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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. The rules and principles of the design of such an important drainage system should be carefully studied by the owner who cares about the effective and long service of his country property.

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 of 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 eaves overhangs and the outside of 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 by internal heat, which prevents ice jams from occurring in the 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 option involves 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 hampered by insurmountable circumstances: lack of a 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 according to the internal scheme, a slope is created towards the installation site of the water inlet 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.

In any case, the 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 for the most convenient location for connecting it to the storm sewer.

The organization of internal drains is subject to various types. 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 of ​​staircases near walls, columns, and 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.

In fact, drainage from a flat roof should be organized like a standard drainage system: with inspection wells, revisions, etc. In the construction of a suspended drainage pipeline, ceramic, plastic, cast iron, and asbestos-cement pipes are used that can withstand pressure when clogged.

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 construction of concrete floors with a bitumen coating and wooden analogues coated with. 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 bowls of the water collectors 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 expansion joints, which allow maintaining the tightness of the connections during shrinkage of 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.

And roofs constructed using mechanical fasteners are equipped with two-level water intakes that ensure water collection 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.

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.

Fixing the external drain on the eaves of a flat roof is carried out according to the 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.

Video instructions for installing gutters

The video will introduce you in detail to the principles of design of internal drainage systems and the specifics of their installation on a flat roof.

Assembly and installation of external drainage system:

Installation of slopes on a flat roof:

Installation of a water inlet funnel for an internal drain

Information about guidelines for choosing the optimal drainage system will help you properly equip your roof with reliable protection from the destructive effects of water.

Knowing the technological principles of the device is useful for independent craftsmen and owners of country real estate who want to use the services of third-party contractors. A properly constructed drain will prevent damage to the coating and destruction of building materials; it will serve for a long time without creating problems.

The main enemy of any roof is water, the destructive effect of which leads to a reduction in the service life of the roofing material and leaks. Gable, hip and even single-pitched types of roofs have something to resist melt and rain water.
These are their slopes, thanks to the slope of which moisture, without lingering on the roof, slides down. Flat roofs are less protected; puddles accumulate on a flat surface and do not have time to dry.

Stagnant water methodically destroys the waterproofing layer; in addition, dust blown by the wind settles in them, forming a swampy substrate. Plant seeds that fall into this “soil” germinate and destroy the roofing pie with their roots. To avoid extending its service life, it is equipped with a drainage system that drains water from its surface into the storm drain.

Flat roof drainage system

The drainage system of a flat roof is a set of elements that collect, transfer and discharge water that appears on the roof surface as a result of precipitation or melting snow. equipped with the following types:

1. Disorganized. It consists in the fact that the water simply slides off steep slopes. This method of self-drainage is used in private houses with pitched roofs, but is not suitable for buildings with a flat roof.
2. External. Consists of a gutter and downpipes fixed to the wind dock or rafters. By gravity, due to the slope of the roof, water is removed from the slopes and drained into a drainage ditch or storm drain. External drainage is used to drain water from a small flat roof, in particular for utility buildings.
3. Interior. A characteristic feature of the internal drain is that it is laid inside the roofing pie. It is designed taking into account the specifics of flat roofing.

Internal flat roof drainage

They are not placed outside, but under layers of waterproofing and insulation. It consists of:

• Drainage funnels installed on the roof surface, in low places constructed during slope. The function of funnels is to collect and filter melt and rain water falling on the roof.
• Horizontal drainpipes, which are installed under a layer of waterproofing and insulation on a slope, if a gravity drain is installed, or without a slope, if a vacuum drain.
• Vertical drainpipes that collect water flows coming from horizontal pipes and drain into storm drains.

Depending on the method of moving water into the drainage system, there are gravity and vacuum types. The principle of operation of a vacuum drain is that precipitation completely fills the pipes, creating a column of water, which, when moving downwards, air first rises upward, creating a vacuum environment, and then carries water with it from the drain funnel, as if sucking it in. In areas with heavy rainfall, experienced roofers recommend installing a vacuum system, which quickly copes with large volumes of water, and even self-cleans due to its rapid movement through the pipes.

A drainage funnel on a flat roof is responsible for collecting and receiving water accumulating on the surface. It consists of:

• The lower part, which is mounted into the base of a flat roof.
• A seal that hermetically connects the upper and lower parts of the drainage funnel.
• The upper part, passing through the thickness of the insulation and waterproofing.
• A protective grille, which is located above the roof surface and protects the drainage funnel from the penetration of large debris and the formation of blockages.

The tightness of the connections between the elements of the drainage funnel is a prerequisite for the effective operation of the drainage system. When examining a flat roof after a leak was discovered, in 70% of cases the problem was water penetration between the joints of the funnel parts.

