flat roofs in demand in modular construction. Among the advantages of this method are the affordable cost and high speed of housing construction, as well as the possibility of a phased increase in its area.

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 aware of 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. AT 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 a 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 a wooden beam structure. 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 high-density material. There is still hope to save on roofing, however, modern polymer membranes - optimal waterproofing for horizontal roofs - are not cheaper (and sometimes much more expensive) shingles. You won’t need to install snow retainers, but you can’t do without a roof hatch and a drainage system. 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 appropriate only on houses of modern architecture - with a large glazing area and sophisticated 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 top layer from paving slabs or fertile soil. However, for the installation of the structure, it will be necessary to provide a check-in to the site of the truck crane (while steel beams and flooring 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. At the same time, a common feature of 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 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 fundamental schemes - 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: on top of the supporting base, vapor barrier film(polypropylene, polyethylene, butumno-polymer), then follows a heater, for example - plates from mineral wool, having a compressive strength at ten percent deformation of at least 30 kPa, in one or two layers with a total thickness of 200 mm or more. Above is a separating layer (for example, from 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 system (Rockwool) or TechnoNIKOL Slant, 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 must 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 in household sewerage(the latter must be equipped with a water seal). The outlet pipe is cleaned through 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 usable area Houses. Water is discharged through parapet funnels or branch pipes embedded in the parapet, under which classic funnels are installed (as on pitched roof) and pipes-descents attached to the walls with brackets. When calculating, it is assumed that for every square meter of roof area there should be 1–1.5 cm2 of the cross section of drainpipes. Elements outdoor system can be made of PVC, steel, copper, zinc-titanium.

For exploited roofs, as well as roofs arranged in regions with harsh 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 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 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, when installing a polymer membrane, it is not used open flame, 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 watering 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 floor, so it should be provided 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

Roll materials based on modified bitumen, as a rule, are fused with a gas burner, while 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 professional approach for 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 kits). one system). Estimated service life of the coating - more than 50 years; price - from 700 rubles. for 1 m2.

Flat roof: pragmatic view

Advantages	disadvantages
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 a house with a pitched roof, you need to solve a difficult architectural and design problem).

Many people think that modern house with a flat roof looks unusual, rich and original. Using such a roof for country cottages and villas in construction, the owners emphasize their wealth, sophistication of taste and originality of thinking. Country houses with this type of coverage are great place where you can take a break from the routine and gain strength for new achievements. A flat roof is not only original, but also practical.

Building a house with a flat roof is often used in areas with low rainfall. Often the choice of the type of roof is influenced not only by the desire of the owner, but also by climatic conditions. Therefore, if you decide to equip a flat roof in an area where there is frequent rainfall, then you definitely need:

• take into account the maximum load;
• apply in the construction of beams with a good section;
• use strong fastenings of all elements.

The most common form of construction of houses with a flat roof is the shape of a square. A square house with such a coating turns into an original penthouse that meets the standards of European style. In this article we will tell you how to make a flat roof with your own hands, write down all the pros and cons of this roof.

Advantages and disadvantages

Advantages:

1. The use of this type of roof not only expresses the originality of the external shape of the building, but also allows you to equip the upper surface of the surface for your needs.
2. One of the advantages of such a house is the arrangement of a pool with a place to relax or plant ornamental trees, shrubs and lawn. In addition, on such a roof you can save a lot of money, because it does not require complex truss systems and is easy to build with your own hands.
3. A flat roof is also good because it has a special niche in the cavity, which is an additional insulation that retains heat in the building and significantly reduces heating costs in winter period.
4. Repairing a flat roof will take a little time and will not be too difficult. In addition, if you choose roofing material or some other material for the roof a budget option, this will help to save additional funds.
5. The whole essence of the repair usually does not come down to a full overlap of the roof surface, but only to timely periodic prevention in the form of repairing cracks.

Disadvantages:

1. The undoubted disadvantage is that the process of designing a flat roof and its installation must be very accurate. The slightest gaps in the work of builders can turn into costly repairs inside the building.
2. In addition, it should be remembered that a flat roof must be made at a certain slope (usually varies from 3 to 15 degrees, depending on the design and the level of annual precipitation). Otherwise, precipitation will remain on the roof covering for a long time, which will create an extra load on the structure and reduce the life of the roof.

The flat roof has its own undoubted advantages, and the cons are easily corrected by a careful approach to the very process of its construction.

Device

The structural system of a flat roof for an unheated space consists of the following:

• bearing beams;
• rack or metal crate with a small step (50-70 cm);
• roll cover.

Note! The angle of inclination of such a roof is provided by the entire structural system, starting with the beams. Therefore, care must be taken during installation to maintain the slope. To do this, check it every few meters. If desired, you can make a gentle frame for the truss system (tilt angle - 10 degrees). To do this, you need to install it along the roof. After that, you can attach the crate.

