Sectional diagram of a soft roof. Flat roofs, their types and designs

Many people associate a flat roof with urban high-rise buildings. And very few people picture in their imagination a country house with a flat roof, which combines saving precious space and the possibility of creating luxurious places for relaxation 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 you can experience the full extent of the pleasure from a flat roof only if the builders and the customer himself listen carefully to the advice of a specialist in installation technology and choice necessary components roof structures. 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 structures and parts for the device 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 flat covering houses are called fashionable architectural feature project. A house with a roof without slopes looks more modern.

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 cite a lot of obvious advantages for buildings with this 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 obtain additional space 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 reinforced concrete slab or profiled metal sheet) on which it is laid thermal insulation material along a vapor barrier layer, which is protected from precipitation by a waterproofing layer.

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):

1. Vapor barrier.
2. Insulation.
3. Waterproofing.

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 a higher 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

It is very important to ensure the free escape of wet vapors from the roofing. Necessary elements are ventilation accessories. 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 time. It negatively affects both wood and metal. If too much condensation accumulates, wet spots form on the ceiling and mold develops. In addition, moisture accumulating in the 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.

With this task the best way This is done 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 thermal insulation 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. 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 for the functioning of the roofing material. With a good slope, even a small defect in the roofing will be insignificant.

Another important element of the roof is gutters, which “carry away” moisture and snow along a given route. This is most often done on a flat roof. Special fittings 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.

It is more often used in private homes, because the internal one is more suitable for constructing 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.

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

When building a house, the final, but no less important process is the roofing, often called by architects the “fifth facade”. The classic option for private houses is considered to be pitched roofs, but recently their flat counterparts have become increasingly popular. And the whole secret is that installing a flat roof has a lot of advantages.

Flat roof of a 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 construction 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 changes and mechanical deformations to which the base of the roof is subject to be perceived well enough, such a carpet must be highly elastic. The basis for it can be load-bearing slabs, screeds, as well as a thermal insulation surface. All layers stacked on top of each other form a so-called flat roof pie.

Operated and non-operated flat roofs

The use of exploitable roofs is advisable on those buildings that provide frequent access to the roof of people or the presence of any heavy objects on her. The design of this type of flat roof has its own peculiarity, which consists in the need to lay a rigid base or a special screed on the waterproofing layer. This is necessary in order to roof structure could 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 exploited roofs, for non-exploited roofs there is no need to lay a rigid base on top of the waterproofing. In this case, soft insulation is used. The use of such roofs is appropriate when no maintenance is required during the operational period, that is, there is no pressure on the roof surface. But even if there is a need for maintenance of such a roof, the issue can be solved with the help of special ladders or transition bridges, which will help to evenly distribute the pressure exerted on the roof surface.

The installation of a flat roof of a non-exploited type will cost an order of magnitude less than that of a used type, but its service life will also be much shorter. Therefore, the choice of roofing should be approached by carefully weighing all the pros and cons.

Other types of flat roofs

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

• classical;
• inversion;
• ventilated.

The traditional option is considered to be the classic flat roof, which also has another name - soft roofing. Its base is a load-bearing slab, on the vapor barrier layer of which thermal insulation material is applied (in most cases, mineral wool slabs 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 design of an inversion-type flat roof differs from the previous one in that the insulating layer is located above the waterproofing carpet, and not under it. This feature makes it possible to protect waterproofing from the harmful effects of ultraviolet radiation, freezing and thawing cycles, sudden changes in temperature, as well as mechanical damage, which can significantly increase the service life of the inversion roof. This design can be used as a serviceable flat roof. For example, you can plant grass and create flower beds on it, place a small amount of furniture, or just sunbathe.

The moisture that accumulates in the floor slabs and insulation is the main cause of 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 can be easily resolved by using so-called “ventilated roofs”. Flat roof units of this type involve partial fastening of the first layer of carpet to the roof using glue, or laying it 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 connections along the contour of the roof, or through special exhaust deflectors.

