The slope of a flat roof is minimum and maximum - what SNiP say. The slope of a flat roof: how to calculate and correctly carry out installation? Minimum slope of built-up roof

Since the flat roof used to cover office buildings, industrial facilities and residential buildings, does not have slopes, high demands are placed on the quality of waterproofing. To avoid leaks, three to five layers of material are used, but a flat roof surface is not able to drain water as efficiently as a pitched one. Because of this, areas are formed on it where moisture accumulates, they dry out only in the hottest periods of the year. The rest of the time, non-evaporating puddles negatively affect the waterproofing layer, destroying it.

In addition, in places where moisture accumulates, particles of soil and dust settle, forming a kind of substrate. The wind brings seeds into this favorable environment, and they germinate. Destroying the roofing cake. In order to organize the removal of excess moisture and their movement to drainage system lay a slope flat roof. So the name "flat" is just a figure of speech, in fact, its surface is located at a slight angle, not noticeable to the eye, without the use of a special geodetic tool. What should be the slope and how it can be created, we will tell in this article.

building codes

The minimum slope of a flat roof is regulated by clause 4.3 of SP 17.1333, adopted and approved in 2011. It allows the angle of inclination of the roof surface in the range of 1.5-10% or 1-6 degrees. That is, the smallest slope allowed by the regulations, 1.5% or 1 degree, it creates conditions for the movement of water to downpipes and gutters, and prevents stagnation. Steeper angles are rarely used, as on a large roof area, rolled waterproofing materials slide off to the base.

The process of creating a slope is called flat roof slope. This task is performed in various ways, using:

1. Thermal insulating material;
2. backfill materials;
3. Light mixes of concrete with filling materials;
4. Lightweight mixtures of concrete with polymers.
5. Plastic panels

Important! The slope of the operated flat roof should not exceed 3 degrees, since its increase reduces the safety of use.

Razklonka thermal insulating materials

The structure of any flat roof implies the presence of a layer of thermally insulating material. To set the angle of the roof surface, adjust the thickness of the insulation. To prevent slipping and maintain a given angle, it is fixed to the base of the roof with self-tapping screws. If the base of the roof is well cleaned, the insulation can be glued to it or special plastic supports can be used that grab the layers of the thermal insulator together.

This method of unfolding has advantages, it is good because:

• It is relatively cheap. Since the insulation is already necessary for the formation roofing cake, costs increase only due to the purchase of glue or fasteners.
• Fairly accurate. Using this method, it is possible to set an angle of 1-4 degrees with great accuracy, which is quite sufficient for effective drainage.
• A light weight. Unlike most other methods, flat roofing with insulation does not require strengthening the base, since the thermal insulating agent, most often mineral wool or polystyrene foam, has a low mass.

Razklonka backfill material

Creating a slope angle for a flat roof using backfill material begins with the installation of waterproofing material. This role is most often played by glass isol, it is modern based on fiberglass, due to which it has increased tensile strength, a service life of more than 20 years. Expanded clay or perlite is poured onto the glass isol so as to withstand the required slope angle. After that, the filling material is covered with a polyethylene film located in overlapping strips and the remaining layers of the roofing cake are laid according to the project.

However, this method of creating a flat roof slope has disadvantages:

• Large granules (more than 20 mm) do not allow you to accurately observe the specified angle and make it smooth.
• Backfill material cannot be rigidly fixed, which is why it shifts over time. Moreover, this can happen even at the stage of the formation of the roofing cake, if the claydite is not poured with cement milk. However, in this case, the time spent on drying increases.
• Backfilling is done almost by eye, so it is impossible to maintain the exact angle of inclination.
• Due to the heavy weight of the backfill, reinforcement of the concrete base of the roof is required.

Razklonka concrete mixtures

Concrete-based mixtures can be used to set the slope. This method is not suitable for reconstruction or partial repair, it can only be used for newly created roofs. In order to make a roof slope with concrete mixtures, special equipment and highly skilled workers are required. Two types are used concrete mixtures:

• With the addition of expanded clay and perlite, slag.
• With the addition of polymeric materials.