The device of the heated room has a slightly different look. It includes:

• bitumen primer for screed;
• roll coating;
• screed based on cement mortar;
• roofing felt (overlap 15 cm);
• heaters, such as expanded clay, slag and other similar materials, are the main components for creating a roof slope;
• load-bearing beams (step from 0.5 to 1 m, section from 100x100 to 150x200 mm);
• plank sheathing (flooring).

Monolith roof

Instead of wooden beams, metal I-beams (from 12 to 15 cm) are being laid, on the lower shelves of which a solid plank crate lies. Roofing material is laid on it. Then a reinforcement frame is mounted in two rows (a profile with a cross section of 10-15 mm). It is important to observe the distance between the reinforcing cage and the roofing material. The next step is filling concrete mix which needs to be compacted periodically.

Note! If the weather is hot, the concrete layer must be covered with a protective polyethylene film so that it does not harden quickly, but evenly and efficiently. It is advisable to remove the film not earlier than after three or four days.

In the absence of such a film, you will have to monitor the process of concrete hardening and periodically water it with a small amount of water. After the layer has dried, it is necessary to give the roof a certain slope with the help of heaters, and then make a screed and lay a roll coating. On this, the device of a monolithic roof can be considered complete.

Roof base

Can be used for flat roofs reinforced concrete slab or corrugated board.

Decking is used in cases where the upper part of the roof will not be used as an additional platform. This type of base is the most economical, however, it needs additional insulation.
First, a base layer is installed, and a vapor barrier layer is laid on top of it. The latter is used to save warm air in the house and prevent it from escaping into the air space. Vapor barrier is mainly made from rolls of a certain length and cutting width. The place where the vapor barrier overlaps must be carefully glued, melted and welded. Polyethylene can be used as a vapor barrier material.

At the next stage, thermal insulation is laid, for which special plates are used with a certain joint between them. Most often, a two-layer thermal insulation system is used.

After that comes the equipment for waterproofing from a polymer film. It protects the inside of the roof from the outside environment. Waterproofing is welded, and then laid down in several layers.

When the hydro- and vapor barrier are ready, it's time to put the final coat. Its role is played by a concrete building screed and reinforced concrete slabs.

Polycarbonate base

AT recent times in construction work on roofs, polycarbonate was often used.
A roof made of this material may suit you if you do not want to make a room under it. Alternatively, you can build a covered greenhouse or gazebo.

Polycarbonate has increased strength and at the same time is a very light material that is quick and easy to install. It does not need additional structural reinforcement.

Thus, a flat roof can be made in various forms. In any case, no matter which option you choose, you should always be careful about the installation, because with serious errors, you can run into big expenses and a complete alteration of the roof from scratch.

Warming and waterproofing

Flat roof waterproofing can be done using the following components:

• PVC and EPDM membranes;
• waterproofing film;
• hydrophilic rubber;
• liquid rubber, sprayed waterproofing (polyurea);
• penetrating materials;
• lubricants;
• silicone-based resins, as well as emulsions (injectables).

New to the technology market are waterproofing materials such as PVC, PDM and diffuse membranes. Super-diffuse material has become especially popular, which does not need to make a gap between heat and waterproofing, qualitatively repels moisture and does not let it through to the heat-insulating layer. In addition, these membranes have long term services (up to 25 years), are fireproof and environmentally friendly.

In the form of waterproofing, mastic can be used. It is applied both on a flat roof and on a roof with a slight slope.

According to the method of application, they are divided into cold and hot. Cold mastics should be applied to the surface at positive temperatures, and hot mastics require preheating (160 degrees) before application and can be used at almost any time of the year. The principle of operation of mastic is based on the fact that it firmly sticks to the base. The validity period of this type of coating is about 20 years.

In some cases, paint waterproofing may be used. In the process of such insulation, bitumen, emulsions, paints and varnishes are applied to the surface of the coating. The coating takes place in several layers until the desired thickness (5 mm) is reached. A layer of fine-grained sand is applied on top of the coating. The service life of waterproofing is 5-6 years.

Note! One of the most reliable and proven types of waterproofing is glued waterproofing. It is the use of roofing material, which, after preheating, is glued to the surface of the coating.

After selecting and installing waterproofing, you should do insulation - very milestone flat roof construction. There are several types of insulation:

• By location: external and internal.
• By the number of applied layers: single-layer and two-layer insulation system.

The two-layer system makes it possible to reduce the load on the floor. The bottom layer plays the role of a heat insulator in this case. Upper - has a distribution function, has a denser structure.

Now you know how to make a flat roof with your own hands. As you can see, it's quite easy. You just need to carefully approach the matter, and soon the coating for your home will be ready.

Video

The choice of a particular design largely determines the possibility of using the attic as an additional living space, resolves the issue of the need for insulation and determines the type of roofing.

A flat roof is a specific option that does not allow you to equip the attic as a living space (due to its absence).

But it offers a lot of opportunities for using the territory as an auxiliary site, a place for placing equipment or as a private recreation area, isolated from the external space.

In this regard, a flat roof can provide many interesting possibilities, but its use has its limitations.

