Gutter for flat roofs: reliable protection against water collection. Flat roof drainage: specifics of construction of internal and external options Storm drain funnels

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Today, buildings with a flat roof, common for industrial and multi-storey 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, garden. To ensure protection of the roofing covering from destruction under the influence of moisture, it is important to provide effective system for drainage of melt and rain water, take care of correct installation and heating of water intake funnels.

Choosing a drainage system

For roofs flat type There are two options for drainage systems:

Traditional (requires installation large quantity funnels, water flows through the pipes of the system by gravity).
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 to the vertical pipe a drain 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 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);
efficiency (funnels and pipes are used smaller diameter compared to a traditional system without loss of performance);
ability to self-clean (the throughput of the system does not change over time).

For comparison: a funnel vacuum system With horizontal release 75 mm can pass 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 sheet metal. Polymer products are suitable for installation on soft roofs.

Funnel for flat roof may have a round or rectangular shape, 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 metal flange are fixed using a clamping method using fasteners made of of stainless steel. Funnels with a polymer flange equipped with sealing collar, are attached with adhesive.

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 in the following way: each funnel should have no more than 200 sq. m. surface, the distance between funnels is at least 50 cm. Minimum diameter pipes - 10 cm. Despite 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 from above, passing through the roofing carpet and a layer of insulation, it is inserted into bottom 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. On last stage 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 a suitable cross-section, securely fixed to the roof base. 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. To install fasteners in a flange, sealing gasket holes are provided on the side of the funnel. 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 time in cold climates they need heating 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 sunlight surrounded by a thermal insulator (a layer of insulation in the roofing cake) 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, arrange 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

What type of roof drain can be made? Let's find out together what roof drains exist, what they are made of and what technical requirements presented for installation. And finally, I will show you how to install a funnel for a flat roof in 3 options.

Types of funnels and technical requirements

In general, there are 2 types of funnels - for a sloping (pitched) roof and for a flat roof:

Water inlet for pitched roof built into the gutter system. According to the rules, with a gutter width of 100 mm or more, 1 drain is installed for every 10 m of gutter. The arrangement technology there is simple; the funnel is either screwed to the front board with self-tapping screws, or clings directly to the gutter;

A storm funnel for a flat roof is usually built into the roofs of multi-storey buildings and large hangars. You can install it yourself, but the technology is much more complicated.

A flat roof is called conventionally. In any case, there is a small slope there (minimum 3%, maximum 10%), it is needed so that the water flows exactly to the place where the funnel is installed.

What are water intakes made of?

PVC. Plastic reigns supreme in the budget sector. Plastic water inlets are the easiest to install; they are simply glued to the base. But these products break easily from external loads; if you step on them, the funnel will crack;
Metal plums- the most durable and reliable, but they also have a decent price; metal is used on open terraces and habitable roofs. Most often they are made of stainless steel, but there are also cast iron models, however, they can only be mounted on reinforced concrete floors;
Combined models- the base is made of metal, and the insides and superstructure are plastic. Combined plums are " golden mean", they are durable, reliable and not as expensive as stainless steel.

Technical requirements

Installation of gutters is regulated by GOST 25336-82. If we highlight the main points of this document, then the main parameters are the throughput of funnels and their number per m2.

As for the quantity, on average, 1 drain funnel with a pipe diameter of at least 100 mm is installed per 200 m² of roof, but with regard to throughput, it is worth mentioning separately.

There are 2 types of hidden roof water intakes - traditional and vacuum:

In traditional water intakes water flows by gravity, so the diameter of the pipes in them is larger (from 100 mm);
For vacuum systems pipes are needed in half. The water intake funnel here is two-level and this allows you to fill the pipe completely, as a result a vacuum arises and the water leaves several times faster. If you have ever drained fuel from a car tank with a hose, then you will understand the operation of this system.

Three options for installing a funnel on a flat roof

Roof funnels come in different varieties and are installed in different ways; we will start with the currently most progressive installation of funnels for siphon or vacuum drainage system.