Types of drainage funnels

The roof drain can be made of galvanized metal, copper or polyvinyl chloride. Galvanized copies are used more often than others, due to their affordable price. Copper funnels have not gained popularity due to their exorbitant cost, especially since they are not compatible with all roofing materials. Products made of polyvinyl chloride are excellent for installation on soft tiles, shingles, and ondulin.

The following types of drainage funnels are available in specialized stores:

When installing gutters, professional roofers adhere to the following principles:

• Place funnels in places located below the main roof level. The slope between the base and the funnel should be at least 2 degrees, and at a distance of 50 cm increase to 5 degrees. The slope is set when tilting with insulation slabs, expanded clay or concrete.
• Gutter funnels are distributed evenly over the surface of a flat roof at the rate of 1 piece per 25 meters of length.
• Regardless of the roof area, the minimum number of drainage funnels is two. Since in the event of a clogged drain or during heavy rainfall, the second one will insure a funnel that is out of order or cannot cope with a large volume of water.
• The smallest permissible distance between drain funnels is 50 cm. And from the edge of the roof - 1 m.

Installation procedure

Install drainage funnels on a flat roof as follows:

The drainage system, including funnels, must be periodically inspected and cleaned so that an unexpected downpour does not lead to a roof collapse. A properly organized drain will not only extend the life of the roof, but will also become a source of water for irrigation if you are concerned about preserving natural resources.

Video instruction

One of the most destructive factors that shortens the life of a roof is water. However, whatever the design of the roof, there are fairly reliable methods that can effectively withstand precipitation and melt water. In this article we will talk about what drain funnels there are for flat roofs and how to install them correctly.

It is worth noting that roof slopes make it easy to cope with the problem of intense rainfall, since water simply drains from them. But in cases where the roof is completely flat, puddles form on it because the moisture does not have time to evaporate. As a result, the waterproofing undergoes gradual destruction, and a layer of dirt accumulates on the roof surface.

Often wind-blown plant seeds germinate in this layer, further destroying the roofing pie. It is the drainage of melt and rainwater into the storm sewer system that is the main purpose of drainage funnels on flat roofs.

What is a drainage system

The term “drainage system” implies a set of devices through which melt and rainwater are collected, transported and removed from the surface of a flat roof.

There are the following types of drains:

1. Unorganized, or natural. In this case, it means that precipitation rolls down steep slopes. For roofs with large slopes, this method is quite acceptable, but it is absolutely not suitable for flat roofs.
2. External. It includes a set of pipes and gutters for water drainage, installed on rafters or wind boards. Precipitation enters such drains by gravity and is discharged outside into the storm drain. For flat roofs, this type of construction is applicable only in small buildings.
3. Interior. This type of drainage is laid in the thickness of the roofing pie. It is most preferable for flat roofs.

Internal drains for flat roofs

The structure of the internal drainage system suggests the placement of its elements under the insulation and waterproofing layer.

Such a system contains the following components:

• roof funnel – they collect and filter water;
• horizontal pipes - laid under insulation and waterproofing with a slope - for gravity drainage, and without a slope - for vacuum drainage;
• vertical drain pipes - they transport sediment from horizontal pipes to the storm drain.

Depending on the principle of fluid movement, vacuum and gravity drainage systems are distinguished. With a vacuum type of drain, liquid quickly fills the pipe throughout its entire thickness, forming a continuous column of water. As it moves downward, the air mass tends to rise upward, creating a vacuum. The resulting space, as it were, sucks water from the drain funnel, ensures its rapid removal from the roof surface and prevents the accumulation of debris due to the rapid movement of liquid.

Structure of a drainage funnel

By design, a drainage funnel for a flat roof consists of the following elements:

• the lower section, which is laid into the base of the roofing pie;
• a sealing gasket that seals the joint between the upper and lower sections of the funnel;
• the upper section, which passes through the layer of waterproofing and insulation;
• grate - serves to prevent large debris from entering the drainpipe.

Please note that reliable sealing of the joint between the upper and lower sections of the drainage system funnel is mandatory for the effective operation of the roof. As a rule, it is the penetration of water into the seams of the funnel that causes leaks.

Types of roofing funnels

On sale you can find funnels for flat roofs made of polyvinyl chloride, copper or galvanized steel. The latter are used most often because they are affordable. Copper products are too expensive for buyers, so they are not in high demand. In addition, they cannot be combined with any roofing covering. Polyvinyl chloride roofing funnels are used on roofs made of ondulin, shingles and soft tiles.

