Flat roof: pros and cons, corrugated board device. DIY flat roof device. Projects of houses with a flat roof How to make a flat roof on a house

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

Flat roof structure

There is nothing complicated about the roofing layers of a flat roof. In fact, it is a multi-layer coating that includes bituminous, polymer and mixed products with a high level of waterproofing.

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

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

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

Now, I will paint each layer separately.

• As already mentioned, the role of waterproofing in most cases goes to the coating. It can be laid by surfacing, self-adhesive and pouring methods. If we consider the first variety, then roll materials are used as materials, for example, roofing material or membrane. With regard to bulk, the most common product of this type is liquid rubber and mastic.

If cheap roll material is used, then it is often laid in several layers. This provides an increase in the durability of the product and a good waterproofing of the surface. It is advisable to lay up to 5 layers of roll product on flat roofs. The average lifespan of roofing material is about 10 years, after which the surface must be covered with new material

• A cement-sand screed is not always arranged. Its filling is carried out only in the case of exploitation of the roofing surface. An example is houses in European countries that have gardens or recreation areas on their rooftops. This layer will give the surface additional rigidity, as a result of which the underlying materials will remain intact when exposed to loads.
• It is best to use mineral slabs as thermal insulation material. In addition to its functional task, it performs functions similar to a screed and protects the inner layers from damage. It should be noted that this layer must always be dry, otherwise moisture will play a cruel joke with it. The liquid trapped in the insulation slabs significantly "cut" its useful qualities and, having reduced them once, they will not return. Alternative materials for insulating a flat roof are: foam plastic, basalt fibers or bulk products
• Vapor barrier material is an integral part of flat roofs. Thanks to them, moisture coming from living rooms through condensation will be blocked, therefore, will not be able to get to the insulation boards.
• The base is most often reinforced concrete slabs and profiled metal sheets, but not so long ago an alternative was found - wood. If for a high-rise building, in which loads reach serious values, reinforced concrete elements are needed, then for a small private house flat roof can also be laid on wooden beams. Such a design seriously saves your finances, and due to its low weight, it reduces the load on the foundation.

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

It should be understood that these roofs must eliminate excess liquid without any problems, otherwise the waterproofing material can give slack, and water will get inside and then you definitely will not get out of expensive repairs.

IMPORTANT: If you plan to install roll weld products on a wooden system, you should consider its flammability. Under such conditions, it is impossible to work with a burner, but then how to be? You will have to fasten the first layer with ordinary nails, and only then carry out the work in the usual way, using an open fire.

I will explain how to correctly make a flat roof of a house a little later, but for now I consider it important to understand its types.

Types of flat roofs

The structure of a flat roof roofing cake will differ significantly from its functional purpose... If wood or reinforced concrete slab is used as a base, then you can afford an exploited roof.

This is exactly the variety, the area of \u200b\u200bwhich you can equip at your own discretion, but let's get it all in order.

• Unexploited roof. Laying of its layers takes place using the traditional method. It consists in the fact that the waterproofing material is located above the thermal insulation plates. Such an arrangement of the material does not even allow a person to withstand, therefore, to maintain such roofs, it is necessary to arrange bridges or ladders. As a rule, self-leveling products are used as a coating for such surfaces. An unexploited roof is advisable on temporary structures and outbuildings
• Operated roof. Here, the structure of the roofing cake will be slightly different. Thermal insulation boards are located above the waterproofing. They are laid from a dense material such as mineral wool. Thanks to the screed on top, the surface can withstand significant loads. On the surfaces of such roofs, you can arrange not only recreation areas or a garden, but also swimming pools or parking lots. You just need to understand that for this you need to make additional calculations and acquire auxiliary materials. As a rule, when medium loads are planned on the operating roof, then it is laid on its surface paving slabs or other hard coating. The method for laying the layers of this roof will be called inversion

A building with a flat roof in most cases does not stand out for its beauty. Therefore, it is best to turn to an experienced designer to increase these indicators. He can advise you to decorate your comfort with a balcony or terrace. It is worth noting that the property of cheapness does not apply to the construction of operated roofs, but it will differ insignificantly from the standard gable system.

