Flat roof houses: expectation vs reality. Features of a flat roof: the pros and cons of using it House with a flat roof pros and cons

Flat roofs in our time are undeservedly forgotten and are not spoiled by the attention of developers. In private housing construction, they are found mainly in southern regions where heavy rains and snowfalls are rare. hipped roofs, on the contrary, are firmly established in the projects and minds of homeowners.

This state of affairs is explained simply: until recently, builders did not have reliable and durable waterproofing.

Standard roofing material - cardboard impregnated with bitumen, cannot resist moisture and temperature changes for a long time. Even a thick 4-layer coating of it has to be changed after 6-8 years.

Today, interest in flat roofs is starting to grow.

There are several reasons for this:

• Economic benefit. The cost of arrangement is lower than that of a tented one (more simple design and smaller area)
• Additional usable area. There is a possibility of rational use(flower garden, playground, recreation area, swimming pool);
• Availability for maintenance and operation (cleaning drains, installation of air conditioners, antennas, inspection of coatings, ventilation and smoke channels);
• The layer of snow plays the role of additional thermal insulation, reducing heating costs.
• Original appearance building.

Types of flat roofs

Strictly speaking, you will not see a completely flat roof on a building. Any of them has minimum slope from 1 to 4%, necessary for the runoff of atmospheric precipitation.

There are four types of flat roofs:

• unexploited;
• exploited;
• green (lawn);
• combined.

Unexploited roofs are found on industrial buildings.

Exploited roofs have found application in public and private construction. They equip recreation areas, place cafes and restaurants, use them as parking lots and helipads.

Green (lawn) coatings are made to decorate buildings, as well as when there is a shortage of space on the site. In addition to the aesthetic function, they perform an important practical task. A layer of vegetable turf is an excellent heat and sound insulator.

Combined roofs with a flat surface are the most common option. Comfortable outdoor recreation surrounded by green grass and flowering plants everyone likes it.

According to the method of drainage, houses with a flat roof are divided into two types:

• WITH internal drain;
• With external water discharge (along the perimeter of the roof).

Internal drainage is cheaper than external drainage, since it does not require a large number of gutters, pipes, funnels and high-altitude installation work. In execution it is more difficult. Errors in creating a slope, poor-quality sealing of joints lead to leaks and a violation of the integrity of the protective layer of waterproofing.

In operation, flat coatings with internal drainage are more profitable. In winter, icicles do not grow on the overhangs near such a roof. Downspouts run inside the building and therefore do not freeze. Cleaning funnels from debris is easier and easier than hanging gutters.

Device Features

According to the arrangement and location structural layers experts distinguish two types of flat roofs:

• Classic;
• Inversion.

The classic roofing "pie" is equipped according to the following technology:

• on reinforced concrete floor slabs, they make a ramp out of a cement-sand mortar;
• lay vapor barrier and insulation;
• lay a waterproofing membrane or roofing felt carpet;
• if the coating is to be used, then the waterproofing is protected with ceramic tiles.

The construct of the classical flat roof

The main drawback of the traditional design is the vulnerability of the outer insulating layer to solar ultraviolet radiation and temperature changes.

Working on a solution to this problem, engineers came up with the idea of ​​inversion coating. In it, the main structural elements (insulation and waterproof membrane) are interchanged. Waterproofing is hidden under the foam, which is protected from external influences by a ballast layer of gravel or tile trim.

Inversion coating design

Accordingly, the technology of work is changing. A waterproof carpet made of roofing felt or an EPDM membrane is glued onto the slab or spread on it, fixing it at the junction with the parapet.

The slope in this case is created in one of two ways:

• Mortar screed on the plate;
• Insulation, changing the thickness of its installation.

Installation of thermal insulation on a flat roof

Water intake funnels and pipes are installed at the lowest points of the slope. In addition to them, ventilation is installed to remove water vapor that accumulates in the zone of contact between the vapor barrier and the insulation.

When arranging a coating designed for planting plants, the construct is supplemented with an upper layer of waterproofing. Drainage layers of gravel are poured along it, geotextiles are laid and a fertile layer of earth is poured.

In addition to roofing laid on reinforced concrete slabs, projects have been developed for houses with a flat roof on wooden beams.

Construction technology in this case may include the following operations:

• Beams are mounted on the walls in increments of 50-100 cm, fixing them to the masonry with anchor studs. The cross section of the beams depends on the width of the span, the design load and can range from 10x20 cm to 15x25 cm;
• OSB boards are laid along the beams, tightly joining them together;
• Spread the waterproofing membrane in 2 layers, gluing the joints of the canvases with high quality.
• They make thermal insulation from durable (extruded) foam plastic, gluing it to the membrane. A slope for water flow is created by laying the insulation in layers of different thicknesses;
• From above, the heat insulator is protected with a cement screed, reinforced mesh or tiled.

Examples of private houses

Among the developers there are many supporters of flat roofs. They are attracted by the ease of construction, the low cost of work and the possibility of placing a site for summer recreation.

