When creating a roof, all details are taken into account. It is especially important to determine the slope of the surface, since not only appearance, but also the durability of the structure. This indicator depends on many factors, including the climatic conditions of the area. In this case, it is taken into account that the roof provides protection from environmental influences, but it itself is exposed to all these negative factors. This is why it is important to calculate the slope flat roof even before construction begins.

The nuances of choosing a slope angle

To begin with, the effect of wind on the coating is considered. In regions with strong winds, roofs with a slight slope are preferable. IN in this case If you have a high roof, there is an increased likelihood that gusts of wind will tear off some of the material. To prevent this you need to do rafter system more massive, which causes an increase in the cost of installing the structure, and also negatively affects the weight of the entire structure. In areas where precipitation falls especially frequently in winter, it is enough to make the roof slope within 45°. This will ensure free flow of snow and eliminate increased load on the roof surface.

If there is little snow falling in winter, you can limit yourself to a low-slope roof, that is, the slope in this case will be minimal. According to SNiP, when creating such a structure, it is recommended to use membrane materials to prevent leaks. When creating a flat surface, importance is also given to drainage; it is this that is entrusted with the function of draining water and preventing its accumulation on the surface. To reduce exposure to sunlight, you can use bitumen covers, green, turf or pebbles.

In regions where harsh climates often prevail in winter, it is recommended to combine external and internal drainage. The latter will no longer be exposed to negative natural factors.

The choice of materials depending on the angle of the slope

Each material has its own requirements for use. A rough roof surface will prevent water gadflies from draining away, while a smooth surface will facilitate this. The design of the rafter system is also important. When creating a flat roof, it can be lighter, but designed to withstand heavy loads from water and snow. From a roof that has a slope, water rolls off faster and snow does not linger, but the roof itself must be more durable due to the complexity of the structure. The type of rafters and the pitch of the sheathing are also influenced by the choice of roofing material.

The choice of roofing material should depend on the level of slope. To create high roofs the range of roofing coverings is wider, and externally such buildings are particularly attractive. In order to perform correctly installation work on the roof, the following rules should be followed:

Slope angle measurement

For the correct selection of materials and design of the rafter system, it is important to calculate the angle of the slope. This action is performed using a protractor or through mathematical calculations and is expressed in degrees, percentages and ratios.

The simplest is mathematical calculation. To do this, you need to know the width of the blood and its height. Using trigonometric formulas, the angle is calculated in the form of cosine, sine or tangent. The result obtained is converted into percentages using the table.

You can also calculate using another method. To do this, divide the height of the future roof by half the width of the room, and multiply the result by one hundred. The result is compared using a table to determine the slope and is also expressed as a percentage.

If you have a protractor, all actions consist of determining the angle and selecting materials to create the roof. Only after this can you do right choice, be sure to compare it with the requirements of SNiP.

Features of creating a low-slope roof

Most often, the slope of a flat roof is carried out using the following methods:

• backfill insulation, that is, perlin, expanded clay and others;
• concrete mixtures based on insulation materials;
• polymer materials and concrete mixtures based on them with the mandatory addition of fillers;
• use only insulating materials.

Each of the listed methods has its own advantages and disadvantages. Expanded clay and perlin can change position over time and disrupt the slope of the roof. As a result of this minimum slope after a while we can become a flat roof. The size of the material also matters, since large components do not allow the slope to be made sufficiently uniform.

Concrete mixtures are especially often used for flat roofs. The main disadvantage of these materials is their weight. That is, it is necessary to calculate the additional load when developing the design of the rafter system. Considering this disadvantage, we can conclude that concrete mixtures can be used to create a flat roof during the construction phase or during overhaul. They are not suitable for partial repair flat roof, as they cause additional load.

According to SNiP, polymer materials are ideal for such work. Given their wide range, they should be chosen not only depending on the angle of the slope, but also take into account the features of the rafter system.

Stagnant puddles of rain or melt water are the merciless enemy of flat roofs. With dogged persistence they destroy coatings and components. roofing pie. In order to prevent atmospheric negativity from creating threats, it is necessary to provide and carry out protective measures. The most effective and affordable method is to form slopes that facilitate the rapid outflow of water.

For the sake of long service life of the roof and the one located under it building structure you need to know how to slope a flat roof. In order to create the most effective protection You should familiarize yourself with the applicable options for its design.

The slope of the plane is necessary so that, under the influence of standard gravitational forces, water is transported by gravity to the drainage points. It is required so that the surface is freed from rain and melt water at the highest possible rate, all year round threatening the internal and external components of the roof structure.

