Private houses with flat roof cons. A house with a flat roof with your own hands - device options. Laying thermal insulation on a flat roof

Most people associate a flat roof with multi-storey buildings. In private housing construction, such roofing structures were practically not used ten years ago. 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 of country houses an attic is provided, for others not. Therefore, they are classified:

By destination:

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

recreation areas, lawns, flower beds;
greenhouse or winter garden;
children's and sports ground;
parking;
pool;

The strength of the floor of the house and the load-bearing walls must be appropriate for the type of roof use. 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 the case of its maintenance, repair, as well as when it is necessary to maintain the structures located on it, such as ventilation caps, cable lines, antennas, overhead power lines, etc.

Important! In regions with abundant snow, flat roofs are usually not used due to sufficiently large snow loads.

By construction type:

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

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 the listed 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 structure for a country house, the developer receives the following advantages:

There is no need to equip the rafter system, therefore, you can significantly save on building materials.
Additional objects can be organized on the roofing 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 erect such roof structures than pitched ones.
Interior rooms will not have sloped walls.
It is much easier to carry out repair work on a flat roof than on an inclined one.
It is much more convenient to install and fix additional equipment on a flat surface: solar panels, air conditioners, etc.

Important! To prevent precipitation from lingering on the surface of a flat roof, the minimum angle of inclination 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. Failure to clean it in time 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 (an excessive load that 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 difficult, so it can be completely built with your own hands. But in this case, you need to take into account some important points:

In order to perform work at a quality level, it will be necessary 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 and snow loads.

Important! Using only high quality building materials.

How quickly time flies! It's been 4 years since I built an unusual country house with my own hands. Many non-standard technical solutions were used in the house, which were practically never used in individual construction in Russia. Firstly, the house is heated with help, and secondly, the house has a flat roof.

Even from the very beginning of construction in 2012, I was constantly told that a flat roof is not for our climate (but for which one?), That it will leak (why?), And in general, with such a roof, the house looks like a transformer box (poor Europeans, they have to live in transformer booths).

But most often they tried to prove to me that it is necessary to constantly remove snow from a flat roof (I wonder why?). Of course, if anyone wants, you can clean, no one forbids. But on houses with a flat roof, there is no need to remove the snow. For example, now I have over 80 centimeters of snow on my roof! And somewhere under the snow she hid.

2. Snow on the roof is an additional and completely free insulation.

By the way, as it turned out, many do not know that a flat roof is not a plane in the direct sense, but a surface with a slope of about 2-4 degrees (in fact, a roof is considered flat if its angle of inclination is from 2 to 20 degrees). And any flat roof must have a drain. It is more correct to make an internal drain for a flat roof, but you can do with a classic external one. At the time of the start of construction, I did not have sufficient knowledge to design and implement an internal gutter, so I made an external one. The advantage of the internal drainage system is the absence of pipes on the façade.

3. Summer 2013 just done. A flat roof is significantly cheaper than any pitched roof (at least because its area is, on average, 1.5 times less than that of a pitched roof). With it, there is no loss of space and such a useless place in the house as the attic. It is easier and easier to insulate it - everything is in the same plane.

Let me remind you the construction of my roof pie (bottom to top):
1. Precast-monolithic overlap with filling with aerated concrete blocks - 250 mm;
2. Thermal insulation by means of extruded polystyrene foam - 150 mm;
3. Insulation and creation of a slope using wedge-shaped plates of extruded polystyrene foam - 0-150 mm;
4. Cement screed - 50 mm;
5. Two-layer weld-on waterproofing (top layer with sprinkling).

4. Another huge plus of a flat roof - it is not afraid of a hurricane. Watch the chronicles of hurricanes and how easily it rips off and breaks the rafter system on classic pitched roofs.

5. In the summer of 2016, I finished all the other landscaping work in the surrounding area and decided to do it.

6. By the way, if anyone does not know, then any concrete floor by default has a bearing capacity of at least 400 kg per square meter (usually 600-800 kg / m2). While the snow load for the Moscow region is only 180 kg per square meter. This is the maximum design snow load, which in reality is rarely achieved, but it is obvious that any floor has a huge margin of bearing capacity.

7. Another important advantage of a flat roof is that it has completely sealed joints. While the seams on a pitched roof are not tight, and if the pitched roof is covered with snow and it starts to melt from below (due to insufficient insulation), the pitched roof will leak (especially at the junction of two slopes - valleys). Look at the neighboring houses with pitched roofs - amazingly, there is snow on them too!

Why isn't a flat roof made using technology leaking? Everything is very simple. Because it is insulated!

