External drain according to snip. Organized drainage from the roof: system options Unorganized drainage from the soft roof

The drainage system is used to drain precipitation from the roof to storm sewer or another place to collect water. An organized drainage system protects foundations and walls and prevents the formation of puddles around the house.

Depending on the location, drainage systems can be internal or external. The internal drain is installed inside the building before carrying out finishing works. It is installed on flat roofs, as well as in regions with a high probability of water freezing. External roof drainage is more common. Its installation is carried out upon completion of all construction and finishing work.

The advantages of such a drainage system are obvious:

ease of installation and dismantling;

no need for specialized skills and tools;

ease of maintenance.

Materials for drainage system

Currently, external roof drainage can be made of metal or plastic. For metal systems, galvanized or carbon steel, titanium, copper, and aluminum are used.

The choice of material depends on various factors:

Type of roof. On an elite building, plastic pipes look ridiculous; copper or titanium are more appropriate here.

Easy to install. The easiest way to install a drain is made of plastic.

Resistance to mechanical damage. Best properties in steel, copper and titanium.

Weir elements

External roof drainage consists of a number of elements, the number of which depends on the size and design features of the building. Gutters are horizontally installed parts for draining water. By location there are: cornice, parapet, and groove. Parapets are mounted between the parapet beams. The grooves are placed at the junction of several slopes.

According to the cross-sectional option, gutters are divided into semicircular, square and embossed. Square ones are used in areas with high precipitation. Embossed ones serve to protect against debris, leaves, etc. Internal and external corners designed for outlining roof elements. The gutters are fastened using brackets with a pitch of 50 cm. Plugs are installed at the ends of the gutters.

The second element of the external roof drainage is the drainpipe. Its cross-section must coincide with the cross-section of the gutter. For roofs whose area exceeds 200 m2, it is recommended to use square pipes. According to SNIP, for roofs with an area of ​​up to 30 m2, pipes with a diameter of 80 mm are suitable, for roofs from 50 to 125 m2 - with a diameter of 90 mm, and for an area of ​​more than 125 m2 - 100 mm. The pipes are secured using clamps. The gutters and pipes are connected to each other by drainage funnels. Special nets are installed on them to retain debris. Docking various elements passes through the couplings.

Organized external drainage from the roof provides for the flow of water into a storm sewer, but it can also simply be discharged onto the ground at least 60 cm from the foundation.

Installation of external roof drainage

The event is held in two stages:

First- development of a drainage system project. It includes drawing up an estimate and plan for future work. At this stage, taking into account the area of ​​the roof, its design features and angles of inclination, the required number of gutters, pipes, funnels and fasteners is calculated.

Second phase- installation of a drain. In addition to the parts of the drainage system and assembly instructions, the following tools are needed: drill, saw, hammer, screwdriver, as well as nylon thread.

Installation is carried out in the following order:

6. Roofing.

Organization of drainage on the roof. Questions and answers.

The main reason for the formation of icicles and ice on the roof of a building is the lack of ways for melt water to drain. What other factors cause ice to form on the roof?

The main factor in the formation of ice and icicles on the roof is improperly organized drainage. Other factors that contribute to the formation of ice dams:

Atmospheric heat – daily difference in air temperature, solar radiation;

The roof’s own heat generation, which is facilitated by:

Insufficiently effective heat and vapor barrier (when using the under-roof space for living). To protect the thermal insulation layer and the base under the roof from being moistened by moisture penetrating from the room, a vapor barrier should be provided in accordance with the calculation.

All types of household activities are accompanied by a significant release of water vapor, the penetration of which into the roof structure occurs under the influence of steam pressure and air movement. Even if the vapor barrier in the roof structure is done carefully, moisture still penetrates into the insulation through leaks around communications, material joints, etc. Moisture condenses in the insulation, due to this its thermal insulation ability is sharply reduced. The most important quality of a vapor barrier is its continuity;

Lack of under-roof ventilation: ventilated attics (if the attic space is not used for living) and vents or an air gap between the thermal insulation and the roofing (if the attic space is used for living). The most rational method of removing moisture is to have an air gap between the thermal insulation and the roof covering to ventilate the under-roof space. A continuous ventilation slot is provided in the eaves, and a ventilation opening is provided in the ridge or gable. Traditionally, when installing thermal insulation into a structure, two ventilation gaps are left, forming two ventilation zones - upper and lower. Through the lower ventilation gap, located between the waterproofing coating and the insulation, condensate air coming from inside the room is removed. And through the upper ventilation gap formed between the roof and the waterproofing, moisture that gets inside from the street is removed. At modern way for insulation, vapor-permeable (diffusion) membranes are used as waterproofing. Ventilation is carried out through one ventilation gap between the roof and the diffusion film, through which condensate from the room passes.

SNiP 11-26-76, paragraphs 4, 5; SNiP 23-02-2003, clause 9

How to ventilate the under-roof and attic space to minimize thedeterioration of thermal insulation and formation of condensation on the inner surface of the roof?

To ventilate the attic space, it is necessary to provide supply and exhaust openings in the external walls (in each wall with a total cross-sectional area of ​​at least 1:500 of the covering area) or a device in the covering dormer windows. These holes must be covered with a mesh with cells no larger than 20x20 mm. The area of ​​the supply and exhaust openings should not be less area cross sections of the ventilated layer. Ventilated height air gap above thermal insulation is determined based on calculation and cannot be less than 50 mm. It is not allowed to use wood and heat-insulating materials based on it in non-ventilated coatings. SNiP 11-26-76, clause 5

How to reduce icing on the roof surface?

Icing occurs due to increased exposure solar radiation on the roof, the absence of hydrophobic properties of the surface, as well as intense adhesion of water, ice and dust to the roofing materials. To reduce the effect of these factors, it is necessary to use light-colored paint compositions that have increased water-repellent properties.

On which roofs should internal and external drains be provided?

