Flat roof description. Economic nuances of using a flat roof

The choice of a particular design largely determines the possibility of using the attic as an additional living space, solves the issue of the need for insulation and determines the type roofing .

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

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

In this regard, a flat roof can provide many interesting possibilities, but its use has its limitations.

Main Feature flat roof almost horizontal surface. such surfaces is low - up to 8 degrees, it is needed only to drain rain or melt water.

According to the conditions of the plane location, there is practically zero wind load (at correct device without hanging edges) at maximum snow.

Wherein, roof structure has a complex multilayer structure, which ensures the tightness of the coating and the working condition of the insulation.

Most favorable conditions operation of flat roofs:

• A small amount of snow in winter period . The most successful use is in regions with warm or little snowy winters, when removing snow from the roof is not difficult.
• The strength of the wind does not have a significant effect on the roof, therefore, it is permissible to build such roofs in areas with strong or heavy winds.

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

The use of flat roofs residential buildings more characteristic of the southern regions, where the problem of high snow pressure in winter is absent.

Flat roof

The structure of the roofing pie

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

• The purpose of the roof;
• Cover type;
• Roofing material.

The decisive factor determining 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 ceiling, how exactly it will be insulated, what is the optimal coating material in this case.

flat roof insulation soft roof produced outside, since this method is much more convenient and reliable in terms of the tightness of the cake.

The general technology of insulation looks like this:

• Base (concrete, wooden floor);
• vapor barrier film;
• layer of insulation;
• The top layer of waterproofing;
• Roofing.

This is a general plan, in practice it is often supplemented or complicated in order to more reliably protect against water penetration or the formation of cold bridges.

roofing cake

One of the flat roof options is inverted roof. This is a relatively new kind of pie construction that takes into account the shortcomings of conventional options.

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

To eliminate this phenomenon, an inverted roof is used when a reliable waterproofing carpet (often multilayer) is installed between the ceiling and the insulation.

The composition of the pie is built like this:

• overlap;
• Waterproofing preparation layer - usually a building primer;
• Waterproofing carpet;
• Geotextile layer;
• Insulation (optimally - extruded polystyrene foam);
• The top layer of geotextile;
• Ballast bulk layer of gravel.

On top of the ballast layer, if necessary, a hard coating can be laid to maintain a uniform thickness of the ballast and ease of movement.

Inverted roofing cake

Roof base - wood or concrete?

Wood or concrete can be used as the basis 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 truss system is made and the roofing is laid on top. However, wooden floors are also used for residential buildings.

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

CAREFULLY!

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

Often, for the roofs of residential buildings used, a concrete slab is used as the basis. Such an overlap has a number of significant advantages:

• Reliability;
• No noticeable deformation from loads;
• The penetration of moisture into the material will not cause decay;
• Finishing a concrete floor is easier than wood.

Since it is produced outside, the lower surface of the concrete floor (the ceiling of the upper floor) will be open, which allows the use of any available type of finish - from simple painting to the installation of 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 from existing loads.

Photo of the foundations of the roof in section:

wooden base

concrete base

Flat roofs: arrangement of private houses

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

• Lightweight. A roof that serves only as protection from rain. It is mainly used for auxiliary buildings for household purposes;
• Operated. Such a roof serves as a platform for accommodating various equipment, for arranging 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 overlap 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.

So, for a flat roof of an outbuilding it will be enough:

• Rafter;
• crate;
• Roofing (, metal profile, etc.).

Lightweight roof

For a used roof, which is used as a platform for installing solar panels, satellite TV dishes or other equipment, composition is much more complex.:

• Concrete floor slab;
• Cement screed forming a slope for water flow;
• waterproofing layer;
• Drainage material that removes water from under the upper layers;
• insulation layer;
• Geotextile layer;
• Sand preparation layer;
• Paving slabs.

In this case, paving slabs serve as an external coating, as a durable and cheap material.

ATTENTION!

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

exploited roof

Green roof pie chart:

• Concrete floor slab;
• Layer ;
• Multilayer waterproofing carpet;
• insulation;
• . It consists of a separating layer of reinforced screed, a double layer of technoplastic (EPP and Green), and a geodrainage rolled layer;
• Soil layer with plantings.