Flat roof over timber beams

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

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

1. First of all, you need to take care of favorable construction conditions. For most materials, the weather between 5 and 25 degrees Celsius is optimal. As a rule, flat roofs are covered with bituminous products, therefore, this temperature range should not be ignored. The fact is that at negative temperatures bitumen becomes brittle, and at very high temperatures it begins to melt
2. After the walls are erected, the support bar is laid - the Mauerlat. It should fit on the upper chord, in which embedded parts have already been inserted. They are needed so that the Mauerlat does not go with the roof. In most cases, the material for the support bar is coniferous lumber with a section of 15x15 centimeters. Anchor bolts, used in the absence of embedded parts, are considered reliable fasteners in this matter, but not infrequently these fastening methods are combined with each other. Do not forget that the Mauerlat is primarily wood, and it absorbs moisture very well, therefore waterproofing is laid between the bearing wall and this element
3. A flat wooden roof is laid from planks. They will perform functions rafter legs, therefore, their thickness should be at least 10x15 centimeters. In places where the support bar will pass, it is necessary to make a recess, which is half the height of the element itself. For example, if the height of a beam is 100 millimeters, then the indentation will be 50. The spacing of the beams should be in the range from 60 to 120 centimeters. However, everything will depend on the roofing
4. After working with the base and laying the vapor barrier layer, you can proceed to the installation of insulation boards. Most of the material is 1.2 meters wide, so it won't take long to install. For insulating flat roofs, glass wool, basalt fiber and slag wool are best suited. This material is laid in several layers between the beams
5. Before laying the roofing, care must be taken to create a solid base and for this you need moisture resistant plywood or wood flooring... If the roof is to be laid by the deposited method, then the first layer is fixed with nails and strips, and only then a burner is used. Modern construction has and alternative option - self-adhesive bituminous products, but it should be understood that the price for them is significantly higher
6. In most cases, a flat roof is created in order to exploit it, and if you are pursuing the same goals, then do not forget about the waterproofing of the parapet. As a rule, roofing material is used as a material for this purpose. At the junction of the vertical element and the roofing plane, a special wedge is equipped. It makes the sharp corner more rounded

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

A flat roof with your own hands is a great way to erect a building in a very short period and at the same time save a lot.

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

For example, in the first case, antiseptics, various paints and varnishes and the like can be used, but the second will require a more thoughtful approach, because fire safety - an important component of all construction.

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

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, etc. Finding answers to them is not so easy. The fact is that domestic contracting firms working in the field of cottage and, as a rule, do not have the most popular design - pitched, and they usually have no experience in erecting flat roofs, arranged in a completely different way.

Flat roof cost

The fact that the area of \u200b\u200ba flat roof is less than that of a pitched roof immediately attracts attention, which means that less 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 middle lane To ensure the reliability and durability of a horizontal roof, Russia needs to apply rather expensive engineering solutions.

Beam floor

In principle, when erecting a floor, you can use a combination of beams (wood, steel) and load-bearing corrugated board. 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. A roof covering made of steel I-beams and corrugated board with a wave height of 60 mm and a wall thickness of 0.7 mm allows covering a span of up to 12 m and withstands a pressure of at least 6 kPa. But in general, it is less durable than concrete, and is relatively rarely used in individual construction. It is wiser to use corrugated board as fixed formwork, which, by the way, does not negate the need to build a reinforcing cage.

It turns out that 1 m2 of flat concrete or steel base, the load-bearing capacity of which will support the weight of the snow cover, costs 2–2.5 times more than a timber girded roof structure. The difference in the volumetric consumption of insulation is leveled due to the fact that a more expensive material is needed for a flat roof high density... There is still hope to save on roofing, however, modern polymer membranes - the optimal waterproofing for horizontal roofs - are not cheaper (and sometimes much more expensive) shingles... It is not necessary to install snow guards, but without a roof hatch and drainage system not enough. If you try to reduce costs according to 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 operational loads without significant deformations

Finally, it should be noted that flat roofs are only appropriate for houses. modern architecture - with a large glazing area and sophisticated finishing with the latest facade materials. Both are not cheap at all.

On a solid foundation

As a rule, in low-rise housing construction, a flat roof slab is a precast or monolithic reinforced concrete slab. Reinforced concrete slabs (PB, hollow PC, PV, etc.) can 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 labeling). 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 access to the site of the truck crane (while the steel beams and the flooring are easy to lift with the help of 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 up 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 installed in winter

Flat roof classification

Flat roofs are subdivided into unexploited and exploited. The former visit only for revision, maintenance 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 kind of exploited - a roof with greenery, lined with a sod layer over the main heat-insulating cake; usually they arrange paths and a recreation area on it. A convenient exit should be provided to the operated roof, for example from the vestibule superstructure.