The main feature of a flat roof is an almost horizontal surface. such surfaces is low - up to 8 degrees, it is needed only to drain rain or melt water.

According to the conditions of the plane location, there is practically zero wind load (at correct device without hanging edges) at maximum snow.

Wherein, roof structure has a complex multilayer structure, which ensures the tightness of the coating and the working condition of the insulation.

The most favorable operating conditions for flat roofs:

• Small amount of snow in winter. The most successful use is in regions with warm or little snowy winters, when removing snow from the roof is not difficult.
• The strength of the wind does not have a significant effect on the roof, therefore, it is permissible to build such roofs in areas with strong or heavy winds.

For areas with cold and snowy winters, the use of flat roofs is only recommended. for small commercial buildings with a relatively small area.

The use of flat roofs on residential buildings is more common in southern regions, where the problem of high snow pressure in winter is absent.

Flat roof

The structure of the roofing pie

There is no specific, classic composition of a flat roof roofing pie. The structure of the layers most often based on the following factors:

• The purpose of the roof;
• Cover type;
• Roofing material.

The decisive factor determining the composition of the roof from the very beginning of construction is the purpose of the roof. It depends on him what material is needed for the construction of the floor, how exactly it will be insulated, what is in this case optimal material coatings.

Warming of a flat roof from a soft roof is made from the outside, since this method is much more convenient and reliable in terms of the tightness of the cake.

The general technology of insulation looks like this:

• Base (concrete, wooden floor);
• vapor barrier film;
• layer of insulation;
• The top layer of waterproofing;
• Roofing.

This is a general plan, in practice it is often supplemented or complicated in order to more reliably protect against water penetration or the formation of cold bridges.

roofing cake

One of the flat roof options is inverted roof. This is relatively the new kind cake design, taking into account the shortcomings of conventional options.

The fact is that a common misfortune of flat roofs is the seepage of water through the insulation into the ceiling and the appearance of stains and streaks.

To eliminate this phenomenon, an inverted roof is used when a reliable waterproofing carpet (often multilayer) is installed between the ceiling and the insulation.

The composition of the pie is built like this:

• overlap;
• Waterproofing preparation layer - usually a building primer;
• Waterproofing carpet;
• Geotextile layer;
• Insulation (optimally - extruded polystyrene foam);
• The top layer of geotextile;
• Ballast bulk layer of gravel.

On top of the ballast layer, if necessary, a hard coating can be laid to maintain a uniform thickness of the ballast and ease of movement.

Inverted roofing cake

Roof base - wood or concrete?

Wood or concrete can be used as the basis for a flat roof. Both options are acceptable, but not interchangeable.

So, wooden base is used for small buildings, most often for economic purposes.

If there is no heating, then such a roof is not insulated, it is made simple rafter system and roofing is laid on top. However, wooden floors are also used for residential buildings.

This is due to the desire to lighten the roof, remove excess load from the walls (for example, with the frame method of construction).

CAREFULLY!

This option imposes certain restrictions on the functionality of the roof, excluding the presence of heavy equipment on it, a large number of people, etc.

Often, for the roofs of residential buildings used, a concrete slab is used as the basis. Such an overlap has a number of significant advantages:

• Reliability;
• No noticeable deformation from loads;
• The penetration of moisture into the material will not cause decay;
• Finishing a concrete floor is easier than wood.

Since it is produced outside, the lower surface of the concrete floor (the ceiling of the upper floor) will be open, which allows the use of any available type of finish - from simple painting to the installation of a stretch ceiling.

If the ceiling is made of wood (beams), then the finishing should be done taking into account possible deformation - “sagging” of the ceiling from existing loads.

Photo of the foundations of the roof in section:

wooden base

concrete base

Flat roofs: arrangement of private houses

The composition of a roofing cake is never chosen at random. The main selection criterion is the general purpose of the roof:

• Lightweight. A roof that serves only as protection from rain. It is mainly used for auxiliary buildings for household purposes;
• Operated. Such a roof serves as a platform for accommodating various equipment, for arranging recreation areas, small greenhouses, swimming pools, etc.;
• Green. On such a roof there is a lawn with grass, plants, etc. Serves as a mini-square for relaxation.

Depending on the purpose of the roof, the type of overlap is selected, which, in turn, largely determines optimal type roofing material. Therefore, the composition of the roofing cake may have its own individual characteristics.

So, for a flat roof of an outbuilding it will be enough:

• Rafter;
• crate;
• Roofing (, metal profile, etc.).

Lightweight roof

For a used roof, which is used as a platform for installing solar panels, satellite TV dishes or other equipment, composition is much more complex.:

• Concrete floor slab;
• Cement screed forming a slope for water flow;
• waterproofing layer;
• Drainage material that removes water from under the upper layers;
• insulation layer;
• Geotextile layer;
• Sand preparation layer;
• Paving slabs.

In this case, paving slabs serve as an external coating, as a durable and cheap material.

ATTENTION!

