimum costs for the purchase of building materials and minimal labor costs, however, the service life of a roof of this design is very short.

Rolled building materials must be fixed with slats with a laying step of 70 cm; the laid slats should not block the flow of precipitation from the roofing surface. The minimum slope of this type of roof should be 3° so that water drains on its own.

If the room over which you need to build a roof will be heated, you should choose an insulated type of roof.

A roofing pie of this kind, consisting of several layers building materials, provides the necessary level of thermal insulation and protection of the insulation itself from moisture.

There are many technologies for constructing insulated flat roofing structures, but to construct them yourself you need to use the most simple options. The base of that roof is made up of beams on which the plank flooring is placed. Roofing material is laid on top of it with an overlap of 15 cm. Insulation made of expanded clay or slag is poured on top of it, and the direction of the slope must be taken into account.

After leveling the insulation, a 2-3 cm screed of Portland cement is made above it. This must be done so as not to inadvertently damage the roof, as a result winter cleaning from the snow. After the screed has dried, it is covered with a bitumen primer, and then a flexible roll is laid roof covering.

It is important to take into account the distance between the support points of the load-bearing beams, since the reliability of the future structure depends on its value. If this value is more than 6 m, then it is better to entrust the construction of the roof to professional builders. If the distance between the walls is less than 6 m, a 10x15 cm beam or an I-beam made of steel is used as a beam.

An alternative to timber flat roof construction is reinforced concrete. With such a roof, the main burden falls on the load-bearing steel I-beams.

These roofs do not have a frame. A reinforced concrete slab must be reinforced longitudinally and transversely, thus increasing the concrete's resistance to bending and damage.
If the roof span is less than 5 m, then beams with a height of no more than 15 cm are used to construct the roof.

When a flat roof is built with your own hands from a cement-concrete mixture, you need to purchase sand, crushed stone and cement, and you will also need water. You can prepare the mixture by hand, but it is better to use a concrete mixer. The ratio of ingredients in the mixture varies and depends on the brand of cement. So for PC-400 grade cement the ratio of parts crushed stone-sand-cement will be 8:4:3 and 2 parts water.

Formwork is made from unedged boards. They are laid end to end along the lower edges of the I-beams, then roofing felt is laid. The next stage of work is the laying of a reinforcing structure consisting of reinforcement, which is placed both along and across the beams. For these purposes, steel rods with a diameter of at least 1 cm are used. The pitch for mesh elements made of reinforcement should be 20 cm. The reinforcement is carefully fixed with steel wire or welding to prevent displacement of the elements during the process of pouring the structure.

Pouring concrete is carried out in different ways, but always until the entire surface of the roof under construction is covered with concrete. The laid mixture is carefully compacted (so as not to damage the structure) with a vibrator. The resulting structure is dried naturally.

During the construction of the roof of a modern house, thermal insulation is required, which reduces the overall heat loss of the house through the roof. Flat roofs can be insulated, unlike other types of roofs, both from the inside and outside. Initially, during construction, insulation is done on the outside, and the inside can be done later - already when the structure is in use. Mineral construction wool is used as insulation. Also, another insulation material—expanded polystyrene—is becoming increasingly popular among builders. It is mounted on wooden blocks, which are placed in increments of 30-40 cm. And the slabs are glued to the wood with mastic or special glue.

The construction of a flat roof is completed by laying waterproofing. Usually they use special material sold in rolls.

The flexible roof covering itself is laid with an overlap of 7-10 cm.

Important: each layer of flexible roofing building material is laid in such a way that the bottom seams of the elements of the rolled flexible building material are placed closer to the middle. All coating strips are laid in the same direction.

Video instructions

Several centuries ago, a flat roof was considered a poor-quality structure that began to leak immediately after intense rainfall, but today the situation has changed dramatically. Flat roofing system allows not only to reliably protect the building from precipitation, but also to save significantly. Of course, such a building will have its own nuances.

