Flat roofing - design and types. Photo of the roof greening process

Performed using modern techniques and materials, the device of a flat roof allowed this particular type of roof to become an integral part of the architecture of buildings for various purposes. And if until recently flat roofs were mainly found in industrial and agricultural buildings, now they are an attribute of many residential, administrative buildings and even country cottages. And the main thing is that time “works on them”, reliably confirming that flat roofs in all their qualities are no worse than the good old ones pitched roofs.

The flat roof has been steadily gaining popularity in recent years. With a small amount of construction work, for example, when erecting a barn, outbuildings, garage, even a non-professional can easily cope with such a design. Of course, although a roof of this type is considered flat, it is not horizontal. A prerequisite for the long-term operation of such a structure is the presence of a minimum technological slope, which should be about 1.5-2.5% per 1 m of length, provided that a usable space is constructed on the roof. In other situations, the technological bias should be about 3-10%. Sometimes structures with a slope of 10-20% are classified as flat, which is not true. Such coatings are already classified as pitched, only consisting of one slope.

A flat roof means a minimum of details and simplicity of design

Term trouble-free operation a flat roof is directly related to the professionalism of the builders involved in the construction of the structure. To install a high-quality coating, it is necessary to competently approach the issue of choosing a roofing material, the properties of which must correspond to certain parameters.

This is important to know! Even small violations, deviations from the technology of constructing a flat roof, not to mention obvious errors and shortcomings, or the use of low-quality building materials can cause a significant reduction in the service life of not only the roof itself, but also the entire building as a whole.

Flat roof installation

Advantages of flat design:

• a flat roof is an example of simplicity and minimalism, which are fashionable now, according to architects;
• savings in materials used due to its smaller surface area;
• long service life;
• simplicity and safety of installation work;
• convenience of carrying out preventive inspections of the roof and repair work on her;
• flat roof – additional free space, for example, for a cafe or green lawn;
• no problems when servicing chimneys, television antennas, ventilation ducts;
• resistance to high wind loads.

The green lawn on the roof is so nice!

If the installation of a flat roof is carried out competently and with high quality, there are no disadvantages in its operation. In the case of unprofessional installation, defects are possible that will become apparent in the first rainy autumn or snowy winter.

Flat roof design: studying the basic requirements

1. The high strength of the roof is especially important during the snowy season, when it is forced to withstand the pressure of thick layers of snow and ice. This indicator is also important in cases where the flat roof is used.
2. The roof must be a reliable barrier to water during rain and melting snow and have a slope.
3. The design of a flat roof must not respond to the effects of bitter frost and scorching sun rays, to the influence of changes in ambient temperature and hail strikes the size of a chicken egg.
4. The roof must perform an excellent thermal insulation function.
5. All materials used must be fireproof.

A lot more snow always accumulates on a flat roof in winter than on a pitched roof.

Classification of flat roofs and features of the roof plan

All flat roofs, depending on the functions they perform, can be divided into two groups:

1. An unused roof, which is a normal element of a building structure and performs the usual functions of a roof.
2. Operable roof, which is also used as an additional roof effective area. If this is the roof of a house, then a swimming pool or lawn can be organized on it. And if this is the roof of some underground building, then on top there may be a parking lot, a cafe, a park, etc. One thing is clear that such a flat roof will experience completely different loads than an unused one.

Operable roof with a cozy terrace

Depending on the installation features and materials used, there are also two types of roofs. In accordance with this, the flat roof pie in each case will have its own characteristics:

Traditional method

The traditional method, in which the topmost layer is waterproofing. In this case, it is she who is exposed to temperature, physical and mechanical stress.

The role of the load-bearing base can be performed by a reinforced concrete slab, special reinforced profiled steel sheet or roofing sandwich panels. The required slope is usually achieved using concrete or expanded clay. concrete screed. Sometimes polystyrene foam or slag is laid.

The next layer is a vapor barrier that prevents fumes from the room below from reaching the insulation. As a result, it always remains dry. For vapor barrier, a thick film of polyethylene or polypropylene is used. Its strips should be located perpendicular to the slope of the surface and overlap each other at the joints. Sometimes a bitumen membrane is chosen as a vapor barrier.

With the traditional arrangement of layers, waterproofing becomes the most vulnerable point

Then the thermal insulation material is laid. Usually mineral is used basalt wool, characterized by good compression resistance, vapor permeability, fire safety and low thermal conductivity. Its first layer (70-200 mm) will serve as insulation, and the second (40-50 mm) will serve as a load distributor. In general, the thickness of this layer is calculated in accordance with the climatic conditions of the region.

To redistribute pressure, the heat insulation layer is sometimes covered with a cement-sand screed, which is additionally reinforced with metal mesh to prevent cracking.

And finally, the finishing layer is waterproofing, for which special liquid mastics have proven themselves to be good, forming a rubber-like layer, built-up roofing material and roofing membranes.

What are the good things about the latter? They have a long service life and are capable of letting steam out. Roofing membranes are easy to install and, if the technology is followed, form an excellent waterproof coating.

Inversion method, when a layer of thermal insulation is placed on top waterproofing material, which here also serves as a vapor barrier. This is the most the best option for installation of existing roof structures. The size of a flat roof made using the inversion method will be different depending on what the roof is used for (swimming pool, pedestrian area, lawn, park, etc.). But in any case, a monolithic screed is placed on top of the concrete base to level its surface. The next layer is a waterproofing material, which in the future is reliably protected from the influence of any environmental factors. Then all this is covered with a heat insulator, on top of which, if, for example, the roof will serve as a pedestrian area, it is laid on a sand-cement mixture paving slabs.

The inversion method can be used to create a flat roof for an underground parking lot

In the design of any building with a flat roof, one of the mandatory items should be a plan for the roof of the flat roof. This is necessary not only to improve the aesthetic qualities of the structure, but also to increase the functionality of the future roofing structure. In addition to the exact calculation of the amount of all necessary materials, the plan includes the actual technology for carrying out the work, a diagram of the drainage system, features of the slope, ventilation and other aspects.

Horizontal ventilation in a flat roof structure

During the operation of the roof, damage to the vapor barrier layer is possible, which leads to moisture entering the insulation and freezing it into the insulation. winter time. All this reduces the thermal insulation ability of the material. Therefore, it makes sense to design the roof in such a way that it is ventilated. A flat roof ventilation system is a whole system of aerators (metal or plastic tubes) located under the roofing membrane. The system has exits to the roof in the form of umbrellas protected by nets. Best places for aerators - the highest points of the roof.