This method has only two disadvantages: high cost, consisting of the wages of highly skilled workers and the high cost of polymers, and the second is the large weight of concrete, which increases the load on the roof base.

Screeding with panels

The most innovative way to set the angle of the roof is to use special plastic panels. They, like pieces of a children's puzzle, are collected and laid on a pre-prepared base, and then poured liquid rubber. Different thickness of the panels ensures the most accurate observance of the angle of inclination of the surface. But this method also has its own characteristics:

Decreasing Efficiency Control

To check whether the slope is well-done and whether water is efficiently drained from the roof surface, use one of two methods:

Sloping, carried out in accordance with building codes, protects the upper floors from leaks and extends its life.

Video instruction

• Choosing a roof slope only based on your aesthetic preferences would be somewhat reckless. Since the reliability and strength of the future structure largely depend on the correctly calculated value of the angle of inclination, taking into account the climatic features of the area. That is, the slope of the roof must be optimal from both a practical and an aesthetic point of view.

  The fact that ideally "flat" roofs simply cannot be beyond doubt. After all, it must rainwater get away with it in some way. Therefore, they make a ramp to get at least a minimal slope of a flat roof.

  It ensures the most efficient collection of rainwater from the surface. roofing and directs it either to the parapet or to the internal funnels.

  minimum roof pitch

  The minimum roof slope depends on many parameters, including the material of the waterproofing coating, the type of roof itself (standard or inverted), the number of waterproofing layers, and more.

  Basic requirements that determine the slope of a flat roof: SNIP

  What will be the minimum slope of the roof, depending on various factors, special building rules and regulations dictate.

  The dependence of the angle of inclination of the roof on waterproofing is regulated by paragraph 4.3 of SP 17.13330 for 2011, according to which the slope of a flat roof varies in the range of 1.5–10%. Large angles (up to 24%) are extremely rare, since it is very difficult to choose a material for waterproofing that would not slide to the base of a sloping roof when the temperature rises.

  On a note

  The smallest slope for a flat roof is 1.5% or 1°.

  As a rule, a roof with a small slope has a rather large surface area and it is very problematic to achieve its ideal value. Surely there will be areas where water will stagnate, which can cause wear of the roofing material or leaks. Relatively accurately, you can perform the slope geometry with a screed. It is also possible to use polystyrene concrete or foam concrete filling. To increase strength, a thin layer of durable concrete screed is already made on top of the laid layer.

  In turn, there is a specific relationship between the steepness roof structure and the number of layers of waterproofing. The more it is, the water, of course, leaves faster, which means that less waterproofing layers will be required (clause 5.5).

  The slope can be easily checked with a bucket of water. Water is poured onto the selected area, if the water goes to the funnel almost without residue, then the slope at flat roof sufficient. A similar check can be carried out on the entire surface of the roof.

  At the design stage, it is calculated by calculation how many water intake funnels are required for a given roof, and already during construction, with the help of slopes, it is necessary to ensure unimpeded outflow of water into the funnel from any point on the roof.

  How to calculate the slope of the roof: which method is better

  As you know, in addition to flat (sloping) structures, there are also pitched and high ones, and there are even more materials for roofing. In order to correctly navigate this diversity, according to SNiP, special tables and diagrams have been developed that reflect the relationship between the steepness of the slope and the type of roof.

  The slope of the roof is determined by the following parameters:

  • type and amount of material intended for roof covering;
  • necessary protection from wind and moisture;
  • ridge height for repairing an existing roof.

  How to calculate the angle of inclination in degrees and percentages

  Roof Slope Calculator

  

  Using this calculator is extremely simple. In fact, any roof can be divided into ordinary gable roofs, the calculation of which is based on a triangle. It is on this position that the work of the calculator is based. The following options are used:

  • H is the height of the ridge, that is, the leg of a right triangle;
  • W - the second leg, equal to half the width of the base;
  • L is the length of the rafters, it is also the hypotenuse.