Option #1. Funnel for vacuum drain

The Geberit Pluvia company is considered one of the leaders in this direction, so we will consider how to install water inlet for a flat roof from this particular company.

Illustrations	Recommendations
	Sectional design. This storm funnel is initially based on an insert; in the photo on the left, the insert is shown with an arrow. To begin with, we need to concrete floor cut a square niche to fit the insert.
	Attaching the base: We place the lower part of the structure in the niche using construction glue; We rotate the metal plate on the insert so that the holes are above the floor slab; Using a hammer drill, we drill holes in the concrete for dowels;
	Insert the dowel nails and hammer them in with a hammer.
	Installation of the structure. The kit includes a rubber gasket, this gasket is placed on the studs;
	Next, we roll out the soft roofing material over our funnel and cut out holes for the studs with a mounting knife;
	We put a fixing ring on the studs and tighten the nuts around the perimeter; By the way, the nuts are not tightened in a circle, but on the contrary, that is, after tightening one nut, move on to the one that is opposite (on the opposite side of the circle).
	Do not tighten the nuts too tightly, the main thing here is that the “ribs” of the gasket fit tightly with adjacent surfaces;
	Carefully cut out roof covering from the drain funnel.
	We mount the cap: The cap consists of 3 parts, the side mesh is installed first. To install the mesh on the base there are 2 ears, arrows point to them;
	Next, the main protection of the hood is installed. For fixing, this plate also has 2 hooks; the plate is simply pressed until it clicks;
	The top cover is also secured with latches.

Option #2. Simpler doesn't mean worse

A siphon roof funnel is often installed in new buildings; there is no point in installing it in old houses, because in addition to the funnel itself, pipes must also be laid according to a special pattern.

For the old gravity roofing system There is a proven old-fashioned method:

Illustrations	Recommendations
	Cutting out a niche. This instruction is similar to the previous one, but it is simpler. A niche is cut out around the technological hole; most old houses, as a rule, already have this niche.
	Mounting the base: Drain funnel Take a simple one for a gravity system. There is no platform on it, so we plant the platform directly on concrete, more precisely on Emaco S88 construction adhesive;
	We press the cuff of the funnel and coat the perimeter with glue again.
	Apply bitumen primer.
	We fasten the structure: After this, TechnoNIKOL soft roofing is laid in 2 layers, first along the niche, and then over the entire roof area; Next, screw the fixing ring to the studs and cut out the center;
	Now all that remains is to insert the leaf net. Everything is simple here: take the mesh and insert it until it clicks.

Option #3. Gutter for light roofing

Roof drains are one of the main components of high-quality drainage from roofs. Climate change forces people to protect their buildings from unfavorable precipitation in every possible way. Therefore, it is very important that the storm drain works efficiently and without failures, because the façade and foundation of the house are at stake. Big problem industrial and government buildings have a flat roof, because water has a destructive effect on the roof carpet.

There are no completely flat roofs, so its reliability depends on the slope. For effective drainage, a slight slope is required. A good indicator would be a slope of 2-5 percent. In this situation, water will easily drain from the surface of the roofs, which will give more freedom for the functioning of the roofing carpet. If small defects appear, they will not cause much damage.

IN Lately there is not enough inclination, so when constructing a building, attention is paid storm systems drainage systems, which provide protection and reliability, and preference is given to the use of water inlet funnels.

The concept and principle of operation of a storm funnel

The main component of a drain is called a storm funnel. She's working on collection and removal Wastewater from the roofs With its help, rain and sediment liquid is transported first into pipes that are located inside or outside the building, and then into the sewer or to specially designated places.

Roof funnels are also the most important roofing structures for buildings. Representing a central location for collecting liquid, they require the correct installation of even a small wire on flat surfaces. The slightest miscalculations in system design can lead to malfunctions and loss of money.

