Receiving funnel for a flat roof. Gutter funnel for a flat roof - types, design features and materials of manufacture. What is a drainage system

25.11.2019

Precipitation has a positive effect on vegetation, contributes to the saturation of the earth with moisture, useful properties and are needed to fill rivers and reservoirs. But, in addition to useful moments, precipitation has an inactive effect on buildings. Constant exposure can ruin concrete, wood and other Decoration Materials. Therefore, it must be purposefully removed from the roof. For this purpose, a special drainage system. Roof drain funnels play an important role in it. It is they who catch the streams of water and direct them through the pipe system.

What are the features of such funnels? How do they differ from each other? How to properly install them? We will learn the answers to these questions from this article.

Types of gutters for the roof

Depending on the design of the roof, there are different types drainage system. The roofs themselves can be divided into two large groups:

Flat roofs.
Inclined roofs, with different levels of slope.

The drainage system is also divided into two varieties, starting from the roof group:

If we talk about funnels in one and the other system, then in the first case it plays a crucial role. Her choice should be treated with special attention. Gutter funnel in the photo:

It is these funnels for flat roofs that will be discussed, since horizontal drains have built-in funnels that do not need to be selected. It's about about gravitational-vacuum systems. Such a vertical type drain was invented more than 30 years ago. His homeland is Scandinavia. Now it is widespread not only in Europe, but also in other countries. The principle of operation is simple, it is based on the so-called ejection ability of the liquid in the pipes. In this case, one medium entrains another, in the water drainage system it is air. In the riser, gaseous masses begin to move upward. But when sewage enters the system, it is directed downwards under the influence of gravity, and the air layer is directed in the opposite direction. It turns out a vacuum environment in which moisture begins to flow at high speed into the collector through a pipe system. The movement of water is determined by pressure from air masses, therefore, for its free movement of the slope is not required.

Such a system has many advantages:

High flow rate.
Can be used to create narrow pipes.
The structure will self-clean.
The drain is light weight.
For installation, you do not need to engage in a large amount of earthwork.

The note! If we compare such a vacuum system and a traditional horizontal drain, the difference is immediately visible.

For example, gravity-vacuum-type funnels, in which the branch pipe has a cross section of 75 mm, can pass through about 15 liters of precipitation in just 1 s. But the traditional type system is much inferior, since in order to pass 1 s of 15 liters of water, you need a funnel with a diameter of 200 mm.

Funnel materials

Internal gutter funnels are made of different materials which have their own characteristics, advantages and disadvantages. Before you buy a funnel, you need to find out this information. Here are the materials from which the elements of the system are made:

After evaluating all the features of each type of funnel, you can choose one or another option.

Requirements for products for the drainage system

Installation of the system is specified in GOST 25336-82. The main points are related to the throughput of funnels, as well as their number on a horizontal roof. The roof area for one drain funnel is prescribed in SNIP 2.04.01-85, in the section "Internal drains". So it says there that there should be at least two funnels on the roof and in one valley. The greatest distance between them should be 48 m no more. It turns out that 1 funnel is required for 230 m 2. At the same time, its diameter should be 10 cm, not less.

Given these indicators, you need to purchase one or more funnels for the house, and then install them. The roof area for one drain funnel is 230 m 2, so you won’t have to spend a lot of money. In addition, it is worth paying attention to the fact that the funnel can become clogged with debris. This is foliage, and dust, and cellophane. So that they do not penetrate the system and do not clog it, a special grate is installed on the drain funnel on the roof. It performs a protective function, while not affecting the throughput in any way. However, so that the leaves accumulated on the grate do not prevent water from entering the funnel, you will have to look at the drain from time to time.

Varieties of funnels for a flat roof

There are several parameters by which storm water inlets are distinguished for flat roof. Today, companies produce a variety of models, which allows you to easily choose a product for yourself. So the types are:

Important! Funnels for precipitation have different sections. Be that as it may, the diameter of the funnel and the drain pipe must match. A 10 cm section is usually used. This will be enough to redirect all the water from the roof to storm system.

Installation of a funnel on the roof

Before installing a drainage funnel and other elements of the system, the following nuances should be taken into account:

Now you can start the installation process. It is slightly different from each other, depending on the roofing and type of funnels. However, the principle is the same for all. We will consider installation on soft roof. The instruction is as follows:

To begin with, a niche should be cut around the technological hole. Most houses already have it.
Next, you need to take the funnel and plant it directly on the concrete. If there is no fold on it, then glue is used.
Next you need to apply a buty primer.
After that, along the carved niche, and then along the entire perimeter, you need to lay a soft roof.
The structure continues to grow. The kit comes with a fixing ring that needs to be installed in its place and screwed. A hole is cut in the center.
It remains only to install the cap or filter grill for the funnel.