Monolithic reinforced concrete floors are erected from heavy concrete using removable (for example, from OSB slabs on jack stands) or fixed (from corrugated board) formwork. It is reinforced with a two- or four-level welded frame made of rods with a diameter of 12 mm or more. Dimensions monolithic slab are not regulated (unlike a prefab), which provides the architect with freedom in designing a building; other advantages are the absence of seams, the comparative simplicity of the device of the passage units (chimney, ventilation ducts) and high load-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. This means that the roof must protect from winter cold and summer heat. Wherein common feature flat roofs consists in the fact that the heat-insulating layer is located on top of the supporting structure (in pitched roofs it is usually located between the rafters). If the room is insulated from below, the dew point can shift into the thickness of the floor, which will reduce the service life of the latter.

Mastics should be used primarily on complex roofs

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

Schemes of the roof structure "Technonikol"

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

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

"TN-ROOF Green": 1 - overlap; 2 - expanded clay ramp; 3 - reinforced screed; 4 - bituminous primer; 5 - Technoelast EPP; 6 - Technoelast Green; 7 - geotextile; 8 - EPS; 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 cake; in this case, the roof waterproofing is fixed with gravel ballast, paving slabs on supports or special dowels. Some materials, for example the "ROOF UKLON" (Rockwool) or "TechnoNICOL Slope" system, allow you to do without a screed at all: the slabs have variable thickness, and with their help it is easy to create smooth level drops to ensure water flow.

The inversion roof is arranged differently: it has a heat-resistant insulation material (usually extruded polystyrene foam - EPS) 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 not difficult to turn an inverted roof into an exploited 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, gutters need to be discussed separately.

Thermal insulation for flat roofs has special requirements. The material should not only have a low coefficient of thermal conductivity, but also resist well mechanical loads - both distributed (pressure of the upper layers of the roofing cake, equipment, snow) and local, arising during installation. In addition, it is important that the material is hydrophobic and non-flammable. At the moment, there are several ways to install thermal insulation: using mechanical fasteners, adhesive and free installation. In addition to the traditional two-layer insulation, laying in one layer is becoming an increasingly popular solution. Rockwool company offers unique double density slabs, which consist of a hard top and a light bottom layer, which speeds up the work and improves their quality.

Grigory Gromakov

ROCKWOOL Flat Roof Development Specialist

Flat roof drainage

A flat roof is equipped with a parapet (attic) with a height of 30–90 cm, helping to provide an organized; on an exploited 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 over 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 an outdoor one. Let's talk more about its main elements.

Water intake funnels are installed in lowered sections of the roof. As a rule, on roofs with an area of \u200b\u200bup to 150 m2, two funnels are mounted - the main one, connected to the riser, and the emergency one with water discharge through the hole in the parapet. With an increase in the number of funnels and risers, the reliability of the system increases, but its cost also increases.

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

Traditional covering 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, special funnels are used to prevent air from being sucked in by the water flow. Thanks to them, the speed of movement of the liquid 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 a more accurate calculation than gravitational ones.

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

The 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 blocking the outlet with ice, therefore, the riser should be equipped with a “winter” outlet to the domestic sewer (the latter should be equipped with a water seal). The branch pipe is cleaned through a dismountable joint or an inspection module.

Drawing: Vladimir Grigoriev / Burda Media

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

When choosing the standard size of the elements of the traditional gravitational system, one proceeds from the intensity of rain in a given area, focusing on SP 32.13330.2012.

The external drainage system is more vulnerable than the internal one, and also affects the appearance of the facades, but it does not require the installation of holes in the roof and ceilings and does not eat up the useful area of \u200b\u200bthe house. Water is discharged through parapet funnels or nozzles embedded in the parapet, under which classic funnels are installed (as on pitched roof) and downpipes attached to the walls with brackets. The calculation is based on the fact that for each square meter the area of \u200b\u200bthe roof should have 1–1.5 cm2 of the cross-section of the drain pipes. Elements of the 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, it is protected from mechanical influences, as well as from temperature drops 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 widespread, and in addition, it allows you to level out possible errors when fusing the material. For a polymer membrane, one layer is enough, and reliability is provided by automatic welding equipment, which greatly increases the speed of work. In addition, no open flame is used when installing the polymer membrane, therefore the technology is considered safer.