It is the insulation that determines the durability of the roof. It is known that the roof accounts for an average of 40% of the heat loss of the entire building. If the roof is not insulated, or it is not insulated well enough, then the heat will rise upward, and the snow lying on the upper roof carpet will melt. With the onset of frost, the thawed snow will freeze again, and when freezing, as you know, water expands in volume. These multiple thaw-freeze cycles will eventually rupture the waterproofing (after 2-3 years) and the flat roof will start to leak.

8. In the last century, when building houses, they did not think about energy efficiency and saving energy resources, therefore, roof insulation was usually not done. This led to the fact that the waterproofing of the roof was constantly destroyed and the roof was leaking.

If the roof is properly insulated, then it has only one "enemy" - the sun and its ultraviolet radiation. But to protect against this, waterproofing is used with a package, or with special additives (if used). And the most effective way to protect waterproofing from damaging ultraviolet radiation is to make a lawn on the roof, fill in pebbles or lay tiles. By the way, a more promising waterproofing today is a polymer membrane.

A flat roof is even easier to operate than a pitched roof. From a flat roof, snow will never fall on your head and gutters will not tear off. There is no need to clean the snow, and if there is a lawn, there is no need to keep the gutters clean (all water is filtered through geotextiles and they will not be clogged by fallen leaves).

Therefore, a flat roof is the most reasonable roof option, especially for a house from. The main thing is not to violate the technology and not to save on insulation.

And cleaning snow from a flat roof is not only useless, but also harmful - you can accidentally break the waterproofing with the sharp edge of a shovel and the roof will begin to leak.

You can familiarize yourself with all the reports on the construction of a country house with your own hands in chronological order.

A house with a flat roof, in a series of similar "boxes" with a pitched roof, looks fresh and unusual. Therefore, every year the number of suburban residents who are seriously considering the construction of such a house for permanent residence is increasing. Admirers of the "cubic" design are captivated by the wow effect and increased attention from the neighbors. Someone wants to place engineering equipment on the roof, or to lay out a lawn and equip places for rest. Still others believe that it is cheaper and easier to build a house with a flat roof than with a pitched one. Is it really? Consider the main pros and cons of these buildings and conclude whether they are suitable for our country. And for this we will answer the following questions:

Why is it difficult to choose a suitable site for a "cubic" cottage
Is it true that flat roofs are not for our climate
Why is a flat roof leaking?
A flat roof is easier and cheaper than a pitched roof - this is a myth.
Why flat roofs are difficult to repair

1. House with a flat roof and domestic realities

Most of the country dwellers are skeptical about cottages with a flat roof, calling these houses "boxes". Why? Houses with a flat roof came to us from abroad. Traditionally, they were erected in countries with a warm climate, where there is practically no winter, heavy snowfalls, severe frosts with sudden thaws, prolonged rains, but strong winds blow. For example, somewhere on the Mediterranean coast. Then these houses turned into a fashionable design trend "not for everyone" in Western Europe, and from there they came to us.

Tretin FORUMHOUSE user

I see that we mainly build houses with pitched roofs. But, is it really necessary? In Germany and Switzerland, projects of houses with a flat roof have been proposed for a long time. What are the disadvantages of a flat roof, except for the imaginary unaesthetic look?

Indeed, can anyone leave indifferent a cottage with panoramic windows in the photo below?

Or such a high-tech flat-roofed house in a forest.

Or a cottage, on the roof of which an observation deck is made, a lawn is laid out and a place for rest is equipped.

Now imagine these houses with us. Harsh winter. In an ordinary - not an elite village, where roads float in spring and autumn, and areas are fenced with a professional sheet. The houses are mostly finished with siding or facing bricks. And pitched roofs are covered with slate, metal tiles or, less often, a more expensive solution - flexible tiles. The picture does not add up. Something's missing, isn't it? I no longer want to sit on the flat roof of the house, as I dreamed, with a cup of tea or coffee. After all, the view from there is not the ocean, sea, mountains or nature untouched by man, but the dense village buildings or, at best, fields overgrown with grass.

A house with a flat roof, in high-tech style, looks advantageous only on a spacious, isolated area, for example, on a slope, with a beautiful view of a forest, lake or river. A flat-roofed cottage is lost without landscape design, and among solid, but similar houses, it looks like a "white crow".

This is where the first "pitfall" - dreams of a stylish flat-roofed house are shattered when you understand,how much will the plot cost, on which the cottage will look right.

Having conceived the construction of a house with a claim for a non-standard foreign design, select the appropriate site for it.

