Flat roof. The device of flat roofs of various types

All city high-rise and industrial building These are houses with flat roofs. Moreover, today many who love modern style in architecture prefer to have a flat roof in their private homes. It really looks stylish, but, among other things, houses with such a roof are more functional - they can be equipped winter Garden or use the roof as a place to relax in the warm season. Therefore, we immediately proceed to the description of the installation steps and consider in detail its device.

A flat roof is great for those who use it as an open floor.

The subtleties of installation and the design of the roofing "pie"

Mounting flat roof suggests the presence of a roofing "pie". It has high heat-shielding properties that prevent overheating of the attic in summer time and keep warm in winter. In addition, the roofing “pie” is able to prevent the formation of condensate, the insulation will be protected from moisture, and icing and icicles will not appear on the roof. It is important to observe its correct device.

The design of the roofing "pie" involves the presence of several layers:

bearing base;
vapor barrier layer;
multilayer insulation;
hydroprotection.

You should start by preparing the foundation. It needs to be leveled, cleaned, cracks in concrete filled with polyurethane sealant, based on a consumption of 180 g per 1 running meter with a joint width of 5 cm and a depth of 0.3 cm. The next step is priming using an epoxy primer. On porous surfaces, you will need 0.2 kg per 1 sq.m, on non-porous surfaces - 0.12 kg. The primer is mixed with a low-speed mixer until a homogeneous mass is obtained, after which it is diluted ½ with water. Apply to the surface paint roller or brush. After all of the above, the base surface can be reinforced. For this, a special mastic is applied (14 kg per 1 cubic meter). Before polymerization, a construction bandage is laid on it, and after polymerization, another layer of mastic is laid.

Any roof needs a vapor barrier. For this, polypropylene and polyethylene films are used, which are fastened with nails or binders or glued. At the same time, it is necessary to maintain a 10 cm gap for ventilation so that steam does not accumulate under the film. The thermal insulation material must adhere tightly to the roof surface, pipes and ventilation units.

Roof insulation and thermal insulation materials

Insulation is responsible for maintaining warmth and comfort in the house. Properly selected thermal insulation materials will not only bring comfort to its walls, but will also significantly save on heating. Therefore, you should always pay attention to such qualities of roof insulation as low thermal conductivity, fire safety, vapor permeability, which is necessary for good ventilation of the room; resistance to moisture and various mechanical damage.

It is very important that the material of which the insulation consists is resistant to point loads. In 80% of cases of damage to roofs, they are the cause of many problems. The main ones are:

violation of waterproofing, as a result of which moisture reaches the roofing “pie” and destroys it;
causing serious damage during a thaw due to freezing of snow;
the appearance of "cold bridges" that increase heat loss.

To protect the roof from such troubles, you need to ensure that everything happens in accordance with all the rules and regulations of construction, and you also need to control the quality of the materials used. One of the most common materials, without which thermal insulation is indispensable, is stone wool. It is very easy to install and withstands temperatures up to 1000°C. In addition, polyurethane foam, foam concrete, foam glass and extruded polystyrene foam are often used as roofing heat-insulating material. Let's take a closer look at each type of material.

Polyurethane foam (PPU) is highly adaptable and has additional waterproofing properties. However, it cannot be left as a finishing coating, since ultraviolet radiation on the PPU will make it brittle and reduce its service life, insulation is its main purpose. But this material has good maintainability and is easily amenable to local repair. For 1 cubic meter, 60-80 kg of polyurethane foam will be needed. This amount is due to the fact that polyurethane foam is prone to burning, but its use in this particular ratio reduces its combustible qualities. When exposed to direct fire, PPU melts, and when the source of fire is eliminated, it instantly fades.

Foam concrete has a higher thermal conductivity compared to polyurethane foam, so reliable insulation will be obtained if its thickness and material costs are higher, on average, 250 kg per 1 cubic meter. However, this increases the load on the roof above the roof.

Extruded polystyrene foam belongs to board materials thermal insulation. Warming with its use has become very widespread and is very popular due to the ease of installation. The slabs are tightly laid over the entire surface and glued together, after which the roof is considered to be fully insulated.

Thermal insulation using stone wool implies a laying method identical to the previous one. The difference lies in the material itself. Stone wool slabs usually have two degrees of density. The side with increased density is often marked with a black stripe. This side of the plate should lie up.

Foam glass is laid on a flat, dry surface filled with molten bitumen. Blocks of foam glass are superimposed at some distance from adjacent blocks and move towards them diagonally. To fix the position of the plate and remove excess bitumen from under it, you need to press your foot in the middle. High-strength foam glass, resistant to high temperatures and the influence of many acids, has a low thermal conductivity, which provides maximum insulation. However, its high cost often makes it less attractive for use as a thermal insulation material.