At the same time, rain or melt water can quite easily penetrate into the insulation layer, so it must be resistant to moisture, impervious to water, or, alternatively, painlessly pass water to drain through the drainage layer to the drain.

exploited roof

Green roof pie chart:

• Concrete floor slab;
• Layer ;
• Multilayer waterproofing carpet;
• insulation;
• . It consists of a separating layer of reinforced screed, a double layer of technoplastic (EPP and Green), and a geodrainage rolled layer;
• Soil layer with plantings.

In this case, there is a multi-stage hydroprotection that reliably cuts off the insulation material from the upper soil layer. Such a cut-off, at first glance, is too complicated, necessary to guarantee the creation of a reliable barrier to water.

The soil is an active accumulator of moisture, which will surely seep into the lower layers, so the complexity of the composition of the cake is fully justified.

green roof

How to cover a flat roof

The material for covering a flat roof is selected based on its purpose.

Unused surfaces are most often covered with roofing felt with sealing joints with liquid bitumen..

Recently, a large number of similar materials with improved characteristics have appeared, which make it possible to more reliably protect the roofing pie.

Operating surfaces require a more rigid and durable coating. At the same time, the task of hermetic cut-off of the insulation from external influences is not removed, therefore, most often a sand-cement cushion and a working layer - paving slabs are laid on top of the soft roof.

Coating

Installation of an operated flat roof

How to make a flat roof? First of all, you need to decide on the main parameters - the type of roof, device, etc. Consider the option of installing an operated flat roof with concrete floor and external drainage using gutters:

1. The surface of the overlap is covered with a layer of slope-forming concrete screed(decline). To save concrete, a layer of gravel is first poured with a slope, after which a screed is laid on top. Since this stage refers to "wet" work, then it is recommended to cover the overlay surface with a layer of primer or similar material.
2. Laying vapor and waterproofing. As a material, various deposited films or rolled membranes can be used. Laying with an overlap, glue the joints with adhesive tape.
3. insulation layer. Either stone mineral wool or extruded polystyrene foam is used. Insulation is laid in several layers, at least 2 layers. This requirement is due to the need to exclude the penetration of cold through the cracks in the joints of the insulation.
4. over the insulating layer laying a layer of waterproofing.
5. Backfilling of the ballast layer - gravel, sand, etc.. The role of this layer is twofold: protection of the film coating and removal of water from melting snow or precipitation in the summer.
6. over the ballast layer if necessary, a layer of paving slabs can be laid for ease of walking on the surface. In this case, you will need an additional sandy preparatory layer, a direct substrate for tiles.

The specified sequence is one of the options; there are many similar methods that are equivalent in result, but differ in details.

The device of a flat roof, traditionally considered an accessory of auxiliary buildings, can be carried out in such a way that the roof surface turns into an additional platform that can be used for various needs.

Depending on the climatic conditions of the area, the surface of a flat roof is turned into a green lawn, into a technical area for placing equipment, into a recreation area.

All variants of the operated roof require careful arrangement and expensive materials.. The qualitative result directly depends on the qualifications of the people doing the work and on the financial capabilities of the owner of the house.

But do not forget that you can build a flat roof with your own hands.

Investments in an equipped used flat roof will be justified only in regions with short mild winters and low average monthly rainfall. All other issues are solvable and do not cause serious problems.

Waterproofing

Warming

Useful video

In this video you will learn what is the device of a flat roof made of welded materials:

In contact with

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

The structure of the roofing cake

Looking at the structure in section, this species roof is a multilayer structure, which includes:

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

The vapor barrier layer is made of rolled or bituminous materials. It prevents the penetration of moisture from the premises into the heat-insulating layer of the roof structure.

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

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

The waterproofing layer is traditionally made of bitumen-based roll materials. Special mastics or a PVC membrane can also be used.

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

The structure of the pie depends on the functional features of the roof. The following types of roofing are distinguished:

Flat roof slope

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

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

Lightweight concrete with a filler of perlite or expanded clay has similar characteristics. This material is cheaper, but its weight is even greater, while the resulting roofing cake is less durable.

The device of a flat roof can be carried out with the use of monolithic heaters, which allow to perform a slope. In this case, sheet material (mineral wool, expanded clay sheets, etc.) is mounted on the prepared surface. Fastening can be carried out on a strong, tenacious glue, which excludes the displacement of sheets over time. Dowels with a plastic spacer can also be used - it is advisable to exclude metal contact with the base of the roof so that the roofing cake does not have cold bridges.

The most time-consuming is the device of the roof with the use of bulk materials for spreading. Difficulty pouring concrete loose insulation(expanded clay or perlite), observing the required angle of inclination of the roof plane, since the granules can move.

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

In accordance with SNiP, the slope of the roof is carried out towards the water intake funnels (if there is an internal drain), or towards the water intake gutters external system catchment, which should be attached under the roofing carpet or on the outer wall of the building.