In this case, there is a multi-stage hydroprotection that reliably cuts off the insulation material from the upper soil layer. Such a cut-off, 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 surely seep into the lower layers, so the complexity of the composition of the cake 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 with sealing joints with liquid bitumen..

Recently there has been a large number similar materials with improved characteristics, allowing more reliable protection of the roofing pie.

Operating surfaces require a more rigid and durable coating. At the same time, the task of hermetic cut-off of the insulation from external influences is not removed, therefore, most often a sand-cement cushion and a working layer - paving slabs are laid on top of the soft roof.

Coating

Installation of an operated flat roof

How to make a flat roof? First of all, you need to decide on the main parameters - the type of roof, device, etc. Consider the option of installing an operated flat roof with a concrete floor and external drainage using gutters:

1. The surface of the overlap is covered with a layer of sloping concrete screed (decrease). To save concrete, a layer of gravel is first poured with a slope, after which a screed is laid on top. Since this stage refers to "wet" work, then it is recommended to cover the overlay surface with a layer of primer or similar material.
2. Laying vapor and waterproofing. As a material, various deposited films or rolled membranes can be used. Laying with an overlap, glue the joints with adhesive tape.
3. insulation layer. Either stone mineral wool or extruded polystyrene foam is used. Insulation is laid in several layers, at least 2 layers. This requirement is due to the need to exclude the penetration of cold through the cracks in the joints of the insulation.
4. over the insulating layer laying a layer of waterproofing.
5. Backfilling of the ballast layer - gravel, sand, etc.. The role of this layer is twofold: protection of the film coating and removal of water from melting snow or precipitation in the summer.
6. over the ballast layer if necessary, a layer can be laid paving slabs for ease of walking on the surface. In this case, you will need an additional sandy preparatory layer, a direct substrate for tiles.

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

The device 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 of the area, the surface of a flat roof is turned into a green lawn, into a technical area for placing equipment, into a recreation area.

All variants of the operated roof require careful arrangement and expensive materials.. The qualitative result directly depends on the qualifications of the people doing the work and on the financial capabilities of the owner of the house.

But do not forget that you can build a flat roof with your own hands.

Investments in an equipped used flat roof will be justified only in regions with short mild winters and low average monthly rainfall. All other issues are resolved and serious problems do not call.

Waterproofing

Warming

Useful video

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

In contact with

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

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

A flat roof is a minimum of details and simplicity of construction

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

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

Flat roof device

Advantages of a flat design:

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

The green lawn on the roof is so cute!

If the device of a flat roof is made competently and efficiently, there are no shortcomings in its operation. In the case of unprofessional installation, defects are possible, which will come to light on the very first rainy autumn or snowy winter.

Flat roof construction: we study the basic requirements

1. The high strength of the roof is especially important during the snow season, when it is forced to withstand the pressure of thick layers of snow and ice. This indicator is also important in cases where a flat roof is exploitable.
2. The roof must be a reliable barrier to water during rain and snowmelt and have a slope.
3. The design of a flat roof must not react to the effects of bitter frost and scorching sunlight, to the influence of changes in ambient temperature and hail strikes the size of a chicken egg.
4. The roof should perfectly perform a heat-insulating function.
5. All materials used must be fireproof.

On a flat roof in winter, much more snow always accumulates than on pitched roof

Classification of flat roofs and features of the roofing plan

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

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

Operated roof with a cozy terrace

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

traditional method

The traditional way, in which the topmost layer is waterproofing. It is she who in this case is subjected to thermal, physical and mechanical loads.

The role of the bearing base can be performed iron concrete slab, special reinforced profiled steel sheet or roof sandwich panels. The required slope is usually achieved by means of concrete or expanded clay concrete screed. Sometimes expanded polystyrene concrete or slag is laid.

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

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

Then stacked thermal insulation material. Mineral basalt wool is usually used, which has good compression resistance, vapor permeability, fire safety and low thermal conductivity. Its first layer (70-200 mm) will act as a heater, and the second (40-50 mm) will act as a load distributor. In general, the thickness of this layer is calculated in accordance with the climatic conditions of the region.

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

And, finally, the finishing layer is waterproofing, which has proven itself well with special liquid mastics that form a rubber-like layer, built-up roofing material and roofing membranes.

