Flat roof with unorganized drainage. External drain: types and features of installation

Without a competent organization of the gutter system, a flat roof will quickly require unscheduled repairs. Stagnation of rain and melt water on the surface will gradually wash away the protective outer layer of the coating. As a result, the bare base will begin to rapidly collapse from the zealously attacking sun rays. When frozen, water crystals will easily break the material.

A properly constructed flat roof drain can prevent and prevent negative impacts. The rules and principles for arranging such an important drainage system should be carefully studied by the owner, who cares about the efficient and long service life of suburban property.

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

Regardless of the thermometer readings and the amount of precipitation, the drain must accept and promptly convey the liquid substance to the sewer, to a rainwater collection tank or simply to the ground.

Classification of rainfall systems

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

outdoor disorganized. Assuming spontaneous runoff of atmospheric water. They are used for arranging small outbuildings with a height of no more than two floors.
outdoor organized. Assuming the collection of water using gutters or gutters, coupled with funnels, with subsequent transfer to the drainpipe. The system is laid along the cornice overhangs and the outer side of the load-bearing walls. It is used in the arrangement of residential and non-residential buildings, mostly low-rise, but the scheme is acceptable for organizing runoff from the roofs of houses up to five floors high.
Interior. According to this, water intake is carried out by gutter funnels designed specifically for flat roofs, mounted in the roofing system. Water is drained through risers located inside the treated building.

Outdoor gutter systems work great in the southern regions, where the water in the pipes rarely freezes or does not freeze at all during the entire cold period. For areas of the domestic temperate climatic zone, external drains 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 the heat coming from inside. Getting into cold pipelines, melt water will form ice jams.

If a flat roof has an attic, then the snowmelt process can be regulated. By opening the dormer windows, the temperature on the roof can be significantly reduced, due to which the snow will melt much more slowly or completely stop.

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

Cold storage facilities, for example, are equipped with a remote reinforced concrete slab with a side and a drain riser. The impressive area of \u200b\u200bsuch a structure helps to equalize the temperatures of the system and the environment, so that ice plugs do not form.

Residential houses with flat roofs, built in the regions of the northern and temperate zones, are equipped with internal-type drains. The construction is more expensive, but works flawlessly all year round. The risers located inside the buildings are constantly heated by internal heat, which prevents the occurrence of ice jams in the pipelines. In the southern latitudes, drains of the outer variety are in the lead.

Structural components of gutters

In the device of gutters of external and internal type there is a lot in common. Each system built for flat roofs includes elements similar in purpose and design, these are:

Drainage funnels and gutters designed to receive wastewater and transfer them to the drainpipe.
Risers, providing at the points of reception the maximum speed of the water flow due to the forces of gravity.
Drainpipes required for the removal of atmospheric precipitation to the unloading facilities.

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

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

If it is impossible to lay the smallest highway, they look for other ways to drain water: a ground or underground pipeline leading to the most convenient place of unloading is diverted from the riser.

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

The specifics of the slope formation

To stimulate an 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 installation site of the gutter. 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 to 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 decrease in a radius of 50 cm.

Inlet funnels of internal drainage systems can be installed not only in the central area of the roof, but also near the outer wall, at a distance of at least 60 cm from it. Therefore, the envelope scheme of the tilt device 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 likeness of 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 in practice:

Tilt device during construction by setting 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 plates 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 an internal drain

As it should be for any facility under construction, the drainage system of a private house must be calculated and designed in advance. It is necessary to choose in advance the shortest possible route for laying the pipeline and provide for the most convenient place for connecting it to the storm sewer.

The organization of internal drains is subject to a variety of. They are arranged on roofs with and without attics, operated and non-operated categories. Taking into account the planning specifics of the house, an independent designer needs to take into account that:

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

In fact, a drain from a flat roof should be organized like a standard weir system: with manholes, revisions, etc. In the construction of a suspended drainpipe, ceramic, plastic, cast iron, asbestos-cement pipes are used that can withstand pressure in case of blockages.

For laying underground parts of the pipe from the same materials, but without requirements for hydrostatic conditions. Steel long pipes are used only at production facilities with characteristic manifestations of vibration.

According to technological requirements, one catchment 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 scale for low-rise construction is not very typical. In short, there should be at least one funnel on the roof of a small private house.