Roof knots

In order for the roofing cake to be reliably protected from external influences, special attention should be paid to the places where it adjoins building structures - parapets, walls, pipes, external parts ventilation systems etc. There are various nodes of a flat roof, first of all, this is a node:

• adjoining;
• overhang;
• passage through the roof.

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

The node must ensure the tightness of the joint and its thermal protection, therefore, the installation of the nodes should be taken very carefully.

The device of an unexploited flat roof

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

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

Covering an unused flat roof can be done using mastic. This is liquid material, which is applied over a rigid, even heat-insulating layer. Mastic is made on the basis of flexible, hydrophobic polyurethane resins. On the outdoors, after a certain time after being applied in an even layer, it polymerizes, forming a continuous rubber-like membrane. The device of such waterproofing allows you to reliably protect the roofing pie from moisture penetration.

A popular technology is the use of built-up waterproofing. This is an affordable option in terms of price and quality ratio - the durability of such a roof is from 25 years. Bitumen-polymer material based on a rot-proof canvas creates a heavy-duty waterproofing layer. Using this material, it is possible to carry out the device of exploited roofs.

Operating roof device

This design of a flat roof is much more expensive to install, but allows you to profitably use additional space. Today, this type of roofing is in great demand for equipping sports fields, green areas, cafes, parking lots, etc. Installation of a reinforced roof is also necessary if heavy objects, including equipment, are to be installed on the roof. In accordance with SNiP, the roof structure must withstand an uneven high load, that is, it must not deform in limited areas of the area. The section of a flat exploited roof differs from the usual one by the presence of a rigid base in the pie or a special screed over the waterproofing layer. Such a coating excludes punching of the waterproofing carpet with its subsequent destruction.

Inversion Coating Features

The structure of an inverted roof is fundamentally different from other types of roofs. When it is arranged, first of all, a waterproofing layer is mounted on the base. In the context of a roofing pie, it looks like this: base slab, waterproofing, insulation, drainage layer, geotextile. This design allows you to protect the waterproofing material from the damaging effects of ultraviolet radiation and temperature extremes, mechanical damage. Geotextiles, in turn, provide insulation protection. Paving slabs are used as the outer layer. Such a roof is able to withstand high loads, including being used as a parking lot.

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

Installation of a traditional roof structure can be done independently, but for the arrangement of flat roofs using modern materials and technologies, it is recommended to involve specialists with the necessary equipment.

Flat roof device: construction and nodes

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

Flat roof device

For many people, a flat roof is certainly associated with urban high-rise buildings. And very few draw in their imagination Vacation home with a flat roof, which combines the saving of precious space and the possibility of arranging luxury places on the roof.

Flat roof cake.

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

What are the benefits of flat roof structures?

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

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

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

Scheme of installation of a flat roof.

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

1. A flat roof in most cases is equipped as a green recreation area.
2. Saving material, because the area of ​​a flat coating is less than the area of ​​a pitched one with the same architectural basis.
3. Laying a flat roof is much more convenient than a pitched one - it is easier to mount the cover under your feet than in an unsafe position at high altitude.
4. Maintenance of flat roofs is not an extreme climbing activity, but an ordinary procedure.
5. Plus, the design of flat roofs makes it possible to obtain additional space without increasing the contour of the structure.

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

Components of a flat roof

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

Scheme of an inverted flat roof.

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

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

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

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

1. Breakdown of waterproofing by strong gusts of wind.
2. Loss of the bearing capacity of the base due to electrochemical corrosion in the “wrong self-tapping screw + corrugated sheet” system.
3. Clogged or frozen funnel, which caused the roof to fill with moisture and leaks.

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

flat roof insulation

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

The basis of a flat roof is a bearing slab made of monolith, reinforced concrete or metal profiled sheet. From above, it is covered with a vapor barrier material that protects the insulation from water vapor, thus preventing its swelling from getting wet and ensuring the preservation of all properties. After that, thermal insulation is installed on the roof, which, in turn, is covered with a waterproofing carpet to protect it from atmospheric precipitation.

For a flat roof, one- and two-layer thermal insulation systems are distinguished. Now in construction, a two-layer system is more often used. It works like this: the lower layer, 70-200 mm thick, is assigned the main function of thermal insulation, while the upper one, which is 30-50 mm, is responsible for the redistribution of mechanical loads. Despite being thinner, the second layer is stronger and has a higher density. Such a distribution of flat roof coating layers makes it possible to significantly reduce its weight and, thereby, the load on the floors. The heater must meet the following requirements:

1. Low thermal conductivity and water absorption.
2. Fire safety.
3. High vapor permeability.
4. Compressive and tear strength of layers.

Drainage device

Drainage system on a flat roof.

In the arrangement of roofs, it is very important to ensure the free exit of wet vapors from the roofing. Ventilation accessories are essential elements of modern roofing. As a result of human activity, water vapor is continuously generated inside the building. Due to the convective process and diffusion, it rises and, when cooled, condenses in the space under the roof. This process is especially intense in winter. It negatively affects the elements of the roof - both wooden and metal. If too much condensation accumulates, then wet spots form on the ceiling and mold develops. In addition, moisture accumulating in the heat-insulating material reduces its properties, which leads to an increase in the cost of heating the room. To avoid such situations, you need to take care of the proper removal of moisture outside the building.