The list of risk factors associated with water stagnation includes:

• Damage and rupture of coating. A phenomenon characteristic of periods of fluctuations of positive and subzero temperatures, for sharp frosts. During the process of crystallization, water noticeably increases in volume, which leads to peeling of the mineral protective coating on bitumen roofs. Due to the violation of the protective layer, the material becomes vulnerable to UV radiation. On membrane and self-leveling roofs, due to alternating freezing and thawing of water, a network of small cracks appears.
• Excessive stress on waterproofing carpet. The difference in temperatures outside the building, inside and inside the structure creates unnecessary stress on the coating. Around stagnant puddles, the state of tension intensifies, resulting in ruptures and cracks.
• Deflection of a thin load-bearing base. A typical example is roofing with profiled sheets, on which the accumulation of sediment can cause deformation and subsequent rupture of the coating.
• Humidification of thermal insulation. Microscopic cracks undetected by the naked eye will let water into the body of the roofing system, which may not happen if the water is drained at a brisk pace. An equal problem on roofs with poor-quality seams. Wet insulation loses half of its insulating properties and gains weight. Weighting is very undesirable for roofing systems, arranged on corrugated sheets.
• Origin of vegetation. Dust accumulated on a flat roof, coupled with stagnant water, is an excellent environment for wind-blown plant seeds to take root and flourish. Not all roofing coverings capable of steadfastly resisting the life-loving roots invading them.

Flat roofs built from heavy-duty materials are not afraid of horror stories from the above list, but they are creepy expensive materials. Someday, when the hearts of their manufacturers tremble with sympathy for the average consumer and the price tag becomes more humane, the need for constructing means for draining water from a flat surface will probably disappear.

However, for now, the method of preventing damage and premature aging is to install slopes, thanks to which currents of melt and rainwater independently move to water intake gutters and funnels or simply roll off the roof onto the ground.

Options for tilting a flat roof

Spontaneously, without mechanical stimulation, water with flat surface will not drain. In order not to wait for it to evaporate or destroy the roof, it needs to create conditions for movement - i.e. incline. Guidelines for the installation of systems with bitumen and polymer coating recognize the ideal angle of inclination for a flat roof as 1.5º; 1º-2º are considered acceptable, which in percentage gradation means from 1.7% to 3.4%, respectively.

It is possible to tilt the roof plane of a small household facility during the construction period. To do this, according to pre-made calculations, the difference in the height of the walls on which the two responsible sides of the slope will have to rest is set. This is a separate topic, suitable for buildings with an external organized and unorganized type.

Now we are much more interested in the formation of a slope equal at all points of the roof plane, mounted on load-bearing walls of equal height. Owners of country property often have to solve such problems and often do it themselves.

The slope of the flat roof forms a barely noticeable relief with valleys and watersheds reminiscent of the ridge ridges of pitched roofs. The essence of its formation is to regulate the flow of water.

The decrease in relief is always directed from the rising parts of the roof, including chimneys, skylights, roof aerators, etc., towards water intakes, which include drainage funnels with gutters. If two or more drain funnels are installed to drain water from a flat roof, then there must be a watershed between them, cutting the flow into different sides parts.

Stagnations along the parapets of flat roofs are eliminated by installing fillets. The design of a simple part is akin to floor plinth just no bulges. Along the line where the walls of a parapet or a standard wall with a flat roof meet, a block with a triangular cross-section is installed, which can be made by longitudinally splitting the block into two halves.

Instead of a split bar, a similar device made of basalt wool or expanded polystyrene is used. The fillet can be constructed directly on the site using concrete mortar.

To install a slope on a flat roof, the following practice-proven methods are used:

• Application of backfill thermal insulation: most often expanded clay or perlite, less often vermiculite. To create a ramp fill insulation The roof area is divided into segments. Guides are installed at the required angle, between which the material is poured. A screed is placed on top of the backfill concrete mixture marked M150. Concrete pouring must be reinforced with road mesh. The finishing layer of concrete can be replaced by a dry screed made of plywood or sheets flat slate. The obviously labor-intensive method is not very accurate due to the inherent displacement of bulk particles. In addition, it is difficult to form a smooth increase in slope in this way.
• Pouring light varieties of concrete– mixtures containing expanded clay, expanded polystyrene chips, perlite and similar fillers. It is carried out according to the traditional screed design, only the guides are installed at the required angle. The disadvantage of this method is weather restrictions, because... The screed cannot be poured when the thermometer readings are below zero. The concrete ramp will take at least 28 days to dry, during which the screed will need to be moistened and protected from rain and wind.
• Installation of metal structures. They are made from PP profile nomenclature 75×50×05 or similar material according to the dimensions of the rise and fall. The distances between structures are calculated depending on the upcoming load. Sheets of flat slate are laid on top of the formed relief. The disadvantages of the method lie in significant material costs and labor investments.
• Construction of sheathing. It is used extremely rarely, because the application is unprofitable, and it is also too difficult to implement such insignificant slopes, but it is still mentioned among other methods.
• Application of wedge-shaped thermal insulation boards, produced from basalt wool, foam glass, polystyrene foam, polystyrene foam specifically for making slopes on flat roofs and for creating an outflow of water from parapets.

