A flat roof has advantages over a pitched roof in terms of its ability to withstand the challenges of bad weather.

The windage of a flat roof is much smaller, so it can withstand large wind loads.

But on a flat roof, a roof is laid, which is conditionally called flat, because it necessarily has a slope.

Why is a slope made on a flat roof?

The roof takes on all the effects of the environment and is designed to protect the building from them.

In addition to the wind, precipitation brings serious tests.

The function of the roof is to ensure that moisture does not linger, but flows down to the drainpipes.

Properly organized water flow significantly contributes to extending the life of the roof.

A flat roof, no matter what materials it is made of, will not withstand moisture if water lingers on it, especially during the cold months of the year.

The processes of turning water into ice and thawing will destroy the layers of the roof.

In stagnant puddles, dust settles over time, the wind brings plant seeds, which contributes to their germination.

This is how grass, bushes and even trees appear on the roof, which completely destroy the covering material with their root system.

To prevent these negative phenomena, a slope is made on a flat surface, and this process is called a slope.

Minimum roof pitch

The slope is a value that indicates at what angle the roof line is in relation to the base, it can be measured with a geodetic inclinometer tool.

Each type of roofing material has the smallest and largest roof slopes allowed by the standards.

These values ​​are collected in a graph that makes it easy to determine which roofings correspond to which roof slope values.

In the same graph, you can convert the percentage value to degrees and vice versa.

There are tables of such translation.

If you divide the height of the roof by the width divided by two (the projection of the slope) and multiply the result by one hundred, you get the value of the slope as a percentage.

The slope is determined by the climatic conditions of the region, the purpose of the building, the type of coverage.

The angle at which the roof should be tilted is calculated at the design stage.

SNiP II-26-2010 “Roofs” defines its minimum value for roofing from rolled materials and from mastics from 1.5% (1 o) to 10% (6 o).

For operated roofs, its minimum value is within 1.5% ÷ 3% or 1 o ÷ 2 o.

A graph of the mutual conversion of percentages and degrees, expressing the slope and the compliance of the roofing material with it, is given below.

flat roof structure

The basis for a flat roof can be a reinforced concrete floor slab or metal profile sheets.

A flat roof consists of layers:

• cement-sand screed, if the base is concrete;
• vapor barrier using roll materials or bituminous mastics;
• insulation: mineral wool mats, polystyrene foam slabs, expanded clay bedding, concrete mixtures;
• waterproofing: several layers of rolled material.

If welded materials are used for a flat roof, then there will be slightly different components of the roofing pie.

In a building where the project provides for an internal drain, funnels for the catchment will be present in the roof device.

Materials used for spreading

Bulk insulation

Expanded clay, perlite, slag and other bulk heaters are used for slope planning on a flat roof.

The features of these materials, namely the fact that they are free-flowing, create some difficulties.

The minimum slope may be violated over time and the insulation will take a horizontal level.

In addition, if large granules are present, it will be difficult to create a slight slope.

Sometimes, when using loose insulation, a screed is made on top of it, which makes the roof heavier.

Glass isol is used as waterproofing.

Concrete mixtures

As a heater, concrete mixes with fillers from slag, expanded clay, perlite can be used.

Due to the fact that this material is heavier than other heaters, it is used during construction or if major repairs are being made.

Concrete mixtures are not suitable for partial repairs.

To carry out the work, skilled workers and special equipment will be required, which will increase the cost of construction.

Polymeric materials as a filler

Resin-filled concrete mixes are a good option for sloped flat roofs.

The disadvantage is that the weight of concrete, although lightweight, is much greater than that of other heaters.

And, as in the previous case, the involvement of specialists increases the cost of work.

Plastic panels

The modern method is the use of plastic panels with an individually set angle of inclination.

The panels are assembled on the roof like puzzles, filled with liquid rubber.

The disadvantage of this method is the high cost of the material.

Warming materials

One of the most popular ways to ensure the slope of a flat roof is the use of heaters: mineral wool and foam boards.

Such materials are economical, easily attached to the base with mastics or adhesives.

Creating a Minimum Slope

The slope of the roof is created at the time of laying the insulation.

The method of forming the slope depends on the type of insulation chosen.

If bulk material, pour it, setting the required angle.

For fixing, pour cement milk.

From foam concrete, the slope will be performed by specialists; this method cannot be dispensed with without them.

When using heat-insulating materials to create a given slope, either heat-insulating plates made with a slope are used, or plastic supports are used that can be adjusted.

The main task of the slope is to ensure the unhindered movement of water to the catchment funnels anywhere on the roof.

If you check - pour a bucket of water, it should leave without delay.

