Flat roof do it yourself. Do-it-yourself roof made of monolithic concrete

Well insulated by itself roof truss from wooden blocks cannot create that cozy atmosphere that arises under a monolithic roof. This is explained by the fact that roof elements made of porous concrete or bricks have not only thermal insulation properties They also store heat. Thus, a monolithic roof is a good alternative to traditional wooden beams.

Preparing for the construction of a monolithic roof

The most expensive part construction works for the construction of a monolithic roof falls on the stage preceding the laying of the slabs. Whereas, in the worst case, underlays can be made in the support of a building truss from wooden beams, and the walls of the gable will take their final form later, in the case of a monolithic roof, there is hardly any possibility of such a correction. Therefore, when erecting monolithic roof supports, you need to do the work very meticulously. Already in determining the right angles of the horizontal projection, a lot of effort must be expended, but if the structure is characterized by beveled corners and balconies, then it is necessary to double-check the roof slope angles and the position of the ridge ridge with mathematical accuracy. It is best to pull the cords in the plane of the support plates. Each block is first fitted dry, and the line of curvature of the supports is marked. Cutting blocks is very easy, especially if you build from porous concrete and have a band saw at your disposal.

Reinforced concrete ring anchor device

If a reinforced concrete ring anchor is needed as a support for the slabs, the work can be difficult, since the connecting fittings are removed from the support, which then must fit into the gaps between the slabs with accuracy. In this case, the participation of a construction expert is recommended. The formwork for the ring anchor is made from the side of thin blocks. Then the reinforcement of the ring anchor is coupled with the connecting reinforcement and poured with concrete. Moisten the masonry walls first. We advise that the statics calculate whether to build the support with masonry or make it concrete. With a monolithic roof, supports and formwork are unnecessary. After the cast-in-place roof slab supports are in place, lay the prefabricated blocks together with two assistants and a construction consultant from the cast-in-place roof supplier.

Installation of a monolithic roof

Within a few hours the roof is covered. Roof slabs consist of reinforced porous concrete or reinforced brick elements, which have full load-bearing capacity already on delivery, so supports and formwork are superfluous with a monolithic roof. Typically, porous concrete monolithic roof slabs rest on gable walls and load-bearing interior walls, so any roof pitch and almost any span can be built. However, for production reasons, prefabricated blocks can only have a maximum length of 6 m. If large spans are to be covered, then reinforced concrete beams and steel I-beams, which you already know from porous concrete floors. At a time when reinforced concrete beams under the roof, like large lintels, cross the room and are visible, steel supports can be built into the plane of the slab and later completely invisible. In this way, monolithic roof structures are produced for almost every plan.

Roof window installation

Skylights can also be built into the plane of a monolithic roof. In any case, this is only done with a custom-made steel frame. Such a steel construction part in most cases rests on the side walls and serves as a reliable support for those roof slabs that have been separated for the construction of a roof window. The larger the window should be, the more expensive the frame will cost. Skylights can be made from a steel frame near load-bearing internal walls running parallel to the gable if the separated roof slabs respectively have at least two supports: on the gable and on inner wall. The roof slabs are then laid as cantilever slabs, similar to balcony slabs, and do not need a steel frame. Of course, a maintenance hatch can also be made in a monolithic roof.
Remember that embedding in the plane of a monolithic roof skylights hindsight is completely excluded! A monolithic roof, like a floor covering, is building block, the bearing capacity of which is guaranteed in a unified system for calculating the static load parameters.

In the second part of the article "Construction of a monolithic roof" read about the concreting of the ring anchor, the thermal insulation of the roof, the installation of the battens, the gutter and the roof of the monolithic roof.

Flat roofs in our time are undeservedly forgotten and are not spoiled by the attention of developers. In private housing construction, they are found mainly in the southern regions, where heavy rains and snowfalls are rare. Hip roofs, on the other hand, have become firmly established in the designs and minds of homeowners.

This state of affairs is explained simply: until recently, builders did not have reliable and durable waterproofing.

Standard roofing material - cardboard impregnated with bitumen, cannot resist moisture and temperature changes for a long time. Even a thick 4-layer coating of it has to be changed after 6-8 years.

Today, interest in flat roofs is starting to grow.