This task is best handled by special roofing components - a roof fan, otherwise it is called an aerator. The aerator is pipes of different diameters made of plastic or metal, which are covered with caps in the form of umbrellas.

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

On flat roofs, aerators are placed evenly over the entire surface at the highest points of the roof plane at the junctions of heat-insulating plates with each other. It is advisable to install aerators at the same time as the roof itself. Otherwise, the cost of installing ventilation increases significantly.

There are a large number of accessories for a flat roof device. The need for their use is due to the design of the roof. For example, in Western countries, much attention is paid to equipping roofs with natural smoke removal devices that enable people to safely leave the building in case of fire.

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

It is undesirable to equip roofs with a slope of less than 2 percent. The best option is a slope of 2.5 percent. In this case, the structure is freed from water in a short time, providing more comfortable conditions for the functioning of the roofing material. With a good slope, even a small defect in the roofing will be insignificant.

Another important element of the roof is gutters, which “carry away” moisture and snow along a given route. On a flat roof, an internal drainage system is most often made. Special drain funnels or fittings located on the roof surface effectively drain water in heavy downpours, eliminating roof flooding. Their location and number must be determined taking into account the design rules for these structures and the construction requirements for the design of drains and sewerage of buildings. The required number of funnels on the roof depends on its operating conditions, architecture and rainfall. A special filter is included with the funnel, which protects the drain from foreign objects entering it. So that the water in the drain does not freeze, the mouths of the funnels are equipped with special thermal cables, which guarantees a quick drainage of water at any time of the year.

As a drainage system from a flat roof in private houses, an external drain is more often used, because the internal one is more suitable for constructing flat roofs of large industrial buildings. External drainage is usually carried out using overflow windows, which are installed in the parapet along with roof storm water inlets. Ideally, self-regulating thermal cables should be used in this case, since the storm inlet and overflow window, due to their design, are subject to icing in winter.

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

flat roof construction

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

The device and installation of a typical flat roof: a thorough overview of the technological subtleties

The external simplicity of a flat roof is often misleading for beginner home builders. An elementary configuration suggests thoughts about the efficiency and low cost of construction. The minimum number of structural elements can dull the vigilance of independent performers who are ignorant of the intricacies of roofing. In reality, the installation of a flat roof requires scrupulous observance of the rules inherent only to it, which guarantee the flawless operation of the structure and long-term operation.

The specifics of flat roofs

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

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

In the regions and districts of the fatherland, located in the middle lane and to the north, flat roofs are used mainly in industrial construction. Private traders hoist them over one-story outbuildings, garages, household buildings. For an independent craftsman, a flat roof over a barn or change house is a great option to practice in the field of a roofer.

Briefly about the construction of a flat roof

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

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

• Vapor barrier covering the base. It is necessary to protect the insulation from the penetration of household fumes.
• Insulation, stacked in one or two tiers. Required to prevent leakage of heat waves through top floor, is used exclusively in insulated systems.
• A screed created with insufficient rigidity of thermal insulation or in the absence of slopes for a drain.
• Waterproofing that protects the insulation and ceiling from the destructive work of atmospheric water. It is laid with a continuous waterproofing carpet.
• Finishing coating that gives the structure an aesthetic appearance.

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

Due to the slight slope of flat roofs, the use piece materials in the arrangement is contraindicated, tk. multiple joints between elements create a risk of leakage. It is undesirable to use large sheet metal due to the harmful effect on the material of water stagnant on a flat surface during heavy rains and snowmelt.

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

For laying and fixing the above elements of the roofing pie of a flat roof, a truss structure is not needed. They lay them directly on the base, which can be a ceiling, a screed created on top of it, or the upper plane of the attic structure. For fixing PVC-coated systems, adhesive, mechanical or ballast methods are used. Bulk roofs are applied according to their name, the descendants of the roofing material are melted or glued.

Unlike pitched counterparts, in flat systems there are no battens that create ventilation ducts for washing the insulation with air currents. Therefore, the selection of a constructive solution, materials and their hermetic installation should be approached with due respect and focused attention. A ventilated flat roof only happens when lumber is used in the construction of floors and attics. The latter option is most often used in private construction.

Applicable types of floors

The construction of flat roofs is carried out on floors made of reinforced concrete, wood and profiled sheet. The choice of material for the overlap device depends on the purpose of the roof structure, the size of the overlapped span, possible operation and ease of maintenance.

One of the weighty advantages of a flat roof is the likelihood of organizing an exploited site on it: a place for recreation, a solarium, a green area, a terrace, etc. Of course, the overlap for such objects should be powerful enough. In addition, in the flat family there are roofs that do not involve passing use, therefore, do not require a solid overlap.