A thick layer of snow on a flat roof is not a problem, but additional insulation

The design of buildings with such a roof fits perfectly into the style of minimalism, providing project developers with a wide field for creativity.

Spacious, comfortable and nothing more - the motto of everyone who chooses a house with such a roof. A pitched roof visually makes the building heavier, while a flat one, on the contrary, makes it light and airy.

The appearance of the facade of a one-story house with a flat roof compares favorably with the fairly boring variations of the "teremkovo" character.

On it, most often you will not see gutters and pipes, the water from which gets on the walls and spoils the appearance of the finish. Internal drainage is effective, practical and invisible.

During the construction of urban high-rise buildings and industrial facilities, the basis of a flat roof is usually a reinforced concrete slab. But for private houses, especially frame and wooden ones, this choice is most often unacceptable. In this case, a flat roof is built on wooden beams. Its main advantage is its light weight, which reduces the load on walls and foundations.

The device of such a roof is simpler and cheaper than when using heavy reinforced concrete slabs. But the functionality is the same. Therefore, this option of a flat roof is often chosen by those who want to build it with their own hands.

The main share of such roofs falls on private houses and cottages, whose owners appreciate the futuristic style, convenience and practicality. Still - on the floors of verandas, terraces, balconies, garages. As a rule, all these buildings are wooden or frame, requiring a light roof structure. But this is not a mandatory rule. Wall material can be any - brick, aerated concrete, foam concrete, etc. In this case, often wooden beams crash into the Mauerlat - wooden beam, running along the perimeter of the walls and connected to them with anchor bolts or studs.

A flat roof is especially attractive to developers because its horizontal surface can be used as a usable area. Moreover, this is possible even for the roof, which is based on wooden beams.

Of course, you should not use the freed meters for a parking lot, a swimming pool or a tennis court. Still, such projects require a more monumental foundation. But an open terrace, an observation deck, a home greenhouse, wooden beams can easily withstand. The main thing is to correctly calculate and not save on the thickness of the lumber.

Types of flat roofs on beams

On wooden floors, you can build a flat roof of the following types:

• unexploited;
• exploited;
• inversion.

That is, all possible types - without restrictions.

Unexploited roof- ordinary, ending with a waterproofing finish. It is intended solely to protect the premises from environmental conditions and has no other purpose. It is impossible to use it as a place of rest, to move in large companies, to install terrace furniture and flowerpots. The coating of such a roof is designed for the fact that 1-2 people will periodically climb it, solely for the maintenance of the structure.

exploited roof- more interesting and more difficult. In addition to direct protective functions, such a roof plays the role of an additional usable area for the homeowner. The construction pie ends not with waterproofing (prone to damage), but with a protective coating - paving stones, decking, wooden deck, paving slabs, sod layer, crushed stone or gravel.

inverted roof- roof-reversible, a qualitatively different option. It can be both operated and non-operated. Its feature is the inverted order of the layers in the cake. If in a conventional roof the waterproofing is laid on top of the insulation, then in the inversion roof the opposite is true. Waterproofing lies under the insulation, and vapor barrier is generally excluded from the structure of the pie. Due to this, the waterproofing is protected from the outdoor environment and its service life is increased.

However, under the influence of unfavorable outdoor conditions, there is a heater, therefore, as part of inverted roofs, the choice of this type of insulation is limited. Only EPS (extruded polystyrene foam) and nothing else! This material has almost zero water absorption, high density and strength. From above, EPSS in inverted roofs is loaded with washed gravel, paving stones, paving slabs or a sod layer.

An interesting option for operated roofs (including inversion ones) is green roof. It can also be held on wooden beams. The cake of such a roof ends with a soil layer on which plants are planted. There are other elements that are not used for other types of roofs: a drainage layer (gravel, expanded clay, crushed pumice or geomats), a filtration layer (geotextile).

Flat roof frame on a wooden base

The frame of the described roofs are wooden beams, laid according to the type of interfloor overlap. Full-length sawn wood or multi-piece (glued) timber can be used. Often beams are made of boards with a section of 100x150 mm.

Beams are laid with support on the walls, similar to interfloor ceilings. If the building is wooden or frame, then the beams rest on the upper crown of logs or the upper trim. If brick or block - then on a pre-fixed Mauerlat. As a Mauerlat, a bar with a section of 150x150 mm or 150x100 mm is usually used. It is mounted on the upper belt of the walls using anchors or studs. To protect the wooden Mauerlat from the material of the walls, 1-2 layers of waterproofing (roofing material) are laid between them.

On the beams, cuts are made under the Mauerlat, they are laid and fixed with metal corners or nails. The step between the beams is maintained 50-120 mm (depending on the calculated load).

When installing beams, it is important to ensure a roof slope of 1-6 °. Despite the fact that the roof is called flat, it is not absolutely horizontal. A slight slope is necessary to ensure the movement of water to the drain and thus prevent its stagnation.