The installation of slopes using wedge-shaped plates is leading due to its numerous impressive advantages. They were developed and introduced into the construction industry purposefully in order to eliminate the disadvantages of all the previously listed methods.

It is not without reason that wedge-shaped thermal insulation boards are recognized as the optimal way to solve the problems of drainage from a flat roof. This is the most convenient, cheapest and simple circuit, which does not require the performer to have in-depth skills and fundamental knowledge in the roofing business.

Wedge-shaped slabs are cut at the factory, which guarantees the accuracy of the result of the upcoming work. The material kit must be accompanied by practical installation instructions.

Advantages of using wedge-shaped slabs

Expanded polystyrene and mineral wool slabs for forming slopes have an equivalent set of advantages, these are:

• Low weight, due to which the slope made of insulation creates the least load on load-bearing building structures.
• Transportation to the installation site without the use of lifting construction equipment.
• Independence of technology from weather conditions. The ability to carry out successful installation, despite unfavorable forecasts for builders.
• Tangible relief and acceleration of actions to form inclined planes. No need to transfer finishing works due to the need to withstand technological interruptions. For example, wait 28 days for the cement-sand screed to gain the required hardness parameters.
• Significant reduction in the cost of constructing slopes necessary and sufficient for the unhindered flow of rain and melt water.

Important: despite the traditional thermal insulation qualities of materials, wedge-shaped slabs cannot replace the insulation layer. Elements of different thicknesses do not have equivalent thermal properties at all points. Therefore, the actual insulation layer is constructed and calculated separately. Its thickness has nothing to do with the upcoming installation of wedge-shaped slabs.

SNiP II-26-76 prescribes that work on installing the slope of the finishing coating of a flat roof should be carried out after laying the insulation, if thermal insulation was provided for in the project. If there was no need to insulate the roof plane, wedge-shaped slabs are laid on a base coated with steam or waterproofing.

Wedge-shaped thermal insulation is used in the construction of new roofs and when performing repairs and restoration work. With the help of lightweight, convenient slab modules, you can create literally any terrain to direct flows in a given direction.

How to make a slope with slabs?

Wedge slabs are supplied in kits that allow you to gracefully and quickly form slopes and counter-slopes on a flat roof. The sequence of laying the slope elements does not depend on what type of insulation they are made of. However, the composition of the slabs influences the design of the inclined planes.

For example, a layer of geotextile must be laid between the finishing polymer membrane and polystyrene or foam boards. Without a separating layer, the roof will blithely say goodbye to plasticizers and will certainly become unusable. But the finishing coating can be laid on basalt wool without fear, without using a separating layer, which will significantly reduce costs.

The polymer membrane is strictly prohibited from direct contact with bitumen and bitumen-polymer waterproofing. They can only coexist if the same separating layer is laid between them.

A geotextile backing is also required when laying slabs directly on rough surfaces. concrete covering, i.e. if they are used exclusively to form a slope on an uninsulated roof.

Marking of ramp elements

Within a single manufacturer, wedge-shaped slabs are produced according to general principle, regardless of the composition of the product. The elements are marked to facilitate the installation procedure and have identical dimensions.

The Russian manufacturer of building systems TechnoNikol, for example, offers sets of wedge-shaped slopes made of polystyrene foam and mineral wool. In both cases:

• Plates marked with the letters A and B are intended for assembling slopes measuring 1.7%.
• If the material is marked with the letters J and K, then it is used when constructing slopes of 3.4% and 4.2%.
• Flat insulation boards with letter designation C are used to gain altitude. Elements marked C can be laid both under the slope and on top of it.

More details on the diagrams:

The instructions from the material manufacturer usually contain a laying diagram with a visual representation of the sequence of arrangement of wedge-shaped slabs. The construction of one plane directed towards the drainage gutter, or two adjacent planes directed towards the drainage funnel, will not pose a serious problem for home handyman. Laying should begin from the lowest point of the roof and continue upward to the created watershed.

It is a slightly different matter if a complex terrain with several valleys and watershed ridges is being constructed. You will have to draw a plan and think through the course of action in advance. In plan, complex terrain usually looks like a collection of rhombuses and triangles. In such cases, laying starts from the edge of a rhombus or triangle and finishes the process in the center of the conventional figures.

The required height is achieved by means of a set of slabs with required thickness. When constructing a rhombus, it is as if divided into quarters, and a triangle into halves. Each segment is assembled separately, after which the actual trimming is done.