2. Reliability of a flat roof in our climate

When you look at beautiful houses that are more than one hundred years old, ask yourself why they were built this way and not otherwise. Why do houses built in the coastal zone somewhere in Norway, Sweden or Scotland have no overhangs and the usual drainage system? They are simply not needed because of the strong winds that turn rain into a horizontal stream of water hitting the walls. Likewise with flat-roofed houses. They were built in a warm climate, where there is little rainfall, but a strong wind load.

A flat roof is more wind-resistant than a pitched roof.

dmitrievich-50 FORUMHOUSE user

Our ancestors are smart people. They considered the construction of the house from the point of view of practicality, based on the climatic conditions of residence. Why were flat roofs built in Central Asia? Are they pitched on the Central Russian Upland? In the Baltics, not just pitched, but with an acute ridge angle? A pitched roof with a slope of 45 degrees, in the Moscow region or in Saratov, will provide reliable protection from rain or snow for 20-25 years, even if covered with cheap corrugated board or slate.

A flat roof, with the right approach to construction and using modern materials, will also provide reliable protection of the house from precipitation and will not leak.

The only question is how much will cost 1 sq. m of such a roof with a guarantee that it will not flow quickly with frequent transitions through 0. Icing. Nighttime freezing and daytime thawing of snow cover. Lingering showers. And most importantly - how to make such a roof so that it will serve for a long time in our climate?

The second difficulty in building a cottage with a problem-free flat roof is the harsh Russian operating conditions.

3. The main problem of building a reliable house with a flat roof in the Russian Federation

link82 FORUMHOUSE Member

The firm built a flat-roofed house for me. 6 pieces were made around the edges. heated funnels and led out to the sides, through the parapet, drain pipes. Is it correct? Maybe it was necessary to make a slope to the center and, with a small roof area, put two funnels instead of six? And put the pipe inside the building. Discharge in the basement and further into the storm sewer? I am afraid that the knee, which is brought out of the funnel into the street, will freeze. The ice on the pipes has already formed. What if the pipe bursts due to frost? How to fix it? Throw a heating cable? So much money has already been spent on this roof!

The house with a flat roof was built in 2013.

In addition to problems with water disposal, another one was added. When link82 I came to check the house and found that the roof was leaking in several places. Water went from the second floor to the first. All the drywall swam. Now you have to argue with the builders. Try to take the money, and completely redo the roof. According to Michael-snabss(the user of the portal is professionally engaged in the construction of flat roofs) in this example, a whole bunch of errors has been collected. The main one is builders who simply do not know how to make flat roofs correctly.

When building a house with a flat roof, do not pursue cheapness. Each step of the builders and the stage of work needs strict control. More thorough than when erecting a pitched one. Mistakes are costly!

The roof was most likely made of a welded waterproofing material - glass insulation. The tree played and the fiberglass tore. Repair of this roof with a special roofing membrane will cost from 130 to 200 thousand rubles.

The third factor complicating the construction of a cottage with a flat roof in the Russian Federation - lack of highly qualified builders who know exactly how to build just such houses. How to use and combine materials with each other. What tools are needed for this. Even if the future owner of a flat roof house has a detailed project, and he should be, then everything can be spoiled by "specialists" who work according to the principle: "we always build this way and no one has ever complained!"

Flat roofing should only be done by professionals.

4. Is a flat roof cheaper and easier than a pitched roof?

Usually, when it comes to the advantages of a flat roof, you can hear the argument that it is cheaper than a pitched roof. Why? Less floor space means less material wasted. It is easier to make the overlap, because the classic rafter system is not needed. There is no need to equip an attic floor, etc. And it's true, but as they say, the point is in the little things.

If we simply consider the "pie" of a flat roof, then on the base, for example concrete floor slabs, are laid:

vapor barrier;
thermal insulation;
waterproofing.

Or the so-called. inverted flat roof, where the layers go like this:

waterproofing;
thermal insulation;
finishing layer.

In an inverted flat roof, the waterproofing layer is located under the insulation and "works" in more gentle conditions, because from above, from the negative influence of weather phenomena, it is protected by gravel, tiles or soil with a lawn. Those. a ballast flat roof is arranged.

But, when building a flat roof, it is necessary:

Organize slopes for water drainage - about 2 cm per 1 running meter. Slopes are usually made with a concrete screed or wedge-shaped insulation elements.
Lay several layers of insulation. If stone wool is used instead of extruded polystyrene foam, install aerators to remove water vapor from the thermal insulation.
Put electrically heated water inlets otherwise, due to the formed ice, they will not drain the water from the roof.

One water intake funnel, 110 mm in diameter, removes water from an area of up to 300 square meters. m.