An increase in the number of water intakes will be required 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 the same roof structure, there are elements separated by parapets, expansion or expansion joints. Each sector of such a roof should have two water inlets.

Drainage funnels are produced for operated and non-operated flat roofs, for combined structures and systems with attic space. There are models used in the arrangement of concrete floors with bituminous coating and coated wooden counterparts. For all options used in construction, water inlets are made of cast iron, ceramics, galvanized steel, and polymers.

Water inlets are manufactured in a variety of sizes. The standard design consists of the funnel itself with wide sides and a removable cap with holes that provide water flow.

More complex representatives of the class of roof funnels are equipped in addition with an umbrella that protects the drain from clogging, a removable glass and a clamping ring designed to clamp the edges of the soft cover in the device. All models must be serviceable and cleanable.

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

The bowls of the water collectors are rigidly attached to the coverings or load-bearing decks. For fixing, clamps are used in an amount of at least two pieces.
After installation, the funnel must ensure the tightness of the roof at the installation site.
The pipes of the funnels are connected to the risers with the help of compensators, which make it possible to maintain the tightness of the joints during shrinkage of building structures.
Funnels are connected to suspension systems with shaped bends.
The water intake bowl is installed below the level of the finishing roof to eliminate the possibility of stagnant water. Caps of water inlets on non-exploited roofs have a rounded shape in plan, they usually rise above the coating. Funnel caps for serviceable roofs are installed flush with the coating, they are most often square in plan, so that it is easier to lay tiles around the device.

To increase the sealing and reliability in the area of intersection of the funnel roof structure, the use of thermal insulation is allowed. Roofing systems of the usual type are equipped with single-level funnels.

And the roofs constructed with the help of mechanical fasteners are equipped with two-level water inlets that collect water over the waterproofing and over the vapor barrier.

It is customary to equip roof structures with a polymer membrane coating with water inlets with a polymer clamping flange, which is glued or welded to the roof.

This method achieves the maximum possible waterproofing in the area of \u200b\u200binstallation of the water intake device. The areas for gluing the flanges of water intakes must be reinforced with additional layers of waterproofing deposited material. You can replace it with fiberglass glued to the mastic.

Construction of an external drain

The construction of external varieties of drains from a flat roof is carried out in the southern regions. Their installation in residential and office buildings is recommended in areas with low 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 discharged by gravity along the cornice overhangs.
Organized drainage, recommended for equipping non-residential buildings in the northern and temperate latitudes, residential buildings in the southern regions with little rainfall. The principle of operation consists in the systematic collection of precipitation into an external drain funnel with guide edges adjoining it or into a gutter, followed by drainage into a storm sewer or into the ground.

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

Containers were installed to unload the drain and receive treated water. This means that the site for connecting the system to the sewer is abolished. An interesting scheme allows you to profitably solve two problems at once: to get water of drinking quality and to protect a flat roof from water stagnation.

An unorganized type of drainage system requires reinforcement of cornice overhangs. They must be upholstered with galvanized roofing steel, and then glued on top with two layers of rolled roofing. Additional layers are laid with an overlap.

Strengthening the overhang of a mastic flat roof is strengthened 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 eaves.

Fixing the external drain on the eaves of a flat roof is carried out according to the traditional scheme. On sale are a lot of ready-made kits with detailed instructions for assembling systems. First, brackets are attached to the frontal board, into which a chute assembled from plastic or metal modules simply fits.

In a place convenient for further transportation of water, a gutter funnel with a branch pipe is installed, to which the riser is connected. The pipe is fixed on the wall with brackets. The edges of the system are closed with plugs, and completed with the installation of a curly outlet.

Video instructions for installing gutters

The video will acquaint you with the principles of the device of internal drainage systems and the specifics of their installation on a flat roof in detail.

Assembly and installation of an external drainage system:

Flat roof slope device:

Installation of a water intake funnel for an internal drain

Information about the guidelines for choosing the optimal drainage system will help to competently equip the roof with reliable protection against the destructive action of water.

Knowing the technological principles of the device is useful for independent craftsmen and owners of suburban real estate who wish to turn to the services of third-party performers. A well-constructed drain will prevent damage to the coating and destruction of building materials, and will serve for a long time without creating problems.