Flat roof structure

There is nothing complicated about the roofing layers of a flat roof. Essentially, this is a multi-layer coating that includes bitumen, polymer and mixed products that have high level waterproofing.

Depending on the functionality of the building and its purpose, the roofing method is selected. Roofers know only two methods: fusing and pouring.

If you make a longitudinal section of the roofing carpet, you can distinguish the following layers:

Waterproofing. As a rule, this is the coverage
Cement-sand screed
Dense mineral wool slabs
Vapor barrier layer
Reinforced concrete slab as a base

Now, I will paint each layer separately.

As already mentioned, the role of waterproofing in most cases goes to the coating. It can be installed using the built-up, self-adhesive and pour-on method. If we consider the first type, then the materials used are rolled materials, for example, roofing felt or membrane. As for liquid liquids, the most common product of this type is liquid rubber and mastic.

If cheap rolled material is used, it is often laid in several layers. This ensures increased product durability and good waterproofing plane. It is advisable to lay up to 5 layers of roll product on flat roofs. Average duration The service life of roofing felt is about 10 years, after which the surface must be covered with new material

A cement-sand screed is not always possible. It is poured only when the roofing surface is in use. An example is houses in European countries that have gardens or recreation areas on their roofs. This layer will give the surface additional rigidity, as a result of which the underlying materials will remain intact when exposed to loads
It is best to use as a thermal insulation material mineral slabs. In addition to its functional task, it performs functions similar to a screed and protects the internal layers from damage. It is worth noting that this layer must always be dry, otherwise moisture will play a cruel joke on it. Liquid that gets into the insulation boards significantly “cuts off” its useful qualities and once they are reduced, they will not return. Alternative materials for insulating a flat roof are: polystyrene foam, basalt fibers or bulk products
Vapor barrier material is an integral part of flat roofs. Thanks to them, moisture coming from living rooms will be blocked by condensation and therefore will not be able to reach the insulation boards
The base is most often reinforced concrete slabs and profiled metal sheets, but not so long ago an alternative was found - wood. If for high-rise building, in which the loads reach serious values, reinforced concrete elements are necessary, then for a small private house a flat roof can be laid according to wooden beams. This design seriously saves your finances, and due to its low weight it reduces the load on the foundation

The drainage system of flat roofs is a sore subject. It can be performed both internally and externally. The first type has some advantages, but most developers prefer the second due to its simplicity and low cost. Despite the fact that the surface is flat, there are still slight slopes on it, this is called a slope. It is thanks to it that precipitation can be set in motion.

It is worth understanding that these roofs must eliminate excess liquid without any problems, otherwise the waterproofing material may weaken, and water will get inside, and then you will definitely not get away with expensive repairs.

IMPORTANT: If you plan to lay on wooden system roll welded products, then you should consider its flammability. Under such conditions you cannot operate the burner, but what should you do then? You will have to fasten the first layer with ordinary nails, and only then carry out the work in the usual way, using open fire.

I’ll explain how to properly make a flat roof for a house a little later, but for now I think it’s important to understand its types.

Types of flat roofs

The structure of a flat roof roofing pie will vary significantly depending on its functional purpose. If wood or a reinforced concrete slab is used as the base, then you can afford a serviceable roof.

This is exactly the variety whose area can be arranged at your discretion, but let’s do everything in order.