It can be carried out in many ways, but the most popular of them is bituminous. Let's stop on it. Bituminous mastic is stirred with a drill with a nozzle for 5 minutes. The first layer is made more liquid than subsequent ones. It is applied with a density of 90-120 g per 1 sq. cm. The next layer of bitumen is applied after the previous one has dried, after about 10-12 hours. The more layers there are, the higher the protection.

Features of a flat roof device

The device of flat roofs divides them into operated, non-operated, inversion and traditional. The device of the inverted roof is different in that the thermal insulation layer is located above the waterproofing, and not below it. This allows you to protect it from ultraviolet radiation, mechanical damage, temperature changes. does not imply additional use of the roof, its installation is most affordable. involves the active use of the roof surface (the presence of a sports or helipad, a cafe). In this regard, its device is more expensive than the device of non-exploited roofs, but also more durable.

Despite the fact that the roof is called flat, it still has a slight slope (1-4%). This design allows precipitation to descend on its own. The device of any roof structure must withstand a load of 200 kg per 1 sq.m, its own weight and the weight of the roof covering. Therefore, it is laid on durable reinforced concrete slabs 4-5 cm wide and 40 x 40 cm in size to increase reliability.

This option for arranging the upper part of the building is used, as a rule, in the construction of "high-rise buildings", as well as various administrative, industrial, warehouse and some other buildings: pavilions, showrooms and the like. Despite the fact that a flat roof has a number of disadvantages, this does not reduce the popularity of such a design, including in private housing construction.

Benefits of flat roofs

Firstly, the installation of a flat roof can be carried out independently, and not to invite assistants or hire professionals, as, for example, when constructing a roof of complex configuration (, four-pitched, etc.). Consequently, they will not have to pay for their work (we are not talking about large areas where it will be problematic to cope alone).

Secondly, the construction of such a roof provides significant savings both in terms of materials (money) and in time (the coverage area is much smaller than with pitched equipment). You don’t have to make numerous calculations or order a project (which will cost a lot), assemble a complex system of rafters, install jibs, sprigs, and so on. In addition, there are no restrictions on the choice of the type of roofing.

Thirdly, a flat surface is much easier to maintain and repair, which also gives tangible savings in the future.

Fourth, a choice of arrangement options. Flat roof can either serve only as a traditional "cover" for the house, or be used (inversion). For example, greenhouses, summer gardens, solariums and the like are mounted on it. There are even heliports. This fully compensates for the inconvenience due to the lack of an attic room.

disadvantages

Increased requirements for waterproofing. Since the roof is located horizontally, water falling in the form of precipitation will stagnate on it. You can use eg.
Debris will constantly accumulate (for example, fallen leaves), so such a roof will have to be serviced more often.
Lack of an attic (mansard) space

What to consider

The maximum load that the roof will experience (for roof structure). This refers to the weight of the frame itself, roofing material, layers of insulation and insulation, as well as possible snow cover. In addition, you need to rely on the fact that the roof must withstand the weight of people who will subsequently walk on it.
The purpose of the building and the possibility of further use of the surface (for example, terrace equipment). Depending on this, the type of overlap is determined.

Work technology

The simplest version of a flat roof is when reinforced concrete slabs are laid (for example, a garage, a barn). Everything is extremely simple here. On the surface, the so-called " layered cake»: vapor barrier, if necessary - insulation material, waterproofing layer. For the equipment of the latter, roll materials are most often used.

Insulation of a reinforced concrete slab can be done by pouring a layer of expanded clay and equipping a cement screed on top. Slag and some other materials are also used.

Traditionally, roofing material is used for waterproofing, which is covered with bituminous mastics on top. It should be noted that this material will last no more than 5 years, and then you will have to deal with repairs. It is more expedient to lay polymeric materials, for example, membranes, as a "waterproofer". Liquid rubber is also great.

Since the installation of plates requires the involvement of special equipment, with independent device flat roof can be equipped with the simplest truss system from wood.

First of all, supports - Mauerlats - are laid on the upper parts of the bearing walls. The most commonly used material is timber. It must be taken into account that these structural elements must be rigidly fixed in order to exclude the possibility of their horizontal displacement.

Therefore, metal pins are immured in their upper end surfaces along the entire length of the walls. Their length is calculated so that after the installation of the Mauerlat they rise above the beam by about 5 cm. Threads must be cut at their ends.