Mount the downpipe with a slope of 3 cm per 1 running meter.
High-quality waterproofing made of PVC, TPO or expensive EPDM membranes. TPO membranes are less elastic than PVC membranes, but at the same time they have higher strength. For welding TPO membranes, professional fitters with special equipment are required. The advantage of EPDM membranes is the large format, and the fewer welds, the more reliable the flat roof.

When installing a flat roof, you will have to take into account many nuances.

Calculate the snow load depending on the region of residence. For example, Moscow and St. Petersburg belong to the third climatic region. Snow load on a flat roof, with a slope of 2%, in the Moscow region will be 180 kg per 1 sq. m. In the fourth climatic region, the snow load is 240 kg per 1 sq. m. m, and in the fifth already 320 kg. Do not forget that the weight of 1 m 3 of loose, freshly fallen snow is on average 50 - 100 kg. Already packed 350 kg. A cube of wet or melting snow weighs approximately 400-600 kg.

It is not necessary to clean off snow from a correctly calculated flat roof in winter. The excess is blown away by the wind, and loose snow becomes a heat insulator.

But, the load on a flat roof must be considered with a greater margin than on a pitched roof, taking into account force majeure. For example, the water intake funnels are clogged, the heating cable burned out, and the water did not leave the roof. In a couple of days, the monthly norm of snow fell, but there was no wind to blow it off and it lies on the roof. The additional weight on the roof puts pressure on the walls, which in turn transfer the load to the foundation, which redistributes it to the subgrade. The farther north, the greater the load. Add a mass of crushed stone or soil with grass if a ballast flat roof is arranged.

Hence - the optimal construction of a cottage with a flat roof is not a frame or a wooden house, but a stone structure, calculated by the designer and built of aerated concrete, bricks, warm ceramics, using monolithic technology. Because "Cubic" design allows for large unsupported spaces, then blocking the span of more than 6 m with a tree will no longer work. Requires trusses, I-beams, hollow reinforced concrete floor slabs, monolithic floors or precast-monolithic floors. Do not forget to add expensive facade finishing solutions to the cost of a flat-roofed house.

You can't do a house like that cheaply.

Planken, burnt wood, hand-molded bricks, a wet facade, combined wood and stone facades are used. And you can't put standard windows in a house with a flat roof. Large or panoramic are required. Add to this additional areas of the parapets, which also need to be insulated and trimmed. This increases the cost of construction.

The fourth factor is that a house with a flat roof cannot be called a budget construction..

Consider the costs not only for the roof, comparing the final estimate with flat and pitched, but at the total cost of the entire "box" with finishing.

5. Low maintainability of a flat roof

sv2321 FORUMHOUSE user

I have a flat roofed house. Waterproofing - with a membrane. I'm suffering with the roof. As they say, water will always find a hole. I like the flat roof, but I think I will abandon it and convert it to a pitched one, although I will have to change the entire architecture of the house. And that's why:

There is no absolute guarantee that all joints of a flat roof will be airtight. Enough microcracks and gone. If there is a bias, then small defects are not critical;
Snow lingers on a flat roof. It melts. Water fills in microcracks. Frost hit at night. The water is frozen. With frequent daily freeze-thaw cycles, microcracks increase, then break. They are getting bigger. The pitched roof has no welded areas and there is nothing to tear. In the worst case scenario, a small temporary leak will appear without progressive consequences. It is easy to find and repair;
The most unpleasant thing. On a flat roof, you never know exactly where the defect is. There is a leak in one place, and water from the ceiling is dripping in a completely different place. The craftsmen will come, check the joints and find one of the defects, and the rest will remain. If the roof is inverted or laden with gravel, then troubleshooting is an even bigger problem.

According to the user, the optimal roof for our climate is pitched. The angles at the slopes compensate for the crooked hands of the builders and the change in material properties over time, and the overhangs protect the walls and finishes from precipitation.

So, the fifth is low maintainability.... The quality of a flat roof is greatly influenced by the human factor.