You can create the required slope in the following ways:

1. Immediately lay the beams with the desired slope. Then, if a horizontal ceiling is supposed to be installed under the roof in the room, it is made suspended or sewn onto a horizontal crate.
2. Lay the beams horizontally, and to maintain the required angle, nail wooden plates of different heights to them.
3. Lay the beams horizontally, and form the corner due to the different thicknesses of the thermal insulation laid on top of the frame.
4. Use beams with unequal height allowance.

Most often, the first option is used, that is, beams with a slope are immediately laid. The easiest way to do this is to pin along the top bearing wall a strong run from a bar or board, which will lift the frame (beams) on one side. Instead of a cross purlin, you can also install short radial beams extending from the central double diagonal beam.

Flat roof pie: what's inside?

A flat roof cake on a wooden frame can have a different structure. There are many design options, many of them are posted on the Internet. And they will all work!

Option 1. Roof with insulation over beams

Flat roof insulation layers can be laid over the beams. For example, a proven working option (classic roof with insulation):

• floor beams;
• vapor barrier;
• waterproofing material - polymer membrane.

When used in the structure at the same time EPPS insulation and PVC membranes, a separating layer (geotextile, fiberglass) is necessarily laid between them. The matter is that these two materials are incompatible and at their direct contact there is a destruction of PVC.

The polymer membrane is fixed on the insulation by a mechanical method or loaded with ballast. Crushed stone or gravel (for all types of roofs), paving stones (for operated roofs), soil (for green operated roofs) are used as ballast. However, when choosing a ballast, one should soberly evaluate the reliability wooden frame, its ultimate load.

If the use of welded-on waterproofing or an EPDM membrane with adhesive fixation is supposed to be used as a finish coating, a change is made to the scheme discussed above. It consists in the fact that sheets of plywood, OSB or DSP are laid between the insulation and waterproofing.

It turns out such a scheme:

• floor beams;
• crate (if necessary);
• solid sheathing made of plywood, DSP, OSB;
• vapor barrier;
• insulation - EPPS, mineral wool;
• sheets of plywood, OSB, DSP;
• waterproofing material.

The installation of a built-up roof traditionally requires the use of a gas burner, therefore, according to existing fire regulations, it is unacceptable on wooden structures. Therefore, they act as follows. The first layer of waterproofing is nailed or glued to a wooden base, and the second layer is fused, as it should be. It is also convenient to use euroroofing material with a special adhesive base, for which it is recommended cold mounting without heating with a burner.

Installation of a membrane roof on a wooden base is shown in the video plot:

Option #2. Roof with inter-beam insulation

Another principle for assembling a flat roof cake is associated with laying insulation in the inter-beam space. This option is more convenient than the first if EPDM membranes with adhesive fixation or welded roofing are used as waterproofing.

The following roofing pie scheme is often used:

• floor beams;
• vapor barrier (between beams);
• insulation (between the beams);
• crate (if necessary);
• solid sheathing made of plywood, DSP, OSB;
• waterproofing.

In principle, a similar system is used in the formation of classical pitched roofs.

Option #3. Roof with internal insulation

In this case, sheets of plywood, OSB or DSP are sewn onto the supporting structure (beams), and waterproofing is laid on them. The remaining insulating layers of the roofing cake are sewn from the side of the room.

A rough ceiling is fixed on the beams (from boards or sheet materials), to it, perpendicular load-bearing beams, screw the slats in increments of 40 cm. Place between the slats polystyrene boards by sticking them on mastic or glue. A vapor barrier film is sewn to the insulating layer. Close the insulating cake with a finishing ceiling.

Or you can go against all the "traditional" solutions and build an inverted roof on the beams. Due to the fact that the waterproofing will be covered with insulation, that is, protected from stress, exposure to oxygen, UV rays and precipitation, its service life is significantly increased.

When constructing an inversion roof, you can use the following scheme (from bottom to top):

• beams;
• solid crate;
• waterproofing;
• separating layer (when using a PVC membrane as a waterproofing);
• EPPS insulation;
• separating layer - geotextile;
• ballast, paving slabs, decking, etc.

The principle of inverted roofing is often used for green roofs. For example, you can do this:

What top coat to use?

The wooden base of a flat roof, along with its advantages, also has features with a minus sign. This is an increased fire hazard and low bearing capacity (compared to reinforced concrete slabs).

For waterproofing such a roof, it is desirable to use materials that do not require hot installation. Ideally - polymer membranes. When choosing built-on bitumen-polymer coatings (from a series of euroroofing materials), the first layer of material is mounted mechanically, and the second - by welding. In order to minimize the possibility of fire of structures during installation, it is recommended to use non-combustible DSP boards as a continuous sheathing (on which waterproofing is laid).

When constructing exploitable and ballast roofs, it should also be remembered that excessive load for wooden base may be fatal. Therefore, if the bearing capacity of the beams used is low, light materials should be selected for the finish coating - decking, deck board, rubber paving slabs (rubber mats), etc.