Preparing the base

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

The first step in flat roofing is preparing the base. The load-bearing covering for this type of roof is most often a reinforced concrete slab, profiled steel sheet, or solid wood covering.

If the reinforced concrete base has an uneven surface, it is necessary to create a leveling screed from 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 the screed is first placed on the valleys and only then on the slopes. In the case of a slope of more than 15%, the actions are carried out in the reverse order: first the slopes are leveled, then they move on to working with gutters and valleys.

Any elements protruding above the roof, be it chimneys or parapet walls, are treated with plaster to a height of 25 cm. At the top of the plastered surface, special slats are installed that serve to secure a 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 dirt and dried thoroughly.

Preparation of roofing soft materials

The roof plan for a flat roof must include: preparatory work roofing materials for their further use.

When using rolled materials, they must first be carefully inspected for various types of defects: unevenness, cracks, oil stains. And then they are kept rolled out or turned inside out for 24 hours.

Roofing mastic can perform two functions at once. It can be used as a stand-alone material providing a seamless coating for repair work. It is also applicable as an adhesive for connecting rolled materials to the base. Bitumen mastics can be used both hot and cold.

Using 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 flat roofs, mastic, as a roofing material, has a lot of obvious advantages: it is safe and reliable, has high resistance to impact ultraviolet rays, sediments and various microorganisms, has high adhesion to any building surface and, moreover, 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 through the roof plan for a flat roof, important point is the choice of the roofing material itself. The most suitable in terms of their properties are rolled materials. Laying of rolled panels for soft roof produced on overlapping slopes. If the roof slope is more than 5%, the overlap in the inner layers of the carpet should be 70 mm, and in the outer layers - 100 mm. In the case of a slope of less than 5%, the overlap width in any layer is 100 mm or more. Roll strips are laid strictly in one direction.

If the panel deviates to the side during gluing, 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.

Rolled sheets are laid in layers, and if they are attached to cold mastic, it is necessary to observe a 12-hour interval between gluing each layer.

Thermal insulation in soft roofs

Considering the installation of a flat roof, its insulation can be done in one of the following ways: external or internal. The ease of installation of external thermal insulation makes this method more widespread. In addition, using this method, insulation of both a building under construction and one already in operation can be carried out.

Flat roofs have a design that provides 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 engineering calculations and strength requirements for the roofing structure. To lay thermal insulation boards on top of the supporting structure, the principle of “staggered seams” is used. With a two-layer coating, the joints of the lower and upper slabs should also be spaced apart. In those places where thermal insulation slabs adjoin walls, parapets and lanterns, thermal insulating transition sides are created. To secure thermal insulation, one of the following methods is used:

• mechanical. The corrugated sheet is fastened with self-tapping screws, the reinforced concrete base is fastened with plastic dowels with a core;
• adhesive;
• using ballast, which is pebbles or paving slabs;
• based.

The main mistakes in installing a flat roof

Errors in installation 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 slabs are attached to the wall. Such “cold bridges” can create heat loss of up to 50%, in addition, they can cause the formation of condensation and subsequently mold.

The most common reason for the formation of “cold bridges” is the use of fastening dowels with a metal nail. This phenomenon can be avoided by using roofing works flat roof stone wool. This is explained by the fact that glue will be enough to attach it, 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 two-layer insulation. But in this case, the top layer must be laid so that the joints between the bottom slabs are covered with 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 more than just its primary function of protecting you from precipitation? Would you like to turn it into a beautiful garden, recreation area or outdoor sports ground? Then flat roofing is the perfect option for you!

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-construction DIY flat roof.

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

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

Wooden or steel beams are installed on load-bearing walls, which transfer the load from the roof to the walls and foundation.

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

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

For correct selection diameter and size of the beam, take into account all the loads that act on them. In addition, to construct a high-quality flat roof, choose the right finishing coating that is durable and performs well. performance characteristics.