There are several reasons for this:

• Economic benefit. The cost of arrangement is lower than that of a tented one (more simple design and smaller area)
• Additional usable area. There is a possibility of rational use(flower garden, playground, recreation area, swimming pool);
• Availability for maintenance and operation (cleaning drains, installation of air conditioners, antennas, inspection of coatings, ventilation and smoke channels);
• The layer of snow plays the role of additional thermal insulation, reducing heating costs.
• The original appearance of the building.

Types of flat roofs

Strictly speaking, you will not see a completely flat roof on a building. Any of them has minimum slope from 1 to 4%, necessary for the runoff of atmospheric precipitation.

There are four types of flat roofs:

• unexploited;
• exploited;
• green (lawn);
• combined.

Unexploited roofs are found on industrial buildings.

Exploited roofs have found application in public and private construction. They equip recreation areas, place cafes and restaurants, use them as parking lots and helipads.

Green (lawn) coatings are made to decorate buildings, as well as when there is a shortage of space on the site. In addition to the aesthetic function, they perform an important practical task. A layer of vegetable turf is an excellent heat and sound insulator.

Combined roofs with flat surface- the most common option. Comfortable rest outdoors surrounded by green grass and flowering plants everyone likes it.

According to the method of drainage, houses with a flat roof are divided into two types:

• With internal drain;
• With external water discharge (along the perimeter of the roof).

Internal drainage cheaper than external, because it does not require a large number gutters, pipes, funnels and high-altitude work on their installation. In execution it is more difficult. Errors in creating a slope, poor-quality sealing of joints lead to leaks and a violation of the integrity of the protective layer of waterproofing.

In operation, flat coatings with internal drainage are more profitable. In winter, icicles do not grow on the overhangs near such a roof. Downspouts run inside the building and therefore do not freeze. Cleaning funnels from debris is easier and easier than hanging gutters.

Device Features

According to the method of arrangement and the location of the structural layers, experts distinguish two types of flat roofs:

• Classic;
• Inversion.

The classic roofing "pie" is equipped according to the following technology:

• on reinforced concrete floor slabs, they make a ramp out of a cement-sand mortar;
• lay vapor barrier and insulation;
• lay a waterproofing membrane or roofing felt carpet;
• if the coating is to be used, then the waterproofing is protected with ceramic tiles.

The construct of the classical flat roof

The main disadvantage of the traditional design is the vulnerability of the outer insulating layer to solar ultraviolet radiation and temperature changes.

Working on a solution to this problem, engineers came up with the idea of ​​inversion coating. In it, the main structural elements (insulation and waterproof membrane) are interchanged. Waterproofing is hidden under the foam, which is protected from external influences by a ballast layer of gravel or tile trim.

Inversion coating design

Accordingly, the technology of work is changing. A waterproof carpet made of roofing felt or an EPDM membrane is glued onto the slab or spread on it, fixing it at the junction with the parapet.

The slope in this case is created in one of two ways:

• Mortar screed on the plate;
• Insulation, changing the thickness of its installation.

Installation of thermal insulation on a flat roof

Water intake funnels and pipes are installed at the lowest points of the slope. In addition to them, ventilation is installed to remove water vapor that accumulates in the zone of contact between the vapor barrier and the insulation.

When arranging a coating designed for planting plants, the construct is supplemented top layer waterproofing. Drainage layers of gravel are poured along it, geotextiles are laid and a fertile layer of earth is poured.

Except roofing, laid on reinforced concrete slabs, projects of houses with a flat roof on wooden beams have been developed.

Construction technology in this case may include the following operations:

• Beams are mounted on the walls in increments of 50-100 cm, fixing them to the masonry with anchor studs. The cross section of the beams depends on the width of the span, the design load and can range from 10x20 cm to 15x25 cm;
• Lay on the beams OSB boards, tightly joining them together;
• Spread the waterproofing membrane in 2 layers, gluing the joints of the canvases with high quality.
• They make thermal insulation from durable (extruded) foam plastic, gluing it to the membrane. A slope for water flow is created by laying the insulation in layers of different thicknesses;
• From above, the heat insulator is protected with a cement screed, reinforced mesh or tiled.

Examples of private houses

Among the developers there are many supporters of flat roofs. They are attracted by the ease of construction, the low cost of work and the possibility of placing a site for summer recreation.

A thick layer of snow on a flat roof is not a problem, but additional insulation

The design of buildings with such a roof fits perfectly into the style of minimalism, providing project developers with a wide field for creativity.