A still unusual decoration of country cottages is a flat roof. It is believed that flat roofs are intended only for urban development or for industrial buildings. But it's not. The roofs of houses in historic neighborhoods are often pitched. And at a private house you can make a flat roof.

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

Types of flat roof

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

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

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

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

Roofs are subdivided according to functionality, the device of the roofing pie and the type of coating. Here are some of the main varieties:

• The unexploited roof is flat. It is built solely for the sake of originality and economy of material. It does not need to strengthen the structure.

• Operating flat roof. It can be used for any purpose, from the placement of an outdoor pool and ending with a parking lot.

The type of overlap depends on the intended purpose: it is obvious that with high expected loads, the base should be a concrete slab. But this does not mean that the entire building should be brick or concrete. For example, a flat roof wooden house can also be exploited. Of course, it cannot be used as a heliport, but it is quite possible to arrange a solarium, set up a garden or put up a gazebo for tea drinking. Of course, a sparse crate cannot be made, only a solid one.

• traditional roofing. The classic version of the roofing cake: a waterproofing layer on top of the insulation, the base is concrete, for the outflow of water - expanded clay concrete (sloping screed).

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

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

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

note

According to the device, these roofs differ from simple non-attic ones; it is impossible to make them exploitable.

With a house height of ten meters or more, as well as on exploited roofs, a parapet must be installed without fail. For exploited - not less than 1.2 meters.

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

General arrangement of a flat roof

It is obvious that the devices used for roofs for various purposes will differ:

When constructing a pool - increased attention to waterproofing;

A “green” roof is also a solid waterproofing plus soil filling, etc.

The most common coating is flat roofing. This is cheapness, simplicity and high laying speed, excellent waterproofing. The cheapest material that can be used to cover a flat roof is roofing material.

The disadvantages of rolled materials (and roofing material in particular) are low durability, low mechanical strength. For exploited roofs "with high traffic" tiles are preferable.

A flat roof made of corrugated board and a flat roof made of corrugated board can only be made in a non-exploited version and with the necessary slope. When choosing a material, you need to read the instructions for the model: some types of profiled sheets and metal tiles can be laid on roofs with a slope of less than 11 degrees.

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

There are other coating materials for unused roofs:

• Polycarbonate;

Pros and cons of flat roofs

Advantages:

• Original look. Flat roofs in cottages are rare.
• Possibility of exploitation.
• Flat roof - easy installation and savings on materials. But it depends on how you plan to operate the roof. And that construction will cost even more than an expensive pitched roof made of ceramic tiles.
• Laying, maintenance, repair on a flat roof is easier than on a slope.
• Flat roofs are windproof, pitched roofs have windage.

Minuses:

• A flat roof leaks more often than a pitched one. It is necessary to constantly monitor the condition of the waterproofing layer.
• The need to clear the roof of snow.
• Flat rolled roofing requires more frequent repairs and resurfacing than metal profiled, tiled and other pitched roofs.

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

Building a flat roof

Consider the option when the profiled sheet is used as the basis of the roof:

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

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

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

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

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

6. On flat roofs it is possible to lay the built-up roof in several layers.

In other cases, a flat roof on wooden beams is arranged more traditionally: a solid plywood or OSB crate is nailed onto the beams, a roofing cake is laid (vapor barrier + basalt wool), a waterproofing layer and a rolled roof are directed.

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

Not so long ago, such a fashion as a flat roof in a private house came to the CIS countries. Most developers did not consider this appropriate and continued to build pitched roofs. They can be understood, because a few decades ago, when the quality of materials was in doubt, the construction of a flat roof was carried out only on temporary structures. But today, when the quality of materials has improved significantly, it is foolish to refuse this roofing type.

Flat roof roofing cake

It is not necessary to say again that a residential building with a flat roof is reliably protected from the wind. As for moisture removal, roofers also learned how to solve this problem qualitatively. They realized that a low slope device would naturally remove excess moisture from the roof plane, but this could be prevented by materials whose structure has various roughnesses.

That is why installation work should be thought out in more detail, but it's worth it. After all, you save a lot on lumber and the time it takes to build a flat roof.