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

1. Initially, a vapor barrier is laid on the surface, preventing moisture from penetrating into the insulation. For the manufacture of vapor barriers, reinforced bitumen film based on fiberglass is most often used. The edge of the film is placed behind the vertical line of the ceiling, and all seams are carefully soldered.

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

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

There are two options for flat roofing, depending on the type of room for which it is being built:

• flat roof for a heated room;
• flat roof for an unheated room.

Erection of a flat roof over an outbuilding, barn, or gazebo does not require any special skills. To create a stack, a slight slope in one direction is enough.

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

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

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

3. Install a screed 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 roll carpet is additionally glued onto the screed.

It is recommended to create a flat roof with a minimum span, thus reducing the difficulties of its hydro- and thermal insulation. Roofs whose width exceeds 600 cm are recommended to be erected only by specialists. Incorrect calculation of loads on beams leads to dire consequences: improper load distribution and reduced service life of roofing materials.

Technology for installing a flat roof made of monolithic concrete

As load-bearing structure for a concrete flat roof, I-type steel beams act. If the roof span does not exceed 500 cm, then beams 15 cm thick are used to construct the roof.

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

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

Next follows the process of installing the boards on the lower flanges of the beams; roofing material is mounted on the boards and reinforcement mesh, with a minimum cell size of 10 mm. To connect the intersections of the mesh, use knitting wire or welding machine. The gap between the mesh and roofing felt is about 4-5 cm; for this, crushed stone is placed under the mesh. 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 within one day. After pouring, the surface is compacted with a concrete vibrator or hand tools. When compacting concrete, be careful not to deform the mesh.

Next, a polyethylene film is installed on the roof, preventing excessively rapid evaporation of moisture and cracking of the top layer. After the roof has completely dried, a slope is constructed using insulation to allow water to drain.

Thermal insulation of a flat roof with your own hands

Flat roofing differs from standard single-pitched and gable roofing types in that it requires both internal and external insulation. First, the roof is insulated from the outside, and, if necessary, from the inside.

Previously, rigid thermal insulation boards were used to insulate flat roofs, but due to their heavy weight, nowadays they are practically not used. Replacement this insulation steel thermal insulation materials based on basalt and mineral wool. The thermal conductivity of this material is much higher, and the weight does not burden the structure.

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

In addition, materials in the form of:

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

Construction of a flat roof and technology for creating a roofing pie

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

• load-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, a textile layer is laid after the insulation, then covered with crushed stone and finishing. This type of roofing is called inversion and is used extremely rarely due to its heavy weight. It is suitable for buildings with high requirements on fire safety.

The installation of a flat roof implies compliance with all loads arising 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 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.

DIY inversion flat roofing

Inversion flat roofing has good performance characteristics and high fire safety. The installation technology for this roofing 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:

• difficulty in destroying waterproofing;
• absence of condensation on the insulation, since it is located on top of the roofing pie;
• ease of repair and replacement of thermal insulation material.

Excessive moisture that forms in the thermal insulation layer causes deterioration in 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. A complete lack of ventilation leads to peeling of the roof from the base.

In this case, we recommend installing a breathable roof. For the manufacture of roofing, roll materials are used, with excellent tightness and a long service life. Thermal insulation material is installed between the bitumen mastic, and roofing aerators are used for additional ventilation. Among the advantages of this coating we note:

• no need to dismantle the flooring, additional reinforcement of waterproofing;
• laying the second layer with a slope improves 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

Materials for finishing a flat roof must meet certain requirements, such as:

• high level of strength;
• a light weight;
• thermal insulation and sound insulation characteristics;
• resistance to ultraviolet radiation;
• duration of operation;
• ease of installation and maintenance.

Quite often, roofing felt 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 temperature fluctuations. Every 8-10 years of operation, the roof is re-covered with roofing felt.