High-quality roofing work will significantly extend its service life.

Video about the device of a flat roof.

Sergey Novozhilov is an expert in roofing materials with 9 years of practical experience in the field of engineering solutions in construction.

Since a flat roof used to cover office buildings, industrial facilities and residential buildings does not have slopes, increased requirements 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 the drainage system, a flat roof slope is laid. 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 insulation is already necessary for the formation of a roofing pie, costs increase only through 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. There are two types of 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 assembled and laid on a pre-prepared base, and then filled with 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

A flat roof, which is built in accordance with the requirements of building codes, always has a slight slope. If it is minimal, an inexperienced observer will not notice. But if there is no slope at all, it will be visible immediately. The fact is that in the absence of at least some slope of the structure, rain or melt water will necessarily collect on it.

Even if the surface of a flat roof is created perfectly flat, and, it would seem, there can be no talk of any puddles, the reality is different. Under the influence of wind, solar radiation, rains of various acidity, temperature changes, the roof deforms over time, zones are formed on it, in which water or dirt brought by the wind can linger. If there is a minimum slope, the chances that water or snow will linger on the roof for a long time are much less.

What's the point in dodging

It would seem that sooner or later the snow lingering on the roof will melt, and the water will either dry up or the drainage system will cope with it. The experience that eventually resulted in the recommendation of the Building Code suggests otherwise. Water tends to destroy the structure of the roof in a variety of ways.

Firstly, the water on the roof is not completely distilled, its chemical analysis will show the presence of dissolved oxygen and a whole range of substances that will actively destroy the roof material. Secondly, in the cold season, water can change its state of aggregation several times a day. Among other things, it is also a change in volume, which carries a powerful destructive force.

The slope of a flat roof is also needed so that dust does not accumulate on it. Many saw vegetation on the roofs of residential and industrial buildings. It would seem, where does the grass and trees come from? But wind, water and sun do their work steadily. And the roots of plants, as you know, are able to destroy even very strong materials.

What is measured and how the slope is determined

The parameters of a flat roof, which include the minimum slope, are regulated by the set of rules SP 17.13330.2011 SNiP II-26-76. A document so complex in designation is easier to distinguish by name. It is called the "Code of Roofing Rules", or Theroofs in English.

The scope of the document is the design of roofs using rolled, bituminous and other roofing materials, several types of tiles, slates and tiles, galvanized steel and copper sheets, profiled sheets, aluminum, zinc-titanium and other structures.

Before considering the table available in the set of rules, it should be clarified that the slope of a flat roof can be measured either in degrees or as a percentage. There are also relative units like 10/12, but they are rarely used.

Slope Table

In paragraph 4.3. of the set of rules mentioned above, there is a table in which the norms are prescribed that determine the slope of a flat roof, that is, its minimum size. The values ​​depend on the type of materials used for the arrangement of the roof, as well as on some other factors.

So, if the roof is made of rolled materials or bitumen-based mastics, it should be sloped in the range from 1 ° to 6 ° (1.5-10%) if gravel or other coarse-grained substances are poured on top. If the top layer is foil, the slope of a flat roof varies from 1° to 16° (1.5-25%).

When using polymer roll materials, the slope should not exceed 1° (1.5%) without a protective layer and 2° (3%) with a protective layer.

Quite different values ​​are provided for piece materials, metal sheets and concrete structures. For shingles and slates, the minimum slope of a flat roof is between 12° (20%) and 22° (40%). Metal sheets can be placed at a minimum of 7° (12%), reinforced concrete trays - 3°-6° (5-10%).

The norms allow the use of significant slopes, but some additional requirements are required.

How slopes are created

The process of creating roof slopes is commonly referred to as sloping. This process uses:

• bulk materials, in particular perlite and expanded clay;
• lightweight concrete compositions based on the same perlite and expanded clay;
• lightweight concrete compositions based on polymeric materials;
• insulating materials.

Which material will be used depends on the design of the building, on the required slope and on some other factors. For example, lightweight concrete in some cases may be too heavy, creating a significant load. On the other hand, when using bulk materials, it is impossible to create a large angle. In general, different materials have their own advantages, disadvantages and scope.

Stagnant puddles with rain or melt water are a merciless enemy of flat roofs. With stubborn persistence, they destroy the coating and the components of the roofing cake. In order for atmospheric negativity not to create threats, it is necessary to foresee and carry out protective measures. The most effective and affordable way is to form slopes that contribute to the rapid outflow of water.

In the name of the long service life of the roof and the building structure located under it, you need to know how the flat roof is flattened. In order to create the most effective protection, you should familiarize yourself with the options used for its design.