If a pitched roof with a cold attic is leaking, then it is not difficult to find and repair the defective area. In extreme cases, you can dismantle the coating and perform local repairs or get to the problem area from the inside. In the case of a flat roof, leak detection and repair is complicated by a complex “pie”. Many layers in the structure, especially in the so-called. "Green roof". The presence of a concrete screed, etc.

conclusions

Houses with a flat roof certainly look beautiful and stylish. Make a flat, problem-free roof that will last for many years in our climate also possible... The only question is the total cost of all decisions and its feasibility. Anyone who, in our climate, has been engaged in the installation or repair of a roof knows that in the summer, a hot roof in the sun is the last place where you would like to sit with your family or friends. Hot and stuffy. I would like to quickly go into the shadows. If there are small children in the house, then an exploited flat roof is an extra headache for parents. You can also organize a shaded private place to relax with barbecue on a small area. It is pleasant to sunbathe in the garden on the grass, throwing a towel or spreading out a chaise longue, and not in full view of all neighbors and passers-by on the roof. Out of town corny wants solitude, and not stick out your private life for everyone to see. Let's add our changeable weather. Rain. The wind, which is felt at high altitude, is not at all the same as below. So, how many days in a year really will be left to relax on a flat roof? Let's add the need to arrange a place to go to the roof directly from the house. Do not climb the stairs on the flat roof, which is fixed to the facade. What remains? Unusual "fashionable" design to attract attention. Therefore, it is up to everyone to decide whether to build a house with a flat roof or not, and FORUMHOUSE offers you proven solutions for this.

how to properly build in our climate a house with a roof without overhangs with a hidden drain, and what are its advantages.

Stone house with a flat roof: a harmonious combination of exterior and interior. The video shows the structural features of a monolithic stone house with a flat roof and an unusual facade finish.

The construction of a gable or hip roof is not always rational and expedient when it comes to outbuildings, industrial and commercial facilities, and sometimes private houses in a modern style. The high consumption of material, the complex rafter system make the construction of these structures an economically unprofitable, protracted event. While flat roof projects significantly reduce building costs, builds quickly and is suitable for almost any facility.

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

The situation is complicated by the fact that the surface of roofing materials has a rough structure, which does not allow moisture and snow to slide freely. Therefore, the device of a flat roof, assembled by hand, must comply with the stringent requirements of building codes for waterproofing, slope and construction technology.

The structure of the roofing cake

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

Flat base made of concrete slabs or profiled metal sheets... It provides the rigidity of the structure, carries the weight of the roofing cake, transferring it to the load-bearing partitions and, as a result, to the foundation. At the operated roof, the base should be as rigid as possible.
Vapor barrier... The layer that is necessary in order to protect the flat roof from the penetration of vapors from the inner heated rooms into the thickness of the insulation. By settling on the thermal insulation in the form of condensate, water irreversibly reduces its insulating properties by more than two times. As the simplest vapor barrier, polyethylene film or bitumen-based coatings are used.
Insulation... For thermal insulation of a flat roof, filling materials are used, such as expanded clay, perlite, slag, rolled, for example, mineral wool and in the form of plates, in particular expanded polystyrene. By the way, insulation is used not only to regulate the temperature regime, but also to unfold a house with a flat roof. The main requirements for insulation are low hygroscopicity and thermal conductivity, light weight.
Waterproofing... A flat roof allows you to use rolled materials for covering in order to protect against moisture: bituminous, polymer and bitumen-polymer. In addition to high waterproofing qualities, they must be resistant to temperature changes, elasticity, and long service life.

Types of roofs and the nuances of their installation

The flat roof design determines the design and use. In certain types that require a special approach during construction, the following are distinguished:

Installation of a roof for unheated buildings

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

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

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

Roofing material strips are laid in stages with an overlap of 10-15 cm and fixed with wooden slats or steel slats every 60-70 cm in the direction of the drain, so as not to block the way of the flowing moisture. A flat roof of an unheated room can be easily assembled by oneself even by one worker without the help of helpers.

Installation of roofs for heated buildings

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

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

Monolithic concrete roof

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

The unclassing process

- device of a small angle of the roof surface for the organization of the drain. Before building a house with a flat roof, it is better to decide in advance which gutter you will install, internal or external, and make a drawing.

If provided, the water by means of a slope should be drained into the water-catching funnels, which are located at 1 per 25 square meters or more. If you make an external gutter, then moisture must enter the gutter. The deflection is formed by the following methods:

A flat roof without proper deviation is an unreliable shield between you and bad weather. Moisture, which has no outlet, will accumulate on the surface of the roof, provoking the destruction of the roof and leaks.

Video instruction

For many, a flat roof is associated with urban multi-storey buildings, faceless and monotonous. But we are ready to surprise you! A flat roof in a private house will be a pleasant discovery for you if there is not too much snow in your area, but the winds are strong enough. The fact is that in winter all snow accumulations from such a roof will simply be blown away. And the main thing is that not a single strong hurricane can blow off the roof, which simply does not exist! And also a whole ocean of possibilities opens up before you, which now you can build over your head: a cafe, a dance floor, a mini-garden and even a whole greenhouse!

The main thing is just to know about all the intricacies of the arrangement of houses with a flat roof, and everything will work out. And we will reveal all the secrets now.