Spacious, comfortable and nothing more - the motto of everyone who chooses a house with such a roof. pitched roof visually makes the building heavier, and flat, on the contrary, makes it light and airy.

Appearance facade one-story house with a flat roof compares favorably with the fairly bored variations of the "teremkovy" character.

On it, most often you will not see gutters and pipes, the water from which gets on the walls and spoils the appearance of the finish. Internal drainage is effective, practical and invisible.

Principal device thermal insulation of modern flat roofs.

Rice. 2. Appearance of a traditional modern roof. 2 - reinforcing mesh; 3 - cement screed; 5 - heat-insulating layer of mineral wool or expanded polystyrene.	Rice. 3. Flat roof with monolithic foam concrete. 1 - Waterproofing carpet; 2 - Structural foam concrete D600 screed; 3 - Heat-insulating layer and slopes to the spillway from extra-light foam concrete D200.

Table 1. Comparative thesis justification for the choice of flat roof construction.

Shrinkage during operation.

Styrofoam and mineral wool during operation, especially under load from the overlying layers of the roof, decrease in size. At the same time, the roofing "pie" slides down, tearing off the waterproofing from the parapets.

Rice. 4. Traditional roofing with mineral wool or styrofoam insulation within 2 years after installation. 1 - waterproofing carpet; 2 - reinforcing mesh; 3 - cement screed; 4 - expanded clay gravel to create slopes to the spillway funnel; 5 - heat-insulating layer of mineral wool or expanded polystyrene.	Fig.5. The same roof after 3-5 years of operation. Damage to the waterproofing at the junction with the parapet due to subsidence of the heat-insulating layer is shown. 1 - a layer of mineral wool or expanded polystyrene after shrinkage during operation for 1-3 years.

In addition, due to uneven snow load, mechanical loads (people walk along the roofs along certain paths, and not evenly over the entire roof), due to the heterogeneity of the insulation material itself and the uneven thickness of the mortar screeds in traditional roofs, depressions form in the roof planes, the so-called lenses, where water accumulates. The roof becomes “hilly” over time. In places where “lenses” are formed, the screed is usually broken, and with the slightest violation of the tightness of the upper layer of the roofing carpet, water from the lenses enters the roof.
In foam concrete roofs, the formation of "lenses" and recesses is impossible even if people are constantly on the roof, since foam concrete is a hard and durable material.

Compressive strength

Mineral wool and foam plastics, including extrusion ones, do not have compressive strength. They are characterized by the values ​​of the load during deformation. This indicator gives us the strength value, which shows a 10% compacted material. Those. in uncompressed state mineral wool, no foams are able to resist the load.

Strength at 10% deformation of mineral wool with a density of 100-150 kg / m 3 and extruded foam does not exceed 300 kPa (0.3 MPa). The strength of foam concrete with a density of 200 kg / m 3 starts from 0.3 MPa (300 kPa). Those. foam concrete withstands the same load as mineral wool or extruded foam when squeezed by 10%. But under such a load, foam concrete is NOT deformed.

Water absorption of foam concrete.

Majority thermal insulation materials applied on roofs has big water absorption. 60% of heat-insulating roofing materials are presented various types mineral wool, the real water absorption of which is up to 70% by volume (1500% by weight). This figure exceeds the water absorption of foam concrete by one or even two orders of magnitude.

State standards do not standardize the water absorption of mineral wool, since it is understood that this material should work only in conditions of complete absence of the ability to absorb water. Naturally, in practice, in the conditions of a real construction site, this is impossible - both during the period of work and during operation. Also, practice shows that it is almost impossible to dry the mineral wool that has become stale, especially in the conditions of the lower layer of the roofing pie, which cannot be ventilated.

Polymeric foamed plastics do slightly better in terms of water absorption, including the highest quality extruded polystyrene foam currently achievable. Despite the low "paper figures" for the absorption of water by foams, we forget that on top of the foam there is material for creating roof slopes. In most cases, this is the cheapest bulk material - expanded clay, on top of which cement strainer, or mounted sheet materials ( asbestos cement sheet, cement particle board, etc.) By the way, exactly the same roof construction is made on mineral wool slabs. But in this case it is not so important, due to the already huge water absorption of mineral wool.