Internal organized drainage should be provided on rolled and mastic roofs, external organized drainage - on roofs made of small-piece materials, asbestos-cement corrugated sheets, sheet steel, copper, metal tiles and metal corrugated sheeting. Internal organized drainage and external unorganized drainage on roofs made of reinforced concrete tray panels can only be provided in buildings up to 10 m high. TSN KR-97 MO, clause 4.8 (SP 31-101-97 MO)

How to properly place water intake funnels on the roof?

Water intake funnels of internal organized drainage must be evenly distributed over the roof area. For 1 cm2 of the cross-section of the funnel pipe there is 0.75 m2 of roof area. Each section of the roof limited by walls and expansion joints must have at least two funnels, and for a roof area of ​​up to 700 m2, one funnel with a diameter of 100 mm can be installed. The bowls of water intake funnels should be located in the lowest places of the roof, no closer than 500 mm to parapets and other protruding parts of the building. In places where funnels are installed, a local lowering of the roof of 15-20 mm within a radius of 0.5 m is provided. TSN KR-97 MO, clause 4.9; 4.10; 4.11 (SP 31-101-97 MO)

How to perform external organized drainage?

When installing external organized drainage, the distance between drainpipes should not exceed 24 m, and the cross-sectional area of ​​the pipe is taken at the rate of 1.5 cm2 per 1 m2 of roof area. Suspended and wall gutters must have a longitudinal slope of at least 2%. TSN KR-97 MO, clause 4.12 (SP 31-101-97 MO)

When and how is the operation of gutters checked?

This happens in the fall. The work is carried out in order to timely carry out all roof repair operations and prepare them for winter.

The roof plan shows areas of stagnant water and the degree of contamination of the funnels. In case of unorganized external drainage, the places and degree of soaking of facade walls and plinths with water flowing from the roof, the flow of rainwater through balconies into the premises of the upper floor, and through pits into the basement floors. It is also necessary to clean the water intake devices from leaves, pine needles and dust (it is prohibited to sweep leaves and debris into the drains). To clean roofs, wooden shovels, brooms or polymer scraping devices should be used.

How to eliminate stagnation and freezing of water near parapets, roof railings, architectural details,facing roofs with external drainage?

First of all, you need to find the reason. This is probably the placement of unnecessary architectural details and vertical elements on the roofs that prevent water from flowing out.

It is necessary to redesign all elements of the roof covering, including taking into account the possibility of installing an anti-icing system.

What is an anti-icing system and where is it used?

Anti-icing systems are used in places where it is necessary to prevent the formation of ice and icicles - on roofs, open terraces, porches, steps, ramps - and to prevent freezing and damage to pipelines (heating, water supply, sewerage, etc.). Anti-icing systems for open areas, steps, and garage entrances allow them to be used safely in winter.

Anti-icing systems are most often used to prevent the formation of ice on roofs. Even a properly designed drainage system does not always cope with the task of drainage. In winter and spring periods this leads to the formation of ice and icicles on the roof. The snow on the roof melts and flows to colder edges, where it freezes again, forming ever-growing ice. Gutter systems also freeze and are unable to drain water that melts on the roof, causing damage to the roof and siding of the home. In most cases, it makes more sense to install an anti-icing system than to make constant repairs. The basis of anti-icing systems is heating cables laid in places most susceptible to ice formation. Since the entire anti-icing system is energized during operation, its device must meet all the requirements of PUE, SNiP 3.05.06-85 and SP 31-110-2003.

What are the typical heated zones of an anti-icing system?

Typical heated zones:

Full length drainpipes;

Gutters and gutters;

Drainage funnels and areas around them with an area of ​​about 1 m2;

Entry nodes for gutters drainpipes;

Valleys (joint lines of roof planes);

Other connections to the roof plane ( skylights, lanterns, attics);

Water cannons and water jet windows in parapets;

Roof eaves; drips;

Surfaces of flat roofs and concrete gutters;

Drainage and catchment trays in the ground under drainpipes.

In which parts of the roof are anti-icing systems installed?

Heating cables must be installed on horizontal parts of the roof and along the entire path of melt water. If there are entrances to storm sewers - down to the collectors below the freezing depth.

What are the requirements for anti-icing systems from the point of view of fire and electrical safety?

The system must include only those heating cables that have certificates of conformity and fire safety(as a rule, these are non-flammable cables or cables that do not support combustion);

The heating part of the system must be equipped with an RCD or differential circuit breaker with a leakage current of no more than 30 mA (for electrical safety requirements - 10 mA);

Complex anti-icing systems must be divided into separate parts with leakage currents in each part not exceeding the above values.

PUE, SNiP 3.05.06-85, SP 31-110-2003, SNiP 21-01-97*

What technical components does the anti-icing system include?

Anti-icing system includes:

The heating part, consisting of heating cables and accessories for attaching them to the roof. This part directly carries out the task of turning snow or frost into water until they are completely removed. The heating part may include some snow retention elements that interact with the heating elements;

Distribution and information network, which provides power to all elements of the heating part and conducts information signals from sensors to the control system panel. The system includes power and information cables that meet the operating conditions on the roof, distribution boxes and fastening elements;

A control system containing:

Control cabinet;

Special thermostats;

Temperature, precipitation and water sensors;

Starter control and protective equipment corresponding to the power of the system.

How do anti-icing systems work when outside temperatures vary?

The system must be equipped with temperature, precipitation and water sensors, as well as a corresponding specialized thermostat, which can be called a mini weather station. It must control the operation of the system and allow the possibility of adjusting temperature parameters taking into account the specific characteristics of the climate zone, the location of the building and the number of floors in it.

Are anti-icing systems designed to last throughout the winter?

The operation of anti-icing systems at temperatures below -18...-20°C is, as a rule, not necessary. Firstly, at such temperatures, ice does not form and the amount of moisture sharply decreases. Secondly, under these conditions the amount of precipitation in the form of snow also decreases. Thirdly, melting snow and removing moisture at such temperatures requires significant electrical power. When developing and installing an anti-icing system, it must be borne in mind that the designer must provide the water resulting from the operation of the system with a free path - up to complete removal from the roof and from the gutters.