Such a roof is much smaller in area than the flattest pitched roof. And this is saving on materials.
Such a roof is being built much faster than a gable and even more hip.
Comfort and safety of all rafter work. You still need to manage to fall from such a roof!
Convenient subsequent repair and replacement of roofing.
Unlike a gable roof, dismantling the old flat roofing is usually not necessary - this is additional waterproofing and protection. The new cake is made just like the old one, which saves a lot of time and effort.
The ability to use the roof as an additional useful area where you can set up a flower garden, make an open terrace and even build a greenhouse.
The ability to install transparent roof elements (with careful waterproofing), and thus make a view of the night sky.
Possibility to build a house with a laconic architectural form. Minimalism is at the height of fashion!

And now - about the cons and disadvantages:

Such a roof generously accumulates snow in itself. After all, he now has nowhere to slide, and the snow itself often becomes the cause of leaks.
On especially generous days, the snow will have to be mechanically removed, which often damages the roofing.
The structure of the roof is becoming more complicated: now gutters are needed, which, in addition to everything, also clog up.
The difference is that water drains off the pitched roof quickly enough (and it happens that it does get into the under-roof space). But on a flat one, it generally stands!
Control of the moisture content of the insulation and the general condition of the roof should be regular.
But, despite the fact that for its arrangement of building materials much less is needed than for a pitched roof, a flat roof in terms of installation is much more complicated. Let's just say, there are many more different subtleties and nuances that are important to know about.

That is why many have fair doubts about the reliability of such a roof. But the European and overseas experience of private residential houses with a flat roof is successful, and therefore you can safely get down to business.

Consider only such points:

There is much more snow in Russia than in warmer European countries.
The only thing worse than snow is the big difference between summer and winter temperatures, for which not all foreign roofing materials are designed.

And here technology decides everything!

What is a flat roof?

So, what acts as the supporting base of a flat roof:

Reinforced concrete slab.
Roofing sandwich panels.
Reinforced steel sheet.

And thanks to the fact that they learned to make a flat roof "breathable", i.e. with internal ventilation, now it has become possible to use completely non-breathing waterproofing - roofing material similar to it.

Any roof that we call flat, in fact, still has a slight slope: to one side or purposefully towards the drainpipe.

Here is the simplest example of a flat roof for a private house:

Types of flat roofs: unexploited and inverted

Of course, unexploited roofs are cheaper. And the exploited ones, which are correctly called "inversion", include additional materials.

A separate type of flat roof of a residential building is exploited. Those. the one on which people will walk and what objects will stand. This is the same garden, or sports ground, or outdoor cafe. All this creates considerable loads on the roof, and therefore its device is already different from that which is intended only to protect the house from precipitation.

So, the main difference in the structure of traditional and inverted roofing is that in the first layer of thermal insulation is located under the waterproofing, which is quite logical, and in the second - above it. But in the second version, the waterproofing is more protected from ultraviolet rays and temperature extremes. This design is more durable and functional: you can safely arrange a lawn or lay paving slabs on it.

And now in more detail.

Unused roofing: standard pie

But on an unexploited roof, a person can also occasionally climb - for the same repair, for example.

Those. in a traditional flat roof, the top layer is waterproofing, and it is this that is subjected to all mechanical and thermal stress.

A separate type of it is a roof with a pressure layer, which is designed for a person to walk on it from time to time:

Inverted roofing: reverse pie

The standard slope of the inverted roof is 5-7%. The inversion method assumes that the layer of thermal insulation is already located on top of the waterproofing, which now also serves as a vapor barrier at the same time.

Moreover, the pie of inversion flat roofs can be very different. It all depends on what you are going to arrange on the roof: a terrace, a mini-pool (and this is not uncommon) or a garden. But the base will still be common: a monolithic screed is made, which levels the entire surface, then waterproofing is laid and all this is covered with insulation. And already on top - a cement-sand mixture or rubber coating.

Note that the active operation of the roof is frequent damage to the insulating layer, due to which moisture makes its way to the insulation and freezes in winter. Over time, the entire roofing cake deteriorates, and therefore a flat roof ventilation system is indispensable.

A cement-sand screed is able to even better distribute the pressure layer on the heat insulator, but it must be additionally reinforced with a grid against cracking.

Subtleties of flat roof insulation

A layer of thermal insulation for a flat roof is required. For comparison: a gable roof is insulated only when a residential attic is equipped under it, and in all other cases, a maximum of mineral wool is laid on the attic floor. But for a flat roof, insulation is always necessary.