  By substituting two known parameters, one can almost immediately determine the slope angle of a roof with similar characteristics. By the way, the third parameter is calculated automatically. Software calculator uses the properties of an isosceles triangle and the simplest trigonometric formulas.

  Using a goniometer

  

  This device, which is also called an inclinometer, has a simple design: several rails with marked divisions and a pendulum. In calculations, the main rail is placed perpendicular to the ridge. The pendulum pointer shows the required angle on the division scale. As you can see, nothing complicated.

  The formula for calculating the slope of the roof

  

  And, finally, the required slope slope can be calculated by yourself without the use of slope measurement devices, mathematically. To do this, you need to know the value

  • vertical height (H), measured from the highest point of the slope, usually a ridge, to the lowest point - a cornice;
  • laying - the horizontal distance from the bottom to the projection of the top point of the slope.

  Calculate the angle of inclination of the roof in degrees or percentages and denote it in the drawing with the letter "i".

  Mathematically, the calculation of the magnitude of the steepness of the roof as a percentage is carried out as follows.

  i \u003d H: L, i.e. the angle of the roof slope is found from the ratio of the roof height to the foundation.

  After that, in order to get the desired value as a percentage, the value of the resulting ratio is multiplied by 100. A special ratio table helps to express the value of the slope in degrees.

  

A perfectly flat roof cannot be by definition. Otherwise, it will accumulate rain and melt water which will cause it to wear out quickly. Therefore, according to generally accepted standards, a flat roof has a slope of 1 to 11.5 degrees. At the same time, the average value fluctuates around 1-5 degrees, which in practice is 1.5 or more centimeters of slope per meter.

How to calculate the angle of inclination

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

• Know the height of the parapet.
• Know the thickness of the roofing cake.
• Know the exact location of the intake funnel.

As an example, take a parapet height of 500 mm; the thickness of the roofing cake, excluding the slope 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 5 meters away, which means that we need to go to zero for these 5 meters: 200/5=40. Thus, the slope of the roof 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 too large, it can be reduced to a minimum of 1.5%. So, if there are 5 meters from the funnel to the parapet, and we will rise 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. The formation of a circular system. That is, make a slope in such a way that water flows evenly over the entire area of ​​\u200b\u200bthe roof.
2. The formation of scarves. Draw a 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.

markup

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 with a construction pencil along the perimeter of the entire roof. In the absence of a laser level, you can use the usual, or hydraulic. Then we find the thickness of the parapet in one place and, adding a level, draw a line along the entire perimeter. You can check that the line does not crawl up or down using the hydraulic level.

Further, a lace is pulled from the parapet to the funnel. Beacons can be set along the cord, so it will be more convenient to work. If the unfolding occurs with the help of the formation of kerchiefs, the lace must be stretched along their border.

Roofing with polystyrene concrete

Polystyrene concrete is a type of lightweight concrete made from cement, water, mineral filler and various additional additives. For the purpose of weighting, the addition of sand is permissible. To produce polystyrene concrete at home, you will need:

• Concrete mixer. Specialists use a special unit that allows you to supply concrete through a hose directly to the roof.
• Cement 500 brand.
• Polystyrene crumb. Manufactured from defective polystyrene boards.
• Water.
• Liquid soap.
• Sand.

It is made at the rate of: 2 shovels of cement, a shovel of sand, 5 ten-liter buckets of polystyrene okroshka, 50 grams of liquid soap, water, until the mixture reaches the desired consistency. Concrete should not be liquid and not too dry.