If the masonry is old, then a "tape" of concrete mortar is arranged on top of the walls. After that, pre-planned holes are drilled in each wooden blank with a diameter slightly larger than the cross section of the metal "fingers". First, strips of roofing material (or similar waterproofing material) are laid on the tape, and then Mauerlats. They are mounted on pins, and a washer is put on top of each, and with the help of a nut, the beam is securely fixed at the installation site.

Next, floor beams are laid. It should be noted that the roof should protrude beyond the dimensions of the house by 50 - 60 cm (required overhang). This will protect both the walls and the blind area from water flowing from it, as well as from raindrops.
Support frame device. Depending on the type, it can be either solid (boards, slabs) or cellular (battens).

Vapor barrier.

Insulation. For flat roofs there is a nuance. The absence of an attic space deprives such a building of an “air cushion” from above. Therefore, insulation is carried out both outside and inside. But at the same time, it is necessary to take into account the weight of such material, since it is an additional load on the truss system.

Waterproofing.

Roof covering.

Overhang finishing.

This is only a general list of necessary activities. The technology for the production of work for each item depends on local conditions and on the selected materials.

Any "wood" used in construction must be well dried. The moisture in its structure gradually “leaves” (natural shrinkage of the material), which leads to a change not only in the volume of the workpiece, but also to its deformation (for example, twisting).
Wood has two significant drawbacks - it burns and is prone to decay. Therefore, before using it, all wooden parts of the structure are pre-treated with flame retardants and antiseptics. It is better to spend money on these funds than to suffer with frequent repairs later.
When installing Mauerlats, you need to constantly monitor their horizontal position using the building level. Otherwise, the roof will turn out to be skewed. If necessary, either the tape is leveled, or a rigid lining is made under the Mauerlat.
To exclude stagnant water on the roof, it is advisable to make it with a certain slope (approximately 3 0 - 5 0). As a rule, the decrease goes towards the rear side of the building. To do this, the height of the front Mauerlats increases, so the floor beams will fall with a slope.

There are several types of roofing depending on the shape: single-pitched, gable, complex and flat. The last option is the fastest, but at the same time technologically difficult. Get to know the technology self erection flat roof do it yourself.

The device of a flat roof and the principle of its construction

Flat roof - has a fairly simple configuration, and with the right approach, the process of its construction takes a maximum of two days. First of all, decide on the construction technology, draw up a project, purchase and prepare materials for work.

On the load-bearing walls, install wooden or steel beams that transfer the load from the roof to the walls and foundation.

In addition, beams perform several other important functions, such as:

retention of the total weight of the attic and ceilings;
the weight of people who repair and maintain roof structures;
wind loads, the weight of precipitation that accumulates on the roof.

For the correct selection of the diameter and size of the beam, consider all the loads that affect them. In addition, for the construction of a high quality flat roof, choose the right finishing coating, which is distinguished by reliability and good operational characteristics.

One of the most important stages is heat and sound insulation. The flat roof of capital buildings is a floor slab, on top of which a heat and waterproofing cake is laid:

1. Initially, a vapor barrier is laid on the surface, preventing the penetration of moisture to the insulation. For the manufacture of vapor barrier, reinforced bitumen film based on fiberglass is most often used. The edge of the film is wound beyond the vertical line of the overlap, and all seams are carefully soldered.

2. Installation of insulation is the next step. It is possible to use expanded clay for surface insulation, it is initially installed on it concrete screed, and with a lightweight version of the roof, solid versions of polymer insulation are used.

3. The most important and final layer is waterproofing. The life of the roof as a whole depends on the quality of its execution. Most often, waterproofing of a flat roof is carried out using polymer-bitumen materials.

There are two options for a flat roof, in relation to the type of room for which it is being built:

flat roof for a heated room;
flat roof for unheated premises.

The construction of a flat roof over an outbuilding, a shed, a gazebo does not require special skills. To create a stack, a slight slope to one side is enough.

The process of creating a flat roof for a heated room is divided into stages:

1. A boardwalk is installed on the laid beams, which is covered with roofing material or roofing felt with a large overlap on top.

2. A heater is laid on the roofing material, which is based on expanded clay or slag. When filling the heater, adhere to a certain slope, in relation to the discharge of melt or rainwater from the roof.

3. A screed is installed on the insulation based on cement mortar at least two centimeters thick. After it has set, the material is treated with a bitumen-based primer. A rolled carpet is additionally glued onto the screed.

It is recommended to create a flat roof with a minimum span, thus reducing the difficulties in its hydro- and thermal insulation. Roofs with a width exceeding 600 cm are recommended to be erected only with specialists. Incorrect calculation of loads on beams leads to terrible consequences: incorrect load distribution and reduced use of roofing materials.