To avoid leaks and ensure desired speed collecting liquid, it is necessary to control the tightness of all contacts on the wire connections. To increase density, it can be equipped with a pressure flange, an auxiliary drainage ring and an enlarged body. Funnels are installed at all stages of construction and connected by cast iron, steel or plastic pipes.

What parts does the funnel consist of?

Stormwater drainage funnel consists of the following components:

Housing, including 1 or 2 flanges and a drain neck;
Clamping flange that presses the roofing sheet;
Screws and nuts that impart force to the clamp;
Clamping screws that are located in smooth cylindrical holes;
Wires and cables.

Storm funnel design (horizontal and vertical outlet)

Standard scheme:

Extension structure – upper part;
Extension cable – middle part;
The body for embedding heating is the lower part.

Based on the area where they are used, they can be:

With horizontal release;
WITH vertical outlet;

Difference: the location of the outlet pipe (hole for draining water).

With a swivel joint, the angle of rotation can range from 0 to 90 degrees.

In what cases are horizontal and vertical exhaust systems used?

With horizontal outlet they can be used for roofless roofing. The funnel clings tightly to the waterproofing, which is responsible for the heating process. Here it smoothly transitions to sewer risers going down. It is worth taking note that this installation less profitable, since if there is a need to change a part, it will be necessary to open a large section of the roof. Plus, when installing a horizontal funnel, it is necessary to carry out calculations along the heating freezing limit. If there is a miscalculation, the system will freeze and stop functioning.

Types of storm drains and where they are used

Today, market shelves know more than 40 types of storm drains, which are made from the most various materials and can serve for the most various types buildings Depending on the type of structure, there can be: with or without heating system, with horizontal and vertical outlet, with or without filters. But we have already talked about these types a little higher.

Therefore, we will consider their division according to purpose:

For roofing materials (bitumen and membrane);
For roofs in traditional and inversion style;
For roofs that are in use or not;
For balconies and terraces.

To your attention! Typically, architects show points of minimum surface decline. Choosing the right funnel is the main task facing sewer designers.

For the right choice The designer must have the following information:

What is the section of the roof, its layers and dimensions;
The material and diameter of the equipment used for the storm pipe;
Information about: whether heating is needed;
Complete information about the funnel.

Advice! If you have questions, seek help from specialists who will help you obtain information on the roof section.

Types of existing roofs:

Inversion or inverted roofing. It is characterized by laying the waterproofing cable on the base, and the remaining layers underneath it. As a result, the system operates all year round at a temperature of 18-20 degrees Celsius. It is protected from ultraviolet radiation and has virtually no damage, which is reflected in the repair-free period, increasing it by 5-6 times. Penetrated with many wires connected into a cable, the heating system guarantees a stable temperature.
Lightweight roofs. To mount them, special funnels with a box are used, which are attached with a wire to the base.
Used roofs used with funnel models with flat lid, and not in use - a device with a ladder and a special grille;
Roofs with and without heating system. If it is green, then this is a mechanism with a crimp flange with a mesh that traps the grass. Freezing is possible for systems, so the following requirements are set for funnels: strength, lightness, corrosion resistance, long service life, ability to operate at temperatures from -50 to +80°C.

Attention! Important characteristic for funnels – operating period. On average, manufacturers provide a 50-year warranty. During this period, the cable may be damaged; the system will fail completely only if it is damaged intentionally.

Installation. Repair funnels

The area for placing the funnel must be selected based on the basics of building design; it is also worth taking into account the features of sewerage and storm drainage. The number of installed funnels depends on the design of the roof and the amount of precipitation. Basically, they should be located at a distance of 25 m and in a sector - every 200-300 sq.m. We select the type based on the characteristics of the waterproofing cable.

So, the roof slope must be at least 3%. To bypass the blockage of the main funnel, we install at least two similar systems. We connect all components to the sewer pipes and set up an emergency system in case of overload.