Are flat roofs heated?

It is recommended to heat flat roofs with armored resistive cables, based on a specific power of 250-350 W/m2, and higher powers apply to roofs on which there can be large drifts. Laying step armored cables ranges from 100 to 140 mm. The minimum bending radius of the NBMK cable is 45 mm.

Parapets located along the edge of the roof act as guide gutters, but at the same time they contribute to the accumulation of snow and ice. To heat the roof behind the parapets, it is recommended to use the same power as for gutters, but one step higher.

Water cannons in the parapets are very dangerous places, promoting ice accumulation. It is recommended to heat the bottom of the water cannon and the area in front of it at least 1 m2 based on a power of 300 W/m2.

When calculating the power and the required number of heating cables, you should proceed from the following recommendations:

- Drainpipes. The rated power of heating cables installed in pipes in the absence of water ranges from 20 to 60 W per 1 linear line. m. It depends on the length and diameter of the pipe. The use of self-regulating cables is especially effective, capable of increasing heat transfer in the presence of water by 1.6-1.8 times;

- Gutters and gutters. The linear nominal heating power of the gutters depends on the catchment area lying above the gutters (troughs) and can be normalized through the catchment area per 1 m of the trough (trough). With a catchment area of ​​up to 5 m2, the heating power may not exceed 20 W/m, increasing to 50 W/m for a catchment area of ​​25 m2 or more;

- Droppers(depending on the design of the drip tube itself) are heated in one or two threads with a self-regulating or armored cable;

- Cornices, located below the gutters, serve as a source of formation of snow and ice blocks that fall off the roofs. To remove snow on the eaves, installation is carried out either along the eaves (if the latter is up to 300 mm wide) or over the entire area. In this case, both self-regulating and armored cables can be used;

- Endovy also contribute to the accumulation of snow. It is recommended to heat them for at least 1/3 of their length. As a rule, according to the layout of heating sections, heating of valleys is usually combined with heating of gutters.

"Soft roof. Materials and technologies of work: Directory” - M.: Stroyinform, 2007. -500 p.: ill. – (Series – “Developer”).

ISBN 5-94418-032-3

The main purpose of gutters, which are necessary for all buildings, is to organize the controlled drainage of rain and melt water from the roof surface, as in the photo. If you do not arrange a drainage system, then flowing down the roof, the unorganized drainage ends up on the walls, penetrates into the basement and the whole process ends with the destruction of the base and foundation. In addition to the practical role modern systems water drainage should perform a decorative function and be in harmony with the architectural appearance of the building.

Types of drainage systems

There are drainage systems:

• internal . Drainpipes are located inside the building at a certain distance from the external walls. Such an organized drain has water intake funnels along the roof area in low areas at a distance of 50 centimeters or more from the protruding parts of the building (read also: " "). It is also stipulated that the roof covering, gutters and valleys must have a slope towards the funnels (read also: " ").
• external . As the name implies, they are located with outside building.

In turn, the external drainage can be:

• unorganized . In this case, water drains from the roof pitched roof to the ground. SNiP allows for unorganized drainage even for 2-story buildings, provided that there are canopies above the entrance to the building and blind areas. An increase (by no less than 60 centimeters) in the removal of the cornice can at least slightly reduce the destructive effects of water flows. In addition to the fact that unorganized drainage from the roof destroys the foundation and walls, it also spoils appearance buildings. Read also: "".
• organized . Such drainage prevents negative phenomena by collecting water and transporting it outside the site on which the building is located. Gutter systems consist of the following elements: gutters; funnels, drainpipes; brackets; knees; connecting and other parts. Organized drainage is distinguished by the fact that water flowing from the roof through gutters is subsequently discharged to drainpipes.

Material for manufacturing drainage systems

Modern organized external drainage is the most popular system for draining water from the roof surface. Today, on the domestic market, manufacturing companies offer wide choose products that differ in the material of manufacture, shape, cross-section of gutters and diameter of drainpipes, both for and external.

The popularity of flat roofs is rapidly gaining momentum today. It is not only very beautiful, but also practical. This roofing option can be a great solution for purchasing additional footage, since it can be used to organize a recreation area, a garden and much more.

Scheme of water drainage from a flat roof.

This architectural solution was not so common in Russia before, but now flat roofs are far from uncommon. They are perfect not only for covering outbuildings or garages, but also for residential premises. Such roofs have many advantages, but it is worth noting that the issue of water drainage from flat roofs is the main condition for their proper functioning.

Drainage device

It is important to remember that the slope of flat roofs is about 2-5%, so in most cases rainwater drainage does not cause problems. However, in order to avoid troubles in the event of heavy rainfall and to ensure that the roof is always dry, it is necessary to think about a drainage system.

An important point is the waterproofing of flat roofs, which is not a complex process, but nevertheless it is necessary. In order to carry it out according to all the rules, it is worth deciding what materials may be needed. Their choice is not particularly large and includes polymer-bitumen or membrane materials. It is worth noting that when choosing materials it is important to pay attention to their service life. If the calculation is for decades, then it would be advisable to use membrane ones.

Water drainage methods

Returning to the issue of drainage from a flat roof, it is worth emphasizing the main methods. The problem of water drainage from flat roofs can be solved using both traditional methods and new, modern systems.

In the first case, we are talking about a drain, the installation of which is carried out on a special ledge or directly on the lowest roof overhangs. If it is not possible to install gutters on any edges of the roof, then special enclosing walls are installed, the junctions of which with the roof covering must be protected with galvanization.

The main function of these walls is to protect the wall from water drainage. It makes sense to talk about installing a drain on a ledge that is located lower than the roof overhang if it is provided for by the design. In such a case the best solution

There will be rectangular drainpipes and gutters, which should be secured with vertical brackets.