Rules for installing fasteners

Installation of wedge-shaped slabs on the base without preliminary thermal insulation is carried out using methods usually used or bitumen coating. Priority mechanical method fastening to the base, according to which the telescopic plates are fastened with self-tapping screws with a telescopic attachment.

Fixing wedge-shaped parts from mineral wool produced simultaneously with the main layer of insulation. It is recommended to install two fastening units on a slab measuring 600x1200mm. If both linear dimensions of the slab are more than a meter, 4 fastening points will be required.

The wedge-shaped slope must be positioned so that its joints do not coincide with the joints of the underlying thermal insulation, i.e. the principle of seam spacing is observed both in relation to the multi-layer insulation system and in relation to the insulation layer with slope-forming material. If the elements of the thermal insulation slope are laid on the base without insulation, they are glued or simply loaded.

Note that polystyrene foam boards cannot be glued using bitumen adhesive containing large number organic solvents. The material is not friendly with organic solvents and gasoline. Therefore, their proximity should be excluded.

It is recommended to glue polystyrene foam boards together during installation operations. double-sided tape so that they do not move due to careless touches. It is advisable to place a load on the assembled segment of a complex slope so that it maintains its location.

The type of fastener must correspond to the type of base to which the panels are fixed:

• For installation on corrugated sheets, you will need Ø 4.8mm drill-tip screws.
• For attachment to concrete screeds strength B-15 and cement-sand screeds with strength M150 require pointed roofing screws Ø 4.8 mm along with a polymer anchor sleeve.
• For fixation on concrete bases of class B-25, it is necessary to stock up with drive-in anchors.

The size of the screws is selected taking into account the thickness of the layer so that the screw goes into the concrete by 5 cm, and protrudes beyond the back side of the corrugated sheet by at least 1.5 cm. When installing a slope on old roofs being repaired with a bitumen coating, a disc category of fasteners is used. The age of the repaired bitumen roof must be more than a year.

Using insulation fillets

A long piece made of basalt wool, triangular in cut, is used to redirect atmospheric water currents from the junctions of vertical and horizontal surfaces. They are laid along the line where the roof meets the parapet, adjacent wall, sides of skylights, chimneys, etc.

The material, cut with impeccable geometric precision, helps to increase the speed of work on arranging a flat roof. Laying fillets allows you to quickly create a smooth transition from a vertical surface to a horizontal plane.

Video tutorial on installing slopes

For those who want to know how to correctly make an ideal slope on a flat roof, this video will help you get acquainted with the specifics of the work in detail:

The list of options for installing slopes on a flat roof is quite rightly headed by wedge-shaped insulation slabs. They are designed to make work easier and significantly speed up processes. The wedge-shaped tilt copes with its assigned duties excellently.

It has a number of advantages, such as: its installation will take less materials, ease and simplicity of installation and additional useful area.

Many people do not associate the phrase flat roof with a slope. Although this is far from true. Even the smoothest roof has its own slope, even if it is minimal.

At a minimum, this is necessary so that melt water and water after rain can easily flow into the installed funnels, which are part of the internal drainage system, or into the gutter of the external system.

In addition, on such a roof it is easy and simple to install additional, necessary equipment. To date, There are several types of flat roofs:

• Operable roof;
• Unused roof;
• Traditional roofs;
• Inversion roofs.

The slope that should be on this type of roof is is approximately 1-5 degrees, if you neglect this, then water, both rain and melt, will accumulate, which in turn will damage the roof.

In summer you may not encounter such a problem, since under the rays of the sun rainwater dries out. In winter and autumn, such water can freeze at night and melt during the day.

Puddles form, which ultimately leads to moisture gradually penetrates into the insulation. The essence of the mechanism is that moisture penetrates into the layer, which means that inevitable leaks occur.

But this is not the only problem. In addition, puddles on the roof can contain dust, which eventually settles to the bottom. Seeds different herbs and plants can fall into this puddle and grow there.

Often on the streets you can find houses with grass or thin trees on their roofs. It is logical that this spoils the roof and also spoils the aesthetic appearance of the entire building.

To avoid such a nuisance, and thereby extend the life of your roof, it is necessary to carry out the roof tilting procedure. Such complex manipulation is carried out at the time of construction itself.

The process itself is quite complex and includes many different structured activities. The purpose of this procedure is to ensure that the roof itself acquires the required slope.

But before you start pitching the roof, you need to find out what a flat roof consists of.

Flat roof

In essence, it is a cake made of several layers:

• Direct basis, which is reinforced concrete slabs that have a certain wave height;
• , which can be made from different materials, such as bitumen, or roll materials;
• Next layer -, which can be made of mineral wool or other durable material.

The components of such a pie can be changed if the builder wants to make the entire roof using new building materials. It is worth understanding that such a procedure as slope, carried out immediately at the time of laying the insulation.