Installation technology of a flat roof made of monolithic concrete

Double-tee steel beams act as load-bearing structures for a concrete flat roof. If the span of the roof does not exceed 500 cm, then beams with a thickness of 15 cm are used to equip the roof.

crushed stone, fraction 1-2 cm;
cement brand 400.

The ingredients are combined in the amount of eight buckets of rubble and three buckets of cement, four buckets of sand and two buckets of water.

This is followed by the process of mounting boards on the lower shelves of the beams, roofing material and reinforcing mesh are mounted on the boards, with minimum size cells in 10 mm. To connect the intersections of the grid, use knitting wire or a welding machine. The gap between the grid and the roofing material is about 4-5 cm, for this, crushed stone is placed under the grid. The thickness of the concrete layer in this case is at least fifteen centimeters.

At the same time, the strips are laid evenly, it is not allowed to leave an unfinished strip until the next day. This negatively affects the quality of the roof structure. Most best option- pouring the roof for one day. After pouring, the surface is compacted with a concrete vibrator or a hand tool. When compacting the concrete, be careful not to deform the mesh.

Next, a polyethylene film is installed on the roof, which prevents excessively rapid evaporation of moisture and cracking of the top layer. After the roof has completely dried, a slope is constructed with the help of a heater to drain water.

Do-it-yourself thermal insulation of a flat roof

A flat roof differs from standard single-pitched and double-pitched types by the need for both internal and external insulation. First, the roof is insulated from the outside, and if necessary, inside.

Previously, rigid heat-insulating boards were used to insulate a flat roof, but due to their large weight, they are practically not used at present. This insulation was replaced by heat-insulating materials based on basalt and mineral wool. The thermal conductivity of this material is much higher, and the weight does not make the structure heavier.

In addition, the insulation perfectly resists mechanical damage and has a high fire safety. Internal insulation flat roofs are made using refractory structures, 2-3 cm thick. Wooden planks are used to mount the slabs on the ceiling, on which the slabs are fixed with special glue or mastic. Please note that before insulating the ceiling, all lighting fixtures on the ceiling are dismantled.

In addition, as a heater for a flat roof, materials are used in the form of:

mineral basalt wool - does not need an additional protective screed;
extruded polystyrene foam - great option for a roof that is in constant operation, it does not burn, it has good soundproofing characteristics;
polyurethane foam - does not form butt joints, does not burn and is used as a soft roof insulation;
ecowool - contains cellulose, has an additional flame retardant coating, therefore it has a high level of safety;
foam concrete - it has a monolithic structure and a long service life, it is similar in structure to foam, ideal for insulating a flat roof without creating significant loads on the foundation.

Flat roof device and technology for creating a roofing pie

In order to get an ideal roofing with good sound, heat and waterproofing characteristics, you must first create a drawing of a roofing pie, which consists of:

bearing base - concrete or steel beams;
vapor barrier layer;
thermal insulation layer;
waterproofing.

It is possible to change the sequence of layers and add additional materials, it depends on the individual characteristics of the roof and the building itself. Additionally, after the insulation, a textile layer is laid, then covered with rubble and finishing is performed. Such a roof is called inversion and is used extremely rarely, due to the large weight. It is suitable for buildings with high demands on fire safety.

The device of a flat roof implies compliance with all loads that arise during operation. In relation to this indicator, the thickness of each layer in the roofing pie is calculated.

There are several types of flat roofs in relation to the structural characteristics:

uninsulated roof;
insulated roof which has open and closed systems 4
monolithic roofs;
inverted roofs.

In relation to the operational load, a flat roof can be:

exploited;
not exploited.

Depending on the drain:

flat roof with internal drainage;
flat roof with external drainage.

Do-it-yourself inversion flat roof

The inverted flat roof is characterized by good performance and high fire safety. The installation technology for this roof option is as follows:

laying waterproofing;
installation of thermal insulation material;
geotextile component;
drainage system;
protective bulk coating.

Among the advantages of a flat roof of this type, we note:

the complexity of the destruction of waterproofing;
no condensation on the insulation, as it is located on top of the roofing cake;
ease of repair and replacement of thermal insulation material.

Excessive moisture that forms in the thermal insulation layer is the reason for the deterioration of the protective characteristics of the roof as a whole. Soon it becomes covered with cracks and bubbles, especially in the summer, when the insulation releases moisture. Complete absence ventilation leads to peeling of the roof from the base.

In this case, we recommend equipping a breathable roof. For the manufacture of roofing, roll materials are used, with excellent tightness and a long service life. Installed between bituminous mastic thermal insulation material, and roof aerators are used for additional ventilation. Among the advantages of this coverage, we note:

no need to dismantle the flooring, additional strengthening of hydroprotection;
laying the second layer with a slope leads to improved moisture removal;
the possibility of using this method both during the initial installation of the roof, and during repairs.