A ventilated flat roof has a longer service life. Ventilation device

Drainage system in roof structure

Important role The roof slope plays a role in water drainage, which is recommended to be at least 2%. Even a slight slope can prevent moisture from penetrating through possible defects in the roofing.

For a flat roof, the drainage system is of great importance. Its components are receiving funnels and pipes through which water is directed to sewers, storage tanks, or simply into the soil.

Water disposal can be carried out in two ways:

The number of funnels, their diameter and location, the diameter of the pipes must be calculated in accordance with the architectural features of the building, operating conditions of the roof and the amount of precipitation. Funnels are usually equipped with filters that prevent leaves, small birds, etc. from entering the system.

Metal or PVC funnels and pipes are used as materials for the drainage system. Components made of polyvinyl chloride do not corrode, which is why they are more popular.

Roof drains can be equipped with electric heating, thanks to which ice does not form on them in winter

The installation of a flat roof, from its design to commissioning, must be carried out by appropriately qualified specialists. Knowledge of only the basics of creating a roofing structure without taking into account specific features may lead to errors, the correction of which will require considerable financial investment. Therefore, installing a flat roof is the prerogative of professionals.

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

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

The situation is complicated by the fact that the surface of roofing materials has a rough structure, which does not allow moisture and snow to slide off freely. Therefore, the installation of a do-it-yourself flat roof must meet the strict requirements of building codes for waterproofing, slope and construction technology.

The structure of the roofing pie

Necessity high level protection from moisture forces the roofing materials of a flat roof to be placed in layers, one above the other, forming a so-called “pie”. If you look at its cross-sectional structure, you can see the following layers:

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

Types of roofing and nuances of their installation

The construction of a flat roof is determined by the design and nature of its use. Some types that require a special approach during construction include the following:

Roof installation for unheated buildings

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

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

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

Strips of roofing felt are laid in stages with an overlap of 10-15 cm and fixed with wooden slats or steel strips every 60-70 cm in the direction of the drain, so as not to block the path of flowing moisture. A flat roof of an unheated room can be easily installed with your own hands, even by one worker without the help of helpers.

Roof installation for heated structures

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

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

Monolithic concrete roofing

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

Leaning process

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

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

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

Video instruction

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

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

Types of flat roof

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

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

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

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

Roofs are divided according to functionality, roofing structure and type of coating. Here are a few main varieties:

• The unused roof is flat. It is built solely for the sake of originality and saving material. Does not require structural reinforcement.

• Operable flat roof. It can be used for any purpose, from placing an outdoor swimming pool to constructing a parking lot.

The type of floor depends on the intended purpose: it is obvious that for high expected loads, the base should be a concrete slab. But this does not mean that the entire building must be brick or concrete. For example, a flat roof in a wooden house can also be used. Of course, it cannot be used as a helipad, but setting up a solarium, laying out a garden or putting up a gazebo for tea drinking is fine. Of course, you can’t make a sparse sheathing, only a continuous one.

• Traditional roofing. The classic design of the roofing pie: a waterproofing layer on top of the insulation, the base is concrete, for the outflow of water - expanded clay concrete (inclined screed).

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

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

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

note

The design of these roofs differs from simple attics; they cannot be used for use.

When the height of the house is ten meters or higher, as well as on roofs in use, a parapet must be installed. For those in use - no less than 1.2 meters.

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

General structure of a flat roof

It is obvious that in exploited roofs for various purposes the device will be different:

When constructing a swimming pool, pay special attention to waterproofing;

“Green” roofing is also a thorough waterproofing plus soil filling, etc.

The most common covering is flat roofing. It is cheap, simple and fast to install, with excellent waterproofing. The cheapest material that can be used to cover a flat roof is roofing felt.

Flaws roll materials(and roofing felt in particular) – low durability, low mechanical strength. For “high traffic” roofs, tiles are preferable.

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

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

There are other coating materials for unused roofs:

• Polycarbonate;

Pros and cons of flat roofs

Advantages:

• Original look. Flat roofs on cottages are rare.
• Possibility of operation.
• Flat roof – easy installation and savings on materials. But it depends on how you plan to use the roof. Otherwise, construction will cost even more than the expensive pitched roof from ceramic tiles.
• Laying covering, maintenance, and repairs on a flat roof are easier to perform than on a slope.
• Flat roofs are wind-resistant, pitched roofs have windage.

Minuses:

• A flat roof leaks more often than a pitched roof. Constant monitoring of the condition of the waterproofing layer is necessary.
• The need to clear the roof of snow.
• Rolled flat roofing requires more frequent repairs and replacement of the covering than metal profiles, tiles and other pitched ones.

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

Building a flat roof

Let's consider the option when a corrugated sheet is used as the base of the roof:

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

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

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

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

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

6. On flat roofs, a fused roofing can be laid in several layers.

In other cases, a flat roof wooden beams it is arranged more traditionally: a continuous sheathing of plywood or OSB is nailed onto the beams, a roofing pie is laid (vapor barrier + basalt wool), a waterproofing layer and rolled roofing are applied.

If you are interested in a flat roof with a more complex structure, please contact us: we will complete roofing of any complexity quickly and efficiently. affordable price.

One of the practical and fairly simple structures to install is a flat roof. Despite many years of construction experience, such roofs still remain exclusive on the market. Flat coating has many advantages, including ease of DIY assembly.

What types of flat roofs are there, what is their difference?

Flat roofs are:

• exploited and unexploited;
• traditional and inversion;
• breathable;
• green.

Let's take a closer look at each type.

1. Operable roof. The main feature of the coating is to prevent defects in the waterproofing layer using corrugated sheets or concrete screed. As insulation, you should select a material that can withstand high compressive loads. When using an insulator that is not rigid enough, you can achieve the required strength by creating another layer of screed. In conditions of shortage of free space, flat roofs are widely used for arranging summer cafes, parking, and recreation areas. The structure of the roof in use is presented:
   
2. Unused roof. It differs from the previous type of structure in its simplicity of arrangement, low requirements for the base and insulation. The only disadvantage of such a roof is its short service life.
3. Traditional roof. The coating consists of several layers, which includes a vapor barrier laid on top of the base. This film protects the insulation (foam or mineral wool) from moisture.