Based on their structure, the following types of products are distinguished:

1. Flat. Such products are mounted flush with the roof surface covered with asphalt or tiles.
2. Kolpakovaya. This funnel is necessarily equipped with a protective grille that prevents debris and dirt from entering the pipe. The product rises above the surface, resembling a glass or cap.
3. With horizontal or vertical release type.
4. With heating elements. A heating cable is installed inside such a funnel, which melts the snow and prevents the water from freezing and clogging the drain.

Principles for installing a roof drain funnel

Professional craftsmen have developed some standards for the correct installation of funnels on soft roofs:

• Installation of the device must be carried out in places whose level is below the main surface of the roof. The minimum slope between the funnel and the main roof can be 2º, and over a segment of 50 cm it should increase to 5º. The required slope is created by slabs of insulating material, concrete screed or expanded clay backfill.
• The number of funnels on the surface of a flat roof is determined based on one unit for every 25 m of length.
• Whatever the area of ​​the roof, it must have at least two drainage funnels. They will allow large amounts of water to be removed from the roof more quickly if one of the gutters fails.
• The minimum distance between devices is 50 cm, and there must be at least 1 meter to the visor.

Installation sequence on a soft, flat roof

Installation of funnels for removing precipitation from a flat roof is carried out as follows:

• First, the roof is marked, divided into identical geometric shapes. In the central part of each of them, using expanded clay, a layer of insulation and a concrete screed, a recess is created. The lower part of the funnel is connected to a drainpipe laid horizontally and is mounted at the base of the roofing pie.
• Upon completion of the waterproofing and insulation work, the sealing ring is laid and the two parts of the funnel are connected.
• The upper part of the device is placed between two layers of roofing material, after which it is fixed with a built-up bitumen apron.
• At the end, a layer of bitumen or mastic is applied, and a protective mesh is installed.
• To make sure that the water inlet funnel is installed correctly and tightly, two meters from it, pour a bucket of water onto the roof and check how quickly all the liquid moves into the drain.

It is worth noting that the drainage system, in particular roof drains, require periodic diagnostics and cleaning. This will significantly extend the life of your roof and will also provide you with rainwater for watering your garden plants.

Today, buildings with a flat roof, familiar to industrial and multi-story buildings, are increasingly found in private housing construction. Such a roof makes it possible to obtain additional space for arranging a terrace, sports ground, swimming pool, or garden. To ensure the protection of the roofing covering from destruction under the influence of moisture, it is important to provide an effective system for draining melt and rainwater, and take care of the correct installation and heating of water intake funnels.

Choosing a drainage system

For flat roofs there are two options for drainage systems:

1. Traditional (requires the installation of a large number of funnels, water flows through the system pipes by gravity).
2. Gravity-vacuum (features high throughput with a minimum number of communications).

Traditional internal drain. For its effective functioning, it is necessary to properly slope the roof, with funnels mounted at the lowest points. The number of water receivers depends on the size of the roof. The water intake elements are connected using pipes to a vertical drain pipe, through which water from the roof enters the sewer system. It is important to install horizontal pipeline elements with a slope to ensure free drainage of water by gravity.

Gravity-vacuum system. For more than 30 years, it has been actively used in many countries in Europe and the world due to its high efficiency and efficiency. The principle of operation is based on the fact that in a system equipped with a siphon, a vacuum environment occurs, due to which water is sucked from the surface and moves through the pipes at high speed. The advantages of the system include:

• the flow has a high speed;
• simplified installation (fewer funnels and communications are required, pipes do not need to be installed at a slope, since water moves through them under air pressure);
• light weight (does not create additional impact on the roofing system);
• cost-effectiveness (funnels and pipes of smaller diameter are used in comparison with a traditional system without loss of productivity);
• ability to self-clean (the throughput of the system does not change over time).

For comparison: a vacuum system funnel with a horizontal outlet of 75 mm is capable of passing up to 15 liters of liquid in one second. To provide the same throughput of a traditional drain, you will need to install a funnel with a horizontal outlet of 200 mm.

During heavy rainfall, a large volume of water can accumulate on a flat roof, which the drainage system cannot cope with. To avoid collapse of structures due to excessive load, it is necessary to install a special additional drainage system - a storm drain. It can also serve as the main drain when the latter becomes clogged.

Selecting a drain funnel

Funnels for arranging internal drainage are made of polymers, metal or a combination of materials. When choosing a product, it is important to consider the type of material that is used as roofing on the roof. Metal funnels are used for installation on roofs covered with sheet metal. Polymer products are suitable for installation on soft roofs.

A flat roof drain can be round or rectangular, with a horizontal or vertical outlet. The choice depends on the installation location and roof features. The products differ in design, but in any case it is possible to rigidly attach the funnel to the base of the roof and ensure reliable waterproofing of the fastening point.