Why are the latter good? They have a huge service life, they are able to let steam out. Roofing membranes are easy to install and, subject to technology, form an excellent waterproof coating.

The inversion method, when the thermal insulation layer is located on top of the waterproofing material, which here also performs the function of a vapor barrier. This is the best option for the installation of operated roof structures. The cake of a flat roof made in the inversion way will be different depending on what the roof is used for (pool, pedestrian zone, lawn, park, etc.). But in any case, a monolithic screed is made over the concrete base to level its surface. The next layer is waterproofing material, which in the future turns out to be reliably protected from the influence of any factors external environment. Then all this is covered with a heat insulator, on top of which, if, for example, the roof serves as a pedestrian zone, paving slabs are laid on the sand-cement mixture.

The flat roof of an underground car park can be made using the inversion method

In the design of any building with a flat roof, one of the mandatory items should be the plan of the roof of the flat roof. This is necessary not only to improve the aesthetic qualities of the structure, but also to increase the functional abilities of the future roof structure. In addition to accurately calculating the number of all necessary materials the plan includes directly the technology of the work, the scheme of the drainage system, the features of the implementation of the ramping, ventilation and other points.

Horizontal ventilation in flat roofing

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

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

Roof drainage system

An important role in the drainage of water is played by the slope of the roof, which is recommended to be at least 2%. Even a slight slope can prevent the penetration of moisture through possible defects in the roofing.

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

Water disposal can be carried out in two ways:

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

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

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

The installation of a flat roof, from its design to commissioning, must be carried out by specialists of appropriate qualifications. Knowing only the basics of creating a roof structure without taking into account specific features can lead to errors, the correction of which will require considerable material investments. Therefore, the installation of a flat roof is the prerogative of professionals.

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. Familiarize yourself with the technology of self-construction of a flat roof with your own hands.

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, which transfer the load from the roof to the walls and foundation.

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

• total weight retention attic space and overlaps;
• 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 affect them. In addition, for the construction of a high quality flat roof, choose the right finish that is durable and performs well.

One of the most milestones are heat and sound insulation. The flat roof of capital buildings consists of floor slabs, 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, initially a concrete screed is installed on it, 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.

Construction of a flat roof outbuilding, shed, 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 felt 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 based on cement mortar is installed on the insulation, 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 operation. 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 crushed stone and three buckets of cement, four buckets of sand and two buckets of water.

This is followed by the process of mounting the boards on the lower shelves of the beams, roofing felt and reinforcing mesh are mounted on the boards, with a minimum cell size of 10 mm. To connect the intersections of the grid, use knitting wire or 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. Thermal conductivity this material 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 special glue or mastic. Please note that before insulating the ceiling, all lighting fixtures on the ceiling.

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 - an excellent option for a roof that is in constant use, does not burn, 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 individual characteristics 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 fire safety requirements.

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. The complete lack of 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. Thermal insulation material is installed between the bituminous mastic, and roofing 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 changes;
• duration of use.

There are several varieties of bituminous materials for a flat roof:

1. Fiberglass, fiberglass - is 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.

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 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:

It is necessary to determine the design of the roof at the design stage of the structure. If you chose flat version, then it is very important to represent all the positive and negative aspects of the operation of a building with such a roof. The choice of roof type also depends on the use of special materials and technological methods during construction.

Flat roof device

Not always a flat type of roof evoked positive emotions among builders. This was due to some prejudices in the construction and operation of a flat roof - lack of aesthetics, uneconomical, fragility.

Recently there has been a resurgence in popularity flat structures roofs, a significant role in this was played by new construction technologies and innovative materials.

A flat roof made of modern materials reliably protects the house and looks beautiful

A flat roofing device can be represented as a multi-tiered "pie" with several layers:

1. Reliable foundation. Most often, this role is played by a reinforced concrete slab or a metal profile structure.
2. Vapor barrier coating. The most popular bitumen or roll materials.
3. Thermal insulation layer. Mineral wool, expanded clay, expanded polystyrene, cement screed - the main components used by builders for thermal insulation.
4. Waterproofing. There are a lot of materials to protect the roof from moisture (bitumen-based mastics, PVC membranes, compositions for liquid fusing, etc.), the choice depends on the material and production capabilities of the developer.