The system can be completed with:

A crimp flange that is connected by wire to the cable;
Drainage rings and nozzles;
Heating system;
Shut-off valves;
Wires and cable;
Gangways.

A special variety that warms the soul is the repair type. Its purpose is to reduce the cost of repairing the device. If a storm drain breaks down, replacing the heating waterproofing is sufficient. Reconstruction is carried out easily and without special effort. This system does not require heating. Repair devices have receiving indicators in their structure, and they can easily mount the storm drain mechanism.

Conclusions: knowledge of the features of storm drains when installing them on various roofs(used, flat, heating and not heating, etc.) will help you choose correct device, which will give you the opportunity not to interfere with the operation of the storm drain for many, many decades.

Water intake funnels “Polivent” are fixed on the roof between two layers of roofing material, and in the case of a single-layer roofing, on an additional layer measuring 700mm by 700mm.

1. The bottom layer of roofing carpet is laid.

2. in the lower layer of the roofing carpet in the place where the funnel is to be installed, a hole with a diameter equal to the diameter of the upper part of the funnel flange is cut.

3. the place where the funnel collar will be installed is burned with a burner flame to remove the film covering the roofing material
(if there is one), then poured with hot bitumen binder (hot mastic).

4. A water intake funnel is installed on the bottom layer of the roofing carpet, poured with hot bitumen binder.

5. The top layer of roofing material is fused (or laid in another prescribed manner). Short-term exposure to the flame of a propane burner is allowed top part funnel collar.

6. in top layer roofing material, a hole is cut in the place where the funnel is installed equal to diameter funnel flange inlet.

Illustrations	Recommendations
	Laying insulation. Such a roof is called light because the base is made of corrugated sheeting, on top of which dense insulation and a soft roll membrane of the TechnoNIKOL type are already mounted. First, a hole is made in the base and in the insulation along the diameter of the pipe; After which the insulation is placed in its place.
	Setting up a place for a funnel. Our funnel is two-stage, with an extension, and we need to cut a niche for this extension, so we apply it to the insulation and outline it with a marker;

	is a roof drainage funnel with a leaf filter, made of polypropylene. Designed to remove rainwater from flat roofs. It is not subject to corrosion and has good mechanical properties and can be used in all climatic zones RF. It is recommended to install one such funnel for every 300-400 m² of roof, but at least one per roof.
Specifications
Leg height, mm	245
Weight, kg	0,51
Collar size, mm	380
Inlet D, mm	110

Funnel “REPAIR POLYVENT”	Funnel “REPAIR POLYVENT”- made of polyethylene, which gives them the ability to tightly fit any surface. Used in the repair of roof drainage systems. The funnel foot is inserted into the old roof funnel, or into sewer pipe diameter 100-110 mm. A special insert inside the funnel greatly increases the rate of water intake. The funnels are equipped with a leaf filter.
Specifications
Leg height, mm	240
Weight, kg	0,57
Collar size, mm	297
Inlet D, mm	87

	- inserted into old funnels, including cast iron, with a diameter of 60 to 200 mm to prevent leaves and other debris from getting into them. Thanks to the use of a leaf filter, the internal drainage system does not require constant maintenance. The insert, which is inserted inside the funnel, significantly increases the volume of water received.
Specifications
Diameter of protective grille, mm	160/180
Weight, kg	0,14

The main enemy of any roof is water, destructive effect 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:

Disorganized. It consists in the fact that the water simply slides off steep slopes. This method of self-draining is used in private houses with pitched roofs, however, is not suitable for structures with a flat roof.
External. Consists of a gutter fixed to the wind dock or rafters and drainpipes. 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.
Interior. Characteristic internal drainage means 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 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 connections between the elements of the drainage funnel is a prerequisite efficient work drainage system. When examining a flat roof after detecting a leak, 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 from polyvinyl chloride are excellent for installation on soft tiles, shinglase, onduline.

The following types are found in specialized stores: drainage funnels:

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.

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