Dmitry Mikhaylidi

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

Roof greening

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

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

For greening the roof, an additional cake should be laid on top of the main waterproofing layer (with the inversion scheme - on top of the insulation), an additional cake made 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, for example 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 of neutral peat. As for plants, it is easiest to restrict ourselves to meadow grasses and drought-resistant ground covers - sedum, herbaceous cloves, thyme. They do not need to organize an irrigation system, and the thickness of the soil layer can be only 6–12 cm (this type of roof is called extensive). If you plan to walk on the roof among ornamental shrubs, you will have to provide 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, therefore it should be provided at the design stage of the building.

Terrace structure provides convenient communication between the living quarters of the cottage and the Operated roof, which serves as a resting place

No leaks

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

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

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

Roll-on membranes made of ethylene propylene rubber (EPDM) and thermoplastic polyolefins (TPO) , for example Firestone RubberGard, Logicroof P-RP, retain elasticity at low temperatures. Note that EPDM membranes are highly flammable (class G4) and are designed mainly for use in the structure 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 expensive than polyvinyl chloride (mostly imported products).

Polymer-bituminous mastics allow you to create a seamless coating, but it is permissible to apply them only on 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 roll materials.

Polymer and cement-polymer bulk waterproofing , for example Aquascud, Osmolastic, Osmoflex, is highly elastic
and UV resistance. To improve the characteristics, the materials are used in combination with special primers and backing films, reinforced with mineral fiber (all components are supplied as a complete system). Estimated service life of the coating - more than 50 years; price - from 700 rubles. for 1 m2.

A flat roof: a pragmatist's view

Benefits	disadvantages
Eliminates avalanche snow and reduces the risk of ice falling.	Requires significant costs for the construction of a base with a high bearing capacity.
Provides convenient access to chimneys, ventilation pipes, antennas; compared to pitched, easier to maintain and repair.	More susceptible to atmospheric factors than pitched, so durability is guaranteed only if expensive materials are used.
It can serve as a recreation area, a 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.
It 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).

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Do-it-yourself flat roof - most often located on private low-rise buildings, as well as on garage buildings. This type of roofing device is ahead of its competitors. In this article, we'll explain why.

Before we talk about how to make a flat roof, we note that the term "roof" and the term "roof" are not the same thing. The term "roof" refers to those elements that are located above the living area of \u200b\u200bthe house. And the roof is a component of the roof, its top layer. It is he who protects the entire building from influences atmospheric influence... In these conditions, it is very important to create reliable roof country house.

Having familiarized yourself with the difference between the terms, we can state that a flat roof is perfect option for a house with a small area. With an impressive roof area, it is recommended to work with a whole team.

Flat roof and its features

When working on a small house with a small roof area, you can safely do without helpers.

At the beginning of the work, fix wooden or steel beams on the supporting mills. They can help reduce most of the roof mass by directing it to the main walls and foundation.

So, we found out that the main load on the beams is the weight of the roof. But besides this, there are other loads, such as:

• The total weight of the roof and communication elements. As a rule, they are located in the attic or attached to the roof.
• The weight of a person who is repairing a roof or roof. He can also install additional equipment.
• Volume and weight of snow + cold winter wind pressure.

Read the advice of experts on the forums, look at the photos on the Internet - then you can make the right choice of load-bearing beams and avoid critical mistakes. Surely you will be interested in the article flat roof - pros and cons.

If you want to acquire a reliable and safe flat roof, then choose only a suitable roof covering (more details: ""). The choice of accompanying materials that can withstand heavy physical exertion, as well as the effects of natural disasters, is also important.

Don't forget to check everyone technical characteristics materials. To prevent negative consequences, carry out a thorough hydro and vapor barrier.

1. Lay a “pie” of several materials on the slabs (they must have different properties).
2. The first layer is a vapor barrier. Its function is to protect the insulation layer from moisture ingress. A polymer-bitumen film is used as a material for vapor barrier. Moreover, it is often reinforced with fiberglass, and then a flat roof is installed. Place the edges of the film on the verticals of the slabs. It is very important to carefully and accurately seal the seams, as well as understand.
3. Lay insulation on top of the vapor barrier. If expanded clay is used, fill it with a mass of concrete. When constructing a lightweight roof, the polymer insulation must be fixed immediately to the vapor barrier.
4. Moisture insulation is the main layer for a roof without slopes. For the device of this element, you will need membrane or polymer-bitumen materials.