New rolled bitumen coatings are gradually replacing roofing felt and glassine. This is explained by their following advantages:

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

There are several types of bituminous materials for flat roofing:

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

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

Polymer 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 base of the building;
• elasticity and tendency to stretch;
• service life exceeding 50 years;
• do not require the use of open fire for installation, compared to bituminous materials;
• Hot air is used to connect the joints.

Mastic-based materials are ideal for flat roofing. Rolled materials, although they have certain advantages, all of them create seams that, under increased load, allow moisture to pass through. Seamless roof covering with mastic does not create butt joints and is perfectly smooth. This kind of roofing is called “self-leveling”. This roofing is easy to apply, forming a solid sheet; a brush or broom is enough to level the material. First, the roof is treated with primer or primer.

Do-it-yourself flat roofing video:

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

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

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

A flat roof can provide many interesting possibilities in this regard, but there are limitations to its use.

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

According to the conditions of the plane's location, there is practically zero wind load (if properly constructed without overhanging edges) with a maximum snow load.

Wherein, the roof structure has a complex multi-layer structure, ensuring the tightness of the coating and operational state insulation.

Most favorable conditions operation of flat roofs:

• Small amounts of snow in winter. It is most suitable for use in regions with warm or little snowy winters, when removing snow from the roof does not cause difficulties.
• Wind force does not have a significant effect on the roof, therefore, the construction of such roofs in areas with strong or gusty winds is permissible.

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

The use of flat roofs on residential buildings is more common in southern regions, where there is no problem with high snow pressure in winter.

Flat roof

The structure of the roofing pie

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

• Roof purpose;
• Floor type;
• Roofing material.

The decisive factor that determines the composition of the roof from the very beginning of construction is the purpose of the roof. It depends on it what material is needed for the construction of the floor, how exactly it will be insulated, and what kind of optimal material coverings.

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

The general insulation technology looks like this:

• Base (concrete, wooden floor);
• Vapor barrier film;
• A layer of insulation;
• Top layer of waterproofing;
• Roofing.

This is the general plan, in practice it is often supplemented or complicated with the aim of more reliable protection from water penetration or the formation of cold bridges.

Roofing pie

One of the options for installing a flat roof is inversion roofing. This is a relatively new type of pie design that takes into account the disadvantages of conventional options.

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

To eliminate this phenomenon, inversion roofing is used when A reliable waterproofing carpet (often multi-layered) is installed between the ceiling and the insulation..

The composition of the pie is built as follows:

• Overlap;
• The waterproofing preparation layer is usually a construction primer;
• Waterproofing carpet;
• Geotextile layer;
• Insulation (optimally extruded polystyrene foam);
• Top layer of geotextile;
• Ballast fill layer of gravel.

If necessary, a rigid covering can be laid on top of the ballast layer to maintain uniform ballast thickness and ease of movement.

Inversion roofing cake

Is the roof based on wood or concrete?

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

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

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

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

CAREFULLY!

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

More often, for used roofs of residential buildings, they use as a basis concrete slab . This overlap has a number of significant advantages:

• Reliability;
• No noticeable deformation from loads;
• Penetration of moisture into the material will not cause rotting;
• Finishing a concrete floor is easier than finishing a wooden one.

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

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

Sectional photo of the roof basics:

Wooden base

Concrete base

Flat roofs: arrangement of private houses

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

• Lightweight. The roof serves only as protection from precipitation. Mainly used for auxiliary buildings for utility purposes;
• Exploited. Such a roof serves as a platform for placing various equipment, for creating recreation areas, small greenhouses, swimming pools, etc.;
• Green. On such a roof there is a lawn with grass, plants, etc. Serves as a mini-square for relaxation.

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

Yes, for a flat roof outbuilding will be sufficient:

• Rafters;
• Lathing;
• Roofing covering (metal profile, etc.).

Lightweight roof

For a used roof, which is used as a platform for installation solar panels, satellite television dishes or other equipment, the composition is much more complex:

• Concrete floor slab;
• Cement screed that forms a slope for water drainage;
• Waterproofing layer;
• Drainage material that removes water from under the upper layers;
• Insulation layer;
• Geotextile layer;
• Sand preparation layer;
• Paving slabs.