Depending on the operational criteria for flat roofs, they are satisfied with:

• Reinforced concrete floors, if it is planned to organize a usable space above a large-span brick or concrete box.
• Steel profiled decking over metal beams, if an unused roof is being constructed, spanning spans of any size between walls of brick or other artificial stone.
• A wood-based board created from a board 40-50mm thick, up to 180mm wide. It is used to cover medium and large spans of wooden structures in case of planned operation.
• Chipboards and fibreboards on wooden beams, used to cover small spans of wooden and stone buildings. They are used if an unused roof is being constructed.

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

Roll coverings in flat systems with a wooden base then serve only as a waterproofing, on top of which a plank or parquet flooring. If a flat roof is being built over a brick or concrete box, it is wiser to lay a reinforced concrete floor for an operated object or a profiled sheet for an inoperable one.

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

With or without an attic?

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

Depending on the presence of an attic, flat roof systems are divided into:

• Atticless, the elements of which are structurally combined with the ceiling. They are completely deprived of an attic superstructure, due to which the budget allocated for their construction is significantly reduced.
• Attic, with an attic superstructure over the ceiling. The minimum superstructure height is 80cm. The construction of attic structures of flat roofs is more expensive, but due to the separation of the ceiling from the roof, the service life of the system is at least three times longer.

In addition to the budget cost, one of the advantages of non-attic systems is the ability to exclude mechanical cleaning. The snow will melt due to the heat coming from the room. Due to spontaneous precipitation, it is not advisable to equip flat roofs without an attic with parapets. It is enough to install a railing, which further reduces costs. The minus of the absence of an attic will affect when identifying the causes of leaks, because the state of thermal insulation and other layers of the pie cannot be controlled.

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

The undeniable advantage is the possibility of installing insulation after construction, which eliminates its wetting. The disadvantage of flat roofs with attics is the high cost and the need to regularly clean the snow.

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

Subtleties of water drainage

Flat roofs are required to be equipped with gutter systems, which are required to freely drain water all year round at an operational pace. Systems are of external and internal type.

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

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

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

Drainage slope device

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

• Slopes on reinforced concrete slabs are made mainly with the help of a screed, or they are combined with a screed with preliminary backfilling of expanded clay or laying slab thermal insulation. On an unused roof, it is enough to lay wedge-shaped mineral wool slabs, produced specifically for the formation of slopes.
• Slopes along the ceilings from corrugated board are formed using metal structures or wedge-shaped insulation.
• Slopes on wooden bases are set constructively, but in the absence of them in the project, it is possible to use wedge-shaped mineral wool.

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

The nuances of the organization of ventilation

Normal ventilation products can be made by the only method - by installing battens on floor beams, similar methods are dictated to us by the construction schemes of pitched structures. It is clear that this method is only valid for wooden options, and for roofs on a concrete base or profiled sheet, it is unacceptable.

The ventilation system of roofing pies for concrete and corrugated board depends on the type and characteristics of the finish coating. PVC roofing is able to spontaneously pass excess moisture from the insulation to the outside, so there is no need to arrange ventilation ducts between it and the insulation.

When using bituminous and bitumen-polymer materials, it is mandatory to install wind vanes over the entire area of ​​a flat roof. The step of the location of these devices depends on the thickness of the insulation. Vanes-aerators provide the removal of moisture from the under-roof space to the outside.

Flat roof construction algorithm

Consider a common case of building an unexploited flat roof over an extension on a suburban area. It will be equipped with an external drain. Thermal insulation of the structure is not expected, because. climatic conditions and the purpose of the room below do not require thermal insulation.

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

• We mark the installation step of the floor beams, for which we will use a board with a thickness of 40-50mm. Installation step from 50 to 70 cm: choose it based on the actual length of the walls. Between the beams should be equal intervals.
• We install the board on the edge, fasten it with nails or corners. The necessary slope to the lowest overhang is created spontaneously due to the difference in the height of the box walls.
• On the beams we lay a solid flooring of OSB boards, moisture resistant plywood or other similar material. Between the plates there should be a gap of 3-5 mm to compensate for thermal expansion. They are fastened with galvanized screws or ruffed nails.
• We install a wind board along the perimeter of the roof, the edge of which rises 5-7 cm above the plane of the future roof so that a small ledge is formed.
• We nail a wooden lath with a triangular section or an ordinary plinth to the sides. These are fillets necessary to drain water from the edges of the roof.
• We treat all wooden elements with antiseptics, fire retardants. After they dry, apply a primer.
• Along the perimeter, over the fillets, we lay an additional waterproofing carpet in a strip. In the case of junctions and pipes passing through the roof, additional waterproofing is installed on the vertical planes adjacent to it in a similar way, i.e. over the fillets.
• We weld the finish chosen for the arrangement roofing material by heating its back side with a gas burner.

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

Then waterproofing is laid with entry to the sides and junctions. If one of the latest brands of rolled waterproofing material is chosen for the arrangement, then it will also be entrusted with the duty of finishing.