Funnels with a metal flange are fixed using a clamping method using stainless steel fasteners. Funnels with a polymer flange equipped with a sealing collar are attached using an adhesive method.

The drainage system must be protected from clogging. To prevent large debris from entering the drain, funnels are equipped with protective covers or nets. Products with flat covers with slots are used on roofs in use. The lids can support the weight of a person. If you plan to create a “green” roof, it is best to use funnels with a leaf filter in the form of a mesh cap.

The principle of placement of water intakes

Water receivers must be installed in the lowest areas of the roof. It should be evenly distributed over the surface. To prevent the formation of stagnant puddles on the roof, the slope of the surface towards the funnel should be at least 2%, while at a distance of about half a meter to the drain funnel, the slope should be increased to no less than 5%. Changing the slope is achieved by leveling the screed or reducing the thermal insulation layer.

The number of water receivers is calculated as follows: each funnel should have no more than 200 square meters. m of surface, the distance between funnels is at least 50 cm. The minimum pipe diameter is 10 cm. Regardless of the size of the roof, at least two funnels must be installed on it, or one funnel and a storm drain. This will avoid flooding if the water inlet is clogged.

When calculating the number of water receivers and their parameters, the intensity and frequency of precipitation in a given region is taken into account.

Construction of an internal drainage system: installation of funnels

First option. The most practical to use are composite funnels, the body of which consists of two parts. Due to a certain dynamic reserve, such funnels, unlike rigid structures, compensate for movements of the insulation.

The installation of a water receiver begins with installing the lower part of the composite funnel into a prepared passage hole cut in the roof slab. The lower part is inserted into the drainpipe, and the fasteners should not be rigid in order to avoid damage to communications due to temperature deformations.

The outer part of the funnel to create an internal drain is installed on top, passing through the roofing carpet and a layer of insulation, it is inserted into the lower part. There is an o-ring seal between the parts of the funnel. The plastic apron of the upper part should be laid on the lower lining layer of roofing material. An additional lining layer is mounted on top of it and a bitumen apron is fused as the next layer of waterproofing. An outer layer of roofing material is mounted on top of the apron, which is inserted into the funnel bowl and secured with a pressure ring and stainless steel fasteners. At the last stage of the device, a protective grille is installed on the funnel.

Second option. The installation of a water receiver with a pressure flange is carried out in several stages. It is recommended to attach the funnel not to the insulation, but to wooden blocks of suitable cross-section, securely fastened to the base of the roof. The funnel is tightly installed in the hole (it must be rigidly fixed), a rubber-bitumen sealing gasket is installed between the flat side of the funnel and the pressure flange, which is laid under the roofing carpet. At the next stage of the device, the metal clamping flange is fixed with special stainless steel fasteners. For installation of fasteners, holes are provided in the flange, sealing gasket and funnel side. At the end of installation, the cover is secured.

The principle of construction of water intake funnels depends on the configuration of the product and the type of roofing. When installing, you must follow the manufacturer's recommendations.

Heating of water receivers

Drain funnels in winter in cold climates need to be heated to prevent the formation of ice plugs in the pipe and adjacent sections of the horizontal pipeline. The freezing depth reaches one and a half meters, so it is recommended to provide heating for these elements of the drainage system.

Freezing of water in pipes and pipes leads to flooding of the roof surface during thaws and snow melting, since ice hidden from the sun's rays surrounded by a thermal insulator (a layer of insulation in the roofing pie) is the last to melt.

Today, funnels for flat roofs are available for sale, already equipped with a built-in heating system. But by themselves they will not solve the problem: in this case, the ice plug will grow on the outside. Of course, it will melt faster than the internal one, but it can also create a serious problem by cutting off the flow of water to the drain.

To ensure that the water drainage system functions properly all year round, install a heating system for the area around the funnel using a self-regulating heating cable for the roof. In this case, the possibility of blocking the drain with ice is eliminated

Purpose:

The roof funnel is designed to drain rain and melt water from flat roofs into the storm drain.

Description:

Roof drain for an existing roof with a horizontal outlet DN 75, DN 110, with a decorative extension with a PP grating to prevent branches and leaves from entering the rain drain, with a stainless steel clamping element, with electrical heating from a 220V network with a power of 10-30W. A self-regulating cable for electrical heating is laid inside the funnel body. The free end of the electrical cable will be pulled out and down.

Equipment:

1. Eccentric transition from PP DN 75/DN110
2. Profiled stainless steel clamping element for clamping waterproofing (vapor barrier).
3. Set for fastening the clamping element: wing and washer made of stainless steel (6 pcs each)
4. Support flange for extension element.
5. Extension element made of PP with a stainless steel grid 150x150 mm.
6. Funnel body made of PP with fixed steel mounting pins (6 pcs.)