   In a traditional roof, all layers are in the usual order

4. Inversion design. A distinctive feature is the laying of insulation over the waterproofing film, which guarantees its protection from sources of negative influence. The insulation is selected that does not lose its properties even when the humidity level increases, for example, panels made of extruded polystyrene. An inversion roof can be used as a functional roof - it can be a green lawn or a pedestrian area.

   In an inversion roof, the insulation is laid on a waterproofing layer

5. Roof with breathable coating. This type of roofing prevents the formation of steam in the heat-insulating layers and does not require dismantling the old covering, since it can be installed as an additional main carpet.

   Breathable roof covering prevents condensation

6. Roof with landscaping. The lack of lawns near the house can be compensated by arranging a lawn or a whole park on a flat roof. The planning of such a covering is carried out at the design stage of the building, which is explained by the need to calculate the reinforcement under the load exerted by the soil layer. Green roof installation diagram:
   

By type of use, a green roof can be extensive, when only lawn grass is planted, and intensive, when flowers, shrubs, and trees grow on the roof.

Identifying the advantages and disadvantages of using flat roofs

With proper installation and laying of the waterproofing layer, a flat roof has positive qualities:

• allows you to save on building materials due to a smaller construction area;
• erected much faster than other types of roofs;
• Maintenance and repair are quite simple;
• provides the creation of additional area for, for example, sport complexes, recreation areas, flower beds;
• allows the use of paving stones or paving slabs.

The special structure makes the roof more vulnerable to negative climatic conditions, giving it a number of disadvantages:

• the formation of leaks during the melting of a large volume of snow cover;
• need to create drainage system;
• problems arise in the operation of the drain: blockages form, it freezes in winter;
• need for snow removal;
• the need for periodic inspection to prevent moisture from penetrating into the insulation layer;
• the need for quick repairs in case of roof leakage.

Video: what is good about a flat roof

What you need to know when installing a flat structure

Eat certain rules flat roof devices:

1. Horizontal laying without a slight slope is not allowed. The minimum angle value is 5 degrees, which will ensure independent precipitation. To create a slope, in addition to the coating itself, a bedding made of expanded clay or slag should be used. You should not make a slope of 10 degrees or more - it will not allow the heat-insulating layer to be laid evenly.
2. For vapor barrier, a bitumen-polymer membrane with fiberglass reinforcement or a vapor barrier film is used.
3. At the edges, the vapor barrier is attached above the insulation with mandatory sealing of the seams.
4. Thermal insulation material is placed on top vapor barrier film, and above it there is a bitumen waterproofing carpet. When using expanded clay as insulation, it is necessary to pour a cement screed with further installation of a two-layer waterproofing.

There cannot be a perfectly flat roof on a residential building; it must be equipped with a slight slope

Sequence of roof installation on wooden beams

After completing the assembly of the load-bearing walls, you can attach the main floor beams to anchor bolts, taking into account a gap of 0.5–1 m. They are selected according to the calculated weight of the roof and the average annual precipitation. Beams can have a section of 150x150 mm or 100x100 mm.

The process itself takes place in several stages:

1. A continuous sheathing (without cracks or gaps) made of 20–25 mm edged boards is installed on top of the supporting structure.
2. At the next stage, polymer waterproofing is laid so that each top layer is overlapped with the previous one and taped.
3. Then the thermal insulation is installed. The best option is to use fiberglass insulation mats or sheets of extruded polystyrene foam. To avoid the appearance of condensation and destruction of this layer in the future, the material should be tightly fastened together. In addition, unsewn cracks can become a source of cold bridges.
4. Installation of moisture-resistant plywood or OSB boards is carried out. On top of this coverage roofing material is laid. You can choose any, for example, soft tiles.

Features of the rafter system

The purpose of the truss structure is to distribute the roof load across the support points. A flat roof can be erected on rafters of three types of fastening:

1. Hanging rafter system. It is suitable if there is no support between the side beams. The structure is assembled on the ground and then transported to the log house. Pine, reinforced concrete and metal elements are used for work. The rafters are taken with a section of 5x15 cm, the lathing - 5x5 cm
2. Layered system. The rafters are laid at an angle to external walls at a distance of 60–140 cm from each other. The upper part of the structure rests on a beam reinforced with racks and struts. As a rule, such a structure is suitable for the construction of outbuildings.
3. Sliding rafter structure. Installed on houses that undergo shrinkage during the first year of operation (for example, made of timber). Assembly is carried out to the ridge log so that the rafters are overlapped or end-to-end. To avoid sagging of the roofing system and deformation of the frame rafter legs freely fixed to the Mauerlat.

The larger the roof size, the greater the slope of the rafters should be.

Video: covering a flat roof

Performing calculations

When performing installation work, as with any construction project, it is necessary to operate with basic data.

Snow load

For the calculation there is a generally accepted formula: Q=G*S, where Q is the snow load, G is the mass of snow in kg/sq.m (the value can be taken from the snow cover level table), S is a coefficient determined from the angle of inclination of the roof:

• when tilted up to 25 degrees S=1;
• at a tilt of 25–60 degrees S=0.7;
• with a slope of 60 degrees or more, you can not take into account the level of snow load, since precipitation is unlikely to be retained on such a slope.

An example of calculating the amount of snow load when a house is located in Russia with Q equal to 180 kg/m 2.

The roof slope is 23 degrees, which gives maximum snow load Q=180*1=180 kg/m2.

To lay the foundation correctly, you need to know the entire mass of the snow cover using the formula M=Q*S, where M is the mass of snow, S is the area of ​​the roof.

In this example, the area is 150 m2.

When calculating the full load from precipitation in winter, it turns out M=180*150=27000 kg or 27 tons.

Roof area

Flat roofs, as a rule, coincide in area with the area of ​​the house or the under-roof part.

Water intake funnels

One funnel can serve up to 200 m2 of roof, the distance between them must be more than 50 cm, and the diameter of the drainpipe must be from 10 cm. Regardless of the roof area, there must be at least two funnels on it, otherwise flooding or clogging of the system is possible.

To correctly determine the number of water intake funnels, it is necessary to operate with data on the intensity and frequency of precipitation.

Structure of a flat roof roofing pie

Construction of the structure is allowed in two ways:

Installation of roof waterproofing

Waterproofing work, regardless of the type of flat roof, is the same and is carried out taking into account a number of requirements:

• the roof structure should have a slight slope for free flow of precipitation;
• the waterproofing layer is laid in the form of a solid and homogeneous sheet;
• the throughput of the drainage system should be as high as possible;
• The waterproofing near the communications outlet must be slightly raised.