So, in order for all layers to perform their functions qualitatively, they should be laid correctly. This is what a flat roofing pie should look like:

• Base. As a rule, it is made of reinforced concrete slabs, but some use thick profiled metal. This component of the roofing pie will carry impressive loads, therefore, it should be made as stable as possible. Often, flat roofs are made exploitable, for example, a lawn is sown on the surface. If you plan to do something like this with this plane, then check the calculations of the base several times.
• Vapor barrier layer. During operation, this component will play an important role. It will serve as protection against moisture vapor coming from the underlying floors. Remember that if moisture gets to the heat-insulating boards, then they will have to part with their positive qualities, therefore, this layer will become useless. For the installation of a vapor barrier layer, as a rule, polyethylene film or bitumen is used, but developers who have finances can afford a unidirectional membrane. It allows you to remove excess moisture from heaters and at the same time serve as protection for them.
• Thermal insulation layer. A flat roof differs from a pitched one in that there is the possibility of laying unique materials, such as backfill. They are perlite, slag, expanded clay, and so on, but in addition to them, this layer also includes slabs of mineral wool or foam. By the way, roofers try to lay these materials in such a way as to give the roof some slope. As mentioned above, this allows atmospheric precipitation to naturally move away from the roofing plane. The requirements for this layer are as follows: light weight and low hygroscopicity
• The most important component of a flat roof is waterproofing layer. Bituminous, polymeric or mixed products are used as it. You can choose slightly different materials for yourself, but remember that in addition to waterproofing qualities, they must be resistant to sudden temperature changes, good elasticity and a long service life.

A high-quality choice of materials and their installation will significantly affect how long a flat roof will last in a private house. It should be understood that the failure of at least one of them will certainly lead you to repair, therefore, consider the selection roofing materials most seriously.

Varieties of flat roofs and the nuances of their installation

Before you make a flat roof device for a private house, you should figure out what goal you will pursue.

• If you want to create an unused roof, then it is best to use profiled metal sheets. This will save you money and significantly affect the speed of the installation process. But if you are in doubt, it is best to immediately consider this option and resolve this issue.
• Operated roof implies that on its surface you will build some additional structure or arrange a pool or lawn here. This type the roof will great solution in buildings, the dimensions of which do not allow the creation of additional rooms. It should be understood that with the arrangement of the roof space, the load will increase, which puts pressure on the base, therefore, reinforced concrete slabs are laid as it. According to technical documents, the slope of such a roof should not exceed three degrees.
• Inversion. This type is a variation of the traditional one. Their difference lies in the fact that they are laid in an inversion roofing cake a little differently. Waterproofing changes with thermal insulation boards. This option is the most common in private construction, so architects offer it.
• ventilated. Despite the fact that ventilation is more suitable for pitched roofs, there is a flat ventilated roof in construction. To do this, aerators are correctly placed on its surface, which, under the pressure difference, pull the polluted air out and thereby circulate it. Their device is advisable to perform with large roofing areas.

Before you start building, carefully consider all the details. As for load calculations, this work is best entrusted to professionals in their field.

Construction of a flat roof on unheated structures

If it is necessary to cover a temporary structure, for example, a shed, a gazebo or a canopy, a not very difficult structure is created. Support beams are used to control the slope. Tilt at 3cm by 1 running meter slope, which, in fact, will be 3% will be quite enough for precipitation to be removed naturally.

The basis for the roofing cake will be solid wooden crate. By the way, for ventilation between the boards, it is worth leaving a small distance of 1-3 millimeters. This will remove the resulting condensate. Self-tapping screws or long nails are used as fasteners.

The waterproofing layer on this structure will be rolled material - roofing material. This product is a very cheap material and its qualities are enough to cover a temporary structure and protect it from moisture for 10 years, and if repairs are needed, it is enough to buy a couple more rolls of roofing material and roll it up again, on the old basis.

The bituminous material is laid in layers. The overlap of the strips should be at least 10 centimeters. The coating is fastened to the base by means of a device on its surface with wooden or steel slats. Their installation should be carried out in such a way as not to interfere with the natural descent of water from the surface.

Building a flat roof on temporary structures is usually not a difficult job that can be done by one or two workers.

Roofing on heated buildings

The device of a flat roof of a private house, in which heating is provided, will take place as follows:

• First, the floor beams are installed. During this process, it is especially important to follow the horizontal, so for the convenience and speed of the process, get a laser level.
• Unedged flooring is made on the installed beams. wooden planks, the thickness of which is about 4-5 centimeters. If there is a very large distance between the installed support beams, then the cross section of the boards must be increased to the required design value.
• Roofing material strips are rolled onto the created base, but other material can be taken as waterproofing. After cutting off unnecessary parts, some developers leave the bitumen product in this state for a day, but further work can be carried out without waiting for this period. For a reliable connection, the joints of the strips are laid with a ten-centimeter overlap.
• After waterproofing, as a rule, heat-insulating material is laid. You remember that often a backfill product is used for flat roofs. Its device hides some dangers, because with a small mistake, you can come to the conclusion that huge puddles will collect on the roof surface, which will significantly reduce the life of your roof, so I advise you to invite a knowledgeable person to carry out this work.
• Next, the plane is poured with a screed thickness, which should be at least 20 millimeters.
• After the cement mass has hardened, the entire roofing surface is primed, and then the roofing is laid.

If you perform these layers with the highest quality, then your roof will last even longer than the manufacturers of roofing products assure about it.

Monolithic concrete as a roof

In addition to the well-known methods of erecting a flat roof in construction, a new method for creating a roof has recently appeared. So, here technological process construction of a concrete roof.