In this case, the outer covering is paving slabs, as a durable and cheap material.

ATTENTION!

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

Operable roof

Pie diagram for creating a green roof:

• Concrete floor slab;
• Layer ;
• Multilayer waterproofing carpet;
• Insulation;
• . It consists of a separating layer of reinforced screed, a double layer of technoplast (EPP and Green), and a geodrainage roll layer;
• Layer of soil with plantings.

In this case, there is a multi-stage waterproofing system that reliably cuts off the insulation material from the top soil layer. This cutoff, at first glance, is too complicated, necessary to guarantee the creation of a reliable barrier to water.

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

Green roof

How to cover a flat roof

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

Unused surfaces are most often covered with roofing felt and the joints are sealed with liquid bitumen.

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

Operated surfaces require a tougher and more durable coating. At the same time, the task of hermetically sealing the insulation from external influences is not removed, so most often a sand-cement cushion and a working layer - paving slabs - are laid on top of the soft roof.

Coating

Installation of a used flat roof

How to make a flat roof? First of all, you need to decide on the basic parameters - type of roof, structure, etc. Let's consider the option of installing a serviceable flat roof with a concrete floor and external drainage using gutters:

1. The surface of the ceiling is covered with a layer of slope-forming concrete screed(decline). To save concrete, a layer of gravel is first poured on a slope, after which a screed is laid on top. Since this stage refers to “wet” work, then It is recommended to cover the surface of the ceiling with a layer of primer or similar material.
2. Laying vapor-waterproofing. As a material, you can use various fused films or roll membranes. Laying with overlap, seal the joints with tape.
3. Insulation layer. Either stone mineral wool or extruded polystyrene foam is used. The insulation is laid in several layers, minimum 2 layers. This requirement is caused by the need to prevent the penetration of cold through cracks in the joints of the insulation.
4. On top of the insulating layer a layer of waterproofing is laid.
5. Filling the ballast layer - gravel, sand, etc.. The role of this layer is double: protecting the film coating and draining water coming from melting snow or precipitation in the summer.
6. On top of the ballast layer if necessary, a layer of paving slabs can be laid for ease of walking on the surface. In this case, you will need additional sand preparatory layer, direct backing for tiles.

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

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

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

All roofing options require careful arrangement and expensive materials. The quality of the result directly depends on the qualifications of the people performing the work and on the financial capabilities of the home owner.

But don't forget that you can build a flat roof with your own hands.

Investments in an equipped, usable flat roof will only be worthwhile in regions with short, mild winters and low average monthly precipitation. All other issues can be resolved and do not cause serious problems.

Waterproofing

Insulation

Useful video

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

In contact with

A flat roof is a common architectural solution in civil, industrial and private construction. The construction of a flat roof has its own characteristics, but main principle is that the waterproofing layer must 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:

• flat base;
• vapor barrier layer;
• insulation;
• waterproofing.

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 functional features roofs. The following types of roofing differ:

• traditional;
• ventilated;
• exploited;
• inversion

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. Can be used to slope the roof various materials. 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.

Has similar characteristics lightweight concrete with perlite or expanded clay filler. 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 leveling. It is difficult to pour concrete into a layer of bulk insulation (expanded clay or perlite), observing the required angle of inclination of the roof plane, since the granules can move.

An effective, but expensive option for 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 roof slope is to the side water inlet funnels(in the presence of internal drain), or towards the water intake gutters external system catchment, which should be mounted under the roofing carpet or on external wall building.

Roofing units

In order for the roofing pie to be reliably protected from external influences, special attention should be paid to the places where it abuts 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 vertical structure with a cut. 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 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. In the open air, after a certain time after being applied 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 you can perform.

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 equipment 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 pressing of the waterproofing carpet 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 in the following way: 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.