Instructions for finishing a flat roof with your own hands

Flat roof finishing materials must meet certain requirements, such as:

high level of strength;
a light weight;
heat-insulating and sound-proof characteristics;
resistance to ultraviolet radiation;
duration of operation;
ease of installation and maintenance.

Quite often, roofing material with glassine is laid on a flat roof, however, these materials do not have a long service life, they do not tolerate frost well and are destroyed under the influence of vibrations. temperature regime. Every 8-10 years of operation, the roof is re-coated with roofing material.

New roll-bitumen coatings are gradually replacing roofing material with glassine. This is due to their following advantages:

excellent performance characteristics;
ease of installation;
complete waterproofing of the roof;
resistance to chemicals, temperature fluctuations;
duration of use.

There are several varieties of bituminous materials for flat roofs:

1. Fiberglass, fiberglass - characterized by high strength, resistance to mechanical damage and absolute moisture resistance.

2. Bituminous materials based on polyester or polypropylene. They are used as the bottom layer of protective coatings, have a high density, good waterproofing performance and are used on reinforced concrete floors.

Polymeric membrane materials are based on reinforced plastic mesh, rubber and polymer resins. The cost of such materials is much higher than bitumen, however, compared to the latter, they have certain advantages:

light weight, so they do not load the foundation and foundation of the building;
elasticity and tendency to stretch;
duration of operation, which exceeds 50 years;
do not need to use open flame for installation, in comparison with bituminous materials;
hot air is used to connect the joints.

Mastic-based materials are ideal for flat roofs. Roll materials, although they have certain advantages, they all create seams that, under increased load, allow moisture to pass through. Seamless mastic roofing does not create butt joints and is characterized by perfect smoothness. Such a roof is called "bulk". This roofing is easy to apply, forming a single sheet, a brush or brush is enough to level the material. Previously, the roof is treated with soil or primer.

Do-it-yourself flat roof video:

For many people, the name "flat roof" is associated primarily with high-rise buildings. A flat roof - the pros and cons of which we will consider in this article - has practically not been used in low-rise construction since a dozen years ago. However, today the creation of such a roof in country house is not a problem: modern materials and technologies allow you to create a flat roof with proper consumer characteristics and at an affordable price.

A flat roof is much smaller in area than a pitched roof, which saves on materials and construction costs. installation work.
Thanks to the relatively smaller area of a flat roof, it is possible to optimize costs.
The construction of a flat roof is easier and faster than a pitched roof, since the necessary materials for installation are located right at the feet of the workers on a flat surface. The same can be said about the repair and maintenance of a flat roof - working on an almost horizontal roof is incomparably more comfortable than on an inclined one.
On a flat roof, installation and subsequent service work with all kinds of equipment (air conditioning systems, solar panels, antennas, etc.).
The use of a flat roof is an opportunity to get an additional useful area that can be used as a place where you can relax in the fresh air, play sports, create a garden, flower garden, etc. To date, there are technologies that allow you to cover the roof even with paving slabs or paving stones. The roof, paved with beautiful tiles, combined with a green lawn, garden furniture, a gazebo and a fireplace, can become a place for a comfortable family vacation.

Flat roof houses are very popular right now.

A flat roof, in addition to the advantages, has a number of disadvantages:

As a result of heavy snowfalls, a lot of snow accumulates on flat roofs, which, when melted, often causes leaks.
Sometimes internal drains are required.
There is a risk of clogging or freezing of the internal drain.
There is a need for mechanical cleaning of the roof from too large accumulations of snow.
It is necessary to regularly monitor the moisture state of the insulation and the tightness of the roof.

Varieties of flat roofs

There are four types of flat roofs:

Foundation for a flat roof

In accordance with building codes, a flat roof, the pros and cons of which we discussed above, must have a base in the form of reinforced concrete floor slabs or corrugated sheets.

Subtleties of waterproofing

The durability of the roof structure and its resistance to various negative influences depends on the use of special mixtures and technological processes production of roofing materials. Depending on the materials of the roof, it is customary to subdivide into three categories:

Bituminous roofs, as well as polymer-bitumen based on ruberoid. These materials are available due to their low cost. Welded bitumen-polymer compositions are rolled waterproofing and roofing sheets based on synthetics, on both sides of which special bitumen is used, which remains elastic even at extremely low temperatures (up to -50 degrees Celsius). During the installation of waterproofing, carried out using gas burners, the rolls are fused together. Roof waterproofing can also be carried out with self-adhesive materials based on polymers and bitumen. In this case, the mastic is applied on the bottom surface of the roll and in the process of processing with a solvent acquires the properties of an adhesive. The disadvantage of bituminous roofing is fragility.
Membrane roofs with a base of foil, rubber or polymers. This material has solid strength, is resistant to fires and other negative environmental influences. The membranes are glued to the screed or simply lie on the base, being loaded with ballast, or they are attached mechanically or with glue. To connect the membrane sheets, special welders, fastening the material with hot air.
Roofs based on liquid polymers, which, after cooling, do not form seams. Such materials are especially often used for structures with complex geometries.