Professional installation of gutters can significantly extend the life of the roofing and do without unscheduled emergency repairs. After all, the “lakes” gradually render the protective layer of the coating unusable, and the bare base begins to rapidly collapse, falling under the direct influence of rain, sunlight and daily changes in ambient temperature.

Therefore, the main task of installing flat roof gutters is the full-fledged organization of the drainage of rain and melt water from its surface, which effectively performs its functions all year round. At the same time, the drainage system must work equally well for any thermometer readings and the amount of precipitation. The drain must accept all the liquid substance that has fallen on the roof and forward it to sewer drains, to rainwater collection tanks or, corny, to the ground

Classification of rainfall systems

To transport water from the surface of a flat roof, there are the following types of drainage systems:

outdoor disorganized. It involves spontaneous runoff of atmospheric precipitation, it is mainly used in the arrangement of small outbuildings, no more than two floors high;
outdoor organized . Here it is supposed to collect precipitation using gutters, together with funnels, with subsequent transportation of precipitation to drains. The system is laid along the cornice overhangs and the outer side of the load-bearing walls. It is used in the arrangement of low-rise residential and non-residential buildings with a height of up to five floors.
interior . Water intake passes into drain funnels specially created and fixed on the roof surface, water is discharged through risers located inside the building.

Outdoor gutter systems have proven themselves in the southern regions, where water freezes during a short seasonal interval or does not freeze at all. In areas with a temperate climate, outdoor drains are recommended exclusively for attic structures.

On non-attic roofs, the snow will constantly thaw throughout the winter period due to the heat coming from inside the building. Getting, then, into cold water conduits, melt water freezes and.

Of course, if a flat roof has an attic space, then the process of melting snow on the roof surface can be stopped by lowering the air temperature directly in the attic itself by opening the dormer windows.

In the northern regions, there is a threat of rupture of the roofing during a sharp cold snap. Clogs can form in the drainpipes, preventing the free flow of water remaining on the roof. Under the influence of low temperature, the water remaining on the roof begins to crystallize, significantly increasing its volume, along the way breaking the material that has absorbed this water. Therefore, in the northern and temperate domestic latitudes, only non-residential, that is, unheated, buildings and buildings are equipped with external drains.

Cold storage facilities, for example, are equipped with a remote reinforced concrete slab with a side and a drain riser. The impressive area of \u200b\u200bsuch structures helps to equalize the temperatures of the system and the environment, as a result of which the external drainage system is fully functional.

But residential buildings with flat roofs, built in our latitudes, are equipped with internal-type gutters. Although this design is more expensive, it functions properly throughout the year. Risers located inside the building are constantly heated by internal heat, preventing the formation of ice jams.

Gutter elements

There is a lot in common in the device of external and internal drains. Each flat roof drainage system includes elements similar in purpose:

drainage funnels and gutters - designed to receive wastewater and transfer them to the drainpipes;
risers - provide the maximum speed of water flow at the points of reception due to the forces of gravity;
drainpipes - are required for the removal of atmospheric precipitation to the unloading facilities.

The main task of designing a drainage system is to minimize the length of the pipeline from water intake points to system discharge points. The shortest and cheapest option is a riser with a funnel or gutter at the top and a short outlet at the bottom.

The outlet is located at a slight angle, at a distance of 20 - 45 cm from the surface of the storm sewer or just a blind area protected from erosion.

But, often, natural circumstances interfere with equipping a house with such a system: weak soils, lack of a drainage system, an old foundation, for which close proximity to water is undesirable.

If it is impossible to lay the smallest highway, then there are other ways: a ground or underground pipeline leading to the most convenient place of unloading is diverted from the riser.

The pipeline scheme is unconditionally used in the construction of flat roofs with an internal drain, because the system is simply obliged to transport water outside the building.

Gutter installation. The specifics of the slope formation

To stimulate an 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 installation site of the gutter. 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 to the place of the water intake funnel. It is formed according to the envelope principle so that there is a depression within a radius of 50 cm around each water intake funnel.

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. There are enough options for arranging slopes of the roof surface to collect water from its surface. But, in any case, the slope should be oriented towards the water intake.