Drainage from a flat roof.

Installation of the drain on the roof overhang is carried out in special recessed channels. In this case, it is possible to use gutters made independently from galvanized metal or ready-made ones - steel or PVC. Water is drained from the roof by drain pipes, which are routed through holes in channels with installed gutters.

A much better solution would be to provide for the drainage of water from flat roofs using more modern and progressive methods, which include siphon-vacuum and gravity.

In the first case, the system operates on the principle of sucking water from the roof surface. The principle of operation is that the device, located in the roof funnel, does not allow air to enter the system, creating a vacuum effect - thus, only water gets there.

This system has a number of advantages, including efficient passage of drainage channels, fewer waste pipes and their smaller diameter, as well as high performance funnels. However, there are also disadvantages, which include the complexity of installation and design.

The principle of operation of the gravity system is that, once rainwater enters the funnel, it continues to be drained through drain pipes, which are installed at an angle, in the direction where it was intended. Since water comes together with air, the diameter of the pipes should not be small. It should be the same along the entire length. The most preferable option is if the waste pipe is made of polymer and has a round shape.

Basic principles of water drainage

To summarize, it is worth paying attention to the basic principles and concepts of water drainage from flat roofs. The main elements are the roof funnels themselves, which already direct water into the drain pipes, from where it is discharged into the sewer system, the ground, or special containers provided for this purpose. Pipes, in turn, can be located outside the building or inside.

To carry out a problem-free drainage process, it is necessary to place the funnel at the lowest point of the roof, not forgetting about the slope, the minimum of which should be within 3%.

There should be several funnels, in case the main one is blocked, and they should all be connected to one pipe. It is worth installing them every 25 meters, not forgetting about the emergency low tide, in case the main system cannot cope with an excessive amount of water.

They should be selected depending on the design and purpose of the roof, as well as the level of insulation.

It is important to decide whether the sewer pipes will be located outside or inside. It is preferable to choose external pipes, since they are easier to operate, given that they are easy to clean or repair. The only drawback is the aesthetic aspect. However, the appearance of the pipes does not spoil the appearance of the building so much.

Pipes installed indoors have many more disadvantages. They are difficult to access, and in the event of a leak, fungus will inevitably appear.

It is worth considering freezing in areas of the drainage system, which can lead to blockage of pipes. To avoid this, you can install heated funnels.

If we take into account all the nuances described above, a flat roof can not only delight with its unusual appearance and perform additional functions, but also remain dry all year round, regardless of the amount of precipitation in any weather!

Water drainage from flat roofs: dry roof all year round

What is the best drainage system for a flat roof - types and features of the device

When installing a flat roof, you need to think in advance about how water will be drained from it. Unlike roofs with steep slopes, from which water drains on its own, flat structures always have problems with this. The water remaining on the surface of the roof does not pose any particular danger (of course, if the roof was assembled well), but when it freezes, the likelihood of damage to the coating increases many times over.

To avoid the harmful effects of moisture on the roof, it is necessary to provide high-quality drainage. How to make drainage from a flat roof, and we'll talk In this article.

There are two main types of drainage systems:

Traditional drainage systems

If on some sides of the roof it is impossible to provide organized drain water, it is necessary to prevent its flow in order to protect the walls of the building. For these purposes, barrier walls made of concrete or metal are used. Galvanized “aprons” are installed at the junctions of these walls and the roof covering.

Drainage from a flat roof is installed in the following places:

• On roof overhangs located lower relative to others;
• On special ledges.

Using the first scheme, the drainage system must be mounted near the overhang in prepared channels. As these channels, ready-made structures made of metal or plastic can be used, or homemade elements made of galvanized steel. Drainage from a flat roof is carried out through drain pipes located in channels connected to the gutters.

In the case of a protrusion, a flat roof with an external drain will be laid differently. As a rule, rectangular gutters and pipes mounted on vertical holders are used to arrange drainage here. In order for the drain pipes to be attached to the gutters, the protrusion must be made in advance required amount holes.

However, much more effective option The structure is a flat roof with internal drainage. For such a system to work, the roof must be minimum slope 2 degrees is divided into sections. For one such plot of about 150-200 sq.m. a separate riser is required. If total area roof is less than the specified values, then a single riser will be sufficient for drainage.

At points with a slope, external drainage funnels for flat roofs, equipped with dirt traps, are installed. Considering that the drainage is internal, these funnels are most often located near the center of the roof, and the drain pipes are brought into the building and connected, for example, to sewer system. To prevent the liquid from freezing near the funnels, it would be a good idea to connect a heating cable to these areas. Internal elements The drainage system must be heated constantly along its entire length.

Modern flat roof drainage systems

The main element of the external drainage system is a funnel, which collects all the water into pipes (they can be located not only outside, but also inside the building) and transports them to the sewer. The funnel is usually installed at the lowest point of the roof.

Often the drain funnels become clogged, resulting in a significant reduction in the efficiency of the drainage system. To avoid this, it is worth installing several duplicate funnels that are connected to the main drain pipe. For maximum efficiency and the possibility of discharging water in the event of roof flooding, a flat roof with an internal drain is equipped with an emergency drain.

For different types of flat roofs they are used Various types funnels:

• On roofs used as terraces, models with flat covers are installed - they do not interfere with movement on the roof surface;
• For green roofs, funnels with meshes are used to prevent various debris from entering the drainage system;
• Insulated and non-insulated roofs are also equipped with their own types of funnels.

Internal and external gravity drain

Gravity internal drainage is quite simple and can work even if errors were made during installation. The operating principle of this design is also very simple: the liquid collected by a funnel is directed through pipes outside the building. In this type of system, water moves through the system along with air, so large diameter pipes are required for its operation.

As a rule, plastic round products are used for gravity systems, which, in addition to high throughput, practically do not clog due to the smooth inner surface. Pipes are laid in non-residential premises and send water to where it will not harm anyone.