Layer bulk expanded clay has a thickness of 50 to 400 mm and is a cavity under the screed, which can absorb from 25 to 200 liters of water per square meter! Moreover, in the event of a leak through the screed, the leak inside the building can be located at a distance of tens of meters from it, finding a free path for itself in the expanded clay layer. It is extremely difficult to detect damage to the waterproofing of the roof. (See fig. 5.)

A roof with monolithic foam concrete behaves quite differently. Particularly lightweight foam concrete is completely closed from water leaks by a layer of structural "screed" foam concrete, which absorbs water to a depth of about 10 mm. In case of damage to the waterproofing, an array of foam concrete is able to stop the movement of moisture deep into the roof. It should also be noted the remarkable fact of foam concrete self-drying - the water that has got inside the foam concrete array is used by the cement matrix of the material to continue hydration reactions that go with the chemical binding of free moisture. The hydration reaction compacts the foam concrete structure and stops the further movement of moisture. In case of serious damage to the roofing carpet, the roof locks locally - only at the place of damage, and not under the entire surface of the screed, as when using expanded clay to create slopes over foam plastic and mineral wool.

Rice. 5. Leakage of water in a traditional roof. Through the damaged waterproofing, water fills a layer of expanded clay gravel and voids under the thermal insulation layer. Then, through discontinuities in the base of the roof, water enters the room. 1 - damage to the layer of waterproofing carpet; 2 - a layer of water above the thermal insulation; 3 - a layer of water under thermal insulation.	Rice. 6. Water leakage in the foam concrete roof through the waterproofing is localized at the point of penetration. 1 - waterproofing layer; 2 - foam concrete screed with a density of D600, which protects the heat-insulating foam concrete D200 from leaks; 3 heat-insulating foam concrete D200.

combustibility

Styrofoam burns beautifully - thanks to numerous fires, the most distant citizens from the construction industry know about this. The combustion of foam plastics is accompanied by the release of toxic gases, which, by the way, occurs not only during combustion, but also with the slightest increase in temperature. One drop of welding when performing lightning protection on the roof, and a fire is more than likely, even during the construction of the building.

Mineral wool does not burn, but smolders. Smoldering is provided by a phenol-formaldehyde binder. Naturally, during combustion, nothing good will be released into the atmosphere either.

Foam concrete is a foamed stone, and stones do not burn. On the contrary, foam concrete can be used as protection against fire, for example, metal structures.

The design of the roofing pie.

The design of a modern flat roof consists of several elements. As we already described in the “water absorption” section, these are three layers:

Thermal insulation layer (mineral wool or polystyrene);

Layer forming roof slopes to spillway funnels (expanded clay gravel);

Screed ( cement-sand mortar With reinforcing mesh or sheet materials).

In the case of using monolithic foam concrete, the thermal insulation layer and the slope-forming layer are made of monolithic extra-light foam concrete with a density of 200 kg/m3, which significantly increases the thermal protection of the roof. The screed over this layer is also made of foam concrete, only more durable and dense, with a density of 500 kg / m 3.

Naturally, due to their affinity, homogeneous materials work better both in the thermal and structural sense. There are no gaps, delaminations, bubbles and other defects on the roof, so frequent for traditional roofs.

Roof device features

When making a layer of thermal insulation from board material difficulties always arise when performing thermal insulation of complex architectural elements on the roof, in places where communications pass (electrical wiring, ventilation, sewerage, etc.), places for installing building equipment on the roof (air conditioners, etc.). Accurate cutting of slabs is laborious and practically difficult to control. As a rule, all these places will have problems with freezing and getting wet in the future.

Monolithic foam concrete fills all the voids of the roof, forming a continuous warm shell of the building, monolithic roof. The above problems of traditional roofs do not arise by definition.

Roof durability

Both expanded polystyrene and mineral wool (which has a polymeric binder in its composition), like any other polymeric material, is subject to destruction during operation. Especially in conditions of extreme roofing conditions associated with overheating and often moisture.

Hundreds of books and articles tell us that any polymer has a limited lifespan. This is especially true for thermal insulation polymers.

Foam concrete, like any concrete, only gains strength during operation. Our own studies show that foam concrete, having a strength of 0.3 MPa at the age of 28 days, will harden to 0.5 - 0.7 MPa after a year of operation. Recall that hardening occurs when free moisture is bound in the material, due to which the self-drying of foam concrete occurs, even under sealed conditions.

Roofs made of monolithic foam concrete are lighter than traditional roofs, which in some cases makes their installation a non-alternative option, especially when conducting reconstruction work.