If several water intake funnels are installed on the roof, then a kind of “watershed” should be organized between them - a kind of hill, the slopes of which direct the flow of water in the direction of the nearest funnel.

To solve the problem of forming such slopes, there are several methods tested in practice:

device of slopes in the course of construction, by means of installation of overlappings 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 plates of mineral wool insulation.
slopes on large-sized planes are carried out with the help of special, angle-forming metal structures.

Rules for the construction of an internal drain

As it should be of any design, the drainage system must be calculated and designed in advance. The installation of gutters is carried out along a pre-selected shortest path and provides the most optimal place for it to enter the storm sewer, or simply drain into the ground.

A variety of flat roof structures are subject to the organization of internal drains. They are arranged on roofs with and without attics, operated and non-operated categories. Taking into account the planning specifics of the house, an independent designer needs to take into account that:

drain risers are usually located in the area of stairwells near walls, columns, partitions. Preferably near living quarters for spontaneous heating during cold periods of the year. It is strictly forbidden to monolithize risers into walls, they can be installed in strobes, shafts, boxes and placed in closets or similar auxiliary compartments;
installation of drains of an unheated building provides for methods of artificial heating of funnels and risers. To increase the temperature of the external elements of a flat roof, install an electric heating cable or mount risers next to the steam heating;
a flat roof with an attic is best equipped with a pipeline passing within the attic space. It is carried out in the form of a suspended network. To ensure the flow, the horizontal sections of the pipes of the suspension system are installed at an inclination of 0.005, that is, 5 mm should fall on each fire meter of the pipe. depressions towards the spillway;
when laying overhead pipelines, the drain section in the attic area needs to be insulated;
if the installation of a suspension system is not possible, an underground pipeline is laid. There are no regulations on the angle of inclination of underground branches. The main thing is to be connected to the storm sewer. True, the underground scheme is much more expensive, much more inconvenient in terms of control and repair work. In addition, its implementation may be hindered by a too powerful foundation;
when designing, bends should be avoided whenever possible;
the riser, at a distance of about a meter from the surface of the earth, should be equipped with a revision for cleaning.

In fact, a flat roof drain should be organized like a standard weir system: with sight rings, revisions, and so on. Installation of drains in such roofs involves the use of ceramic, plastic, cast iron, asbestos-cement pipes that can withstand pressure during blockages. For laying underground parts, pipes made of the same materials are used, but without requirements for the hydrostatic regime. Steel long pipes are used only at production facilities with characteristic manifestations of vibration.

According to technological requirements, one catchment funnel can receive atmospheric runoff from a roof with an area of up to 1200m 2, the distance between adjacent water intakes must be at least 60m.

An increase in the number of water intakes will be required 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 the same roof structure, there are elements separated by parapets, expansion or expansion joints. Each sector of such a roof should have two water inlets.

Drainage funnels are produced for operated and non-operated flat roofs, for combined structures and systems with attic space. There are models used in the arrangement of concrete floors with bitumen coating and wooden counterparts covered with corrugated board. For all options used in construction, water inlets are made of cast iron, ceramics, galvanized steel, and polymers.

Water inlets are manufactured in a variety of sizes. The standard design consists of the funnel itself with wide sides and a removable cap with holes that provide water flow.

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

bowls of water collectors are rigidly attached to coverings or load-bearing floorings. For fixing, clamps are used in an amount of at least two pieces;
after installation, the funnel must ensure the tightness of the roof at the installation site;
nozzles of the funnels are connected to the risers with the help of compensators, which make it possible to maintain the tightness of the joints during shrinkage of building structures;
funnels are connected to suspension systems with shaped bends;
the water intake bowl is installed below the level of the finishing roof to eliminate the possibility of stagnant water. Caps of water inlets on non-exploited roofs have a rounded shape in plan, they usually rise above the coating. Funnel caps for serviceable roofs are installed flush with the coating, they are most often square in plan, so that it is easier to lay tiles around the device.

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.

Installation of drains on roof structures with a polymer membrane coating is usually carried out with water inlets that have a polymer clamping flange that is glued or welded to the roof.