• Concrete is far from light building material therefore, appropriate products should be used as floor beams. For its role, an I-beam steel beam, the thickness of which is 120-150 millimeters, is ideal. Their installation must be carried out without any slopes, ideally horizontally.
• Experienced developers recommend using a concrete grade of at least 250. It is best to mix it in a concrete mixer installed at the facility. If you still decide to knead the solution by hand, then most likely you will not achieve the desired consistency. Concrete is created in the following ratios: 4 buckets of fine gravel, one and a half buckets of cement, a bucket of sand and required amount water
• The base is all the same lumber located on the lower shelf of the I-beam. Wooden elements should be protected from the solution with waterproofing material, for example, roofing material. After the waterproofing wraps the boards, a reinforced mesh with 2x2 cm cells is laid on top of it
• The next layer is fine gravel, and then comes the prepared concrete

IMPORTANT: Complete the entire pouring process within one working day, otherwise it threatens to cause cracks on the future element.

• Let the screed harden. She will do it in 1-2 days, in addition, do not forget to take care of the concrete, of course, if quality is important to you. To do this, wrap it with plastic wrap or, after some time, water this element with water.
• After complete drying, bulk material - expanded clay is delivered to the resulting plane. Then they make a ramp and lay out a ballast sleeve from paving slabs

In this article, I have mentioned the breakout quite a few times, and for sure not everyone knows what it is, so let's explain.

What is a slope

This process is typical only on flat roofs. It is arranged in order to ensure the natural descent of precipitation from the roof surface. As a rule, a flat roof is arranged with an internal drain, but there are options where it will be external. Therefore, at the very beginning of construction, it is building to think over the moment and decide which drain will be more profitable for you.

If your choice fell on internal system drain, then the slope is carried out so that water enters special water-catching funnels. Their number in everything depends on the dimensions of the roof plane, for example, 1-2 funnels are provided for a roof of 25 square meters.

When an external drainage system is equipped, then with the help of a ramp, water is brought to the edges of the slopes, where a gutter is arranged.

Unfolding can be done in the following ways:

• Create the necessary slope using bulk material. Expanded clay or perlite is ideal for this. Having set the required slope, this material is covered with a screed, and the roofing is already laid on it
• Thermal insulation boards are also able to set the required slope. But I believe that playing with the laying of this layer is much more complicated and costly than purchasing expanded clay
• A specially designed formwork allows you to pour concrete so that it is already with the required slope.
• The most expensive method of unfolding is considered to be a device plastic panels, which differ in thickness from each other. By laying them out in a certain sequence, you can achieve the required slope

A flat roof is a great solution for creative people. After all, this design will not only serve as an excellent protection for your comfort from the weather, but also give you additional square meters that you can use for your own purposes, for example, equip your workshop for crafts on the roof.

Having made special fences on the roof, you can build a rather interesting playground right on your roof! And if the options I have proposed do not suit you, then perhaps you will find the use of these square meters on your own.

Architects and developers are attracted by these unusual buildings, where you can equip an observation platform 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, the choice of materials for insulation and waterproofing, the organization of water flow, maintenance, etc. Finding answers to them is not easy. The fact is that domestic contracting firms working in the field of cottage and are well familiar with the most popular design - pitched, and, as a rule, they do not have experience in erecting flat roofs arranged in a completely different way.

flat roof cost

Immediately noteworthy is the fact that the area of ​​​​a flat roof is less than a pitched one, which means that it will be required less materials and the labor will be cheaper. However, this statement is true only for regions with a warm climate and low snow load, moreover, if we are talking about an unexploited roof. IN middle lane In order to ensure the reliability and durability of a horizontal roof, Russia needs to apply rather expensive engineering solutions.

beam ceiling

In principle, when erecting a ceiling, a combination of beams (wooden, steel) and a supporting corrugated board can be used. However, experts do not recommend the use of 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. Roofing made of steel I-beams and corrugated board with a wave height of 60 mm and a wall thickness of 0.7 mm makes it possible to cover a span of up to 12 m and withstands 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 is wiser to use corrugated board as fixed formwork, which, by the way, does not eliminate the need to build a reinforcing cage.

It turns out that 1 m2 of a flat concrete or steel base, the bearing capacity of which will withstand the weight of the snow cover, costs 2–2.5 times more than the wooden beam structure of a pitched roof. The difference in the volumetric flow rate of the insulation is offset by the fact that a flat roof requires a more expensive material. high density. There is still hope to save on roofing, however, modern polymer membranes - optimal waterproofing for horizontal roofs - they are no cheaper (and sometimes much more expensive) than flexible tiles. It will not be necessary to install snow guards, however, without a roof hatch and drainage system not enough. If you try to reduce the cost of the estimate, then later you will have to pay with the need to repair the roof every 10-15 years.

The durability of a flat roof largely depends on the ability of the supporting base to withstand operating loads without significant deformations.