DIY flat roof for cold rooms

There are buildings that do not have heating. These include sheds and gazebos. They are supposed to create a slope to drain water from the roof. To do this, you just need to equip the roof at the smallest angle.

When constructing a sloped flat roof, its support beams should be located at a slight angle. Boards will be fixed to the beams. This will be a kind of basis for rolled roofing material (in more detail: "").

For the installation of a rolled roofing felt carpet, you will need a frame made of boards. For this it is best to use thin wood planks or steel strips. Secure them along the slope. In this case, the step should be 70 cm. But you should not block the path of the water flowing from the roof. The slope percentage of such a roof is no more than 3%. In other words, it is 3 cm for one running meter of length.

Construction of flat roofs for warm rooms

Consider the nuances of equipping a flat roof for heated houses:

1. First of all, lay a layer of boards on the supporting beams, having previously done it. After that, you should carry out the laying of roofing material or roofing material. Their canvases should be positioned using the overlap method. In this case, the length should be 15 cm.
2. Expanded clay is laid on top of roofing material (you can use slag or other material). Before backfilling the insulation, check that the slope is directed towards the drainage of precipitation.
3. The third stage is filling the insulation layer with cement. After preparing the screed, treat it with a bitumen primer.
4. Only a completely finished screed will be ready to accept rolled roofing material.

As you study the construction of a flat roof, you will see for yourself that roofs with a large pitch between the support beams require several people. It is advisable to invite professional craftsmen who will complete all the necessary work in the shortest possible time.

When attaching support beams, the distance between them must be observed. It should be no more than 1 m.

Monolithic concrete flat roof construction

The first step is to calculate the roof span. If it is 5 m, then 15 cm beams are used. Speaking in professional construction language, this is the "fifteenth I-beam".

To create a monolithic roof, it is recommended to use grade 250 concrete. concrete mortar in place construction works, it is advisable to use a concrete mixer. Otherwise, you are unlikely to achieve the correct mortar consistency. To obtain concrete for a flat roof, it is necessary to mix crushed stone with particles of 20 mm and cement, grade PC-400.

When calculating the components, adhere to the following rules: for eight buckets of rubble - three buckets of cement, 4 buckets of sand, and two buckets of water. If there is not enough water, you can add more, this is not critical.

Thermal insulation of a flat roof with foam concrete, see the video:

Further, the boards are fastened to the lower beam flanges. Roofing material is laid on the dry surface of the boards. Then, a reinforced mesh of a periodic profile is laid on top. The diameter of this element should not be less than 1 cm.The size of the cells in this case is 20x20 cm.

In order not to carry out repairs to a flat roof, the lining of the mesh rods are fixed with a knitting wire. Option with glue is possible. Ultimately, the mesh should not slip when pouring the screed.

For complete coverage with concrete, small pieces of crushed stone are usually laid out at the bottom of the mesh. Due to this, a gap of 4 cm is left. It is necessary to delimit the mesh and the layer of roofing material. Pouring is done in the openings between the beams. Recall that their thickness should be at least 15 cm.

After all the actions, the concrete is covered with a polyethylene film. This is especially true if work is carried out at high temperature... By covering the surface, you will prevent moisture from evaporating from the concrete solution. This, in turn, will protect the top layer from cracking.

The concrete must be under the film for at least three days. After completely drying the concrete mass, pour a layer of insulation. Don't forget about the slopes. The next step is to create a screed and mount a roll carpet.

We insulate a flat roof

Today, a common phenomenon is the replacement of a flat roof with a pitched one. However, in favor of a flat roof is the fact that it can be insulated both from the outside and from the inside. And after it is completed.

Previously, solid insulation boards were used for insulation. However, with this option, the roofing weight increased significantly. Having studied past experience, modern construction has moved away from this method of insulation. Today, most often flat roofs are insulated with basalt mineral wool. This is a fairly lightweight material. In addition, it boasts good thermal conductivity and moisture resistance.

Note that the basalt mineral wool does not undergo combustion processes. In addition, it tolerates even the most negative effects of nature.