The listed order of layers is not mandatory, it can be different in different flat roof structures.

All elements of the roof must be of high quality, a flaw in at least one of them can lead to problems in the normal operation of the roof.

Pros and cons of a flat roof

A flat roof, despite its apparent simplicity, has a number of useful characteristics attracting builders. Such designs also have disadvantages that must be taken into account.

Advantages of flat roofs

Photo gallery: flat roof operating options

Modern technologies make it possible to plant grass on the roof and arrange a playground exactly like on earth. You can get to such a cafe by elevator. Only a flat roof can be decorated so beautifully and modernly. On the roof, you can place a table, benches, a hammock and enjoy your vacation. Swim in the pool. practically without leaving home - you can only dream about it

Disadvantages of a flat roof structure

No roof is perfect. There are significant disadvantages of a flat roof:

• instability to snowfalls (with heavy snowfall, the likelihood of a roof break increases, with abundant spring thawing, leaks are possible);
• the need to build additional drains for water;
• increased requirements for the state of hydro- and thermal insulation of the roof.

If on the surface of flat structures are made internal drains, then they require constant monitoring of their condition (it is necessary to clean debris, eliminate freezing, etc.).

Types of flat roofs

There are two main types of flat roofs:

The structural differences between the two types of flat roofs are in the order in which the layers are laid. In an unused roof, the top layer is waterproofing, which collapses quite quickly when exposed to various natural factors - the sun, wind, precipitation, etc. This option is not suitable for active use roofs.

The inversion roof is “packed” differently. The sequence of layers here is as follows: concrete, waterproofing, thermal insulation, protective coating. The last layer is often made of drainage or geotextile. Such durable structures are in demand among designers who want to make the most of the entire roof space.

Holding concerts, building car parks, summer cafes and studios implies a high degree of load, so builders lay additional reinforced materials between the insulating layers.

flat roof slope

A flat roof does not have to be absolutely flat, a minimum slope must be provided for. Otherwise, sewage disposal will be difficult, moisture from precipitation will accumulate on the roof and contribute to its rapid destruction.

In the absence of a slope, stagnant zones with negative aspects may appear:

• accumulation of moisture;
• germination of seeds carried by the wind;
• lichen formation.

To prevent this from happening, a slope of one to four degrees should be made on a flat roof. With such a difference in the levels of melt and waste water will not linger on the surface, which will extend the life of the roofing.

Work to create a slope on a flat roof is called slope.

To achieve the desired slope on a flat surface, you can use different materials:

1. Backfill components (expanded clay, perlite, etc.).
2. different layers of insulation.
3. Lightweight mixtures of concrete on various bases (polymers, bulk materials, etc.).

Each of these solutions has its own characteristics in relation to the slope. The use of backfill materials during long-term operation of the roof does not give a clear angle of inclination. Bulk materials can slide off the roof, move, which leads to a change in slope. It is difficult to achieve a smooth height difference if using expanded clay large sizes(more than 20 mm).

Accurately leveling an inclined surface with expanded clay is quite difficult.

Lightweight concrete masses are devoid of such disadvantages, but they are quite heavy, not every roof structure provides for such additional weight. These materials cannot be used in cases where the building has already been built and its design is not designed for a large load on the frame and foundation.

Modern industry produces materials that help create the necessary and smooth slope on a flat roof. The polymer base of these mixtures makes them plastic, which is a big plus in the construction of flat roofs.

There are other possibilities for creating a slope on a flat roof:

• installation of metal profile structures covered with flat slate;
• construction of a crate (rarely used due to the cost and impossibility of creating small slopes);
• installation of wedge-shaped heat-insulating plates.

The last of these methods is gaining popularity among builders, because this method of ramping has its advantages:

• simple installation. Plates for thermal insulation are already cut at a certain angle. Their installation does not require any special skills, it is enough just to lay the wedge-shaped slabs on a flat surface of a flat roof to get the necessary slope.
• light weight. During construction work, you will not have to resort to the help of any lifts. In addition, the insignificant total mass of insulation boards will not affect the performance of the roof in any way.
• Independence from external conditions. Laying wedge-shaped thermal insulation can be done in any weather.