It is important that in addition to these main layers of the roof, there must also be water intake funnels or gutters.

The angle of the roof slope is very important, and it depends on many parameters. The first thing you should pay attention to is the wind exposure. If you live in an area where there are frequent strong winds, then it’s worth making a small angle of inclination.

CAREFULLY!

If you make a strong slope of a flat roof, then the wind can tear out roofing sheets. It is important to note that the angle of the roof dictates necessary conditions for the rafter system, as well as for all components of the roof, namely: rafters, sheathing pitch.

Obviously, the steeper the slope of the roof itself, the faster the outflow of water.

Slope in percent

Minimum angle and calculation of roof slope

The minimum slope angle can be determined based on the materials of the roof itself:

• If the roof is made of , then her minimum slope must be at least 12 degrees(according to SNiP). If the roof is made of, the angle increases to 15 degrees. It is important to understand that the cracks in the material and other joints must be treated with a special sealant - frost-resistant/water-resistant. If the angle of inclination is 15 degrees, then the sheets of material should be overlapped by about 200mm, if the angle is smaller, then the overlap should increase;
• The minimum slope angle may be in cases where if the roof of your house is made of artificial materials . These, in turn, include membrane coatings and bitumen-based materials. It is logical that by the magnitude of the slope angle, The number of layers of the roof also affects. If, for example, the roofing is carried out in two layers. then a tilt angle of 15 degrees is quite sufficient;
• Having covered the roof, it is worth understanding that 11 degrees of inclination angle is quite enough, but in this case you need to make a continuous type of sheathing.

Such a process as the slope of a flat roof, made from such materials:

• Extruded polystyrene (technoNIKOL);
• Wool, both mineral and glass/basalt based;
• Polyurethane foam;
• Foam concrete;
• Foam glass;
• Various types of backfill materials.

Each of the materials has its pros and cons. And before you start work, it is worth correctly calculating the angle of inclination. In fact, this calculation is quite easy to carry out; for this you need to use a protractor, or use fairly simple mathematical formulas.

Despite the fact that a flat roof is called flat, it still needs a slope. The minimum slope for a flat roof is 1 degree or 1.7%.

Instructions for the use of bitumen and polymer coatings for degrading indicate that optimal angle the tilt should be 1.5 degrees. A tilt of 1-2 degrees is acceptable.

Everything is very simple here. You need to know the height of the roof and its width. Next, simple trigonometric formulas will help calculate the immediate angle (sine, cosine, tangent). And from the existing table, which was calculated earlier, you can find out the value as a percentage.

There is another way to calculate - the value of the roof height must be divided by half the width, and the result already obtained must be multiplied by one hundred, after which, in the table, you can find out the percentage value of the future angle of inclination. This option is faster, but in terms of accuracy they are both correct.

Minimum slope

Sloping a flat roof using bulk materials

If you decide that the tilting procedure will be carried out using bulk materials, then the first thing worth noting is the diagram according to which such a procedure must be carried out:

1. First of all, on its own concrete base, it is necessary to lay a layer of glass insulation. This material not only has a long service life (30-35 years), but also has high waterproofing performance;
2. Further, it is necessary to pour the main material on it - expanded clay. But at the same time, everyone needs to create the right bias;
3. Necessarily you need to cover a layer of expanded clay with a special plastic film. It is important to note that it must be overlapped;
4. Next, it is necessary to apply the prepared sand- cement screed , doing it smoothly, slowly. Its essence is to level the layer of expanded expanded clay;
5. After these events you can begin shape the roofing “pie”, according to the developed .

Remember that when laying each layer, you need to ensure that the previously prepared angle of inclination is maintained.

ATTENTION!

If you are worried that the expanded clay will move when you start laying sand-cement screed on top of it, you can fill it with cement laitance. But it is worth understanding that because of it, the structure becomes heavier.

If you want to create a minimum angle of inclination, and the roof area is not particularly large, then a sand-cement mortar will be enough.

Bulk material

Thermal insulation materials

Another good material for pitching the roof is thermal insulation materials. Experts say that this is the most affordable option.

Its advantage is that it is quite light and quite cheap, which plays a very important role in construction important role. Mineral wool, the most best material. The process diagram is quite simple.

It is necessary to attach the material to the base itself, using self-tapping screws or dowels. Some prefer sheets of such cotton wool to be glued to a previously cleaned base, special glue. This process can be performed both during and during roof installation.

Thermal insulation material

Foam concrete

A good material that can be used to slope a flat roof is foam concrete. It is immediately worth noting that this procedure must be carried out using special equipment.

A layer of foam concrete is poured onto the base itself, but at the same time the angle of inclination is noted, and only after make a special screed from foam fiber concrete. Next, it is important to apply waterproofing material.