Many people are used to thinking that it is customary to erect flat roofs only on multi-storey buildings and industrial buildings. Recently, however, this type of roof has been increasingly used in the construction of private houses. A flat roof in a private house is easily constructed, taking into account modern technologies and a variety of building materials.

They are distinguished by 4 types:

• Exploited. The main feature of this type is a sufficiently strong base, otherwise there is a possibility of damage to the waterproofing layer. A corrugated board or a concrete screed, acting as a base, allows you to create the necessary slope for arranging a drain. Thermal insulation on such a roof must be resistant to severe loads. All this is done in order to use the roof of the house in any capacity, whether it be a working platform or a recreation area.
• Unexploited. Here, the rigidity of the base of the flat roof structure is not as important as in the above variant. And the strength of the insulation also does not play a significant role. This roof is cheaper than the operated one, but it will also last a shorter period.
• Traditional. A feature of their design is the periodicity of layers - waterproofing goes above thermal insulation. Here, at the base there is a reinforced concrete slab, and an inclined expanded clay concrete screed is used for the drain.
• Inversion. The flat roof device in this version has practically no problems with water leaks. Here the insulation is located above the waterproofing, which gives the latter protection from UV rays and the effects of temperature fluctuations. Such a roofing device is the most durable and functional, which opens up a lot of opportunities for using the roof space.

Important! Angles in the range from 3 to 5 degrees are considered optimal for the slope of the inversion type of flat roof.

The advantages and disadvantages of this design

A flat roof in a private house, like other types of roofs, has a number of pros and cons. It is worth considering the advantages that determine its popularity in modern construction:

• Smaller area than other types of roofs - and this saves effort and money;
• Convenience and safety of work - it is quite difficult to fall from a straight horizontal surface, but all necessary tools are at hand;
• Fast construction - as a consequence of the first two advantages, such work is done much faster;
• Ease of maintenance and replacement of roofing - the dismantling of worn-out parts is usually not carried out, but a new cake is laid directly on the old one;
• The use of additional territory - the arrangement of an exploited roof opens up great prospects;
• There is a possibility of installing transparent roof elements - the view of the open sky on the ceiling is extremely tempting for many;
• Giving your home clear geometric shapes - if the drawing of the house allows, you can give it a unique look with the help of such a design, especially considering that minimalism is now extremely popular.

It is also worth mentioning the disadvantages of this design:

• Snow and leaves periodically accumulate - sometimes mechanical cleaning of the roof is required;
• A more complex structure - the presence of drains suggests their inevitable blockages, especially in bad weather;
• Regular control - the moisture content of the insulation and the general condition of the roof must be constantly checked;

It is not surprising that some people may have doubts about the reliability of this type of structure. But judging by the experience of owners of private houses with a similar roof both in Russia and abroad, this type of roof successfully functions and pleases its owners.

DIY flat roof installation

Now on the Internet you can find many photos of houses with flat roofs of a wide variety of designs. Interested in the question of how to make a flat roof with your own hands? Before you build a roof, you first need to familiarize yourself with the drawing of the house and make sure of its technical characteristics.

The design features of a flat roof depend on many factors. If this is an unheated room and the roof is being built with your own hands, then it is enough to install support beams, on which the base is then laid from uncut boards fastened with self-tapping screws or nails. When installing a flat roof on a garage, roofing material often acts as waterproofing due to its cheapness. Strips of roofing material are applied in the direction of the slope of the roof, fixing them with wooden or steel slats. A flat roof with your own hands on an unheated room is created quite easily - here all the work can be done by one person without anyone's help.

When installing a flat roof on a private house that is planned to be heated, the following procedure is familiar:

• Installation of floor beams. Strict adherence to the horizontal is necessary. Here and in the subsequent stages, the participation of several workers will be required.
• Installation of flooring. Usually, an uncut board with a thickness of no more than 5 cm is taken.

Important! The size of the lumber section increases in proportion to the distance between the support beams.

• Laying waterproofing.
• Insulation laying. In this case, the backfill insulation is enhanced concrete screedthat dries for a couple of days.
• After the screed has dried, a bitumen-based primer is applied to it, then roofing material is laid and glued.

The structure of the roofing cake

In order to make the roof reliably protected from moisture, it is necessary to place the materials in layers one above the other - this arrangement is extremely important. The standard base is made of concrete slabs or profiled metal. It is able to withstand the weight of the entire structure above, transferring it to the load-bearing partitions, which, in turn, transfer it to the foundation of the house.