Table 2. The weight of a traditional roof insulated with polystyrene foam.

Tab. 3. The weight of the roof insulated with monolithic foam concrete.

Please note that monolithic foam concrete allows slopes with a lower degree than traditional roofs with expanded clay screed.

Roofing defects.

The most common defect of a traditional roof is the presence of blisters on the roofing carpet when it is heated in the summer. This happens when water vapor is heated under a layer of waterproofing. Foam concrete roofs are practically devoid of defects of this type, since the excess pressure of water vapor is evenly distributed in the pore space of foam concrete. The mechanism of this phenomenon is considered in more detail in our article “Buffer foam concrete screeds in the reconstruction of flat roofs” in the journal “ Construction Materials for November 2012.

Annex 1. Work in winter conditions

The main disadvantage of roofs with monolithic foam concrete is the limited possibilities for winter work. Industrial production of foam concrete is possible at positive temperatures, for a combination of reasons - the main of which is the freezing of hoses for water supply. In addition, we fundamentally do not recommend roofing in winter conditions, also for a number of reasons:

• Overexpenditure of gas for removal of ice and snow;
• Wage overruns for ice and snow removal;
• The inability to control the absence of snow and ice inside the roof structures;
• Excessive consumption of gas on the sticker of the waterproofing layer;
• Frost damage to materials and equipment.

However, it should be noted that the technology allows you to work at temperatures down to -7 degrees.

Appendix 2. Polystyrene concrete as a heater.

The use of polystyrene concrete on roofs is most often unjustified for economic reasons, since expanded polystyrene granules, which are aggregate, are most often unreasonably expensive.

However, there are additional negative circumstances that must be taken into account when working with this material. Polystyrene granules decrease in size during operation. As a result, in a year or two, instead of polystyrene concrete, we get coarse-pored concrete with polystyrene foam chips. As a result, the strength and thermal conductivity of polystyrene concrete deteriorate sharply. The photos below show a 5 year old polystyrene block.

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

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

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

The structure of the roofing pie

Necessity high level protection against moisture forces the roofing materials of a flat roof to be arranged in layers, one above the other, forming the so-called "pie". If we consider its device in section, we can see the following layers:

1. Flat base made of concrete slabs or profiled metal sheets. It provides structural rigidity, bears the weight of the roofing pie, transferring it to the load-bearing partitions and, as a result, to the foundation. At the exploited roof, the base should be as rigid as possible.
2. vapor barrier. A layer that is necessary in order to protect a flat roof from the penetration of vapors from internal heated rooms into the thickness of the insulation. Settling on thermal insulation in the form of condensate, water irrevocably reduces its insulating properties by more than two times. As the simplest vapor barrier use polyethylene film or coatings based on bitumen.
3. insulation. For thermal insulation of a flat roof, backfill materials are used, such as expanded clay, perlite, slag, rolled, for example, mineral wool and in the form of plates, in particular expanded polystyrene. By the way, insulation is used not only to regulate temperature regime, but also for flat-roofed houses. The main requirements for insulation are low hygroscopicity and thermal conductivity, light weight.
4. Waterproofing. Flat roofing allows the use of roofing to protect against moisture roll materials: bituminous, polymeric and bitumen-polymeric. In addition to high waterproofing qualities, they must be resistant to temperature extremes, elasticity, long term operation.

Types of roofing and the nuances of their installation

The device of a flat roof determines the design and nature of use. The following are distinguished into separate types that require a special approach during construction:

Roof installation for unheated buildings

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

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

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

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

Roof installation for heated buildings

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

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

Monolithic concrete roof

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

Decline process

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

If provided, water should drain with the help of a ramp into the water-catching funnels, which are located 1 per 25 sq.m or more often. If you make an external drain, then moisture should fall into the gutter. The slope is formed by the following methods:

A flat roof without a proper slope is an unreliable shield between you and the weather. Moisture that has no way out will accumulate on the surface of the roof, provoke the destruction of the roof and leaks.

Video instruction

During the construction of urban high-rise buildings and industrial facilities, the basis of a flat roof usually becomes reinforced concrete slab. But for private houses, especially frame and wooden ones, this choice is most often unacceptable. In this case, a flat roof is built on wooden beams. Its main advantage is its light weight, which reduces the load on walls and foundations.