To arrange a flat roof, you can use different materials:

Video: DIY flat roof waterproofing

Laying insulation on a flat roof

Choose insulation from among the practical and practical ones presented today inexpensive materials it won't be difficult:

Any craftsman can independently insulate a roof, regardless of the material chosen, according to the presented diagram:

1. Selection and calculation of insulation. During installation, the slabs are cut into pieces of the required size, so it is recommended to take extra material.
2. Preparing the base for insulation: cleaning, laying vapor barrier.
3. Laying the material. To avoid the formation of condensation, it is recommended to install the insulation at a distance of 2 cm from the film or use anti-condensation material. To attach the thermal insulation material to the base, bitumen mastic, special glue, and liquid nails are suitable, although ordinary nails can also be used.
4. Sealing joints. In order to eliminate inter-tile cracks and gaps, you will need polyurethane foam.

Treatment of wooden roofs against fire

Creation of a fire retardant coating on roof structures is carried out using the following methods:

• constructive - involves the use of fire-resistant heat insulators, screens, partitions;
• mechanical processing method - applying special compounds to wooden elements to slow down or prevent the combustion process. As a rule, such products also have antiseptic properties.

The main tasks of fire retardants are:

• making structures resistant to fire;
• creating clear boundaries of flame spread;
• reducing the level of smoke formation and the release of toxic substances.

There are two types of impregnations:

1. Intumescent - when exposed to heat, they swell and create a kind of hard, fire-resistant shield.
2. Non-intumescent - highly fire-resistant varnish-painting compositions, which, due to their thin layer, prevent the roofing material from catching fire.

All wooden elements of a flat roof must be coated with fire retardant impregnations.

To treat wooden elements, it is recommended to use salt impregnations (the protection lasts for about 2–4 years) or organic mixtures (the fire resistance effect lasts about 17 years). If it is necessary to emphasize the natural structure of wood, you can use protective varnishes and paints. Due to the coating with impregnations and water-based products, the wood does not ignite, but becomes charred.

The maximum protection is deep processing roofing performed under high pressure, which results in the formation new surface, not susceptible to the destructive effects of flame.

One of the dangerous consequences of fire is deformation and collapse metal structures, therefore, applying a protective agent is especially necessary in crowded areas. Thus, steel roof parts are plastered or painted with intumescent agents. Due to the layer of plaster, the metal does not heat up, maintaining its load-bearing capabilities. The disadvantage of this method is the fragility of the coating and low resistance to mechanical damage. A higher quality analogue is considered to be painting, when the coating creates a thick layer with strong heating that does not allow the roof structure to heat up for 0.3–2.5 hours.

Metal roofing material is fire resistant

When choosing a treatment method, you should take into account the characteristics of roofing materials. So, if tiles are laid on the roof, then at the time of a fire only smoke will appear, and the covering will crack. Roofing material based on bitumen-polymer is dangerous due to rapid flammability and the spread of fire to nearby surfaces.

Thus, despite the simplicity of this work, when installing it yourself, it is necessary to take into account the characteristics of the region in which the roof is used, its rafter system and the roofing pie. If all recommendations are followed, the structure will be durable and resistant to negative influences in the form of climate change, precipitation, mechanical loads, and fire.

Ventilation features

Regardless of the design, the roof must be well ventilated, otherwise problems cannot be avoided that can cause damage to the roof. Ventilation is a system that allows you to keep each layer of the roofing cake from moisture. In this case, you must follow certain rules:

1. For proper air exchange, an aerator is used - a metal or plastic pipe, which is located at certain points throughout the entire roof area.
2. It is necessary to install cone-shaped umbrellas that protect the roof from precipitation. Unnecessary moisture is removed due to the pressure difference.

Installation of aerators

The main function of these devices is to remove excess moisture and remove moist air outside. They can be installed both during the construction of the roof and during operation. In some cases, installing an aerator is a preventative measure to prevent rotting outer covering roofs.

The flat roof ventilation system must be equipped with aerators

The number of these parts on the roof depends on its area, the volume of condensate and moisture, and the condition of the roof. It is necessary to increase them in the case of installing a roof over specific premises, such as a bathhouse or a swimming pool.

The ventilation process itself is ensured by special pipes. These are also polyethylene aerators with a diameter of 6 to 12 cm. Their special feature is the presence of umbrellas.

The aerator installation process is as follows:

1. You must first check the condition of the insulation. If this is necessary, the material must be replaced.
2. Lubricate the lower part of the aerator with mastic and then attach it to the base of the roof. Carefully secure the skirt with several self-tapping screws.
3. The junction of the aerators must be sealed with waterproofing material.

Ventilation duct for a flat roof with a superstructure

In the case of a flat roof with a superstructure, the ventilation outlets must be mounted vertically. This way they will be able to direct air flows, create draft, and protect the roof ventilation system from rain and snow. The peculiarity of a flat roof with a superstructure is that its ventilation system does not have connections using adapters. Additionally, you can install an electric fan. It works so silently and efficiently that you will not hear any sound from it.

Aerators can be equipped with electric fans

Lightning protection mesh down conductor

Every home needs lightning protection. In the case of a flat roof, all work is carried out according to the following scheme:

1. An air terminal is used in the form of a mesh, which can be made of round steel with a diameter of 6–8 mm.
2. The tap is a metal conductor made of wire with a cross-section of 6 mm, which must be connected to ground. Underground part It is recommended to make it from rolled steel with a diameter of 10 mm. You can also use pipes and fittings as a down conductor. If there are several of these parts, then they need to be installed at a distance of 25 m from each other.
3. If the flat roof is covered metal material, then the lightning rod system can be supplemented with a steel sheathing, which just needs to be connected to the roof. This system is only relevant for seam roofs.

A mesh lightning rod is suitable for a flat roof.

The mesh lightning rod system can be installed both during the process of arranging the roof and during the laying of the covering. The first option is recommended when using non-combustible insulation. In this case, the mesh is placed under the waterproofing. The second option has no restrictions, but such a lightning rod affects not only the appearance of the house, but also the necessary technical characteristics of the roof. To do this, simply lay the mesh on the roof surface and secure it with special holders. Remember about the need for a ventilation gap if you use flammable materials.