Gutter installation. Outdoor drain

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

Unorganized drains recommended for installation in dry areas. Water is drained by gravity along the eaves.
Installation of drains, recommended for the equipment of non-residential buildings in the northern and temperate latitudes, residential buildings in the southern regions with little rainfall. The principle of operation consists in the systematic collection of precipitation into an external drain funnel with guide edges adjoining it or into a gutter, followed by drainage into a storm sewer or into the ground.

An ingenious solution for an outdoor 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 intake.

To unload the drain and receive purified water, containers are installed, due to which the area for connecting the system to the sewer is eliminated. Installation of gutters with this interesting scheme allows you to profitably solve two problems at once: to get drinking quality water and to protect a flat roof from water stagnation.

It is not difficult to make a high-quality and reliable roof today - the construction market has never known such an abundance of roofing materials and specialists. But why does she and other structures of the house begin to collapse ahead of time? One of the main reasons is the lack or insufficient thoughtfulness of the drainage system.

The organized drain from the roof provides a directed flow of water from the roof, protecting the foundation, walls and eaves. The latter suffers more than others from high humidity, jeopardizing the integrity of the roof. However, you can count on the efficiency of the system only under two conditions:

a project that takes into account all the features of the roof;
competent installation.

Types of organized drainage

Today, there are two types of organized drainage from the roof: external and internal.

outdoor system

Any outdoor drainage system includes gutters and pipes connecting funnels and other additional accessories to each other. Water is discharged through pipes installed on the facades. According to SNiP, the distance between them cannot be more than 24 m, and for the cross-sectional area of \u200b\u200bthe pipe, a coefficient of 1.5 cm 2 / m 2 is used, connecting its value with the roof area. The longitudinal slope of the gutters should not be less than 2%. The outer one is suitable for roofs covered with small-piece roofing material, steel, copper, corrugated board and.

Internal

Another system is internal, consisting of pipes laid inside the house. Even in severe frosts, water flowing from the roof does not freeze in them. It is also provided for mastic roofs.

Water intake funnels are evenly spaced over the roof area: for every 1 cm 2 of the funnel section - 0.75 m 2 of area. Roof sections limited by expansion joints and walls are equipped with at least two funnels. They are located in the lowest places, and between them and the parapets or any other protruding part of the building, a distance of at least 500 mm must be maintained. In areas within a radius of half a meter from the installation sites of the funnels, the roof is lowered by 15–20 mm.

Material selection

According to the material, drainage systems are divided into two groups: plastic and metal. Choose them according to the type of roofing. , of course, metal is more suitable, as for other types, then.

The shape distinguish between rectangular and round profile.

The choice of color solution is quite wide. Most popular with homeowners are shades of red, brown and green to match the roofing, and white is a striking contrast in the design of the design. Unlike other criteria, the color solution is purely consumer preference.

How to make a drain: important rules

In order for the drainage system to work reliably reliably, it is made taking into account specific requirements:

the gutter is installed with a certain slope towards the drain funnel. The slope should be about 10 cm or 1% per linear meter of length. In a situation where two drainage pipes are fixed on the wall, the slope must be made in both directions, starting from the middle of the gutter. If the pipe is one, and is located in the center of the wall, the requirements for the device are the same, only in the opposite direction;

drainage pipes are not recommended to be located at the entrance to the house or near the garage door. During the thaw period in winter, when the snow on the roof melts, water begins to flow down them, and by morning ice forms at the entrance on the porch and paths.

This, however, can be avoided by installing an anti-icing system.

it is strictly forbidden to install drain pipes in the inner corners of the building. In these sections, the risk that there may not be enough capacity to cope with the flow of rain is much higher. And in this case, among the likely outcomes are water overflow and violation of the tightness of the elements.

Installation of a system made of metal and plastic - differences

Products from various materials have certain differences in assembly: metal ones are somewhat more difficult to assemble than PVC ones, the latter have more small parts and features compared to metal ones. In addition, the temperature deformation in them proceeds in each in its own way.

When, unlike metal ones, shaped parts are used that are specially designed to compensate for the linear deformation of the elements. Products made of metal and plastic are mounted on brackets with different pitches: metal - at most 90 cm, and plastic - up to 60 cm.

To assemble all plastic elements, special glue or rubber seals are used.

Whatever material the gutter is made of, it must be protected from snow and ice getting under the avalanche, which can cause deformation. Therefore, snow holders are installed on the roof, which must correspond to the type of roof, for example, tubular roofs are used for metal tiles, and lattice ones are attached to natural ones.