The device of such a roof is simpler and cheaper than when using heavy reinforced concrete slabs. But the functionality is the same. Therefore, this option of a flat roof is often chosen by those who want to build it with their own hands.

The main share of such roofs falls on private houses and cottages, whose owners appreciate the futuristic style, convenience and practicality. Still - on the floors of verandas, terraces, balconies, garages. As a rule, all these buildings are wooden or frame, requiring light construction roofs. But this is not a mandatory rule. The wall material can be any - brick, aerated concrete, foam concrete, etc. In this case, often wooden beams crash into the Mauerlat - wooden beam, running along the perimeter of the walls and connected to them with anchor bolts or studs.

A flat roof is especially attractive to developers because its horizontal surface can be used as a usable area. Moreover, this is possible even for the roof, which is based on wooden beams.

Of course, you should not use the freed meters for a parking lot, a swimming pool or a tennis court. Still, such projects require a more monumental foundation. And here outdoor terrace, an observation deck, a home greenhouse, wooden beams can easily withstand. The main thing is to correctly calculate and not save on the thickness of the lumber.

Types of flat roofs on beams

On wooden floors you can build a flat roof of the following types:

• unexploited;
• exploited;
• inversion.

That is all possible types- no limits.

Unexploited roof- ordinary, ending with a waterproofing finish. It is intended solely to protect the premises from the conditions environment and does not set itself other goals. It is impossible to use it as a place of rest, to move in large companies, to install terrace furniture and flowerpots. The coating of such a roof is designed for the fact that 1-2 people will periodically climb it, solely for the maintenance of the structure.

exploited roof- more interesting and more difficult. In addition to direct protective functions, such a roof plays the role of an additional usable area for the homeowner. The design pie ends not with waterproofing (prone to damage), but protective coating- paving stones, decking, wood decking, paving slabs, sod layer, crushed stone or gravel.

inverted roof- roof-reversible, a qualitatively different option. It can be both operated and non-operated. Its feature is the inverted order of the layers in the cake. If in a conventional roof the waterproofing is laid on top of the insulation, then in the inversion roof the opposite is true. Waterproofing lies under the insulation, and vapor barrier is generally excluded from the structure of the pie. Due to this, the waterproofing is protected from the outdoor environment and its service life is increased.

However, under the influence of unfavorable outdoor conditions, there is a heater, therefore, as part of inverted roofs, the choice of this type of insulation is limited. Only EPS (extruded polystyrene foam) and nothing else! This material has almost zero water absorption, high density and strength. From above, EPSS in inverted roofs is loaded with washed gravel, paving stones, paving slabs or a sod layer.

An interesting option for operated roofs (including inversion ones) is green roof. It can also be held on wooden beams. The cake of such a roof ends with a soil layer on which plants are planted. There are other elements that are not used for other types of roofs: a drainage layer (gravel, expanded clay, crushed pumice or geomats), a filtration layer (geotextile).

Flat roof frame on a wooden base

The frame of the described roofs are wooden beams, laid according to the type of interfloor overlap. Full-length sawn wood or multi-piece (glued) timber can be used. Often beams are made of boards with a section of 100x150 mm.

Beams are laid with support on the walls, similarly floors. If the building is wooden or frame, then the beams rest on the upper crown of logs or the upper trim. If brick or block - then on a pre-fixed Mauerlat. As a Mauerlat, a bar with a section of 150x150 mm or 150x100 mm is usually used. It is mounted on the upper belt of the walls using anchors or studs. To protect the wooden Mauerlat from the material of the walls, 1-2 layers of waterproofing (roofing material) are laid between them.

On the beams, cuts are made under the Mauerlat, they are laid and fixed with metal corners or nails. The step between the beams is maintained 50-120 mm (depending on the calculated load).

When installing beams, it is important to ensure a roof slope of 1-6 °. Despite the fact that the roof is called flat, it is not absolutely horizontal. A slight slope is necessary to ensure the movement of water to the drain and thus prevent its stagnation.

You can create the required slope in the following ways:

1. Immediately lay the beams with the desired slope. Then, if a horizontal ceiling is supposed to be installed under the roof in the room, it is made suspended or sewn onto a horizontal crate.
2. Lay the beams horizontally, and to maintain the required angle, nail wooden plates of different heights to them.
3. Lay the beams horizontally, and form the corner due to the different thicknesses of the thermal insulation laid on top of the frame.
4. Use beams with unequal height allowance.