Rules for the construction of lightning protection mesh:

• the branches must be folded perpendicularly, and cells with equal sides should be formed;
• the distance between them should be a maximum of 12 m; when installing a roof over a garage, this parameter is 5 m;
• When installing devices that rise above the level of the lightning rod, they must contain additional rods in their design.

It is better to fix metal parts by welding.

It is advisable to connect the receiver branches to each side of the down conductor.

A down conductor must be on every roof

Drainage

The drainage system for a flat roof consists of pipes, connecting elements and funnels. It can be external or internal. For a flat roof, the second option is often chosen. All gutters should be installed at an angle greater than 3 degrees towards the center of the house. It is recommended to lay drain pipes on top of the insulation, and funnels under the waterproofing layer.

The drainage system consists of gutters and funnels

A flat roof should have at least three funnels. One of them is the main one, the other two are connected to the riser and storm drain.

The internal system can have a different design:

• gravity flow collects water from the entire roof and only then discharges it through pipes; it has a slope;
• siphon means the use of special devices that, thanks to rarefied pressure, absorb water and direct it into the sewer riser.

There are certain rules for installing a drainage system for a flat roof:

1. Gutters should be located in the lowest places of the roof.
2. The slope from the funnel should be at least 5 degrees at a distance of 50 cm; for this it is recommended to reduce the thickness of the insulation or use a leveling screed. To install drainage funnels, it is recommended to take wooden beam, which must be fixed to the base of the roof and then treated with antiseptic solutions.
3. The diameter of horizontal pipes should be no more than 7.5 cm.
4. If the funnel is located above the freezing level, an electric heating device is required.

Protects the cornice from the negative effects of water.

The drip line prevents the negative effects of moisture on the roof eaves

The drip line is mounted along the edges of the roof, while it is directed downwards. Additionally, this element can be coated with polymer.

The installation process is as follows:

1. Install the flashing parallel to the eaves, placing it under the sheathing board. For fastening, you can use nails or screws.
2. You can also install a dropper on the front board. This method is suitable for roofs with minimum angle tilt, but remember that such a system may not withstand snow loads.
3. The drip tip and the gutter should be as close as possible to each other.

Roofing options

For a flat roof, it is necessary to choose materials that meet increased requirements, in particular, this applies to:

• strength;
• light weight;
• good warm sound insulation;
• resistance to solar radiation, frost, high temperature, fungi and mold, fire;
• long service life;
• efficiency;
• ease of care.

Corrugated sheet

Installation is carried out directly on the floor beams. Allows you to reduce installation costs reinforced concrete covering thanks to the use of the own load-bearing capacity of the profiled sheet. In some cases, concreting can be completely abandoned.

The reliability of such a roof can be increased if the voids between the waves are filled with any non-flammable porous material.

Laying corrugated sheets does not require sheathing

Ruberoid

This type of roofing requires a special roofing pie:

1. First you need to perform a rollover. Gravel is ideal for this purpose.

   Roof slope can be done in different ways

2. Next, you can install a drainage system.
3. The insulation layer is protected with a vapor barrier membrane, on top of which the thermal insulation material is laid. You can put mineral wool or expanded polystyrene under the roofing felt.

   The easiest way to install slab or roll insulation

4. Place sagging waterproofing material on the insulation.
5. You can mount a solid plywood base, flat slate, wood or concrete. This sheathing must be coated with a primer.
6. Now you can lay the roofing material. There are two ways to install roofing felt. Lap laying involves laying the material so that it ends on a vertical surface. The next canvas must be laid in a manner adjacent to the previous one. The amount of overlap varies between 10–15 cm. The next method is to install roofing felt in a fork. In this case, the material is attached to the rail, the connection point is covered with metal aprons.

The number of layers depends on the area and slope of the roof (the smaller it is, the more layers are needed). You can use a gas torch for installation, but be careful not to burn the material. To do this, it is recommended to direct the flame down the roll, which results in the formation of molten bitumen protruding beyond the edges.

They can be used not only for building houses, but also for arranging roofing structures. Moreover, this can be either the construction of a new house or the replacement of the roof of an old building. The material from which the walls were built does not have any role; the panels can easily be mounted on absolutely any structure. The main advantages of sip panels:

• no need for insulation and vapor barrier;
• good sound insulation properties;
• high energy efficiency;
• increased strength.

We also need to remember the disadvantages:

• a ventilation system is required due to the tightness of the cracks;
• before installation protective material external joints must be sealed.

A roof made of sip panels does not require insulation

The masonry of sip panels is carried out parallel to the Mauerlat. The angle of inclination of such a roof must be at least 5 degrees, but only if there is no attic.

The construction of sip panels requires additional covering with other roofing materials, for example, metal tiles or ondulin.

Video: is it possible to make a roof from sip panels

PVC roofing

PVC membrane is a plasticized polymer that can give special strength to the roof due to reinforcement with ether fiber.

PVC roofing has good waterproofing properties

The advantage of this material is its elasticity and resistance to constant temperature changes. But it should not be used with bitumen-based materials.

Installation is carried out in several stages:

1. It is necessary to remove the old waterproofing, and then lay new material in compliance with all rules.
2. Now you can install the membrane film; this can be done on any base.

There are three mounting methods:

1. The first is to use warm welding, that is, with heated air. This guarantees the strength of the seam. This procedure can be done with a special welding machine, which needs to process the edges of the film, after which the roofing material can be fixed on the roof. You can also use special tapes with a double-sided adhesive base.
2. The second type of fastening is suitable for roofs with a slope of no more than 15 degrees. Fixation occurs only around the perimeter and at junctions. After this, ballast weighing more than 50 kg per 1 m 2 is used. To do this, you can take pebbles, crushed stone, concrete block, paving slabs and any other heavy object.
3. Mechanical method. It can be chosen when the presence of additional load on the supporting structure is unacceptable, as well as in cases where there are no drains and parapets. The fastening proceeds as follows. Telescopic fasteners are installed along the perimeter, which can be plastic umbrellas with a large hat and a metal anchor. If the roof slope is greater than 10 degrees, disc holders can be used. The elements are placed at a distance of 2 m. It is recommended to use two rows of fasteners at the junction points.

Video: do-it-yourself PVC flat roof

Cellular polycarbonate

For furnishing residential premises, it is recommended to choose material with the greatest thickness. The peculiarity of installation is that there is a need to install rafters in meter increments. A frame is also required, which can be made of carbonate or metal profiles. They, in turn, are recommended to be protected from dust and dirt. The profile can be fastened with self-tapping screws directly to the rafters.