You can see more about installation in this video:

As for the installation of a funnel for a vacuum drain, the installation process can be seen here:

Summing up

A funnel for a gutter system is an integral part of any gutter system. Thanks to it, it is possible to qualitatively and quickly divert storm or melt water from the surface of the roof, flat or sloping. Otherwise, the presence of water will adversely affect all structural elements. It remains only to choose one or another version of the funnel for a flat roof and start installing it. If you have any questions, you can ask them in the comments below the article. Experienced professionals will answer them for you.

Sergey Novozhilov - expert in roofing materials with 9 years of experience practical work in area engineering solutions in construction.

In the online store "TekhnoNIKOL" you can order roof funnels. The range includes both models with heating and without it. With the help of the proposed accessories, the withdrawal is provided Wastewater from roofs with a slope of less than 2-5%.

Main features of funnels

The roof funnel is different:

resistance to temperature extremes;
high strength;
ease of installation;
stability when exposed to ultraviolet light.

Models with and without electric heating are easy to install and further operate. They do not require special complex maintenance.

Components can be used at temperatures from -50 to +75 degrees. A funnel with or without electrical heating, made of polymer, heat-resistant plastic or stainless steel, will not lose its properties over time and will cope with the tasks. The element can be operated for 40-50 years.

It is also important that the roof funnel with or without electrical heating is compatible with various types roofs It will ensure the removal of moisture from all roll materials.

Interested in the terms of payment or delivery of products? Do you want to know its price? Contact the experts. They will help you buy funnels that match all the features of the roof, its slope and your financial capabilities.

January 3, 2018
Specialization: philological education. Experience as a builder - 20 years. Of these, for the last 15 years he led a brigade as a foreman. I know everything about construction - from design and the zero cycle to interior design. Hobbies: Vocal, psychology, quail breeding.

Greetings, my dear readers!

Now flat roofs, which were previously used for industrial, utility and high-rise buildings are also used in domestic construction. Such a roof provides free space on which you can place winter Garden, sports ground, terrace, etc. To protect the roof from atmospheric moisture, it must be equipped with an exhaust system. Her central element- drain funnel for a flat roof.

Types of roof drainage systems

Roof drains are divided into two types:

outdoor system. It is mounted along the perimeter pitched roofs and very rarely flat counterparts. Horizontal gutters and vertical gutters are used to drain water.
Internal network. It is designed for flat roofs.

Internal drainage systems are divided into two types:

Gravity (traditional, gravity) network. For it, you need to mount a lot of funnels, moisture is drained through the pipes by gravity. For proper functioning gravity system it is required to correctly arrange the slopes on a flat roof. Funnels are placed on the lower sections. The number of water inlets depends on the area of the roof.

Funnels with the help of pipes are mated with a vertical riser. Through it, water is discharged into a storm drain. The horizontal pipes of the network are laid with an inclination so that the water can flow away by gravity.

Siphon-vacuum system. It has a high throughput with a minimum of structural elements. In funnels with siphons, a vacuum environment is recreated. Due to this, the liquid is absorbed from the roofing and flows through the communications very quickly.

Advantages vacuum system sewerage:

the discharged water flows have a high speed;
ease of installation - few water inlets and pipes are needed to equip the network;
low weight - the system does not create heavy loads on the roof;
efficiency - water intakes and communications of a smaller section are used than in a gravity system;
the system is self-cleaning, so the network throughput indicators are unchanged during its operation.

The water inlet of the vacuum network with a horizontal branch pipe with a cross section of 7.5 cm passes up to 16 liters of moisture per second. In order for the gravity system to have the same throughput, funnels with outlets with a diameter of 20 cm will have to be mounted.

The design of the water intake funnel

The water intake funnel is the main element of the roof storm sewer. Through it, melt and rain moisture is removed from the roof. Further, the liquid flows into the stormwater pipes laid inside the building. On them, it is dumped on the ground or into the drainage sewer.

A modern funnel for draining water consists of the following parts:

Lid. She covers the top of the product.
Lattice. Protects the drain from contamination and the penetration of foreign objects into it.
Sealing ring. This element gives the funnel tightness.

Release. This branch pipe can be horizontal or vertical.
water bowl. Liquid flows into it, which is then redirected to the drain.
Stuffing box. It seals the junction points of the downpipe with the outlet.
Flange or bolt. These elements secure the funnel.