Most often, the first option is used, that is, beams with a slope are immediately laid. The easiest way to do this is to pin along the top bearing wall a strong run from a bar or board, which will lift the frame (beams) on one side. Instead of a cross purlin, you can also install short radial beams extending from the central double diagonal beam.

Flat roof pie: what's inside?

A flat roof cake on a wooden frame can have a different structure. There are many design options, many of them are posted on the Internet. And they will all work!

Option 1. Roof with insulation over beams

Flat roof insulation layers can be laid over the beams. For example, a proven working option (classic roof with insulation):

• floor beams;
• vapor barrier;
• waterproofing material - polymer membrane.

When using EPPS insulation and PVC membranes in the structure at the same time, a separating layer (geotextile, fiberglass) must be laid between them. The matter is that these two materials are incompatible and at their direct contact there is a destruction of PVC.

The polymer membrane is fixed on the insulation by a mechanical method or loaded with ballast. Crushed stone or gravel (for all types of roofs), paving stones (for operated roofs), soil (for green operated roofs) are used as ballast. However, when choosing a ballast, one should soberly evaluate the reliability wooden frame, its ultimate load.

If as finish coat the use of welded waterproofing or an EPDM membrane with adhesive fixation is supposed to be used, a change is made to the scheme discussed above. It consists in the fact that sheets of plywood, OSB or DSP are laid between the insulation and waterproofing.

It turns out such a scheme:

• floor beams;
• crate (if necessary);
• solid sheathing made of plywood, DSP, OSB;
• vapor barrier;
• insulation - EPPS, mineral wool;
• sheets of plywood, OSB, DSP;
• waterproofing material.

The installation of built-up roofing traditionally requires the use of gas burner, therefore, according to existing fire regulations, it is unacceptable for wooden structures. Therefore, they act as follows. The first layer of waterproofing is nailed or glued to a wooden base, and the second layer is fused, as it should be. It is also convenient to use euroroofing material with a special adhesive base, for which it is recommended cold mounting without heating with a burner.

Installation membrane roofing on a wooden base is shown in the video plot:

Option #2. Roof with inter-beam insulation

Another principle for assembling a flat roof pie is associated with laying insulation in the inter-beam space. This option is more convenient than the first if EPDM membranes with adhesive fixation or welded roofing are used as waterproofing.

The following roofing pie scheme is often used:

• floor beams;
• vapor barrier (between beams);
• insulation (between the beams);
• crate (if necessary);
• solid sheathing made of plywood, DSP, OSB;
• waterproofing.

In principle, a similar system is used in the formation of classical pitched roofs.

Option #3. Roof with internal insulation

In this case, sheets of plywood, OSB or DSP are sewn onto the supporting structure (beams), and waterproofing is laid on them. The remaining insulating layers of the roofing cake are sewn from the side of the room.

A rough ceiling (made of boards or sheet materials) is fixed on the beams, planks are screwed to it perpendicular to the supporting beams in increments of 40 cm. Placed between the planks polystyrene boards by sticking them on mastic or glue. A vapor barrier film is sewn to the insulating layer. Close the insulating cake with a finishing ceiling.

When constructing an inversion roof, you can use the following scheme (from bottom to top):

• beams;
• solid crate;
• waterproofing;
• separating layer (when using a PVC membrane as a waterproofing);
• EPPS insulation;
• separating layer - geotextile;
• ballast, paving slabs, decking, etc.

The principle of inverted roofing is often used for green roofs. For example, you can do this:

What top coat to use?

The wooden base of a flat roof, along with its advantages, also has features with a minus sign. This is an increased fire hazard and low bearing capacity (compared to reinforced concrete slabs).

For waterproofing such a roof, it is desirable to use materials that do not require hot installation. Ideally - polymer membranes. When choosing built-on bitumen-polymer coatings (from a series of euroroofing materials), the first layer of material is mounted mechanically, and the second - by welding. In order to minimize the possibility of fire of structures during installation, it is recommended to use non-combustible DSP boards as a continuous sheathing (on which waterproofing is laid).

When constructing exploitable and ballast roofs, it should also be remembered that excessive load for wooden base may be fatal. Therefore, if the bearing capacity of the beams used is low, light materials should be selected for the finish coating - decking, deck board, rubber paving slabs(rubber mats), etc.