The fact is that without a heat-insulating layer in a flat roof, condensation will constantly appear on the ceiling in the house (such a roof will just be the cold part onto which water vapor will rush). And this is bad not only because repairs will have to be done, but also because the whole structure deteriorates.

You can insulate a flat roof both from the outside and from the inside - the difference is small. More importantly, in how many layers a particular roof needs to be insulated - in one or two.

Thermal insulation materials must be attached to the base of the roof mechanically, either using screws or dowels, or using glue. Sometimes the mount is not used at all if the heat insulator is located from the outside, and paving slabs or pebbles are pressing on it.

Why two layers? The fact is that the first layer of thermal insulation on a flat roof performs the function of insulation, it is from 70 to 200 mm thick. And the second, from 40 to 50 mm, is designed to distribute all the loads. And the thickness of both layers is important to calculate accurately, based on the climatic features of the area and the future use of the roof itself.

With two-layer insulation, all joints should be staggered, in a checkerboard pattern, so as not to fall on each other. Moreover, in the places where the plates adjoin the walls and the parapet, it is additionally necessary to make heat-insulating sides. A cement-sand screed is able to even better distribute the pressure layer on the heat insulator, but it must be additionally reinforced with a grid against cracking.

Correct drainage system

But this is already a difficult task. Flat roofs are bad because they are completely open to rain. But everything can be solved! The main thing is to correctly organize the drain, and for convenience, we have opened this issue for you in the following schematic illustrations:

Internal ventilation device

Another important point when arranging flat roofs is ventilation. The fact is that if moisture accidentally enters the insulation, it no longer evaporates - it only accumulates. As a result, the insulating material rots, and the waterproofing swells. And there are many reasons for leaks: broken waterproofing, mechanical damage to the upper layer of the roof, cracks and harm from frozen water.

A damp heat insulator is also bad because of it, bubbles and cracks appear on a flat roof in the summer heat - all due to the active evaporation of water. As a result, the roofing also collapses. And if moisture eventually gets under the old screed, then the entire roof begins to flake off. This is why a flat roof needs to "breathe".

For this purpose, the so-called aerators are used on it. In appearance, these are simple plastic or metal pipes, covered with umbrella caps. They should be placed evenly over the entire roof area, preferably at its highest points. The essence of such a mechanism is that different pressures are created inside the roof and the air begins to create flows, simultaneously capturing all excess moisture vapor.

In practice, it looks like this:

In addition, in any living space, water vapor rises up to the ceiling. Moreover, they often successfully overcome this barrier (the water molecule is very small) and get into the insulation, which is bad for him. That is why vapor barrier is required. And not the one that is usually used to insulate the attic, but dense, made of high-quality polypropylene or polyethylene. A bituminous membrane is even more reliable.

Choosing the right roof covering

So what is used as a coating for these roofs?

Option # 1 - bitumen and polymer-bitumen materials

Such roofs are the cheapest for the owners of private houses. Basically we are talking about roofing material and euroruberoid. These are rolled roofing sheets, based on synthetic fabric, and on the sides - bitumen. As an elastic and frost-resistant material, bitumen serves as an excellent protection and waterproofing.

Moreover, the installation of bituminous roofing on a flat roof is absolutely simple, you only need a gas burner. The rolls are easily fused together.

But such a roof has a significant drawback - fragility. And also the fact that the roofing material does not breathe at all, i.e. it is vapor-tight, and therefore it is imperative to arrange ventilation for such a roof, unless you want the insulation to rot in a year:

Option # 2 - liquid rubber

Such roofs have the huge advantage that they do not contain any seams. As we have already said, the minus of a flat roof is, first of all, that snow accumulates on it, which then causes leaks.

But there are some subtleties here. So, you need to take only two-component liquid rubber for a flat roof, preferably the highest quality. And it is extremely important to correctly apply this material to a flat roof: evenly, avoiding unnecessary layers and savings in certain places. So, where the paint was applied unevenly, problems should be expected after 8-10 years.

Option # 3 - PVC, TPO and EPDM membranes

Roofing membranes are valuable as a covering for flat roofs in that they allow steam to escape to the outside. After all, whatever the vapor barrier used, moisture still at least a little, but gets into the insulation, and not only from below, but also from above - after heavy rains, for example.

There are three types of membranes for the device of such a roof: TPO, PVC and EPDM. The most popular is PVC membrane, it is also the most flammable. The EPDM membrane is more durable and affordable, but if mechanical damage occurs in it, nothing can fix it, while the PVC membrane can be melted with a hair dryer. In addition, the joints of the EPDM membrane must be glued with a special tape, which is much less reliable than the welding of PVC sheets.