Classification of water intakes

Flat roof water inlets are classified according to several parameters. Now manufacturers produce many of their models, so it will not be difficult for you to choose the right product.

A flat roof with an internal drain, based on its features, can be equipped with funnels of the following types:

Image	Funnel type
	Kolpakovaya. This type of water inlet is equipped with a convex protective mesh, very similar to a cap. Such a water intake copes well with large volumes of water flows. The mesh effectively filters the liquid from foreign objects.
	flat. Such a funnel is installed flush with roofing. Particularly effective are flat water inlets on exploited roofs lined with paving slabs or asphalt concrete.
	heated. An electrical cable is placed inside such a funnel. It provides heating of the network in winter. Thanks to this, the drainage system is not clogged with frost.
	One or two stage water inlet. The first variety is used on roofs with a rolled polymer or bitumen coating. The second type is used on roofs that are subject to movement (non-ventilated and wooden).
	Water inlet equipped with or without a rebate. This crimping element is a universal fastener that is suitable for all types of base. Funnels without a fold are equipped with an apron made of film or roofing felt. They are selected based on the type of roofing.
	Funnel with vertical, horizontal or hinged outlet. Water from such outlets flows through pipes placed along or across the walls of the building. A vertical water inlet is used for a conventional flat roof. The horizontal analogue is optimal for roofs without an attic. Pivoting water inlets can be connected to the storm riser at any angle up to 90˚.

The funnel for water can have a different section. But in any case, it must match the diameter of the drain. Most often, water inlets with a diameter of 10 cm are used. This size is enough for the speedy discharge of large volumes of liquid from roofs of different sizes.

Funnel materials

Water intake funnels are made from the following materials:

Plastic. The basis of such devices is a durable polymer that is resistant to mechanical stress and external influences. Installation of plastic water inlets is quite simple, it does not need glue.

This option is optimal for installation on a roof that is not in use or used infrequently.

Steel. It is another common water intake material. Metal water inlets have high strength. Therefore, they can be mounted on operated roofs with a high level of traffic.

Most often, metal funnels are made of galvanized or stainless steel. Such material is quite reliable, tough, durable, resistant to deforming loads and corrosion.

Composite. In this case, the funnel is made from a combination of a pair of materials, usually metal and plastic. The body of the water intake is made of plastic, and the protective grille is made of cast iron or stainless steel.

Composite products are used on roofs with an average level of traffic and moderate mechanical loads.

Conclusion

Funnels for flat roofs make it possible to drain melt and storm water from them. There are many types of them. Therefore, you can always choose the water inlets that are best suited for the roof of your house.

If you have any questions, ask them in the comments. I say goodbye and good luck in your endeavours.

January 3, 2018

If you want to express gratitude, add a clarification or objection, ask the author something - add a comment or say thanks!

Roof drains HL with vertical outlet- HL 62, HL 62.1 and others, used for different types flat roofs, both for non-exploited and exploited. Roof drains HL are used with various designs(types) of roofing and filling the "pie" of the roof. They are mounted on exploited inverted roofs, insulated flat traditional roofs, roofs made of corrugated board (profiled sheet), "green roofs", can be installed on balconies and terraces. HL funnels are designed to drain rain and melt water from roofs to rain sewers.

This section presents:

HL drains with vertical outlet for unused roofs. With leaf catcher. DN - 75, 110, 125 or 160;

Roof drains HL with vertical outlet for roofs in use. With grid (150x150 mm) in stainless steel. DN - 75, 110, 125 or 160;

HL drains with vertical outlet for corrugated roofs. DN - 75, 110, 125. For installation in roofs with insulation thickness - 100-160 mm.

Additional equipment for roof outlets HL - extensions, extensions, waterproofing flanges, various leaf catchers, fire couplings.

HL drains with vertical outlet for unused roofs. With leaf catcher. Sizes - DN 75, 110, 125 or 160.