Siphon-vacuum drainage

This system draws water into itself, and the drain funnel is equipped with a special element that prevents air from entering the drain. Due to the resulting vacuum, liquid is sucked into the drainage system.

Among the advantages of such a system are:

• High efficiency of funnels;
• Possibility of using small diameter pipes;
• No need to lay long pipelines;
• Good throughput;
• The system can operate even in the absence of a slope.

The elements and structure of the internal siphon-vacuum drainage system are quite complex, so such a system is rarely used in private construction.

Classification of drainage funnels

Drain fittings have several parameters, depending on which they are distinguished different types these devices:

1. Design. Structurally, funnels can consist of either one or two parts. More complex fittings are usually used on roofs that can change their shape - for example, wooden or unventilated. In this case, the parts of the funnel simply move relative to each other, so the drainage system continues to work with the same efficiency.
2. Bandwidth . This indicator is mainly affected by the diameter of the funnel. Throughput is determined by the volume of liquid that can pass through the funnel per unit time.
3. Connection with waterproofing. Drainage funnels can be connected to waterproofing layer differently. One of the most popular methods requires a special crimping fold. Aprons made of film or roofing felt are also often used. However, it is best to use fittings without aprons - they are suitable for roofs made of any material.

High-quality drainage from a flat roof is very important. A drainage system, regardless of its type and design features, significantly extends the service life of the roof, and therefore the entire building.

Drainage from a flat roof: internal drainage, external drainage funnels for flat roofs, installation of drainage elements, drainage

Flat roof drainage: specifics of construction of internal and external options

Without proper organization of the drainage system, a flat roof will quickly require unscheduled repairs. Stagnation of rain and melt water on the surface will gradually erode the protective outer layer of the coating. As a result, the bare base will rapidly collapse from the zealously attacking sunlight. When freezing, water crystals can easily tear the material apart. A properly constructed flat roof drain can prevent and prevent negative impacts. Rules and principles of the device important system drainage system should be carefully studied by the owner who cares about the efficient and long service of his country property.

Flat roof gutters

The purpose of constructing a drainage system for a flat roof is to fully organize the drainage of rain and melt water from a surface sensitive to their action. It must operate effectively all year round without the formation of dust blockages, ice and leaf jams.

Regardless of the readings of thermometers and the volume of precipitation, the drain must accept and promptly transport the liquid substance to the sewer, to a container for collecting rainwater, or simply to the ground.

Classification of sediment drainage systems

In order for water to be transported without interference or obstacles, you should know exactly what type of system to choose for arranging your country property:

• Outdoor unorganized. Assuming spontaneous drainage atmospheric water. They are used for arranging small outbuildings with a height of no more than two floors.
• Outdoor organized. Involving the collection of water using gutters or gutters coupled with funnels and subsequent transfer to the drainage pipeline. The system is laid along the eaves overhangs and the outside load-bearing walls. It is used in the arrangement of residential and non-residential buildings, mainly low-rise ones, but the scheme is acceptable for organizing runoff from the roofs of buildings up to five floors high.
• Interior. According to this, water is received by drainage funnels created specifically for flat roofs, built into the roofing system. Water is drained through risers located inside the building being treated.

External drainage systems work great in southern regions, where water in pipes freezes extremely rarely or does not freeze at all during the entire cold period. For regions of the Russian temperate climatic zone, external gutters are recommended exclusively for attic structures.

On roofs without an attic, the snow will melt almost without interruption all winter, because the ceiling is constantly heated by heat coming from inside. Once melted water enters cold pipelines, it will form ice jams.

If the flat roof has an attic, then the snow melting process can be regulated. By opening the dormer windows, the temperature on the roof can be significantly reduced, causing the snow to melt much more slowly or stop altogether.

In the northern regions there is a threat of rupture of the coating during a sudden cold snap. A blockage may form in the pipes, blocking the flow of remaining water on the roof. The crystallizing liquid noticeably increases in volume, which leads to damage to the roof that has absorbed it. Therefore, in northern and temperate Russian latitudes, only non-residential buildings are equipped with external drains, i.e. unheated buildings and buildings with a designed low temperature.

Cold storage buildings, for example, are equipped with a remote reinforced concrete slab with a side and a drainage riser. The impressive area of ​​such a structure helps to equalize the temperatures of the system and the environment, so that ice jams do not form.

Residential buildings with flat roofs, built in areas of the northern and temperate zones, are equipped with internal drains. The construction is more expensive, but operates reliably all year round. The risers located inside the buildings are constantly heated internal heat, which prevents ice jams from occurring in pipelines. In southern latitudes, drains of the external variety are the leaders.

Structural components of gutters

There is much in common in the design of external and internal drains. Each system constructed for flat roofs includes elements similar in purpose and design, these are:

• Water intake funnels and gutters designed to receive wastewater and transfer it to the drainage main.
• Risers, providing maximum speed of water flow at the receiving points due to gravitational forces.
• Drainage pipelines, required for the removal of precipitation to unloading facilities.

The main guideline for designing a drainage system is the minimum length of the pipeline from the points of water intake to the points of discharge of the system. The shortest and cheapest outdoor version includes a riser with a funnel or trough at the top and a short outlet at the base.

The outlet is located at a slight angle at a distance of 20–45 cm from the surface above a storm drain or simply above a blind area protected from erosion. However, equipping a house with a drain of such a design is often prevented by insurmountable circumstances: the lack drainage system, weak soils, old foundation, the proximity of which to water is undesirable.

If it is impossible to lay the smallest line, they look for other ways to drain water: an above-ground or underground pipeline is taken from the riser, leading to the most convenient unloading point.

The pipeline scheme is unconditionally used in the construction of flat roofs with internal drainage, because the system is definitely required to transport water outside the building.