The order of work is as follows:

• Creation of markings on the roof. Use a bar or beacons. Please note that the beam subsequently needs to be delivered on time. That is, when one section is flooded, and the mortar has already solidified, the beam is removed so that it does not interfere with the pouring of the adjacent section. The lace in this case is a weak helper. From concrete, it will get wet and sag.
• To create a slope of a flat roof, the resulting mixture must be delivered upward. 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 to the roof, as well as deliver a concrete mixer there. This will greatly simplify the work on the slope.
• Polystyrene concrete is pulled together by beacons using the rule. It is desirable to leave as few irregularities as possible; subsequently, insulation will be laid on the concrete. The solution hardens in a day, and it is already possible to move freely on it.
• A heater is laid along the slope-forming layer, and then everything is fixed with a cement-sand screed, for which a reinforcing mesh is necessarily laid. The thickness of the screed is approximately 6 centimeters.

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

The advantages of this material include:

• Inexpensive cost.

To the disadvantages:

• The complexity of installation, subject to independent work.

Razklonka with expanded clay

Creating a minimum slope of a flat roof is acceptable when using expanded clay. It is obtained by firing clay shale. Expanded clay is laid both on a base of reinforced concrete slabs or corrugated board, and on a heater.

The order of work is as follows:

• Creation of markings on the roof. For this you can use wooden beam, metal profile or just a lace. It is more convenient to work with a beam and a profile, but closer to the end of the work they need to be taken out, and the resulting pits should be leveled. You don't need to do this when using laces.
• Expanded clay backfill. To facilitate this process, you can order a manipulator that will deliver expanded clay directly to the roof. Otherwise, the material will have to be worn manually for a very long time.
• Lighthouse alignment. Align with a rule. For convenience, you can make wooden rule with a handle, according to the principle of a rake, only instead of teeth - an even, wide bar. 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 provide good stock water.
• To fix expanded clay in the desired position, it is poured with cement milk. Prepared from cement and water, with the calculation of 200 kg of cement per 1 cubic meter of expanded clay. The consistency of the milk should be sufficient so that it spills to the base, but at the same time, flooding should not be allowed.

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

• Dismantling markup. If a beam or a metal profile was used, the cavities fall asleep.
• Next, you need to fully fix the slope with a cement-sand screed, about 6 centimeters thick. As in the previous case, a reinforcing mesh must be laid for it.

Expanded clay advantages:

• 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 pull it apart, you do not need to remove excess from the roof. The only problem is to deliver the material to the roof.
• Good thermal insulation characteristics.

• Cement milk, like other fixing solutions, is not able to 100% ensure the safety of the level of expanded clay.
• If it rains during the installation process, this can be a big problem. You can’t expel moisture from under expanded clay, which means you have to wait until everything dries out.

Razklonka with expanded clay concrete

Another popular material for creating a flat roof slope 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 shovel of sand, three shovel of expanded clay. Water is added until the solution reaches the desired consistency.

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

• Markup.
• Delivery of solution to the roof.
• Stretching by level.
• Laying insulation and forming a fixing screed.

Advantages of expanded clay concrete:

• Low cost. Comparable to polystyrene concrete.
• Good thermal insulation.

• Very difficult installation for independent work. The main problem is the delivery of concrete to the roof.

Razklonka insulation

Especially for flat roofs, wedge-shaped insulation is produced. Manufactured in the form mineral wool and extruded polystyrene foam.

Three main elements are used to create the main slope:

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

The order of work is as follows:

• Marking is not needed, therefore, after laying the vapor barrier film, they proceed immediately to the installation of plates. Start from the lowest point, type A plates are laid first.
• Behind the first row, type B slabs are laid.
• Then additional slabs are laid, 40 mm thick, and slabs A are placed on them.
• Again additional slabs with a thickness of 40 mm 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 necessary, mechanical fasteners use special dowels "mushrooms". Average consumption - two dowels per sheet.
• On top of this ramp, another layer of insulation is laid to evenly distribute the load.

To create a counterslope along the resulting gutter, use:

• Plates J
• Plates K
• Additional plates

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

• Simple and fast installation.

• The high cost of wedge-shaped insulation.

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

For many, the phrase flat roof is in no way associated with a slope. Although this is far from true. Even the most even roof has its slope, even if it is minimal.

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

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

• Operated roof;
• unused roof;
• Traditional roofs;
• Inversion roofs.