But the cheapest membrane in its sector is PVC. But it has such significant disadvantages as low resistance to ultraviolet rays and the fear of contact with bitumen, various oils and even expanded polystyrene, otherwise the service life is significantly reduced.

Bonding EPDM membranes requires professional skills. TPO membrane, like PVC, is also hot air weldable. It is not afraid of ultraviolet light, it is more resistant chemically and can be laid directly on polystyrene foam or an old bituminous roof without geotextiles. But its service life is shorter than that of EPDM, therefore, for the flat roof of a residential private house, we recommend using a PVC membrane.

So, the cake of a flat roof device with a PVC membrane is traditionally made like this:

Step 1. We arrange a monolithic floor slab.
Step 2. We put a tear-resistant vapor barrier film.
Step 3. We make a slope of insulation or screed.
Step 4. We put insulation. In private construction, this is usually 35 density foam, and on top is XPS at 50 mm, which is even stronger.
Step 5. Now geotextile, 300-500 g per square meter.
Step 6. Moving on to waterproofing - this is the PVC membrane. The density of the insulation is enough to walk on such a roof. But, if you plan to make an open terrace on the roof, then the pie needs to be continued further.
Step 7. Again, lay geotextile - now directly on the membrane.
We put rubber tiles or a reinforced screed 5-7 cm, on which we already put the paving slabs. Ballast is required to make a screed.

And also such roofs are made of rubber, polymers or even foil. Unlike bituminous ones, they are durable, fire-resistant and firmly adhered to the base. Reach a slight slope using expanded clay concrete or concrete screed.

How to achieve 100% waterproofing?

The main task when installing a flat roof is to make all joints and abutments as tight as possible. Indeed, such a roof is most affected by moisture, hail, temperature extremes and debris carried by the wind. Therefore, the sealants used for sealing such joints must be of high quality and resistant to any influences. This is also a kind of expense that you have to go to.

For the same purpose of waterproofing, it is recommended to make a flat roof slope of at least 2%. Few? In fact, this is quite enough so that all atmospheric moisture does not linger on the surface, but flows down into funnels and pipes, and from them into a septic tank, soil or sewer. Therefore, even at the design stage, you need to think carefully about the future drainage system.

Moreover, the drainage itself is made both internal and external. So, the internal drainage system consists of fittings - funnels located throughout the roof, which take in the flowing water and direct it into pipes that go through buildings, but are isolated from living quarters. The only disadvantage of such a system is that the pipes are clogged with small debris and leaves, for which it is advisable to equip them with special filters and periodically clean them.

External drainage systems are already fixed along the outer walls of the building. Of course, it is easier to clean these when they get clogged, but in cold weather they often freeze over. For which it is customary to additionally supply them with electric heating in the form of cables.

As for the material for the internal and external drainage system of a flat roof, then PVC or metal is quite suitable. Both options have their pros and cons. So, polyvinyl chloride does not corrode, but it is more fragile than metal.

In order to prevent the gutters from freezing in winter, equip them with roofing thermal cables.

Green area on the roof: fashionable and sustainable

Greenery and recreation areas are often lacking not only for the inhabitants of the "stone jungle", but even for the owners of private houses. The thing is that it is not always possible to leave the same beautiful garden furniture in the courtyard of the house, and beautiful rare flowers in the garden bed are often trampled by pets. Therefore, it is not surprising that the green area on the roof has become fashionable among the owners of cottages. Especially if the exit to it goes directly from the bedroom and no one else can disturb your morning peace with a cup of coffee.

There is also a fashion for some cafes to make the roof flat, and put a small greenhouse on it. All the greens are immediately on the table! And it is beneficial, because bringing fresh dill or onions to the kitchen is not so easy, and it is economically profitable - there is where to send kitchen waste. And it's hard to know who borrowed this idea from whom: the enterprising inhabitants of private houses with flat roofs, or the best minds of public catering. But the fact that such an arrangement of closed ground is beneficial is a fact: rodents will not dig under the beds, insects and pests will not get there (as well as pests in the form of neighbors), and the fact that it is always a little hotter on the roof is only a plus for the same tomatoes. But the main thing is to correctly calculate the loads on such a roof during construction!

And the roofing pie is often standard: waterproofing on the floor, thermal insulation, geotextiles, drainage and again geotextiles. And on top, you can already have both the ground and the beds:

Or in this version for more powerful floors:

A flat roof is a huge space for any imagination. Designers and architects love to implement a variety of projects for her: a garden, and a greenhouse, and a jogging track, and a mini-beach with sun loungers, and much more. Some craftsmen even manage to make a parking lot on it!