It is very important to make the correct waterproofing of a flat roof.

Whatever material is chosen, the joints between the rolls and the junctions with various roof elements must be waterproof. One of the main components of a successful waterproofing device is quality sealant. During the period of operation, the roof is subject to negative environmental influences (moisture, hail, stones, strong temperature fluctuations, etc.). Therefore, a high-quality sealant must be resistant to mechanical and thermal influences.

As a sealant, mastic is usually used - putty, which is based on elastic polyurethane resins. After being applied to the roof, the mastic polymerizes, as a result of which a continuous rubber-like membrane is formed, which has waterproofing properties and protects the roofing from mechanical damage.

Mastic is ideal for flat roofing, is safe, has high adhesion to building surfaces, has high resistance to ultraviolet radiation, precipitation and all kinds of microorganisms. It is applied by brush, roller or airless spray in two multi-colored layers, which allows you to control the quality, thickness of the layer and uniform distribution of the sealant.

How to arrange a water drain

Regardless of the materials used, a flat roof must have a certain slope to drain water (usually within 3-5%) that appears on the roof as a result of precipitation. The drainage system should be thought out at the design stage of the building. Gutters determine how efficiently moisture will be removed from the roof surface. To prevent freezing of gutters in winter, they are equipped with special thermal cables.

Drains are organized when both external and internal water supply is created, and unorganized. When creating an internal water supply, the roof surface is divided into approximately equal parts of 150-200 square meters every. In places with a slope, drain funnels equipped with baskets for catching garbage are arranged. Typically, the funnels are located in the center of the roof, and the pipes are inside the building.

Flat roof insulation and vapor barrier rules

Flat roofs need insulation. In the absence of a layer of thermal insulation on the roof surface, condensation forms as a result of the contact of warm air masses and the cold surface of the roof. Condensation appears on the ceilings of the house as water spots, and the roof structure is gradually destroyed.

The roof structure involves a base on which a layer of vapor barrier material is laid. The function of the vapor barrier is to protect the insulation from diffuse moisture coming from the premises of the building. The vapor barrier layer includes a glass fiber reinforced membrane (based on bitumen and polymers) or a vapor barrier film. The layer is laid on top of the screed, and along the edges of the roof structure it is wound vertically to a height exceeding the height of the insulating material. The seams are soldered.

Above the vapor barrier layer, a heater is placed, and on top of it - a waterproofing carpet based on bitumen. If expanded clay acts as a heater, then it is necessary to make a cement screed over it, then laying a couple of layers of waterproofing. If the roof is planned to be light (in the case when significant loads are not expected on it), then the waterproofing is simply glued around the entire perimeter of the roof.

For roofs without attics, both external and internal insulation methods are used. The external method is used more often, so its execution is easier. There are two options for thermal insulation: two-layer and single-layer. The decision on which option to apply in practice depends on the calculations for heat engineering and the requirements for the strength of the roof. Thermal insulation boards are placed on the roof structure based on the principle of "spread seams". With a two-layer coating with thermal insulation "in a run", the joints of the lower and upper plates also go. In the area where the plates adjoin the parapet, lanterns and walls, heat-insulating bumpers are created. Heat-insulating materials are attached to the base mechanically (screws, dowels), ballast (pebbles, paving slabs) or glue.

Features of roof ventilation

The roof structure must be ventilation system. As a result of a violation of the tightness of the vapor barrier layer, moisture enters the insulation layer. A thick layer of waterproofing prevents evaporation, and moisture accumulates in the insulation. As a result, the material loses its insulating characteristics, and moisture appears in the form of spots on the ceilings of the building. In addition, water causes the waterproofing to swell, and at low temperatures, freezing water tears the waterproofing material from the base. Temperature fluctuations, mechanical damage contribute to the formation of cracks in the roof, the result of which is its flow.

To avoid these problems, the roof must "breathe". For this, aerators are used - special devices in the form of plastic or metal pipes. They are covered with umbrella caps and are evenly distributed over the entire territory of the roof, gravitating to its highest points. The aeration mechanism works on the basis of the principle of different pressure, which is created by air flows, removing excess moisture vapor from under the roof and preventing water bubbles from forming.