A huge advantage of this tilt option is high rate thermal insulation, as well as other mechanical characteristics. For example, strength and durability.

Speaking of minuses, there are some here too, or rather one. This is the price. She's tall enough. And again, it will not be possible to carry out such a procedure on your own. Therefore, in this case it is worth turning to professionals.

• If the roof has a minimum slope, then it is important to note that in this case, needs to be installed correct systems drain. The slope itself is done exclusively to the side (funnel, gutter);
• If your roof is bitumen, you should make the slope angle less than 6 degrees, while The bottom layer of waterproofing must be made of membrane materials;
• It is important to know that with small slope angles, it is necessary to ventilate the under-roof space itself, what does all the stingrays have to do with it. The thickness of the gap also depends on the value of the angle (the larger the angle, the smaller the thickness and vice versa).
VKontakte

By definition, a roof cannot be ideally flat. Otherwise, it will accumulate rain and melt water, which will lead to rapid wear. Therefore, according to generally accepted standards, a flat roof has a slope of 1 to 11.5 degrees. Moreover, the average value fluctuates around 1-5 degrees, which in practice amounts to 1.5 or more centimeters of slope per meter.

How to calculate the angle of inclination

In order to find out the angle of the roof, you need to:

• Know the height of the parapet.
• Know the thickness of the roofing pie.
• Know the exact location of the water inlet.

As an example, let's take a parapet height of 500 mm; the thickness of the roofing pie, excluding the slope formation layer, is 250 mm, while 50 mm of the parapet should remain on top, above the roof plane; the water intake funnel is located 5 meters from one of the parapets. Thus, 500–250–50=200 is the thickness of the slope-forming material at the parapet. The funnel is located 5 meters away, which means that within these 5 meters we need to reach zero: 200/5=40. Thus, the roof slope will be 4 centimeters per meter or 4%. With a minimum value of 1.5%, this is a sufficient level.



If you consider this slope to be too large, it can be reduced to a minimum of 1.5%. This means that if there are 5 meters from the funnel to the parapet, and we rise by 1.5 centimeters every meter, then the thickness of the slope-forming layer at the parapet will be 5 * 1.5 + 2 = 9.5 centimeters.

Provided that the water intake funnel is located not outside, but inside the roof, there are two options for organizing the slope:

1. Formation of a circular system. That is, make a slope so that water flows evenly over the entire roof area.
2. Formation of scarves. Draw the roof from the funnel like an envelope. So, improvised gutters are created.

Note that when two or more water intake funnels are located, the roof slope is organized exclusively according to the second option.

Marking

To make it convenient to mark the future screed, you will need a laser level. The laser is aimed at an acceptable level of parapet thickness, in our case it is 200 mm, and a line is drawn along the perimeter of the entire roof with a construction pencil. In absence laser level You can use conventional or hydraulic. Then we find the thickness of the parapet in one place and, placing a level, draw a line along the entire perimeter. You can check that the line does not creep up or down using a hydraulic level.



Next, a string is stretched from the parapet to the funnel. You can set beacons along the cord, so it will be more convenient to work. If the deflection occurs through the formation of scarves, the lace must be pulled along their border.

Roof slope with polystyrene concrete

Polystyrene concrete is a type of lightweight concrete made from cement, water, mineral filler and all kinds of additional additives. For weighting purposes, it is permissible to add sand. To produce polystyrene concrete at home, you will need:

• Concrete mixer. Specialists use a special unit that allows concrete to be supplied through a hose directly to the roof.
• Cement 500 grade.
• Polystyrene chips. Made from defective polystyrene boards.
• Water.
• Liquid soap.
• Sand.

Made from the calculation: 2 shovels of cement, a shovel of sand, 5 ten-liter buckets of polystyrene okroshka, 50 grams liquid soap, water, until the mixture reaches the desired consistency. The concrete should not be liquid or too dry.



The work order is as follows:

• Creating markings on the roof. Use timber or beacons. Please note that the timber must subsequently be removed on time. That is, when one area is poured and the solution has already hardened, the timber is removed so that it does not interfere with the pouring of the neighboring area. The lace in this case is a weak helper. The concrete will make it wet and sag.
• To create a slope for a flat roof, the resulting mixture must be delivered to the top. We advise you to take care of creating a winch in advance. This will make lifting the concrete easier. Even better, initially bring all the material onto the roof, and also deliver a concrete mixer there. This will greatly simplify the leveling work.
• Polystyrene concrete is pulled together along the beacons using a rule. It is advisable to leave as few irregularities as possible; subsequently, insulation will be laid over the concrete. The solution hardens within a day, and you can now move freely on it.
• Insulation is laid over the slope-forming layer, and then everything is fixed with a cement-sand screed, for which it is necessary to lay reinforcing mesh. The thickness of the screed is approximately 6 centimeters.