An impressive range of new polymer-bitumen and polymer coatings is laid in one layer, which helps to save the installer's strength and construction costs. Among them are materials that are highly preferred for home craftsmen and do not require the use of a gas burner. They are glued to the mastics or with the help of the back adhesive side, fixed mechanically, laid freely and loaded with ballast.

Video for do-it-yourself builders

To consolidate information about the difficult task of building flat roofs, a video selection will help:

We hope that the information presented by us will help future roofers who decide to practice with their own hands the device of a not so simple design.

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

Part of the material for writing the article was taken from here:

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

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

Flat roof installation: construction, device, installation, layers, elements

The installation of a flat roof requires strict adherence to the rules for installing elements and a clear arrangement of layers laid during the installation of trussless structures

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Flat roof houses - options and projects

Recently, there has been a growing interest in low-rise flat roof projects. 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 is more complicated than in theory.

The design of a flat roof raises many questions regarding its cost, the choice of materials for insulation and waterproofing, the organization of water flow, maintenance and operation of the roof. Finding answers to them is not easy. The fact is that domestic contractors working in the field of cottage and summer cottage construction are well aware of the most popular design - pitched, and, as a rule, they do not have experience in erecting flat roofs arranged in a completely different way.

Which roof will be cheaper?

Immediately noteworthy is the fact that the area of ​​​​a flat roof is smaller than a pitched one, which means that fewer materials will be required, and the work 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 central Russia, to ensure the reliability and durability of a horizontal roof, rather expensive engineering solutions are required.

It turns out that 1 m 2 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 high-density material. There is still hope to save on roofing, however, modern polymer membranes - the optimal waterproofing for horizontal roofs - are no cheaper (and sometimes much more expensive) than flexible tiles.

You won’t need to install snow retainers, but you can’t do without a roof hatch and a drainage system. 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.

Finally, it should be noted that flat roofs are appropriate only on houses of modern architecture - with a large glazing area and sophisticated finishing with the latest facade materials. That and others won't be cheap.

Flat roof cover

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 provide a check-in to the site of the truck crane (while steel beams and flooring 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. A monolithic w\6 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 device of passage units (chimney, ventilation ducts) and high bearing capacity (subject to the technological regulations).

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 / m 2) - 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 a fixed formwork, which, by the way, does not eliminate the need to build a reinforcing cage.

Types of flat roof

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. At the same time, a common feature of 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 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.

There are special requirements for thermal insulation for a flat roof. The material must 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.

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, manufacturers of coatings and insulation offer more and more new engineering solutions. However, they are always based on one of two fundamental schemes - traditional or inversion.

Traditional flat roof construction in general terms, it is as follows: a vapor barrier film (polypropylene, polyethylene, 6-tumno-polymer) is laid on top of the supporting base, then a heater follows, for example, mineral wool slabs with a compressive strength at ten percent deformation of at least 30 kPa, in one or two layers of total thickness from 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.

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 system (Rockwool) or TechnoNIKOL Slant, 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.

Flat roofs are classified into unexploited 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-hydro-insulating 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.

inverted roof it 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.

For exploited roofs, as well as roofs arranged in regions with harsh 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 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 during the deposition of the material. One layer is enough for a polymer membrane, and automatic welding equipment ensures reliability, 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.

Coil materials based on modified bitumen, as a rule, are fused with a gas burner (a), while it is difficult to prevent small flaws that can cause leakage (if there is no second layer). The quality of welding of PVC coating strips (6) is much easier to control

Drainage and water protection system of a flat roof

A flat roof is equipped with a parapet (attic) 30-90 cm high, which helps to ensure organized water drainage; 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 leak and 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 m 2 - 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.

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

For inverted 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.

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.

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. When calculating, it is assumed that for every square meter of roof area there should be 1-1.5 cm of the cross section of drainpipes. Elements of the external system can be made of PVC, steel, copper, zinc-titanium.

flat roof landscaping

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 are used, dense geotextiles, gravel bedding or drainage and moisture-accumulating membranes made of high density polyethylene, such as PLANTER GEO or Delta-Floraxx.

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 96) 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.

For them, it is not necessary 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 watering 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 floor, so it should be provided at the design stage of the building.

What is the best coating for a flat roof

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 give a brief description of them.

ROLL REINFORCED POLYMERIC-BITUMEN ROOFING.

The mechanical strength of these materials is several times higher than that of roofing paper (roofing material, roofing felt). 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 m 2 and the average service life of a roofing carpet is 15-30 years.

ROLL 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 m 2. It is important to consider that this material does not tolerate contact with bitumen.

ROOF COVERING OPTIONS

Traditional with external drain
1 - overlap; 2 - slope-forming screed; 3 - vapor barrier; D, 5 - mineral wool insulation; 6 - waterproofing; 7 - drain
inversion
with internal drainage
1 - coupler; 2 - PVC membrane; 3 - EPPS; 4 - funnel with a drainage ring; 5 - drainage membrane; 6 - sand; 7 - paving slabs