Unused roof. Its layers are laid traditional method. It consists in the fact that the waterproofing material is located above the thermal insulation slabs. This arrangement of the material does not even allow it to support a person, so to service such roofs it is necessary to install bridges or ladders. As a rule, bulk products are used to coat such surfaces. Non-exploitable roofing is suitable for temporary structures and outbuildings
Operable roof. Here the structure of the roofing pie will be slightly different. Thermal insulation boards are located above the waterproofing. They are laid from dense material, such as mineral wool. Thanks to the screed located on top, the surface can withstand significant loads. On the surfaces of such roofs, you can arrange not only recreation areas or gardens, but also swimming pools or parking lots. You just need to understand that for this you need to make additional calculations and acquire auxiliary materials. As a rule, when medium loads are planned for the roof in use, paving slabs or other hard covering are laid on its surface. The method for laying layers of this roof will be called inversion

A building with a flat roof in most cases does not stand out for its beauty. Therefore, to increase these indicators, it is best to turn to experienced designer. He may advise you to decorate your coziness with a balcony or terrace. It is worth noting that the construction of exploited roofs is not subject to the property of being cheap, but it will not differ significantly from the standard gable system.

Flat roof on wooden beams

A flat roof can be erected with your own hands without any problems, because there is nothing false about it. To do this, it is enough to purchase the exact amount of material and acquire necessary tools. By the way, despite the fact that you can do all the work yourself, it is better to invite a partner. This way the work will be safer and faster.

You will learn how to make a flat roof from the points below.

First of all, you need to take care of favorable conditions construction. For most materials, weather between 5 and 25 degrees Celsius is optimal. Typically, flat roofs are covered with bitumen products, so this temperature range should not be ignored. The fact is that at low temperatures bitumen becomes brittle, and at very high temperatures it begins to melt
After the walls are erected, the support beam - Mauerlat - is laid. He must settle for upper belt, in which embedded parts are already inserted. They are needed to prevent the Mauerlat from moving along with the roof. In most cases, the material for the support beam is coniferous lumber with a cross-section of 15x15 centimeters. Reliable fasteners in this matter are considered anchor bolts, used in the absence of embedded parts, but these fastening methods are often combined with each other. Do not forget that Mauerlat is primarily wood, and it absorbs moisture very well, so between load-bearing wall and this element lays waterproofing
Flat wooden roof laid from boards. They will perform the functions rafter legs, therefore their thickness should be at least 10x15 centimeters. In the places where the support beam will pass, it is necessary to make a recess that is half the height of the element itself. For example, if the height of the beam is 100 millimeters, then the recess will be 50. The pitch of the beams should be in the range from 60 to 120 centimeters. However, everything will depend on the roofing covering
After working with the base and laying the vapor barrier layer, you can begin installing the insulation boards. Most of the material is 1.2 meters wide, therefore, their installation will not take much time. For insulating flat roofs, glass wool, basalt fiber and slag wool are best suited. This material laid in several layers between beams
Before laying the roof covering, you need to take care to create a reliable base and for this you will need moisture-resistant plywood or wooden flooring. If the roof is laid using the fused method, then the first layer is secured with nails and strips, and only then a burner is used. Modern construction also has an alternative option - self-adhesive bitumen products, but you should understand that their price is significantly higher
In most cases, a flat roof is created in order to exploit it, and if you pursue the same goals, then do not forget about waterproofing the parapet. As a rule, roofing felt is used as a material for this purpose. A special wedge is installed at the junction of the vertical element and the roofing plane. It makes a sharp corner more rounded

I hope I clearly explained how to make a flat roof with your own hands, but if you cannot understand any details, contact a specialist. They will not only tell you how to lay the roof, but can also provide their services.

Do-it-yourself flat roofing is a great way to erect a building in a very short period and at the same time save a lot of money.

But do not forget that independent installation should include a complex to protect both the materials and the building itself.

For example, in the first case, antiseptics, various paint and varnish products, etc. can be used, but for the second, a more thoughtful approach will be required, because fire safety- an important component of all construction.

Often, when constructing private houses, preference is given to a pitched roof, but there are also buildings with a flat roof, and the result is very interesting architectural objects. If you decide to build this structure, you need to be prepared for some difficulties. There are pros and cons of a flat roof, and the nuances of its installation.