Polystyrene concrete is used both on reinforced concrete foundations and on foundations made of profiled sheets.

The advantages of this material include:

• Inexpensive cost.

Disadvantages:

• Complexity of installation provided self-execution works

Deflection with expanded clay

Creation minimum slope flat roofing is permissible when using expanded clay. It is obtained by burning clay shale. Expanded clay is laid on a base made of reinforced concrete slabs or corrugated sheeting, and for insulation.



The work order is as follows:

• Creating markings on the roof. For this you can use wooden beam, metal profile or just a lace. It is more convenient to work with timber and profiles, but closer to the end of the work they need to be taken out and the resulting holes should be leveled. When using laces, this is not necessary.
• Expanded clay backfill. To facilitate this process, you can order a manipulator that will deliver expanded clay directly to the roof. Otherwise, you will have to carry the material by hand for a very long time.
• Alignment by beacons. Align using a rule. For convenience, you can make wooden rule with a handle, similar to a rake, but instead of teeth there is a smooth, wide beam. Expanded clay is pulled from the parapet towards the funnel. If there is too much material, it can be stretched to the edges of the parapet to ensure good stock water.
• To fix the expanded clay in the desired position, it is watered with cement laitance. Prepared from cement and water, with the calculation of 200 kg of cement per 1 cubic meter expanded clay. The consistency of the milk should be sufficient for it to spill down to the base, but at the same time it should not be allowed to flood.

Fixing the expanded clay is not necessary, but is desirable, since during the installation of the roof you will often have to walk on it, thereby violating the created level.

• Removing markings. If timber or metal profiles were used, the depressions are filled.
• Next, you need to fully fix the slope with a cement-sand screed, approximately 6 centimeters thick. Just as in the previous case, reinforcement mesh must be laid for it.



Advantages of expanded clay:

• Low cost. Even lower than when using polystyrene concrete.
• Convenience of creating a slope of a flat roof according to SNiP. Expanded clay is lightweight, it is convenient to take it apart, there is no need to remove excess from the roof. The only problem is delivering the material to the roof.
• Good thermal insulation characteristics.
• Cement laitance, like other fixing solutions, is not able to 100% ensure the preservation of the expanded clay level.
• If it rains during installation, this can become a big problem. You can’t get moisture out from under expanded clay, which means you have to wait until everything dries.

Inclination with expanded clay concrete

Another popular material for creating a slope of a flat roof according to SNiP is expanded clay concrete.



To prepare it you will need:

• Cement
• Sand
• Expanded clay

It is made according to the proportion: one shovel of cement, two shovels of sand, three shovels of expanded clay. Water is added until the solution reaches the required consistency.

The procedure is exactly the same as in the case of polystyrene concrete:

• Marking.
• Delivery of solution to the roof.
• Level stretching.
• Laying insulation and forming a fixing screed.



Advantages of expanded clay concrete:

• Low cost. Comparable to polystyrene concrete.
• Good thermal insulation.
• Very difficult installation if you do the work yourself. Main problem consists of delivering concrete to the roof.

Angle with insulation

Wedge-shaped insulation is produced especially for flat roofs. It is made in the form of mineral wool and extruded polystyrene foam.

To create the main slope, three main elements are used:

• Type A slabs creating a slight slope.
• Type B slabs complementary to A slabs.
• Additional slabs required to raise the height.



The work order is as follows:

• Marking is not needed, so after installation vapor barrier film proceed immediately to installing the slabs. Start from the lowest point, laying type A slabs in the first row.
• Type B slabs are laid behind the first row.
• Then additional slabs with a thickness of 40 mm are laid and slabs A are placed on them.
• Again, additional 40 mm thick slabs and slabs B. These operations are repeated until the parapet is reached. At the same time, the flat roof has a slope of 1.7%.
• If mechanical fastening is necessary, special “mushroom” dowels are used. The average consumption is two dowels per sheet.
• Another layer of insulation is laid on top of this slope to evenly distribute the load.

To create a counterslope along the resulting gutter, use:

• J Plates
• Plates K
• Additional slabs

The counter-clone is made in the form of a diamond, with sequential laying of sheets J and K parallel to its lines.



• Simple and quick installation.
• High cost of wedge-shaped insulation.

The minimum roof slope of a flat roof is selected taking into account a number of parameters. These include the roofing material, the structural features of the roof and the climatic conditions of the area where construction takes place.

The minimum slope must be calculated based on the material design features roofs and buildings.

Flat roofing is much cheaper than gable roofing, since there is no need to construct a rafter system. It is advisable to build it in a climate with little rainfall or install it on temporary structures. The slope angle must be such that the roof completely protects the building from negative external factors, is not subject to strong wind loads, and does not retain excess water. (Fig.1)

What materials are suitable for a flat roof?