Finally, it should be noted that flat roofs are only suitable for houses. modern architecture- with a large glazing area and complex finishing with the latest facade materials. Both of these won't come cheap.

On a solid foundation

As a rule, in low-rise housing construction, flat roofing is a prefabricated or monolithic reinforced concrete slab. Reinforced concrete slabs (PB, hollow core PC, PV, etc.) are able to cover a span up to 9 m long and withstand a pressure of 8, 9 or 12.5 kPa (this value is indicated by the last digit in the product marking). They can serve as a "base" for any roofing pies, including those with a top layer of paving slabs or fertile soil. However, for the installation of the structure, it will be necessary to ensure the arrival of a truck crane site (while steel beams and decking are easy to lift with winches). The depth of support of the ceiling on the wall depends on the material of the latter - for example, for a 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 an elastic polymer tape.

The main advantage of membranes based on artificial rubber is that they remain elastic at low temperatures, that is, they can be mounted in winter

Flat roof classification

Flat roofs are divided into non-exploited and exploited. The former are visited only for revision, prevention and repair; for this purpose, a roof hatch is equipped, to which an attic staircase leads. The operated roof in cottages most often serves as a terrace, that is, a durable wear-resistant coating must be laid on it, and the supporting base is designed for increased loads. A variety of exploited - a roof with landscaping, lined with a turf layer on top of the main heat and waterproofing cake; usually it is arranged with paths and a recreation area. A convenient exit should be provided for the operated roof, for example, from a vestibule superstructure.

A monolithic reinforced concrete floor is erected from heavy concrete using a removable (for example, from OSB boards on jack stands) or fixed (from corrugated board) formwork. It is reinforced with a two- or four-level welded frame made of bars with a diameter of 12 mm or more. The dimensions of a monolithic slab are not regulated (unlike a prefabricated one), which provides the architect with freedom in designing a building; other pluses are the absence of seams, the relative simplicity of the arrangement of passage units (chimney, ventilation ducts) and high bearing capacity (subject to the technological regulations).

Roof protection from cold and heat

In the low-rise sector, mostly non-attic flat roofs are in demand, because the attic requires additional costs and violates the architectural proportions of the house. So, the roof should protect from the winter cold and summer heat. Wherein common feature flat roofs lies in the fact that the heat-insulating layer is located on top of the supporting structure (in pitched roofs it is usually located between the rafters). If the room is insulated 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 configuration

As for the options for the execution of the roof, there are dozens of them. Suffice it to say that only in SP 17.13330.2011 there are more than 40 "recipes". At the same time, companies - manufacturers of coatings and insulation offer more and more new engineering solutions. However, they are always based on one of two circuit diagrams- traditional or inversion.

Schemes of the device of roofs "TechnoNIKOL"

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

The traditional design in general terms is as follows: a vapor barrier film (polypropylene, polyethylene, butum-polymer) is laid on top of the supporting base, then a heater follows, for example, mineral wool boards with 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, from a polyethylene film), along which a reinforced slope-forming screed is poured (a flat roof must be given a slope of 2-3% to the center or edges to ensure water flow). The dried screed serves as the basis for a rolled or mastic waterproofing coating.

"TN-ROOF Green": 1 - ceiling; 2 - expansion from expanded clay; 3 - reinforced screed; 4 - bituminous 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 placed at the very bottom of the pie; in this case, the roof waterproofing is fixed with gravel ballast, paving slabs on supports or special dowels. Some materials, for example, the "RUF SLOPE" (Rockwool) or "TechnoNIKOL Slant" system, allow you to do without a screed at all: the plates have a variable thickness, and with their help it is easy to create smooth level drops to ensure water flow.

The inversion roof is arranged differently: in it, a heater resistant to constant exposure to water (usually extruded polystyrene foam - EPS) is located on top of the waterproofing. At the same time, the latter is reliably protected from mechanical damage and is located in the zone of positive temperatures (freeze-thaw cycles are destructive for almost any material). It is easy to turn an inverted roof into an exploitable one, for example, by filling the insulation with a drainage layer of sand gravel and laying paving slabs. The disadvantages of the design include a more complex drainage system. However, drains need to be discussed separately.

There are special requirements for thermal insulation for a flat roof. The material should not only have a low coefficient of thermal conductivity, but also resist mechanical loads well - both distributed (pressure of the higher layers of the roofing cake, equipment, snow) and local ones that occur during installation. In addition, it is important that the material has hydrophobic properties and is non-combustible. At the moment, there are several ways to install thermal insulation: using mechanical fasteners, adhesive and free laying. In addition to the traditional two-layer insulation, one-layer laying is becoming an increasingly popular solution. Rockwool offers unique dual-density boards that consist of a rigid top layer and a lightweight bottom layer to speed up and improve quality.