Video: flat roof flattening

Insulation and drainage for flat roofs

To avoid a quick failure of a flat roof, you should take care of its proper insulation and drainage.

Drainage

A drain on a flat roof is mounted outside or inside the building. The choice of water drainage method depends on climatic conditions:

Video: installation of a receiving funnel on a flat roof

Warming

The thermal insulation of a flat roof is carried out differently than the insulation of pitched surfaces.

This process includes two important points - vapor barrier and thermal insulation. Depending on the type of roof (classical or inversion), the order of the layers changes.

Used as thermal insulation:

• mineral wool;
• Styrofoam;
• polyurethane foam;
• ecological cotton wool;
• foam concrete.

A good vapor barrier can be provided by a polypropylene film and a build-up mass with a bitumen base.

Photo gallery: flat roof insulation

Flat roofs can be insulated in a well-known way - by filling with expanded clay Large surfaces are easier and faster to insulate mineral wool For warming flat roofs increasingly used modern materials, for example, extruded polystyrene foam Foam glass provides not only thermal insulation, but also an excellent soundproofing effect Foam concrete is poured automatically using a pump and a flexible hose, so you can handle this work alone

Flat roof ventilation

To begin with, let's denote the negative points that will arise on a flat roof without ventilation. A roof of a flat design, devoid of ventilation, will be “loaded” with condensate. natural physical processes will lead to the fact that the warm air, rising up, will not settle on the elements of the attic (as on a pitched roof), but on a reinforced concrete base. The result of such adverse processes will be the appearance of fungus and mold on the ceiling.

In the future, steam and heat insulation, other roofing elements will suffer. To prevent this from happening, it is necessary to equip deflectors and aerators on the roof. Their installation is provided at the design stage of the building.

Devices to ensure unhindered air circulation are provided at the design stage of the roof

The inflow and outlet of air is carried out due to different pressures outside and inside the building. A flat roof will "breathe" if artificial ventilation devices are placed on it. This will help keep the layers of hydro and thermal insulation from destruction, eliminate the spread of air bubbles and swelling of the roofing material.

Flat roof covering materials

As roofing materials for flat roofs are used:

• mastics;
• polymeric membranes;
• roll materials on a bitumen basis.

They provide good waterproofing and excellent resistance to mechanical stress and temperature extremes.

Bituminous materials

The basis of many roll coatings is oxidized or modified bitumen. Ruberoid, stekloizol, rubemast, euroroofing material are the main types of bituminous materials used on a flat roof.

Table: characteristics of rolled bituminous materials

Material name	What is	Average service life	Characteristics
			positive		negative
Ruberoid	Cardboard impregnated with bitumen. The material also has a protective layer of backfill - talc, sand, granular expanded clay, etc.	5–10 years	Good waterproofing, resistance to atmospheric collisions and mechanical impacts. Low cost, easy installation.		Does not withstand temperatures of +50 °C and above. Cracks form on the roofing material even at large minus values.
Rubemast	Improved modification of roofing material with a thicker layer of bitumen.	15 years	High ductility and resistance to cracking (with temperature extremes and mechanical damage).	The need for certain skills when welding this material.
Stekloizol	The basis of the material is fiberglass with a bituminous top layer. For protection, there is an additional layer of backing at the top, and a special film at the bottom.	20 years	Doesn't rot, doesn't crack.	Requires professionalism when laying, bubbles and folds may form, burns through the bituminous coating when the gas burner malfunctions.
Euroruberoid	Bitumen supplied with various polymeric additives.	Over 20 years	All characteristics are an order of magnitude higher than those of any other bitumen materials	Assembly skills required. High price.

Polymer membranes

These materials have become popular relatively recently. The advantage of such flat roof coatings is plasticity, resistance to damage, resistance to temperature extremes, and simple installation. Another big plus of polymer coatings is their production footage. The length of one roll of polymer membrane is from 20 to 60 meters, so it can be covered very quickly large areas flat roof.

Polymeric membranes are available in long rolls, so they can quickly cover large areas.

The operating period of roofs with polymer membranes is 30–50 years.

Mastics

The positive aspects in the use of mastic materials are the absence of seams and the integrity of the coating. The service life of such roofs is from three to ten years.