The slope that should be on this type of roof, is about 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 rainwater dries up under the rays of the sun. In winter and autumn, such water can freeze at night and melt during the day.

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

But this is not the only problem. In addition, puddles on the roof can be covered with dust, which at one time settles on the bottom. Seeds of various herbs and plants can fall into this puddle and germinate there.

Often on the streets you can find houses on the roofs of which there is grass or thin trees. 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, Roof sloping needs to be done.. Such complex manipulation is carried out at the time of construction itself.

The process itself is quite complex, and includes many activities of different structure. The purpose of this procedure is for the roof itself to acquire the necessary slope..

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

Flat roof

In fact, it is a pie with several layers:

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

The components of such a pie can be changed if the builder has the desire to make the entire roof with new building materials. It should be understood that such a procedure as a bias, carried out directly at the time of laying the insulation.

It is important that in addition to such 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 to pay attention to is wind effect. If you live in an area where there are frequent strong winds, then it is worth making a small angle of inclination.

CAREFULLY!

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

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

Percent slope

Minimum angle and roof slope calculation

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

• If the roof is made of then its minimum slope must be at least 12 degrees(according to SNiP). If the roof is made of angle increases up to 15 degrees. It is important to understand that the gaps of the material, and other joints, must be treated with a special sealant - frost-resistant / waterproof. If the angle of inclination is 15 degrees, then the sheets of material should overlap 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, materials based on bitumen. It is logical that by the value of the slope angle, affects the number of layers of the roof. If, for example, the roof is carried out in two layers. then an angle of inclination of 15 degrees is quite enough;
• Having covered the roof, it is worth understanding that quite enough and 11 degrees of inclination angle, but at the same time you need to make a crate of a solid type.

Such a process as a flat roof slope, made from these 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. Before starting work, it is necessary to correctly calculate the angle of inclination itself. In fact, it is quite easy to carry out this calculation, for this you need to use a goniometer, or with fairly simple mathematical formulas.

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

The instructions for using bituminous and polymer coatings for sloping indicate that the optimum angle of inclination should be 1.5 degrees. An inclination of 1-2 degrees is acceptable.

Everything is very simple here. You need to know the height of the roof and its width. Further, simple trigonometric formulas will help calculate the direct angle (sine, cosine, tangent). And according to 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 height of the roof must be divided by half the width, and the result already obtained is multiplied by one hundred, after that, in the table, you can find out the percentage value of the future angle of inclination. This option is faster, but they are both correct in terms of accuracy.

Minimum slope

Sloping a flat roof with bulk materials

If you decide that the slope procedure will be carried out using bulk materials, then the first thing worth noting is the scheme by which such a procedure must be carried out:

1. First of all, on the concrete base itself, 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 a high waterproofing performance;
2. Farther, 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 it is necessary to cover the layer of expanded clay with a special polyethylene film. It is important to note that it must be overlapped;
4. Further, it is necessary to apply the prepared sand-cement screed doing it smoothly, slowly. Its essence is to level the layer of poured expanded clay;
5. After these events, you can start carry out the formation of 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 a sand-cement screed on top of it, you can fill it with cement milk. But it is worthwhile to understand that because of him, the design becomes heavier.

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

bulk material

Thermal insulation materials

Another good material, for the slope of the roof are heat-insulating materials. Experts claim 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. Mineral wool, the best material. The scheme of the process 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 with special glue. Such a process can be performed both during and during the installation of the roof.

Thermal insulation material

foam concrete

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

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

A huge plus of this kind of razuklonka - high rate of thermal insulation, as well as other mechanical characteristics. For example strength and durability.

Speaking of cons, they are here too, or rather one. This is the price. She is high enough. And again, to carry out such a procedure on your own will not work. Therefore, in this case, it is worth contacting professionals.