Specifics of slope formation

To stimulate the independent flow of water in the required direction, slopes of 1-2% are formed on flat roofs:

• To organize an external type of drain, the entire plane must be inclined towards the area where the drainage gutter is installed. Most often this is the back wall of the building.
• To organize the flow of water through internal circuit a slope is created towards the installation site of the water intake funnel. It is formed according to the envelope principle so that around each water intake point there is a depression within a radius of 50 cm.

Water inlet funnels of internal drainage systems can be installed not only in the central zone of the roof, but also near the outer wall, at a distance of at least 60 cm from it. Therefore, the envelope circuit for tilting devices has quite a lot of different options.

Anyway inclined plane should be directed towards the water intake. And if several funnels are installed on the roof, a kind of “watershed” should be created between them - a miniature resemblance to a mountain range, the slopes of which direct the flow of water in the direction of the nearest funnel.

To solve the problem of forming slopes, there are several proven methods:

• Tilt device during construction by installing the ceiling at the required angle.
• Backfilling of expanded clay in the form of a wedge-shaped layer, followed by pouring a cement-sand screed.
• Organization of the slope by laying wedge-shaped slabs of mineral wool insulation.

The slope of large-sized planes is carried out using special angle-forming metal structures. They are rarely used in private construction.

Rules for the construction of internal drainage

As befits any constructed facility, the drainage system of a private house must be calculated and designed in advance. It is necessary to select in advance the shortest possible route for laying the pipeline and provide the most comfortable spot connecting it to the storm sewer.

A variety of flat roofing structures are subject to the organization of internal drains. They are installed on roofs with and without attics, in exploited and non-exploitable categories. Taking into account the planning specifics of the house, an independent designer needs to take into account the following:

• Gutter risers are usually located in the area stairwells near walls, columns, partitions. Preferably near residential premises for spontaneous heating during cold periods of the year. Embedding risers into walls is strictly prohibited. Can be installed in grooves, shafts, boxes. It is recommended to place them in closets or similar utility compartments.
• When organizing a drainage system for an unheated building, it is necessary to provide methods for artificial heating of funnels and risers. To increase the temperature of the external elements of a flat roof, install an electric heating cable or install risers next to steam heating.
• A flat roof with an attic is best equipped with piping running within the attic space. It is made in the form of a suspended network. To ensure drainage, the horizontal sections of the suspension system pipes are installed at an inclination of 0.005. Those. For every linear meter of pipe there should be a 5mm reduction towards the spillway.
• When laying overhead pipelines, the drainage section in the attic area must be insulated.
• If installing a suspension system is not possible, underground pipeline installation is carried out. There are no regulations on the angle of inclination of underground branches. The main thing is that there is a connection to the storm sewer. True, the underground scheme is much more expensive and significantly more inconvenient in terms of control and repair work. In addition, its implementation may be hindered by too strong a foundation.
• When designing, bends should be avoided whenever possible.
• The riser at a distance of about a meter from the ground surface should be equipped with an inspection for cleaning.

Essentially, flat roof drainage should be arranged as standard drainage system: with inspection wells, revisions, etc. In the construction of a suspended drainage pipeline, ceramic, plastic, cast iron, asbestos cement pipes, withstanding pressure during blockages.

For laying underground parts of pipes made of the same materials, but without the requirements for hydrostatic conditions. Long steel pipes are used only at production facilities with characteristic vibration manifestations.

According to technological requirements, one drainage funnel can receive atmospheric runoff from a roof with an area of ​​up to 1200 m², the distance between adjacent water intakes must be at least 60 m. Agree, the indicated scales are not very typical for low-rise construction. In short, there should be at least one funnel on the roof of a small private house.

It is necessary to increase the number of water intake devices if:

• The roof area exceeds the limits specified by GOST.
• The house is divided into sections. Then each compartment should be equipped with its own funnel.
• Within one roof structure there are elements separated by parapets, expansion joints or expansion joints. Each sector of such a roof must have two water inlets.

Drainage funnels are produced for exploited and unexploited flat roofs, for combined structures and systems with attic space. There are models used in the arrangement concrete floors with bitumen coating and wooden analogues covered with corrugated sheets. For all options used in construction, water intakes are made from cast iron, ceramics, galvanized steel, and polymers.

Water intake devices are produced in a variety of sizes. The standard design consists of the funnel itself with wide sides and a removable cap with holes that ensure water flow.

More complex representatives of the roof drain class are additionally equipped with an umbrella that protects the drain from clogging, a removable cup and a pressure ring designed to clamp the edges of the soft covering in the device. All models must allow for maintenance and cleaning.

Regardless of the funnel model and the purpose of the building, equal requirements are imposed on all water intakes:

• The water collector bowls are rigidly attached to the coverings or load-bearing decks. For fixation, at least two clamps are used.
• After installation, the funnel must ensure the tightness of the roof at the installation site.
• The funnel pipes are connected to the risers using compensators, which help maintain the tightness of the connections during shrinkage building structures.
• Funnels are connected to suspended systems using shaped elbows.
• The water intake bowl is installed below the level of the finished roof to eliminate the possibility of water stagnation. Water intake caps on unused roofs have a rounded shape in plan; they usually rise above the roofing. Funnel caps for existing roofs are installed flush with the covering; they are most often square in plan to make it easier to lay tiles around the device.

To increase sealing and reliability in the area where the funnel intersects the roof structure, the use of thermal insulation is allowed. Conventional roofing systems are equipped with single-level funnels.

Inversion systems and roofs constructed using mechanical fasteners are equipped with two-level water inlets that collect water above the waterproofing and above the vapor barrier.

Roof structures with a polymer membrane coating are usually equipped with water inlets with a polymer pressure flange, which is glued or welded to the roof.

This method achieves the maximum possible waterproofing in the area where the water intake device is installed. The gluing areas of the water inlet flanges must be reinforced with additional layers of waterproofing weld-on material. It can be replaced with fiberglass glued to the mastic.

Construction of an external drain

The construction of external types of gutters from flat roofs is carried out in the southern regions. Their installation in residential and office buildings is recommended in areas with insignificant precipitation, the volume of which does not exceed 300 mm per year.