Applying a viscous and viscous mastic to the roof surface is a simple process, this layer becomes solid at normal air temperature. Mastics are also used as an adhesive base for mounting roll materials.

There are cold and hot mastics. The first type does not require additional manipulations during the preparation and installation, in the second case, the mixture will need to be heated to 180 °. It is safer to work with cold mastics, but hot materials set faster.

Flat roof repair

Any roof needs constant inspection, care and repair. On the roof, under the influence of various factors, cuts, damage, breakthroughs, swelling, delamination and other problems can occur that interfere with the normal use of the roof. To eliminate such negative conditions, it is necessary to carry out repair work. They can be current, emergency and capital.

Emergency repair is a forced, unplanned measure, emergency measures to restore the integrity of the roof. Current and capital repairs of a flat roof are provided in advance. The volume of work carried out during current and major repairs differs significantly. Major repairs require more time and costs, while the area of ​​repaired coatings is also much larger.

Defects on roofs covered with rolled materials are most often eliminated by gluing patches.

During emergency and scheduled repairs of a flat roof, patches are most often installed on the damaged area. Materials for repair in each case are selected individually. One of the latest "assistants" when updating a flat roof is a self-adhesive tape with a bituminous coating. It is very convenient and effective to use it for roof repair. There is only one limitation: such a tape is not suitable for repairing damage over a large area.

Flat roof repairs are much easier and safer than pitched roofs. The repair time on such a surface is also much less.

Video: flat roof repair technology

Economic nuances of using a flat roof

If you are wondering about economic benefits, then you should consider some points when building a flat roof.

Of course, the construction of a flat type of roof is less expensive, since the cost of building a rafter system is not required. This will also be the case with operation, if repair of the rafter part of the pitched roof is required. In a flat roof, such an expense item is simply absent.

A pitched roof will require more investments also because it is clearly visible, being an integral part of the facade of the building. Materials used in construction upper layers in a flat roof, are not always appropriate for a pitched version. They can be simpler, uncomplicated, while on a pitched roof it is better to use not only reliable, but also beautiful finishes.

The costs of building, maintaining and repairing a flat roof largely depend on its intended purpose. The cost will be much lower if the roof is not in use.

The construction, maintenance and operation of a flat roof have their own natural features. There are advantages and disadvantages to using flat roofs. Given the purpose of using the building, a flat roof should be mounted with strictly defined materials.

December 9, 2017
Specialization: facade finishing, interior decoration, construction of dachas, garages. The experience of an amateur gardener and horticulturist. He also has experience repairing cars and motorcycles. Hobbies: playing the guitar and much more, for which there is not enough time :)

The device of a flat roof can be made according to several schemes. But which option should be preferred? I propose to consider all the most interesting technologies and their nuances, and you yourself can decide which option is best for you.

General information or what is a flat roof

A flat roof is a roof that does not have a slope. True, sometimes a slope up to three degrees is performed, but, in any case, the slope is minimal. In fact, the roof is a ceiling, as it does not have a traditional truss system.

Most often, such a roof is based on a concrete slab. However, there is a lightweight version of it in the form of profiled sheets laid on floor beams, on top of which a roofing pie is laid.

Regardless of the type of roof construction, as a result of the minimum angle of inclination, it requires a special approach to the roofing pie. Currently, as I said, there are various types of it.

All of them have their own advantages and disadvantages. Therefore, you can choose the appropriate option only after familiarizing yourself with their features, which we will do next.

Roof types

Currently, the following types of roofs are most popular:

Option 1: soft

Soft roofing involves the use of bituminous roll materials. Most often, it is performed concrete base. However, profiled sheets can also be covered in this way. The only thing is that you will first have to lay thermal insulation, which will not only insulate the roof, but also ensure a flat roof plane.

Most often, the so-called euroroofing material is used for soft roofing. Its composition includes polymer-modified bitumen, which is necessarily reinforced with fiberglass or other fibrous material.

The roofing cake of a soft roof includes several layers:

• Bituminous mastic. Increases the tightness and durability of the coating;
• Lining carpet. This is a waterproofing layer that is glued to the base either by heating the back surface or by "self-adhesive", depending on the type of coating;
• Base layer. In contrast to the waterproofing layer, top coat on the front side has a protective and decorative dressing.