Roofing is a responsible technological operation. Any, even a minor mistake in the design or construction of the roof can cause it to leak in the future. Therefore, when creating a roof, special attention should be paid to the correct selection of hydro- and heat-insulating materials, to accurately calculate the upcoming loads on the roof structure, and also to select a team of competent builders.

When building a house, the final, but no less important process is the roofing of the roof, often called by architects the “fifth facade”. Classic option for private houses it is customary to consider pitched roofs, but in Lately their flat counterparts began to gain more and more popularity. And the whole secret is that the device of a flat roof has a lot of advantages.

flat roof house

This type of roof is widely applicable in both industrial and private construction. The main difference between flat roofs and pitched "brothers" is the use of piece and sheet roofing materials. The device of a flat roof involves the use of materials that can form a continuous carpet. These include polymer, bitumen and bitumen-polymer materials, as well as mastics. In order for any temperature fluctuations and mechanical deformations to which the roof base is subject to be perceived well enough, such a carpet must be highly elastic. The basis for it can serve as load-bearing plates, screeds, as well as the surface of thermal insulation. All layers stacked on top of each other represent the so-called flat roof pie.

Exploited and non-exploited flat roofs

The use of operated roofs is advisable on those buildings that provide for frequent access to the roof of people or the presence of any heavy objects on it. The construction of a flat roof of this type has its own peculiarity, consisting in the need for laying hard base or a special screed on the waterproofing layer. This is necessary so that the roof structure can withstand any load, often unevenly distributed over the surface. A rigid base in this case will help maintain the integrity of the waterproofing carpet and will not allow it to be pressed through.

Unlike operated roofs, for non-operated roofs there is no need to lay a rigid base on the waterproofing. In this case, soft insulation is used. The use of such roofs is appropriate when maintenance during the operational period is not required, that is, there is no pressure on the roof surface. But even if there is a need to maintain such a roof, the issue can be resolved with the help of special ladders or bridges, which will help to evenly distribute the pressure exerted on the surface of the roof.

The device of a flat roof of an unexploited type will cost an order of magnitude cheaper than in operation, but its service life will be much lower. Therefore, the choice of roofing should be approached carefully after weighing all the pros and cons.

Other types of flat roofs

Depending on the design features, distinguish the following types of flat roofs:

classical;
inversion;
ventilated.

The traditional option is considered to be a classic flat roof, which has another name - a soft roof. Its base is a carrier plate, on the vapor barrier layer of which a heat-insulating material is applied (in most cases, mineral wool plates are used). Thermal insulation, in turn, is protected from the effects of precipitation by a waterproofing carpet, which is based on rolled bitumen-containing materials.

The device of a flat roof of an inversion type differs from the previous one in that the insulating layer is located above the waterproofing carpet, and not below it. This feature makes it possible to protect the waterproofing from the harmful effects of ultraviolet radiation, freeze and thaw cycles, sudden changes in temperature, as well as mechanical damage, which can greatly increase the life of the inverted roof. This design can be used as an operated flat roof. For example, you can plant grass on it and break flower beds, put a small amount of furniture, or just sunbathe.

Moisture that accumulates in floor slabs and insulation is main reason the formation of "bubbles", which subsequently lead to leaks and even ruptures of the roofing carpet. And, unfortunately, removing this cause completely is almost impossible. In the West, this issue is easily solved using the so-called "ventilated roofs". Flat roof units of this type provide for partial fixing of the first layer of the carpet to the roof with glue, or laying on mechanical fasteners. As a result, an air gap is formed between the base and the roof, which eliminates excessive water vapor pressure. It communicates with the outside air through the junctions along the contour of the roof, or through special exhaust deflectors.

Foundation preparation

In order for the end result to be a high-quality and durable roof, it is initially necessary to think over a flat roof plan, the drawing will also be an excellent help in installation work. In most cases, the following main units of a flat roof are distinguished: a supporting structure, which can be a monolith, a supporting concrete slab or a corrugated floor, layers of steam, heat and waterproofing and a slope-forming layer designed to drain water.

The first step in flat roofing is the preparation of the foundation. Reinforced concrete slab, corrugated steel sheet, or a solid wood covering most often act as a bearing covering for this type of roof.

If the reinforced concrete base has uneven surface, it is necessary to create a leveling screed of sandy asphalt concrete or cement-sand mortar. The thickness of the screed will depend on the type of base: for concrete - 10-15 mm; on rigid insulation boards -15-25 mm; on soft insulation boards - 25-30 mm.