		Description
		Roof drain with leaf catcher, thermally insulated, with stainless steel compression flange (with union nuts/wing nuts), with vertical outlet. Recommended for waterproofing polymeric membranes: EPDM, EPB, ECB (ethylene-copolymer-bitumen), EVA (ethylene-vinyl acetate), PIB (polyisobutylene), etc.
		Like roof drain HL 62, but electrically heated. Self-regulating heating cable. Power - 10-30 W. Voltage - 230 watts.
HL62P		Roof outlet with leaf catcher, PVC (polyvinylchloride) body with thermal insulation for bonding PVC membrane, with vertical outlet. Recommended for PVC membranes.
		Like roof drain HL 62P, but electrically heated. Self-regulating electric heating cable with a power of 10-30 W, 230 V.
HL62F		Roof drain with leaf catcher, with body made of PP with thermal insulation for gluing waterproofing FPO membranes. With vertical outlet. Recommended for FPO membranes (based on PP).
HL 62.1F		Like roof drain HL 62F, but electrically heated. Self-regulating electric heating cable with a power of 10-30 W, 230 V.
		Roof funnel with leaf catcher, body made of thermally insulated PP, with waterproofing polymer bitumen sheet 2.5 mm thick and 500 mm in diameter. Recommended for built-up waterproofing materials based on bitumen. With vertical outlet.
		Like roof drain HL 62H, but electrically heated. Self-regulating heating cable. Power - 10-30 W. Voltage - 230 watts.
"Universal" funnels for non-exploited roofs with a leaf catcher. With universal connection to steel, cast iron, plastic pipes.
		"Universal" roof drain, with leaf catcher, with stainless steel compression flange (with union nuts/"wing nuts"), with flexible sealing rings, with vertical outlet. This funnel simply and reliably connects to pipes made of any material (steel, cast iron, plastic). The funnel is inserted into the pipe and does not require expansion pipes.
HL69P		"Universal" roof drain, with leaf catcher as HL 69, but with PVC flange, for attaching PVC membrane, drain with flexible sealing rings, with vertical outlet. Funnel HL 69P is simply and securely connected to pipes made of any material (steel, cast iron, plastic). It is inserted inside the pipe and does not require compensation pipes. Recommended for waterproofing polymeric membranes: EPDM, EPB, ECB (ethylene-copolymer-bitumen), EVA (ethylene-vinyl acetate), PIB (polyisobutylene), etc.
HL69H		"Universal" roof outlet, with leaf catcher as HL 69, but with bituminous polymer mesh, with flexible sealing rings. With vertical outlet. The funnel is connected to pipes made of any material (steel, cast iron, plastic). The funnel is inserted into the pipe and does not require compensatory nozzles. Recommended for waterproofing polymeric membranes: EPDM, EPB, ECB (ethylene-copolymer-bitumen), EVA (ethylene-vinyl acetate), PIB (polyisobutylene), etc.

Roof drains HL with vertical outlet for roofs in use. With 150x150 mm stainless steel grate. Sizes - DN 75, 110, 125 or 160.

		Description
HL 62B		Thermally insulated roof drain with stainless steel compression flange (with union nuts/wing nuts). With vertical outlet. Recommended for waterproofing polymeric membranes: EPDM, EPB, ECB (ethylene-copolymer-bitumen), EVA (ethylene-vinyl acetate), PIB (polyisobutylene), etc.
		Like roof drain HL 62B, but electrically heated. Self-regulating electric heating cable 10-30 W, 230 V.
HL62BP		Thermally insulated roof drain with PVC (polyvinyl chloride) body, for gluing PVC membranes, with vertical outlet. Recommended for roofs with PVC membrane waterproofing.
HL 62.1BP		Like roof drain HL 62BP, but electrically heated. Self-regulating electric heating cable 10-30 W, 230 V.
HL62BF		Roof drain with thermal insulation, with body made of PP (polypropylene) for gluing FPO sheeting. With vertical outlet. Recommended for serviced roofing with FPO-membrane (PP-based) waterproofing.
HL 62.1 BF		Like roof drain HL 62BF, but electrically heated. Self-regulating heating cable. Power - 10-30 W. Voltage - 230 watts.
HL 62 BH		Roof funnel with thermal insulation, with a waterproofing polymer-bitumen sheet 2.5 mm thick and 500 mm in diameter. With vertical outlet. Recommended for built-up waterproofing materials based on bitumen.
HL 62.1 BH		Like roof outlet HL 62 BH, but electrically heated. Self-regulating heating cable. Power - 10-30 W. Voltage - 230 watts.
"Universal" drains for roofs in use with grating (150x150 mm) made of stainless steel. with universal connection to steel, cast iron, plastic pipes.
HL 69 V		"Universal" roof drain, with leaf catcher, with stainless steel compression flange (with union nuts/"wing nuts"), with flexible sealing rings, with vertical outlet. The funnel is simply and reliably connected to pipes made of any material (steel, cast iron, plastic). The funnel is inserted into the pipe and does not require compensatory nozzles.
HL69BP		"Universal" roof drain, with leaf catcher like HL 69 B, but with PVC flange, for fixing PVC membrane, drain with flexible sealing rings, with vertical outlet. Funnel HL 69 BP connects to pipes made of any material (steel, cast iron, plastic). It is inserted inside the pipe and does not require compensation pipes. Recommended for waterproofing polymeric membranes: EPDM, EPB, ECB (ethylene-copolymer-bitumen), EVA (ethylene-vinyl acetate), PIB (polyisobutylene), etc.
HL69BH		"Universal" roof drain, with leaf catcher as HL 69 B, but with bituminous polymer waterproofing membrane, with flexible sealing rings. With vertical outlet. The funnel is connected to pipes made of any material (steel, cast iron, plastic). The funnel is inserted into the pipe and does not require compensatory nozzles. Recommended for waterproofing polymeric membranes: EPDM, EPB, ECB (ethylene-copolymer-bitumen), EVA (ethylene-vinyl acetate), PIB (polyisobutylene), etc.