• If the roof has a minimum slope, then it is important to note that in this case, must be installed correct systems drain. The slope itself is done exclusively to the side (funnel, gutter);
• If your roof is bituminous, it is worth making 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 values ​​of the slope angle, it is necessary to carry out ventilation of the under-roof space itself, with all the slopes. The thickness of the gap also depends on the value of the angle (the larger the angle, the smaller the thickness, and vice versa).
In contact with

During the construction of roofs for household and industrial buildings you need to do at least a minimum. An absolutely flat and even roof is ineffective as a water outlet. Atmospheric precipitation lingers on the roof, and over time, areas of stagnation appear, drying out only in extreme heat. From the outside, such a roof looks flat, as in the photo, but at the same time, the efficiency of removal increases, and, accordingly, the service life of the roofing increases.

Why is it necessary to make a slope

The formation of stagnation zones is harmful to the roofing material. In the cold season, the water constantly freezes and melts, because of this roofing material is destroyed, and all conditions for the occurrence of corrosion are created.

The slope of a flat roof as a percentage should be 1.7-7%.

Roof slope options

Flat roof slope can be done in the following ways:

• using materials for insulation;
• with the use of expanded clay, perlite and other backfill materials;
• with the use of light concrete mixtures based on bulk insulation;
• using lightweight concrete mixtures based on polymer fillers.




Most often, backfill materials are used, but the slope with their help has several disadvantages. This is, first of all, the displacement of the backfill material over time, due to which the angle of inclination changes. Over time, such a decompression may become ineffective. In addition, the large size of the expanded clay unit (approximately 20 mm) does not allow you to create a smooth slope.

Razklonka with the use of lightweight concrete is devoid of these shortcomings, but it can not always be done. The design has a significant mass, which creates a load on a flat roof. Therefore, demolition with concrete can only be done during the construction of the building or overhaul roofs.

If you need to tweak the roof a little, then the slope of a flat roof can be made using special polymeric materials, for example, extruded polystyrene.

Usually a flat roof consists of:

• supporting structure;
• leveling cement-sand screed;
• a layer of vapor barrier materials;
• layer thermal insulation materials;
• waterproofing from roofing roll material.




In addition to these layers, a flat roof must have water inlets if an internal drain is created. If the drainage system is external, water intake gutters are installed, which are attached either to outer wall buildings, or under the roof. Naturally, it is necessary to calculate correctly.

If a profiled metal sheet was used as the base, a profiled sheet structure can also be used for waterproofing. A flat roof may have a different structure, but as a rule, general scheme remains the same.

Razklonka bulk materials

Razklonka inexpensive filling materials are done in the following way:

1. A layer of waterproofing material - glass isol is laid on a reinforced concrete base. This material has a long service life - up to 30 years.
2. Expanded clay is poured onto the glass isol in accordance with the project. Large expanded clay granules do not make it possible to accurately measure the angle, so they have to be poured “by eye”.
3. Expanded clay is covered with a plastic film overlapped. After that, the roof is made based on the project, while creating each new layer, you need to control the angle.




It is inconvenient to make a slope of a flat roof in this way, for the reason that the angle of inclination cannot be accurately calculated, moreover, the displacement of expanded clay begins even when the screed is poured. This can be avoided if expanded clay is poured with cement milk, but the drying time is significantly increased. Plus, there is a load on the floor, as the weight of a flat roof increases significantly.

Razklonka foam concrete

Instead of expanded clay and cement mortar, foam concrete can be used. First, a layer of foam concrete is poured onto the base in accordance with the angle of inclination, then a foam fiber concrete screed is made. A waterproofing material is laid on top of this.




Such a roof has good thermal insulation and mechanical characteristics. But it also has disadvantages - the main among them is the high cost. It is also worth considering that it is unlikely that you can do the laying out of foam concrete on your own, so you will have to hire specialists.

Razklonka with heat-insulating materials

Rauzklonka using heat-insulating materials is inexpensive and easy to perform. You can do the slope both during the construction of the roof and during repairs. The most profitable, based on financial costs and thermal insulation qualities, is a ramp using polystyrene and mineral wool. The undoubted advantage is the low weight of these materials. When using them, there is no need to strengthen the roof.