Pros and cons of a flat roof

It is worth noting from the very beginning that a flat roof for a private house is not ideal horizontal surface. It also has a slope, only a small one (from 1 to 5 degrees). The following main advantages of the roof can be identified:

the ceiling of the upper floor will serve as a supporting structure for the roof;
the same height of the space under the roof will allow it to be used as a full-fledged room;
gives the house an original look;
the possibility of using the roof surface (for example, you can arrange a summer playground there);
simplifies repair work and makes it safer.

The disadvantages include:

strict requirements for the waterproofing layer of the roofing pie;
the need to install an internal drain;
high degree of snow load.

From the above it follows that a flat roof is good decision, provided that everything roofing work will be carried out efficiently and the requirements will be taken into account.

Base for flat roof installation

What will be the overlap of the upper floor directly depends on design features ceilings throughout the house. As a rule, it is performed using the same material as the ceiling between floors.

The most common options are prefabricated or monolithic ceiling made of reinforced concrete, ceiling on a profiled sheet with metal support beams.

An option with a wooden floor is also possible. The fundamental difference from the overlap between floors is the presence of laid insulation and high-quality waterproofing.

Roofing pie options

The type of roofing pie is determined by the nature of its location and purpose. It can be performed in a classic version or made inverse.

A classic roof has the following composition: ceiling, slope made of concrete or expanded clay concrete, vapor barrier, thermal insulation material, roofing covering with a high degree of protection from moisture (mainly bituminous materials).

In an inversion design, the arrangement is different: ceiling, slope, multi-layer waterproofing, thermal insulation material, vapor barrier and, finally, a pressure layer. The latter can be made of concrete slabs, gravel, ceramic tiles, etc.

Name inversion roofing obtained thanks to the mirror arrangement of hydro- and vapor barrier layers in relation to the insulation (unlike the classic version).

This type of roofing is ideal for used roofs. However, the complexity of the technology makes such roofs a rare exception in the field of private construction.

The technology itself is expensive, since the massiveness of the structure makes necessary creation durable ceiling of the upper floor.

Load-bearing structures require detailed calculations at the design stage, and the multi-layer structure of the cake entails significant costs.

Below we will consider only the classic version of the roofing pie, which is often used to equip modern houses with a flat roof.

Roofing material

The material for the roof, namely vapor barrier, waterproofing, insulation and the coating itself, must be selected of high quality.

Vapor barrier is carried out with special membranes, not perforated films. It is undesirable to use polyethylene as waterproofing, since the material does not have the proper reliability.

Insulation for installing a flat roof is selected taking into account the snow load, as well as the load emanating from people working on the roof during repairs.

The insulation must be durable and resistant to wet environments. This can be expanded polystyrene, high-density mineral wool, expanded clay.

The efficiency of the latter is not so high, therefore, when choosing it as insulation, it is necessary to achieve a large thickness of the layer being laid. This increases the load on the supporting structures.

The coating is made from rolled materials: roofing felt, linochrome, waterproofing, etc., and self-leveling mastics are also used. Roll material is considered the most optimal for use when arranging a flat roof.

Roofing technology

The flat roof design involves the following workflow steps. The slope of the roof, albeit small, is achieved by creating a slope.

In this case you can use bulk material(expanded clay), foam concrete (it is advisable to contact specialists), insulation material. The slope is covered from above waterproofing layer, after which the process of laying the roof covering begins.

The next step is laying the first layer. The roll is rolled out, then it is heated using gas burner and sticks to the base.

It is important to ensure that the panels overlap each other and that the material is applied to all vertical roof objects (parapets, pipes, etc.).

Three layers of underlayment and one finishing layer are laid on a flat roof.

The coating installation stage is a labor-intensive process, especially if it is necessary to use adhesive mastic.

For drainage installations, overhead gutters and an internal drainage system are used.

If all the work related to the roof arrangement is carried out correctly, you will have an excellent opportunity to proudly declare the originality of your residential creation. And the photo taken of a house with a flat roof will join the ranks of original design solutions on the Internet.