For a polycarbonate roof you need to use the thickest material possible

Now you can attach the polycarbonate sheets. To do this, you can use fixing profiles and simple self-tapping screws. It is recommended to drill a hole in advance that is larger than the diameter of the screw. It is not recommended to screw these elements in too tightly, otherwise there is a risk of damage to the material due to changes in temperature conditions.

Polycarbonate can be classified as a fragile material, so it is recommended to be quite careful when working with it. Certain rules must be followed:

1. The leaf channels should be parallel to the slope.
2. Work must be carried out on smooth surface using a sharpened tool.
3. The film can only be removed after cutting.

Main nodes

The reliability of the structure largely depends on the correct arrangement of the junction points building structures. This applies to parapets, walls, pipes, ventilation elements.

Cornice knot

The eaves are a roof element that can provide a long service life by increasing the strength of the edges. It must be covered with roofing material on top, and siding or wood can be used to finish the bottom. When the cornice is located at the very bottom of the slope, the following functions are assigned to it:

• giving harmony and logical completeness to the architectural appearance;
• ensuring the protection of walls from high humidity, the blind area of ​​the foundation from the flow of melt water.

The minimum width of the cornice should be 50 cm. This parameter depends on the amount of precipitation in a particular region.

The cornice is designed to protect the edge of the roof

Cold roof units

Their purpose is to ensure insulation of the transition from a horizontal to a vertical surface, as well as sealing seams.

To create cold roof units you need:

1. Install the strip at the junction points, using a sealant. This is necessary to prevent dust and moisture from entering the roofing pie.
2. Make a groove in the wall into which you need to insert the strip into the groove, then secure the system with dowels and a layer of sealant.
3. Now it needs to be connected to the roofing material using self-tapping screws. If the roof is covered with corrugated board or slate, then you need to screw the fasteners into the most protruding point of the wave.

Connections to the parapet

The junction with the parapet requires enhanced waterproofing through the use of rolled roofing; it must be laid with an approach to a vertical surface, and the presence of a special support must be ensured. If you install roofing material without it, a cavity may form, which will cause mechanical damage and failure of the coating. Therefore, it is necessary to provide support at an angle of 45 degrees between the base of the roof and the parapet. It could be cement-sand screed or a wooden block.

The parapet performs a protective function

The waterproofing layer must be glued to the base of the roof, to this side and to the parapet, using heated bitumen mastic.

Before it dries, insert the edge of the waterproofing layer into the prepared groove. This part of the material can then be secured with a metal strip and dowels. Treat the joint area with sealant.

Features of flat roof maintenance

There are certain requirements for the installation of a flat roof.

Heating

There come times when the sun's heat is not enough to turn snow and icicles into water. Therefore heating is required. There are several options for arranging this system for a flat roof:

• use of self-regulating cables;
• installation of resistive heating elements.

Their difference lies in the operating principle of the adjustment and heating elements. In the first case, these are two copper conductors connected to each other by a plastic plate, which is the heating element. This system independently regulates the amount of heat emitted. The lower the air temperature, the lower the resistance of the connecting element, which means the greater the current strength and the amount of heat generated.

Heating a flat roof prevents snow retention and icing

When using resistive heating elements, heat is transferred through its conductive core. The main advantage of such a system is its affordable price, but it is worth remembering that there is no automatic temperature control.

Snow removal

If the angle of inclination of the slopes is insufficient, there is a high probability of snow deposits, which can lead to roof leakage, faster wear, and the formation of icicles on the eaves.

You need to remove snow from a flat roof in a timely manner

In winter, snow removal must be carried out regularly, since even during a thaw, with a sharp drop in temperature, the gutters can freeze, which will lead to deformation and damage to the system.

There are several ways to get rid of icicles:

• ultrasound;
• laser device;
• chemicals.

The advantages of these methods are that the presence of a person on the roof is not required, which makes the process of removing snow and icicles safer.

As preventive measures, you can use special compounds that prevent roof icing:

• synthetic rubber;
• organic silicon;
• fluoroplastic mixture.

These products reduce the adhesion of ice to the roofing material.

The roof is the most important element house design, which is why its installation requires certain professional skills. Installation errors are unacceptable; they can be too expensive.

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

Roofing pie structure

If you look at the structure in cross-section, this type of roof is a multi-layer structure, which includes:

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

The vapor barrier layer is made of roll or bitumen materials. It prevents the penetration of moisture from the premises into the thermal insulation layer of the roof structure.

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

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

The waterproofing layer is traditionally made from roll materials on a bitumen basis. Special mastics or a PVC membrane can also be used.

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

The structure of the pie depends on the functional characteristics of the roof. Vary following types roofs:

Flat roof slope

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

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

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

The installation of a flat roof can be carried out using monolithic insulation, allowing for slope. In this case, sheet material (mineral wool, expanded clay sheets, etc.) is mounted on the prepared surface. Fastening can be done with strong, tenacious glue, which prevents the sheets from moving over time. Dowels with a plastic spacer can also be used - it is advisable to exclude metal contact with the base of the roof so that the roofing cake does not have cold bridges.

The most labor-intensive is the installation of a roof using bulk materials for deflection. Difficult to pour concrete layer bulk insulation(expanded clay or perlite), observing required angle slope of the roof plane, since the granules can move.

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

In accordance with SNiP, the slope of the roof is made towards the water intake funnels (if there is an internal drainage system), or towards the water intake gutters of the external drainage system, which must be mounted under the roofing carpet or on external wall building.

Roofing units

To ensure that the roofing pie is reliably protected from external influences, Special attention should be given to the places where it adjoins building structures - parapets, walls, pipes, external parts ventilation systems etc. There are various nodes of a flat roof, first of all, this is the node:

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

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

The unit must ensure the tightness of the joint and its thermal protection, therefore the installation of the units should be treated with the utmost care.

Installation of an unused flat roof

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

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

Covering an unused flat roof can be done using mastic. This is a liquid material that is applied on top of a rigid, even thermal insulation layer. The mastic is made on the basis of elastic, hydrophobic polyurethane resins. On outdoors, after a certain time after application in an even layer, it polymerizes, forming a continuous rubber-like membrane. The installation of such waterproofing allows you to reliably protect the roofing pie from moisture penetration.