The class of external drainage systems for rain and melt water includes:

• Unorganized drains recommended for installation in dry areas. According to this scheme, water is drained by gravity along the eaves overhangs.
• Organized drainage recommended for equipping non-residential buildings in northern and temperate latitudes, residential buildings in southern regions with insignificant precipitation rates. The principle of operation is the systematic collection of precipitation into an external drainage funnel with adjacent guide sides or into a gutter, followed by drainage of the wastewater into a storm drain or into the ground.

An ingenious solution for an external type system was proposed by zealous craftsmen. The idea is to include a sand filter in the water supply network to purify rainwater, which is installed after the water inlet.

Tanks are installed to unload the drain and receive purified water. This means that the area connecting the system to the sewerage system is eliminated. An interesting scheme allows you to profitably solve two problems at once: obtain drinking water and protect the flat roof from stagnant water.

An unorganized type of drainage system requires strengthening of eaves overhangs. They must be covered with galvanized roofing steel, and then covered with two layers of rolled roofing on top. Additional layers are laid with overlap.

Reinforcement of the overhang of a mastic flat roof is enhanced by analogy. Only instead of glued layers of bitumen or bitumen-polymer material, layers of mastic are applied, alternating them with reinforcing layers of fiberglass or geotextile. The main layer of reinforcement with reinforcement must overlap the edge of the metal upholstery of the cornice.

The external drainage system is fixed to the eaves of a flat roof using traditional scheme. There are a lot of ready-made kits on sale with detailed instructions on assembling systems. First, brackets are attached to the frontal board, into which a gutter assembled from plastic or metal modules is simply placed.

In a place convenient for further transportation of water, a water inlet funnel of the gutter is installed with a pipe to which a riser is connected. The pipe is fixed to the wall using brackets. The edges of the system are closed with plugs, and it is completed by installing a figured outlet.

Flat roof drainage: external and internal ways devices

Characteristics of types of organized roof drainage. Their differences, advantages and disadvantages

A properly selected water drainage system is the key to long service life of the roof. Since a flat roof has no slope, it is easily susceptible to the negative effects of precipitation, which remains on the surface and, when frozen, destroys the roofing material, and before that the protective coating layer. To prevent such consequences, it is necessary to correctly select and install a water drainage system. Any owner of a private home should know the structure of a drainage system.

Buildings with flat roof, no more than 2 floors high, may have unorganized drainage from the roof. If the structure is higher, it becomes necessary to install an organized drainage system (internal or external). That is, on multi-story buildings with flat roof It is necessary to install a structure for drainage of melt and rain water.

External and internal drainage

To prevent negative impact precipitation, special barrier walls with concrete or metal coating are placed on the walls of buildings with flat roofs. The joints on the walls are covered with a galvanized apron. Install a water drainage system on overhangs located below the rest of the surface or on specially designed projections.

In an external drainage system, funnels are installed near the roof overhangs. Then the sedimentary water flows through sewer pipes drawn through holes in the channels where there are special gutters. An internal organized drainage system involves installing funnels directly on the roof surface. Water flows through channels located inside the house.

How does internal flat roof drainage work?

For flat roofs, a special type of outer and internal systems gutter

A flat roof with internal drainage has more complex design than external roof drainage. However, the first system has more advantages, as a result of which the owners of country houses prefer it. A comparison can be made with how a drain works in a bathroom where there is some water left. When the drain is open, this water will flow into the drain. The same principle applies to internal drainage on a flat roof. You can make a design so that melt and rainwater flows not into the sewer riser, but into a special container. This water can then be used for your own purposes.

Advantages and disadvantages of internal drainage

The advantages include the following properties:

• Neat appearance. You don’t have to worry about whether the design will successfully combine with the exterior of the house or building.
• Since the pipes are located inside and not outside the building, they are protected from changes in air temperature. So home owners don’t have to worry about the condition of the pipes.
• When installed correctly, internal roof drainage does its job best.

However, this type of drainage also has some disadvantages. Among them:

• Difficult cleaning process.
• The need to design a house taking into account the installation of internal drainage. In any case, before they even begin roofing, it is necessary to include such a drainage system into the project. Otherwise, you will have to dismantle the roof.

Types of internal drainage structures and materials for their manufacture

There are two types of internal drainage systems:

To find out which system is best to install for a building with a flat roof, it is necessary to make an approximate calculation of the drainage.

In systems of the first type, sedimentary water is extracted by gravity. This system is ideal for country houses and oversized buildings with a small roof area.

To install the second system, special funnels are required for water drainage. If there is little sedimentary water, then such a system functions on the same principle as the gravitational one. When there is a large volume of water in pipes and funnels, it is drawn into the general sewer or wastewater tank due to the draft that appears in the system. This design of organized roof drainage is applicable to large buildings with a large roof area.

Metal or plastic is usually used for manufacturing. This material is lightweight, easy to work with, and yet strong enough if the pipes have stiffeners. However, in harsh climates, plastic parts can quickly fail due to air temperature changes. Metal systems more durable and reliable. The most durable and aesthetic metal is copper. But the price of such structures is quite high. Structures that consist of other metals usually have an anti-corrosion coating, which helps extend the life of the drainage system.

Specifics of the design and installation of internal drainage

An important point during installation is the roof slope. It is made 50 centimeters from the funnel where the water will flow, the exposure level is 5%. Next, it is equally important to correctly calculate the required number of funnels. Their number depends on their diameter and roof area. A funnel with a radius of 10 centimeters can collect water from a roof with an area of ​​240 square meters, and a funnel with a radius of 0.7 centimeters - from a roof with an area of ​​110 square meters. Be sure to install at least 2 funnels. This is done for safety reasons, in case one of the funnels becomes clogged or fails.

In regions with cold climates, there is an increased risk of parts of the water drainage system freezing. A roof and gutter heating system prevents this problem by installing a heating cable in the system. Specially designed nozzles prevent clogging of drainage systems with debris and leaves.