The organization of the drain has a whole list of positive aspects, which primarily include the safety of the structure from the destructive effects of rain and snow. However, is it always necessary to arrange an organized drain from the roof with a whole system of pipes, as well as various gutters. There are times when you can do just fine without it. Here we are talking about an unorganized drain, for the arrangement of which you do not need to spend money on the purchase of additional materials.

What does an unfinished drain look like?

Due to the appropriate slope of the slope and the complete absence of additional structures, there is an uncontrolled runoff of liquid from the roof surface. The simplicity of construction and the minimal cost of its arrangement attract many homeowners. However, do not forget about the negative aspects that can affect the integrity of the roof, and indeed the entire building.

An unorganized drain has a negative effect on the walls of the facade, accelerating their destruction. Therefore, in the process of their construction, an additional layer of waterproofing is required.
Even in areas where there is a minimum amount of precipitation, water will penetrate into the foundation, worsening its condition and slowly destroying it. To avoid this, additional drainage underground should be arranged to remove excess moisture.
Precipitation will also have an impact on the plinth. This indicates the need for periodic renewal of the waterproofing layer.

Given these shortcomings, the question arises whether an unorganized drain from the roof is necessary. To answer it, you need to familiarize yourself with the standards prescribed by SNiP 31-06, which clearly define the features of the building, allowing you to leave the drain unorganized.

Requirements and regulations

The main criterion is the number of floors in the building, which should not be more than five. Also, the amount of precipitation falling in a certain region should not exceed 300 mm. Only in such situations is it possible to do without laying pipes, gutters, as well as other material. Based on the requirements, an unorganized drain from the roof of the SNiP is created with a shed roof, which has a slope to the courtyard. In addition, the following factors must be taken into account:

under the slope there should be no footpaths, a roadway and balconies;
the peak of the roof should be equal to 60 cm or exceed these parameters in order to protect the building from moisture;
additional protection should be provided by a visor installed above the entrance.

Today, too stringent requirements are imposed on the design of buildings. However, caring owners, in order to increase the life of their houses, install a drainage system.

Type of drains

Drainage systems are of two types.

Internal, with pipes located inside the building. Such a device for organized drainage from the roof provides for water intake funnels on significantly underestimated sections of the roof. In addition, all valleys, grooves, roofing must have a slope towards the funnels.

Outdoor, located on the outer sides of the building.

On roofs made of metal tiles, sheet steel, asbestos-cement sheets, corrugated board and small-piece materials, an external drain is provided.

The main requirements for drainage systems look something like this:

In addition, do not forget that:

drainage is provided by a certain angle of inclination of the roof;
the use of "filly" (special stuffing on the rafters, allowing you to create a slope more gentle) reduces the slope to the drainage system;
narrowing of gutters, dumbbells, channels or trays to the water drain is unacceptable;
the device of the channels of the cornices must be such as to provide reliable protection of the building from ice, snow, ice, icicles;
material for drainage gutters should provide elasticity at low temperatures and rigidity of drainage systems.

According to the regulations, the creation of an unorganized drain is quite acceptable. However, even on outbuildings, an organized drain will be more appropriate. Therefore, is it worth the risk of reducing the life of the house and creating problems for yourself in the future with its maintenance. An organized drainage system can save you from many possible troubles.

Due to the lack of a slope, a flat roof is susceptible to water attack. With a large amount of precipitation, water lingers on the surface, and at sub-zero temperatures, ice appears on it, which can cause damage to the structure. That is why a necessary element of a flat roof is an organized drain. Also, the water drainage system allows you to save the materials that make up the building.

unorganized drain

Some buildings with a flat roof have an unorganized drain. But it is worth remembering that, according to the rules of SNiP, such a building cannot have more than 2 floors. If it is higher, the organization of an external or internal drain is necessary.

Thus, any multi-storey building with a flat roof must be equipped with a precipitation drainage system, since an unorganized drain is inefficient. Usually it is installed internally, not externally.

External and internal systems

Barrier walls are installed on the flat roofs of buildings to protect the walls from the effects of water, which are covered with metal or concrete. The junction of such walls to the roof is closed with a galvanized apron.