A popular technology is the use of built-up waterproofing. This affordable option in terms of price and quality ratio - the durability of such a roof is from 25 years. A bitumen-polymer material based on a fabric that is not subject to rotting creates a super-strong waterproofing layer. Using this material it is possible to install exploited roofs.

Construction of a serviceable roof

This flat roof design is much more expensive to install, but makes it possible to profitably use additional space. Today, this type of roofing is widely in demand for equipping sports grounds, green areas, cafes, parking lots, etc. Installation of a reinforced roof is also necessary if heavy objects, including equipment, are to be installed on the roof. In accordance with SNiP, the roofing structure must withstand uneven high loads, that is, not deform in limited areas. The section of a flat roof in use differs from the usual one in the presence of a rigid base or a special screed on top of the waterproofing layer. This coating prevents the waterproofing carpet from being pushed through with its subsequent destruction.

Features of inversion coating

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

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

The installation of a traditional roofing structure can be done independently, but for the installation of flat roofs using modern materials and technologies, it is recommended to involve specialists who have the necessary equipment.

Flat roof installation: design and components

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

Flat roof installation

Many people associate a flat roof with urban high-rise buildings. And very few people draw in their imagination Vacation home with a flat roof, which combines saving precious space and the possibility of creating luxurious places to relax on the roof.

Flat roof pie.

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

What are the advantages of flat roof designs?

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

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

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

Flat roof installation diagram.

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

1. In most cases, a flat roof is equipped as a green recreation area.
2. Saving material, because the area of ​​​​the flat coating less area pitched with the same architectural basis.
3. Laying a flat roof is much more convenient than a pitched roof - it is easier to install the covering under your feet rather than in an unsafe position at a high altitude.
4. Maintaining flat roofs is not an extreme mountaineering activity, but rather a routine procedure.
5. Plus, the design of flat roofs makes it possible to get additional area without increasing the outline of the structure.

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

Components of a flat roof

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

Scheme of an inversion flat roof.

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

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

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

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

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

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

Insulation of a flat roof

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

The base of a flat roof is a load-bearing slab made of monolith, reinforced concrete or corrugated metal sheet. On top it is covered with a vapor barrier material, which protects the insulation from water vapor, thus preventing it from swelling from getting wet and ensuring the preservation of all properties. After this, thermal insulation is installed on the roof, which, in turn, is covered with a waterproofing carpet to protect it from precipitation.

For a flat roof, there are one- and two-layer thermal insulation systems. Nowadays, a two-layer system is more often used in construction. It works like this: the bottom layer, 70-200 mm thick, is assigned the main function of thermal insulation, while the top layer, which is 30-50 mm, is responsible for the redistribution of mechanical loads. Despite the smaller thickness, the second layer is more durable and has more high density. This distribution of flat roof covering layers makes it possible to significantly reduce its weight and, thereby, the load on the floors. The insulation must meet the following requirements:

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

Drainage device

Diagram of a drainage system on a flat roof.

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

This task is best accomplished by special roofing components - a roof fan, otherwise called an aerator. The aerator consists of pipes of different diameters made of plastic or metal, which are covered with umbrella-shaped caps.

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

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

There are a large number of components for installing a flat roof. The need for their use is determined by the design of the roof. For example, in Western countries, much attention is paid to equipping roofs with natural smoke removal devices, which enable people to safely leave the building in the event of a fire.

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

It is not advisable to install roofs with a slope of less than 2 percent. The best option is a slope of 2.5 percent. In this case, the structure is freed from water in a short time, providing more comfortable conditions functioning of roofing material. With a good slope, even a small defect in the roofing will be insignificant.

Another important element of the roof is gutters, which “carry away” moisture and snow along a given route. On a flat roof, an internal drainage system is most often installed. Special drainage funnels or fittings located on the roof surface effectively drain water during heavy rainfalls, eliminating flooding of the roof. Their location and quantity must be determined taking into account the design rules for these structures and construction requirements for the design of drains and sewerage systems for buildings. The required number of funnels on the roof depends on its operating conditions, architecture and amount of precipitation. The funnel comes with a special filter that protects the drain from foreign objects getting into it. To prevent the water in the drain from freezing, the mouths of the funnels are equipped with special thermal cables, which guarantees rapid drainage of water at any time of the year.

External drainage is more often used as drainage from a flat roof in private houses, because the internal one is more suitable for installing flat roofs of large industrial buildings. External drainage is usually performed using overflow windows, which are installed in the parapet along with roof storm drains. Ideally, self-regulating thermal cables should be used in this case, since the storm inlet and overflow window, due to their design, are susceptible to icing in winter.

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

Flat roof design

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

Design and installation of a typical flat roof: a thorough overview of technological details

The apparent simplicity of a flat roof often misleads novice home builders. The elementary configuration suggests efficiency and low cost of construction. Minimum number structural elements is capable of dulling the vigilance of independent performers who are ignorant of the intricacies of the roofing business. In reality, installing a flat roof requires scrupulous adherence to the rules unique to it, guaranteeing the flawless operation of the structure and long-term operation.

Specifics of flat roofs

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

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

In regions and districts of the country located in the middle zone and to the north, flat roofs are used mainly in industrial construction. Private owners install them over one-story extensions, garages, and household buildings. For an independent craftsman, a flat roof over a shed or shed is an excellent option to practice as a roofer.

Briefly about the design of a flat roof

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

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

• Vapor barrier covering the base. It is necessary to protect the insulation from the penetration of household fumes.
• Insulation laid in one or two tiers. Required to prevent leakage of heat waves through the upper ceiling, used exclusively in insulated systems.
• A screed created when the thermal insulation is insufficiently rigid or when there are no slopes for drainage.
• Waterproofing that protects the insulation and ceiling from the destructive effects of atmospheric water. It is laid with a continuous waterproofing carpet.
• A finishing coating that gives the structure an aesthetic appearance.

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

Due to the slight slope of flat roofs, the use of piece materials in the arrangement is contraindicated, because multiple joints between elements create the risk of leaks. It is undesirable to use large sheet metal due to the harmful effects on the material of water stagnating on a flat surface during periods of heavy rain and snowmelt.

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

To lay and fix the above elements of the roofing pie of a flat roof, a rafter structure is not required. They are laid directly on the base, which can be a ceiling, a screed created on top of it, or the upper plane of the attic structure. To fasten PVC-coated systems, adhesive, mechanical or ballast methods are used. Self-leveling roofs are applied according to their name, the descendants of roofing material are fused or glued.