If the roof is warm, a heat-insulating material (extruded polystyrene foam, polystyrene or, for example, mineral wool) is laid on the base, then a screed is poured. Next, the roofing pie is laid according to the scheme described above.

When installing a soft roof, as well as any other, it is important to properly equip the junction points. To do this, the roofing is mounted with a twist on a vertical plane, and a special junction bar is installed.

I must say that sometimes the roll coating is laid directly on the insulation, i.e. without concrete screed. According to this scheme, a roofing cake is usually placed on top of the corrugated board.

The main advantage of a soft roof is cheapness. However, it serves on average no more than 10-15 years.

Option 2: inversion

The principle of the inverted roof is that the waterproofing layer is not placed on top of the roofing pie, but under the bottom. This technology increases the durability of the coating, since the sun, hail, snow and other adverse factors do not affect the waterproofing layer.

An inverted roofing pie looks like this:

• Bituminous mastic. Can be replaced with bituminous primer. The coating performs the same function as in the roofing cake described above;
• Waterproofing. As in the case of a conventional soft roof, a built-up roll material is used;
• Provides protection against any mechanical damage. Sometimes for these purposes, instead of geotextiles, a drainage membrane is used;

• Thermal insulation layer. Most often, the roof is insulated with extruded polystyrene foam, which does not need additional waterproofing;
• Thermally bonded geotextile. Performs the function described above;
• ballast layer. It is a mound of gravel or crushed stone.

As you can see, the insulation is located above the waterproofing layer. Therefore, this technology eliminates the possibility of condensation.

Option 3: operated

The name of this roof speaks for itself - it can be used as a platform for various purposes. For example, it can serve as a terrace, and sometimes even a pool is made on such a roof. Of course, to create any massive structures on the roof, even before its construction, it is necessary to draw up a plan and then take into account all structural features during construction.

As for the roofing pie of the operated roof, its structure is similar to the device of the inversion roof pie. The only thing is that on top of the geotextile, which covers the insulation, a layer of sand is poured and paving slabs are laid. Sometimes, instead of paving slabs, a concrete screed is poured and covered with rubber paint.

Option 4: roof-lawn

Roof-lawn, or green roof, in fact, is a kind of operated roof, however, the construction of a roofing pie is much more complex. It includes the following layers:

• Expanded clay. With its help, a slight slope is made;
• Cement-sand screed. Provides an even and smooth base over expanded clay;
• Mastic and built-up bituminous coating. These two layers are responsible for sealing the roof;
• Insulation. Extruded polystyrene foam of durable grades is used, which is protected from both sides by thermally bonded geotextiles;

• profiled membrane. Provides additional mechanical protection to the lower layer, and also to some extent performs the functions of a hydrobarrier;
• Geotextile. Serves as a separator between the membrane and the soil;
• Ground and lawn. Performs the function of a decorative coating.

In order for the construction to be durable, it is necessary to take a very responsible approach to waterproofing and use high-quality materials from well-known manufacturers for this purpose. If such a roof suddenly “leaks”, its repair will cost more than all the above coatings.

Option 5: membrane

Recently, membrane roofs have become very popular. This is primarily due to the fact that the principle of their device is extremely simple, and the service life is even higher than that of soft roofs, i.e. exceeds 20-25 years.

The principle is based on the fact that special membranes are used as roofing, which are laid on top of the insulation. Therefore, the roofing pie looks like this:

• Vapor barrier. It is used if the heat-insulating material absorbs moisture;
• Thermal insulation. Any slab insulation can be used;
• Membrane. Most often made of PVC. Due to the fact that the canvas is soldered at the joints, it forms a continuous waterproof coating.

Since the membrane coating is quite light, it is often used for roofs covered with corrugated board. The only negative is the high cost of the membrane.

The price of PVC fabric on average starts from 350-400 rubles per square meter. EDPM membrane, which is more durable, costs several times more.

That, in fact, is all modern options flat roof devices on a concrete base and corrugated board, which I wanted to tell you about.

Conclusion

Now you are familiar with all the popular types of flat roofs, and you can choose the one that suits you best. If something caused you questions or you can not decide on a choice, please contact me in the comments, and I will be happy to help.

December 9, 2017

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