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

The list of risk factors associated with stagnant water includes:

• Damage and rupture of the coating. A phenomenon characteristic of periods of fluctuations in plus and minus temperatures, for sharp frosts. Water in the process of crystallization significantly increases in volume, which leads to delamination of the mineral protective dressing on bituminous roofs. Due to the violation of the protective layer, the material becomes vulnerable to UV radiation. On membrane and bulk roofs, due to the alternation of freezing with thawing of water, a grid of small cracks appears.
• Overstressing the waterproofing mat. The temperature difference outside the building, inside and inside the building creates excessive stress on the coating. Around stagnant puddles, the stress state intensifies, resulting in gaps and cracks.
• Deflection of a thin bearing base. A typical example is corrugated sheet roofing, on which the accumulation of precipitation can cause deformation and subsequent rupture of the coating.
• Moisturizing insulation. Microscopic cracks unnoticed 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 equivalent trouble 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 board.
• The origin of vegetation. Dust accumulated on a flat roof, coupled with stagnant water, is a wonderful environment for rooting and further prosperity of wind-blown plant seeds. Not all roof coverings are capable of steadfastly resisting life-loving roots invading them.

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

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

Flat roof slope options

Spontaneously, without mechanical stimulation, water will not drain from a flat surface. 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 for a flat roof as 1.5º, 1º-2º are considered acceptable, which in percentage terms means from 1.7% to 3.4%, respectively.

It is possible to tilt the roof plane of a small domestic facility during the construction period. To do this, according to pre-made calculations, the difference in the height of the walls is set, on which the two responsible sides of the slope will have to rely. This is a separate topic, acceptable 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 to the roof plane, erected on load-bearing walls of equal height. Such tasks often have to be solved by the owners of suburban property and often implemented with their own hands.

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

The lowering of the relief is always directed from the elevated parts of the roof, including chimneys, skylights, roof aerators, etc., towards water inlets, which include drain 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 parts flowing in different directions.

Stagnation along the parapets of flat roofs is eliminated by installing a fillet. The design of a simple part is akin to a floor plinth, only without bulges. A bar with a triangular section is installed along the junction line of the walls of the parapet or a standard wall with a flat roof, which can be made by longitudinally splitting the bar into two halves.

Instead of a split bar, a similar device made of basalt wool or expanded polystyrene is used. Fillet can be arranged directly on the object from a concrete solution.

The following proven methods are used for flat roof slopers:

• The use of backfill thermal insulation: most often expanded clay or perlite, less often vermiculite. To create a ramp with a filling insulation, the roof area is divided into segments. Guides are installed at the required angle, between which the material is poured. On top of the backfill, a concrete mix screed with the M150 marking is arranged. Concrete pouring without fail should be reinforced with a road mesh. The final layer of concrete can be replaced by a dry screed made of plywood or flat slate sheets. The uniquely time-consuming method is not accurate due to the inherent displacement of loose particles. In addition, it is difficult to form a slope rise in this way.
• Pouring lightweight concrete- mixtures with the inclusion of expanded clay, polystyrene chips, perlite and similar aggregates. It is carried out according to the traditional scheme of the screed device, only the guides are installed at the required angle. The disadvantage of the method is in weather restrictions, tk. the screed can not be poured at minus thermometer readings. The concrete ramp will dry for at least 28 days, during which the screed will need to be moistened and protected from rain and wind.
• Installation of metal structures. They are made of profile PP nomenclature 75×50×05 or similar material according to the dimensions of the increase and decrease. 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.
• Lathing construction. It is used extremely rarely, because. the application is unprofitable, besides, it is too difficult to implement such minor deviations, but among other methods it is still mentioned.
• Application of wedge-shaped thermal insulation boards produced from basalt wool, foam glass, expanded polystyrene, polystyrene specifically for slopes on flat roofs and for creating an outflow of water from parapets.

Wedge plate tilting leads the way with numerous impressive benefits. They were developed and introduced into the construction industry purposefully in order to eliminate the shortcomings of all the previously listed methods.

Wedge-shaped thermal insulation boards are not without reason recognized as the best way to solve the problems of drainage from a flat roof. This is the most convenient, cheap and simple scheme that does not require in-depth skills and fundamental knowledge in roofing from the performer.

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

Advantages of using wedge-shaped plates

Expanded polystyrene and mineral wool boards for the formation of slopes have an equivalent set of advantages, these are:

• Insignificant weight, due to which the slope made of insulation creates the least load on the supporting building structures.
• Transportation to the place of laying without the use of lifting construction equipment.
• Independence of technology from weather conditions. Possibility to carry out successful laying, despite unfavorable forecasts for builders.
• Perceptible relief and acceleration of actions for the formation of inclined planes. There is no need to postpone finishing work due to the need to withstand technological breaks. For example, wait 28 days for the cement-sand screed to gain the required hardness parameters.
• A significant reduction in the cost of building slopes, necessary and sufficient for the unhindered flow of rain and melt water.