Installation of a drain on a flat roof is carried out on:

overhangs that are lower than the rest of the surface;
special ledges of a flat roof.

In the first case, the funnels are located near the roof overhang in special channels. With this option, water is discharged through sewers, which are led through holes in channels with installed gutters.

An internal organized drain involves the creation of funnels on a flat roof that are built into the roof. The drainage of precipitation occurs through risers, which are located inside the building.

An external drain, according to the rules of SNiP, is not recommended to be installed on buildings with a flat roof in regions with a temperate climate. This is due to the fact that at sub-zero temperatures, water freezes in pipes and creates ice jams.

Diagram of the device of the internal system

An organized internal drain has several funnels, from which pipes are directed to a common riser that leads water outside the building. The whole system consists of the following elements:

Funnels for receiving rainfall. They can be flat or have a cap. The first type of funnels is installed on flat roofs, and the second on a roof with a slope.
Water pipes. They connect risers and funnels.
Collectors. Installed at the bottom of the building and contribute to the drainage of water.
Wells. They allow you to inspect the system, clean it from contamination and check the performance of its elements.
Additional elements. Such as fasteners, corners and hangers.

Before starting work on the installation of a drainage system, it is necessary to check whether it complies with the norms of SNiP. According to the prescribed rules, downspouts must direct precipitation into the sewer. If the water goes into the ground, it will contribute to the flooding of the foundation.

The funnels of the drainage system consist of several components:

frame;
lattice;
fastenings;
lid.

Funnels made of cast iron are common.

Rules for the design of internal systems

An internal drain having an external outlet can be installed on any building. It does not matter in which climate zone the building is located.

Such gutter systems must ensure the removal of water at different temperatures. The installation of water intake funnels in such systems does not occur near the walls, since at sub-zero temperatures the water freezes in the system, creating a congestion.

When creating such drains, the following rules are observed:

before starting work, the entire surface of a flat roof is divided into several sections;
one riser of the system is created with the expectation of an area from 150 to 200 square meters;
the slope of the roof towards the funnels should be 1-2 degrees (according to the rules of SNiP);
installation of an internal drain requires laying a collector underground, as well as connecting the system to a sewer;
rainwater is discharged to an external sewerage network;
funnels are installed in such a way that between this element and the flat roof decking, water cannot penetrate under the waterproofing.

Types of internal systems

Internal drainage systems are divided into 2 types:

Gravity-flowing. Such structures are designed for the free collection of precipitation and their removal through downpipes with a slope.
Siphon. Such systems are based on their complete filling with sediments.

A feature of siphon sewage is that when a column of liquid moves through a pipe, a vacuum is created in its upper part. Thanks to this, all the liquid enters the funnel not only under the influence of gravity, but also absorbed due to the partial vacuum.

Siphon drains are more efficient because:

pipes of smaller diameter are used to create them;
the roof does not need to be done with a slope;
they require fewer funnels;
the number of releases from the building can be significantly reduced.

Important! When creating an internal drain, all elements are fixed by welding, as this ensures the tightness of the system.

Before choosing a particular drainage system, you should find out what area of \u200b\u200bthe roof is designed for.

Rules for the installation of internal gutters

In order for the drainage system to function efficiently and be able to operate for a longer period, several rules must be observed:

Funnels should be evenly distributed over the entire surface of a flat roof. At the design stage of the roof, the optimal distance between these elements is calculated. Too many of these elements will significantly increase construction costs, and not enough will cause the system to be less efficient.
All funnels are located in places where the slope of the roof is created.
Installation of funnels occurs at a distance of no more than 20 meters from each other. If this rule is not observed, there is a risk of reducing the stability of the structure.
The funnels are mounted in such a way that each of them is located at a right angle relative to the horizontal.
The external drain made of metal is supplied with heating so that at sub-zero temperatures the pipes do not break due to the pressure exerted by ice.
If the building has several roof planes, the distance between which is more than 4 meters, the organized drain has different outlet pipes.

When creating a drain, it is important to pay attention to the waterproofing of funnels and pipes. Roofing material is installed only after the funnels have been installed. In order to carry out all the work correctly and not make mistakes, before starting the activity, it is necessary to plan the whole process and calculate the amount of material.