For each case, the size of the pipes is determined individually, taking into account the amount of precipitation, the degree of temperature difference during the day, and the number of verticals in the structure. Storm drains must be installed at a distance of at least 50 centimeters from each other. It is recommended to install water collection funnels in such a way that they can collect water from equally sized parts of the roof. Near the funnels, it is necessary to seal the holes more effectively or install another layer of waterproofing.

To install a drainage system, it is necessary to make an accurate plan for a flat roof, the parameters of which are individual in all cases. It is also important to take into account the specifics of the climate, the quantity and quality of precipitation and the difference in air temperature.

External drainage structures

These systems are recommended to be installed in houses in the southern regions, where there is little precipitation (no more than 300 mm per year), since the water in the pipes does not freeze there or this happens extremely rarely, so an anti-icing system for the roof and gutters is simply not needed here. For regions with a temperate continental climate, it is possible to install such systems only in the attic. On roofless roofs, snow will constantly melt throughout the winter due to continuous heating by warm air from inside the house. Further, water flowing into cold pipes will lead to the appearance of ice jams.

There is unorganized and organized external drainage from a flat roof.

The second type is suitable for buildings in the northern region with a temperate continental climate. In such structures, water is collected in an external funnel, to which the sides are attached, or in a special gutter. The water then flows into the ground or into a storm drain.

The design of an unorganized external drain is characterized by stronger eaves overhangs. They are upholstered with special roofing steel coated with zinc. Next they are covered with two layers of roofing.

This type of drain is installed as follows: brackets are attached to the front board, where the supply channel and a special container (made of metal or plastic) are placed. Where precipitation will flow, a special funnel is placed to receive water. Behind it is a pipe to which a riser is fitted. The pipe is secured to the wall with brackets. The edges of the structure are covered with plugs, then a figured outlet is installed.

Thus, proper installation and proper care the drainage system will ensure efficient and complete collection of melt and rainwater for a long time. To do this, you will need to first draw up a drainage plan; you must also take into account the type of building (residential or non-residential premises) and climatic features of the region.

Characteristics of types of organized roof drainage

The main purpose of the drainage system is to collect and drain melt and rainwater into a storm or regular sewer system. The purpose of these measures is to prevent moisture from entering the walls, blind area and foundation of the building in order to prevent its destructive effect and the need for subsequent expensive repairs. Additional function drainage system is to give the structure an original and pleasant appearance. Like all other types of building structures, the creation of a drain is regulated by the relevant SNiP 06/31/2009 as amended by SP 118.13330.2012, put into effect on 09/01/2014.

Types of existing drainage systems

There are three main drainage systems:

1. Organized external roof drainage
2. Organized internal drainage
3. Unorganized drainage

A significant part general information You can get it from the video:

Organized external drainage

Currently, this system is considered the most widespread and frequently used. It is a set of gutters, pipes and drainage fastening elements combined into a single whole, installed outside the building by attaching it to its walls. As a result of its action, water from the roof should enter the storm drain or well.

SNiP allows the organization outdoor system drainage both on flat and on pitched roofs almost any type of buildings and structures.

Advantages of an organized external roof drain:

• guaranteed protection against water ingress of walls, foundations and blind areas of the building;
• attractive appearance given to the structure through the use of high-quality modern materials.

The main disadvantage of the system under consideration is the need to invest financial resources for purchase and installation.

The most common systems are made of PVC and metal-plastic, which are actively used instead of traditional ones made of galvanized steel or ferrous metal. The highest quality, visually attractive and durable, but at the same time the most expensive, is the use of copper.

Organized internal roof drainage

When installing this drainage system, pipes are laid directly inside the building. Moisture collects on the roof and is transported along them to storm drains or regular sewers. Almost always, this type is found on flat roofs, which are made of rolled materials and mastics. Its advantage is that the water internal pipes does not freeze even in the coldest times, which is one of the problems of external drainage, especially in domestic conditions.

The disadvantage of organized drainage from a flat roof is also obvious - part of the internal space, which, as a rule, is always missing.

SNiP clearly regulates the basic requirements, the fulfillment of which is necessary for successful work:

• The area of ​​funnels located on the roof is calculated based on the ratio - per 0.75 sq.m. coverage area of ​​at least 1 sq.cm. sections of the water intake funnel;
• on areas of the roof that are limited by walls or expansion joints, at least two funnels must be located;
• it is planned to install water intake funnels in areas of the roof with the lowest vertical elevations;
• These funnels should be located no closer than 50 cm from walls or parapets.

Unorganized drainage

With this system, melt or rainwater flows to the ground directly from the roof. Naturally, the absence of the need for additional materials and means leads to savings in financial resources during construction, which is one of the main advantages of unorganized drainage.

Its use is not allowed on a flat roof, since water drainage occurs due to the existing slope of the roof slope. In addition, even when installing unorganized drainage on small buildings and structures, it is difficult to avoid problems:

• deterioration or even partial destruction of the foundation. The problem can be solved by installing additional drainage underground, the purpose of which will be to remove excess water from the soil adjacent to the foundation;
• negative impacts on the basement of the building. Eliminated by periodic renewal of the vertical waterproofing layer;
• possible mechanical damage to the facade. The problem can also be solved by improving waterproofing and maintaining it in proper condition.

The presence of these problems raises a logical question: how reasonable is it to install an unorganized drainage system? The conditions necessary for this are clearly regulated by SNiP 06/31/2009 in the updated version, put into effect on 09/01/2014. It describes the characteristics of buildings and structures in which an unorganized drainage system is permitted.

SNiP requirements 06/31/2009

• the number of floors of a building or structure is no more than five;
• location in a region with average annual precipitation of less than 300 mm;
• the type of roof on which it is planned to be used - pitched with a slope into the yard;
• roof canopy size - at least 0.6 m;
• the absence of sidewalks, balconies or a highway directly under the roof slope.

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