Unlike pitched counterparts, flat systems do not have sheathing that creates ventilation ducts for washing the insulation with air currents. Therefore, the selection of design solutions, materials and their sealed installation should be approached with due respect and focused attention. A ventilated flat roof is only possible when lumber is used in the construction of the ceiling and attic. The latter option is most often used in private construction.

Types of floors used

The construction of flat roofs is carried out on floors made of reinforced concrete, wood and profiled sheets. The choice of material for the ceiling depends on the purpose of the roof structure, the size of the span to be covered, possible operation and ease of maintenance.

One of the significant advantages of a flat roof is the possibility of organizing a used area on it: a place for relaxation, a solarium, a green area, a terrace, etc. Of course, the overlap for such objects should be quite powerful. In addition, in the flat family there are roofs that do not involve incidental use, and therefore do not require a thorough covering.

Depending on the operational criteria, flat roofs are equipped with:

• Reinforced concrete floors, if organization is planned usable space over a long-span brick or concrete box.
• Steel profiled flooring on metal beams, if an unused roof is being constructed that covers spans of any size between walls made of brick or other artificial stone.
• Wood panel made from boards 40-50mm thick, up to 180mm wide. It is used to cover medium and large spans wooden buildings in case of planned operation.
• Particle boards and fibreboards on wooden beams, used to cover small spans of wooden and stone buildings. They are used if an unused roof is being constructed.

Lumber is a leader in the construction of low-rise residential buildings, because... are ahead of concrete and steel competitors in terms of environmental criteria. Note that wood is inferior in fire resistance. True, fire hazards in low-rise housing construction are not recognized decisive factor. In addition, there are effective means to combat it - fire retardants.

Roll coverings in flat systems with wooden base Then they serve only as waterproofing, on top of which plank or parquet flooring is installed. If a flat roof is being erected over a brick or concrete box, it is wiser to lay a reinforced concrete floor for the object in use or corrugated sheet for the one not in use.

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

With or without an attic?

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

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

• Without roofs, the elements of which are structurally combined with the ceiling. They are completely devoid of an attic superstructure, which significantly reduces the budget allocated for their construction.
• Attics with an attic superstructure above the ceiling. Minimum height superstructure 80cm. The construction of attic structures for flat roofs is more expensive, but by separating the floor from the roof, the service life of the system increases at least three times.

In addition to the budget cost, one of the advantages of atticless systems is the ability to eliminate mechanical cleaning. The snow will melt due to the heat emanating from the room. Due to spontaneous precipitation, it is not advisable to equip flat roofs without an attic with parapets. It is enough to install railings, which further reduces costs. The disadvantage of the absence of an attic will affect when identifying the causes of leaks, because the condition of the thermal insulation and other layers of the cake cannot be controlled.

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

An undeniable advantage is the possibility of installing insulation after construction, which prevents it from getting wet. The disadvantage of flat roofs with attics is their high cost and the need to regularly clear snow.

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

Subtleties of water drainage

Flat roofs are required to be equipped with drainage systems, which are required to freely drain water at an operational pace all year round. Systems come in external and internal types.

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

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

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

Installation of slopes for drainage

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

• Slopes on reinforced concrete slabs are made mainly using a screed, or a screed is combined with preliminary filling of expanded clay or laying slab insulation. On an unused roof, it is enough to lay wedge-shaped mineral wool slabs, produced specifically for forming slopes.
• Slopes on corrugated floorings are formed using metal structures or wedge-shaped insulation.
• Slopes on wooden bases are specified constructively, but if they are not included in the project, it is possible to use wedge-shaped mineral wool.

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

Nuances of organizing ventilation

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

The ventilation system for roofing pies on concrete and corrugated sheets depends on the type and characteristics of the finishing coating. PVC roofing is capable of spontaneously transmitting excess moisture from the insulation to the outside, so there is no need to install ventilation ducts between it and the insulation.

When using bitumen and bitumen-polymer materials, it is mandatory to install weather vanes over the entire area of ​​the flat roof. The spacing of these devices depends on the thickness of the insulation. Vane aerators ensure the removal of moisture from the under-roof space to the outside.

Algorithm for constructing a flat roof

Let's consider the common case of constructing an unused flat roof over an extension on a suburban site. It will be equipped with an external drain. Insulation of the structure is not expected, because climatic conditions and the purpose of the room below do not require thermal insulation.

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

• We mark the installation step of the floor beams, for which we will use a board 40-50mm thick. Installation step from 50 to 70cm: choose it based on the actual length of the walls. There should be equal spaces between the beams.
• We place the board on its edge, fasten it with nails or corners. The required slope to the lowest overhang is created spontaneously due to the difference in the height of the box walls.
• We lay a continuous flooring made of OSB boards, moisture-resistant plywood or other similar material on the beams. There should be a gap of 3-5mm between the plates for compensation thermal expansion. They are fastened with galvanized self-tapping screws or rough nails.
• We install a wind board along the perimeter of the roof, the edge of which rises 5-7 cm above the plane of the future roof so that a small side is formed.
• We nail a wooden strip with a triangular cross-section or a regular plinth to the sides. These are fillets necessary to drain water from the edges of the roof.
• We treat all wooden elements with antiseptics and fire retardants. After they dry, apply primer.
• We lay an additional waterproofing carpet in a strip along the perimeter on top of the fillets. In the case of junctions and pipes passing through the roof, additional waterproofing is applied to the adjacent vertical planes in the same way, i.e. on top of the fillets.
• We fuse the finishing roofing material selected for installation, heating its back side with a gas burner.

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

Then waterproofing is laid over the sides and junctions. If one of the latest brands of rolled waterproofing material is chosen for the installation, then it will also be entrusted with the responsibility of the finishing coating.

An impressive range of new polymer-bitumen and polymer coatings are laid in one layer, which helps to save the paver's effort and construction costs. Among them there are materials that are extremely preferable for home craftsmen and do not require the use of a gas burner. They are glued to mastics or using the back adhesive side, fixed mechanically, laid loosely and loaded with ballast.

Video for DIYers

Pin information about not an easy task A video selection will help you construct flat roofs:

We hope that the information we presented will help future roofers who decide to practice with their own hands in constructing a not-so-simple design.

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

Some of the materials for writing this article were taken from here:

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

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

Installation of a flat roof: design, device, installation, layers, elements

The installation of a flat roof requires strict adherence to the rules for installing elements and a clear arrangement of layers laid when installing rafter-less structures

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