Figure 1. Calculation of roof slope.

There is an inverse relationship between the angle of the roof and the pressure exerted on it by snow cover or accumulated water - the smaller the slope angle, the greater the load experienced roofing structures per unit area. Given this feature, attention should be focused not only on the reliability of the roofing material, but also on the correct installation of the structures holding it.

A flat roof does not use a rafter system in the traditional sense of the term. In most cases, such a roof is laid directly on the floor material, separated from it by a layer of thermal insulation. This has a good effect on total weight structures, because a traditional roof weighs a lot and is intended for permanent buildings with a normal or reinforced foundation.

In this case, it is recommended to use rolled sheets as a coating. bituminous materials. Depending on the characteristics of the roof at its angle of inclination, they can be laid in one or several layers. Due to the fact that a roof with a slope of up to 5° will retain a large amount of water and snow, it is advisable to cover it in 3 or 4 layers - this way you can ensure reliable waterproofing and durability of the structure.

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"Roofing pie" device for a flat roof

Residential and outbuildings with a flat roof can most often be found among multi-story urban buildings, since owners of private houses and summer cottages rarely resort to such an engineering solution. The reason for this is the fear that water and snow will accumulate on the flat surface of the roof. In part, such experiences have a right to exist, but if the roof is installed correctly and a reliable roofing pie is created, external factors will not have a significant impact.



The flat surface of the roof can be used for a practical purpose - to arrange a decorative lawn, a flower garden, or create a small recreation area.

The difference between a flat roof and a regular roof is gable roof is that it consists of fewer structural elements. The main parts of the structure are as follows:

• the base, which is often the concrete floor of the top floor or attic;
• vapor barrier material;
• one or more layers of insulation;
• waterproofing protection.

The main layers are insulation and waterproofing. They protect the roof from getting wet and cold, creating comfortable conditions in the house.

Roof installation begins with preparing the base. Ideally, it is already level, since it is made of a concrete slab. But such favorable conditions occur rarely, so the surface of the ceiling should be thoroughly cleaned of dirt and residues construction waste, repair all cracks and prime the area with an epoxy mixture - primer.

The next step is laying a vapor barrier. In this case, it is important to fulfill an important condition - to leave a free space of about 10 cm high between the base and the film. This is necessary so that water vapor does not accumulate and lead to subsequent problems. To do this, use either wooden sheathing, which is bolted to the slab, or wavy profiled metal sheets are laid.



Most often, roof insulation is done with mineral wool.

From choice and correct installation Insulation depends on the temperature inside the room, so all operations related to its installation should be carried out with special care and precision. As thermal insulation material often use mineral or stone wool— it has excellent heat retention properties, does not support combustion and has a long service life. It is laid in a single or double layer, depending on the climate of the area where the construction takes place.

The last layer is bitumen roll covering. It protects the roof and insulation layer, in particular, from rain, wind and snow. Modern replacement for traditional bitumen roofing felt- self-leveling coating. It is a polymer liquid composition, which, under the force of gravity, occupies a horizontal position on the roof surface. Self-leveling roofing completely fills all the cracks, cracks and unevenness, reliably protecting the insulation from the effects of the external environment. The only drawback that limits the distribution of this type of material is its high cost and the possibility of application only on perfectly flat surfaces.

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Deflection methods

In the usual way, when the layers roofing materials They have the same thickness over the entire area and are stacked on top of each other; it is simply impossible to achieve a slight slope of the roof. In order for the roof to receive the required slope angle, layers of materials are added to its structure, which can be laid according to given parameters. Such materials include:

• backfill materials - expanded clay, sometimes gravel.
• foam concrete;
• a thermal insulation layer of a certain configuration - such insulation is produced already cut to a wedge shape, or the angle of inclination is created manually during installation.



The slope of the roof is made with expanded clay.

The easiest way to make the slope is with expanded clay or other bulk material. In this case, it is leveled over the roof surface at the required angle, after which it is watered with cement laitance and waited until it sets completely. A low-power cement screed is placed on top of the expanded clay, after which the installation of insulation and waterproofing begins.

The advantage of the materials listed above is that they are light in weight, so they do not disturb the roof structure, making it possible to erect it even on wooden buildings. It is not recommended to use concrete for slopes, since the pressure it creates will eventually lead to the loss of the shape of the roof. Foam concrete - good material, but the complexity of its installation limits its use in private construction.

There are some features of roof installation that depend on whether it will be used for some additional purpose or will only perform its direct function. Reinforcement of the roof is necessary in cases where installation of utilities will be carried out on it, or it is planned to equip a recreation area. Otherwise, the roof structure will be much simpler and cheaper.