Grigory Gromakov

ROCKWOOL Flat Roof Development Specialist

Flat roof drainage

A flat roof is equipped with a parapet (attic) 30–90 cm high, which helps to ensure organized; on the operated roof, it also serves as a safety fence. At the same time, the design of gutters should be approached very responsibly, because in the event of an error, a huge puddle can form above your head, which threatens to damage the 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 therefore more durable and reliable than the outdoor one. Let's talk more about its main elements.

Drainage funnels are installed on low sections of the roof. As a rule, two funnels are mounted on roofs up to 150 m2 - the main one, connected to the riser, and the emergency one - with water discharge 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 inverted and green roofs, special funnels with drainage rings have been developed to collect moisture from the intermediate layers. Water intakes must be equipped with electric heating based on a self-regulating cable - then they will properly perform their function during alternating thaws and frosts.

Covering traditional with an external drain 1 - overlap; 2 - slope-forming screed; 3 - vapor barrier; 4, 5 - mineral wool insulation; 6 - waterproofing; 7 - drain

In systems of a new type, the so-called siphon-vacuum systems, 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 gravitational ones.

The drainpipe is made of sewer pipes - polypropylene, PVC, and it makes sense to use noise-absorbing products, such as RAUPIANO Plus (REHAU), or to soundproof the riser, otherwise you will hear the murmur of water for hours. The riser is attached to the funnel using an elastic coupling. When laying pipes, minimize the number of elbows and the length of horizontal sections that reduce the throughput of the system.

A drainage pipe laid in the basement or insulated underground connects the riser to the rain sewer or provides water discharge into the 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 a collapsible connection or revision module.

Image: Vladimir Grigoriev/Burda Media

Roof covering inversion with an internal drain 1 - coupler; 2 - PVC membrane; 3 - EPPS; 4 - funnel with a 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 rains 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 the facades, but it does not require holes in the roof and ceilings and does not eat up the usable area of ​​the house. Water is discharged through parapet funnels or branch pipes embedded in the parapet, under which classic funnels are installed (as on a pitched roof) and downpipes attached to the walls with brackets. The calculation is based on the fact that for each square meter the roof area should account for 1–1.5 cm2 of the cross section of drainpipes. Elements of the external system can be made of PVC, steel, copper, zinc-titanium.

For operated roofs, as well as roofs, arranged in regions with severe climatic conditions, the inversion scheme is ideal. Since the waterproofing layer is located under the thermal insulation layer, it is protected from mechanical influences, as well as from temperature extremes and UV radiation, which significantly extends the life of the roofing system. Waterproofing materials on the basis of modified bitumen, it is necessary to lay at least two layers - this technology is more common, and in addition, it allows you to level possible errors during the deposition of the material. For a polymer membrane, one layer is enough, and reliability is ensured by automatic welding equipment, which greatly increases the speed of work. In addition, an open flame is not used when installing a polymer membrane, so the technology is considered safer.

Dmitry Mikhailidi

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

Roof greening

Turf-covered roofs have been used since ancient times in countries with a moderately cold and humid climate, 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 covering it from ultraviolet rays. In addition, it absorbs rainwater, unloading gutters, dampens the sound of rain, protects the upper floor from overheating in summer and reduces heat loss in winter. It is believed that landscaping almost doubles the life of a roof. Its disadvantages include an increase in the load on the supporting structures of the building and an increase in the cost of construction. In addition, the green carpet needs care, the intensity of which depends on the selected plant species. If you do not pay due attention to plantings, they will freeze and die from drought.

To green the roof, it is necessary to lay on top of the main waterproofing layer (in the case of an inversion scheme - on top of the insulation) an additional cake of materials that will protect the waterproofing layer from roots, filter and drain rainwater. For these purposes, special films, dense geotextiles, gravel bedding or drainage and moisture-accumulating membranes made of high density polyethylene, such as PLANTER GEO or Delta-Floraxx, are used.

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

The terraced structure provides convenient communication between the living quarters of the cottage and the exploited roof, which serves as a place of rest

No leaks

Sheet and piece coatings are unsuitable for a flat roof: water will inevitably seep through the joints of the elements. Therefore, roll materials and mastics are used. Let's bring them brief description.

Roll reinforced polymer-bitumen roofing . The mechanical strength of these materials is several times higher than that of roofing paper (, roofing paper). And modifying additives increase resistance to moisture, air and ultraviolet. The material is glued to the base with mastic, fixed mechanically or (most often) welded. There are coatings for the lower layers of the roof ("Technoelast EPP", "Uniflex EPP", "Bireplast TPP", etc.) and for the upper ones ("Technoelast EKP", "Uniflex EKP", "Hydrostekloizol TKP", etc.). The latter are sprinkled with mineral chips, which reduce the risk of fire and additionally protect against mechanical damage and UV exposure. The cost of waterproofing of both types is low - from 65 and from 150 rubles, respectively. per 1 m2, and the average service life of a roofing carpet is 15–30 years.

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.

Roll 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 mainly designed for use in the construction of an exploited 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 ones (mostly imported products).

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

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

Flat roof: pragmatic view

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