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

SNiP II-26-76 prescribes to install the slope of the finishing coating of a flat roof after laying the insulation, if thermal insulation was provided for by the project. If there was no need to insulate the roof plane, the wedge-shaped slabs are laid on a base covered with steam or hydroprotection.

Wedge-shaped thermal insulation is used in the construction of new roofs and in the performance of repair and restoration work. With the help of lightweight, convenient module slabs, you can create literally any relief in order to direct the flows in a given direction.

How to make a slope with plates?

Wedge-shaped 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 rake elements does not depend on what type of insulation they are made of. However, the composition of the slabs has an impact on the structure of inclined planes.

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

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

A geotextile underlay is also required when laying slabs immediately on a rough concrete pavement, 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 plates are produced according to the general principle, regardless of the composition of the product. The elements are marked to facilitate the laying procedure, they have identical dimensions.

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

• Plates marked with letters A and B are intended for assembling slopes with a size of 1.7%.
• If the material is marked with the letters J and K, then it is used in the construction of slopes of 3.4% and 4.2%.
• Flat insulation boards with the letter C are used for climbing. Elements marked C can be laid both under and on top of the ramp.

More details on the diagrams:

The material manufacturer's instructions usually include a laying plan that clearly shows the sequence of the wedge-shaped slabs. The construction of one plane directed to the gutter, or two adjacent planes directed to the catchment funnel, will not be a serious problem for the home master. Laying should start from the lowest point of the roof and continue up to the created watershed.

It is somewhat different if a complex relief is being constructed with several valleys and watershed ridges. You will have to draw a plan and think over the course of action in advance. In plan, a complex relief usually looks like a combination of rhombuses and triangles. Laying in such cases starts from the edge of a rhombus or triangle, and finishes the process in the center of conditional figures.

The required height is achieved by means of a set of plates with the 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, in fact, trimming is performed.

Mounting rules

The installation of wedge-shaped slabs on the base without preliminary thermal insulation is carried out by methods commonly used or by bituminous coating. The priority is the mechanical method of fastening to the base, according to which the telescopic plates are fastened with self-tapping screws with a telescopic nozzle.

Fixation of wedge-shaped parts made of mineral wool is carried out simultaneously with the main layer of insulation. It is recommended to install two fixing units on a 600×1200mm slab. If both linear dimensions of the plate are more than a meter, 4 fixing points will be required.

The wedge-shaped ramp 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 multilayer insulation system, and in relation to the insulation layer with slope-forming material. If the elements of the heat-insulating ramp are laid on the base without insulation, they are glued or simply loaded.

Note that polystyrene boards cannot be glued with bituminous glue containing a large amount of organic solvents. The material is "not friendly" with organic solvents and gasoline. Therefore, their neighborhood should be excluded.

For the duration of the installation operations, it is recommended to glue the polystyrene foam plates together with double-sided tape so that they do not move from careless touches. It is desirable to place a load on the assembled segment of the composite 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 board, self-tapping screws Ø 4.8 mm are required.
• For fastening to concrete screeds with a strength of B-15 and cement-sand screeds with a strength of M150, pointed roofing screws Ø 4.8 mm are needed together with a polymer anchor sleeve.
• For fixing on concrete bases of class B-25, it is necessary to stock up on driven anchors.

The size of the self-tapping screws is selected taking into account the thickness of the layer so that the screw enters the concrete by 5 cm, and protrudes at least 1.5 cm beyond the back side of the corrugated board. When laying down on old repaired roofs with bituminous coating, a plate-shaped category of fasteners is used. The age of the repaired bituminous roof must be more than a year.

The use of insulation fillets

Triangular in cut, a long piece made of basalt wool is used to redirect atmospheric water currents from the junctions of vertical and horizontal surfaces. They are laid along the joining line of the roof with the parapet, the adjoining wall, the sides of the rooflights, chimneys, etc.

The material cut with impeccable geometric accuracy contributes to an increase in the speed of work on the arrangement of a flat roof. Fillet laying allows you to quickly create a smooth transition from a vertical surface to a horizontal plane.

Video lesson on the device slopes

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

The list of options for slopes on a flat roof rightly tops the wedge-shaped insulation boards. They are designed to make work easier and significantly speed up processes. With the assigned duties, the wedge-shaped ramp does an excellent job.