If the roof slope is less than 15%, then first the screed is placed on the grooves and only then on the slopes. In the case of a slope of more than 15%, the actions are performed in the reverse order: first, the slopes are leveled, then they proceed to work with grooves and valleys.

Any elements protruding above the roof, be it chimneys or parapet walls, are processed with plaster to a height of 25 cm. Special rails are installed on top of the plastered surface, which serve to fix the roll-type carpet. The roof screed is primed with roofing mastics in order to increase the quality of adhesion of the base to the rolled carpet.

Before priming the base, it must be thoroughly cleaned of contaminants and dried well.

Preparation of roofing soft materials

The roof plan of a flat roof in without fail should be included preparatory work roofing materials for their further use.

When using rolled materials, they must first be carefully examined for the presence of various kinds of defects: bumps, cracks, oil stains. And then during the day they are kept rolled out or turned inside out.

Mastic for a roof can perform two functions at once. It can be used as a standalone material providing a seamless coating for repair work. And also it is applicable as an adhesive agent for connecting rolled materials with the base. Bituminous mastics can be used both hot and cold.

The use of mastic as an independent roofing material

The composition of a flat roof may not include rolled materials; it can be made with just the use of mastic. It is a liquid material based on pure elastic, hydrophobic polyurethane resins. And as a result of its application to a flat roof, when exposed to air humidity, it polymerizes and turns into a rubber-like continuous membrane, which has excellent protective and waterproofing properties.

For a flat roof, mastic, as a roofing material, has a lot of obvious advantages: it is safe and reliable, has high resistance to ultraviolet rays, precipitation and various microorganisms, has high adhesion to any building surface, and besides, it does not change its volume during polymerization . The ease of use of this material is also captivating - it can be applied either manually, with a brush or roller, or by airless spraying.

Roof covering with roll materials

Thinking over the roof plan of a flat roof, important point is the choice of the roofing material itself. Roll materials can be called the most suitable in their properties. Laying of rolled panels for soft roofing is carried out on overlapping slopes. If the roof slope is more than 5%, the overlap should be 70 mm in the inner layers of the carpet, and 100 mm in the outer layers. In the case of a slope of less than 5%, the width of the overlap in any layer is 100 mm or more. Laying of roll strips is carried out strictly in one direction.

If, during gluing, the panel deflected to the side, you should try to move it without peeling it off. If the result turns out to be ineffective, then the glued part of the panel should be cut off and pasted with an overlap of 100 mm.

Roll sheets are laid in layers, and in case of their fastening on cold mastic, it is necessary to observe a 12-hour interval between the sticker of each layer.

Thermal insulation in soft roofs

Considering the device of a flat roof, its insulation can be performed in one of the following ways: external or internal. The ease of installation of external thermal insulation makes this method more common. In addition, with the help of this method, both a building under construction and one already in operation can be insulated.

Flat roof - thermal insulation

Flat roofs have a design that provides for two options for thermal insulation, depending on the number of layers: single-layer and two-layer. The choice of thermal insulation is influenced by thermal calculation and strength requirements for the roof structure. For laying on the top of the supporting structure of heat-insulating boards, the principle of "seams apart" is used. With a two-layer coating, the joints of the lower and upper plates must also run "in a row". In those places where the plates of thermal insulation are adjacent to walls, parapets and lanterns, thermal insulating transitional ledges are created. To fix the thermal insulation, use one of the following methods:

mechanical. The corrugated board is fastened with self-tapping screws, the reinforced concrete base - with plastic dowels with a core;
adhesive;
with the help of ballast, which is used as pebbles or paving slabs;
based.

The main mistakes of installing a flat roof

Installation errors can lead to the formation of so-called "cold bridges", which can be window and door openings, concrete building elements or dowels, with which the plates are attached to the wall. Such "cold bridges" can create heat loss of up to 50%, in addition, they can cause condensation and subsequently mold.

The most common reason for the formation of "cold bridges" is the use of fixing dowels with a metal nail. To avoid this phenomenon, the use of stone wool flat roofs during roofing work will help. This is due to the fact that there will be enough glue for its fastening, but the use of dowels in this case is also possible, since a plastic rod is provided for the cotton wool.

Heat loss can also be avoided by using a two-layer insulation. But in this case, the laying of the top layer must be done so that the joints between the bottom plates are covered by the top insulation.

Use large format slabs - this will reduce the total number of joints.

In addition, errors can be identified initially, you just need to draw up a competent and clear plan for a flat roof.

Do you want the roof of your house to perform not only its main function of protection from atmospheric precipitation? Would you like to turn it into beautiful garden, a recreation area or an open sports ground? Then ideal option for you is a flat roof roof!