Important! The operated roof must have the most solid foundation.

Then there are the standard layers: vapor barrier, thermal insulation and waterproofing. When choosing a flat roof roof, you should be guided by the preferences of the owner and the capabilities of the building itself. From a huge cottage to a small cozy house built many years ago, houses with a flat roof will be reliably protected from various environmental influences for many years.

Most people associate a flat roof with multi-storey buildings. In private housing such roof structures ten years ago, they were practically not used. Today they can be seen in many projects of country cottages. Therefore, many developers consider a flat roof in a private house as an option, analyze the pros and cons of its operation.

In this article

Varieties of flat roofs

Any building structures are subdivided into separate types, subspecies. So, for example, for some flat roofs country houses an attic space is provided, for others not. Therefore, they are classified:

By destination:

• Operated roofs - additional objects can be built on their surface, equipment installed, organized:

1. recreation areas, lawns, flower beds;
2. greenhouse or winter garden;
3. children's and sports ground;
4. parking;
5. pool;

The strength of the floors of the house and load-bearing walls must be suitable for the type of use of the roof. It is important to note that sound and vibration should be reliably absorbed.

The main features of the exploited roof. is the sufficient strength of the floors and the protection of the waterproofing layer.

• Unexploited roofs are the exact opposite of the first option. There is nothing superfluous on their surface, only snow can lie in winter.

With an unexploited roof, they rise to the roof only in case of its maintenance, repair, as well as if it is necessary to maintain the structures located on it, such as ventilation caps, cable lines, antennas, overhead lines power transmission, etc.

Important! In regions with heavy snow, flat roofs, as a rule, are not used due to sufficiently large snow loads.

By construction type:

• No attic space... Such structures require high-quality waterproofing, since they are, in fact, the ceiling of the last floor of the building. And in winter, the snow that accumulates on the roof surface will constantly melt thanks to the heating of the room.
• With attic space... Between the overlap of the last floor and the roof is formed free space - attic. Typically, roofs of this type are made without thermal insulation, in winter they do not require special maintenance.

For the arrangement of the roofing cake:

• Traditional - first, there is an insulating layer in the roofing pie, then waterproofing is equipped.
• Inversion - in this design, on the contrary, heat-insulating plates are placed on the waterproofing layer.

Private developers, paying attention to these points, end up with a practical, high-quality flat roof structure.

Advantages, disadvantages of a flat roof

Homes with flat roofs stand out in the private sector among houses with pitched roofs.

When choosing such a roof design for a country house, the developer receives the following advantages:

• There is no need to equip the rafter system, so you can significantly save on building materials.
• Additional objects can be organized on the roof surface, for example, a swimming pool, mini-gym, summer recreation area, etc. But then a flat roof requires an increase in its strength, a waterproofing layer.
• Ease of maintenance, the possibility of arranging an electrical heating system, thanks to which frost will not form on the base of the roof in winter.
• Due to the practically absent slope, it is much easier and faster to build such roof structures than pitched ones.
• Interior rooms will not have sloped walls.
• Much easier to produce renovation work on a flat roof than on a sloped roof.
• It is much more convenient to install and secure additional equipment on a flat surface: solar panels, air conditioners and more.

Important! To prevent precipitation from lingering on the surface of a flat roof, the minimum angle of its slope should be 5 °. This slope can be created by overlapping or using slag, expanded clay.

But a flat roof, like other roofing structures, has, in addition to pluses, minuses, for example:

• In some cases, the organization of an internal drainage system is required, which is often clogged, and freezes in winter. If it is not cleaned in time, it can lead to adverse consequences.
• A constant check of the tightness of the roofing cake, the moisture content of the insulation material is required.
• In case of heavy snowfalls, it is necessary to remove snow from the roof (excessive load, which can lead to damage to the structure) manually.
• Also, when a large snow mass accumulates on the roof surface, the snow below begins to melt - accordingly, leaks are possible.

A flat roof structure in a private house is not complicated, so it can be completely built with your own hands. But you need to consider some important points:

• To perform the work at a quality level, you will need to first calculate the expected loads on the roof during its operation. So, for example, in addition to its own weight, the roof will have to withstand the elements of communication systems, the mass of several people, wind, snow loads.

Important! Using only high quality building materials.