Funnels with vertical outlet for corrugated roofs. DN - 75, 110, 125. For installation in roofs with insulation thickness - 100-160 mm.

		Description
		Roof funnel for corrugated roofs, with a leaf catcher, with a stainless steel compression flange (with union nuts/wing nuts), with thermal insulation, with a sliding mounting box (adjustable in height - 100-160 mm). With vertical outlet. Recommended for waterproofing polymeric membranes: EPDM, EPB, ECB (ethylene-copolymer-bitumen), EVA (ethylene-vinyl acetate), PIB (polyisobutylene), etc.
		Like roof drain HL 63, but electrically heated. Self-regulating heating cable. Power - 10-30 W. Voltage - 230 watts.
HL63P		Roof funnel for corrugated roofs, with leaf catcher, with thermal insulation, with sliding mounting box (adjustable in height - 100-160 mm) like HL 63, but with a smooth PVC flange, for attaching a PVC membrane. With vertical outlet. Recommended for PVC membranes, lightweight corrugated roofs, with insulation thickness - 100-160 m.
HL 63.1P		Like roof drain HL 63 P, but electrically heated. Self-regulating heating cable. Power - 10-30 W. Voltage - 230 watts.
HL63H		Roof funnel for corrugated roofs, with leaf catcher, with thermal insulation, with sliding mounting box (adjustable in height - 100-160 mm) like HL 63, but with a waterproofing polymer-bitumen sheet. With vertical outlet. It is recommended for built-up waterproofing materials based on bitumen, lightweight corrugated roofing, with a thickness of insulation - 100-160 m.
HL 63.1H		Like roof drain HL 63 H, but electrically heated. Self-regulating heating cable. Power - 10-30 W. Voltage - 230 watts.

Accessories for roof drains with vertical outlet series HL 62

		Description
Extensions for funnels series HL 62
		Extension element with a stainless steel compression flange and a sealing rubber ring, 345 mm high, used for hermetic connection with waterproofing, as well as with a roof funnel on flat insulated roofs with a vapor barrier, DN 125
		An extension with a waterproofing polymer-bitumen sheet and a sealing rubber ring, 345 mm high, is used for hermetic connection with bitumen-based waterproofing, as well as with a roof funnel on flat insulated roofs with a vapor barrier, DN 125.
HL65P		Extension element made of polyvinyl chloride, with a sealing rubber ring, 345 mm high, is used for hermetic connection with waterproofing from PVC membranes, as well as with a roof funnel on flat insulated roofs with a vapor barrier, DN 125.
HL65F		Extension element made of polypropylene, with a sealing rubber ring, height 345 mm, used for hermetic connection with waterproofing from FPO sheet, as well as with a roof funnel on flat insulated roofs with a vapor barrier, DN 125.
HL65PE		Polyethylene (PE) extension for gluing FPO membranes (PE-based).
HL 350.0		An extension element with a profiled flange is used for mechanical fastening (pickup) of the second level of waterproofing. Height - 220 mm. DN 145.
HL 350.1		Extension piece with stainless steel compression flange, PP drain ring to receive water flow and mounting kit, used for bituminous waterproofing. Height - 220 mm. DN 145.
HL 350.1H		An extension with a waterproofing bitumen polymer sheet, used to pick up the second level of waterproofing, 225 mm high, DN 145
Funnel extensions for HL 62 series
		Extension for roof outlets and extension element HL350.0, height 155mm. DN 145.
HL 350.2		HL 350.1 with additional side outlet. DN 40.
Waterproofing flanges for funnels series HL 62
HL 84		Waterproof flange with EPDM membrane 500x500 mm for roof drains.
HL 84.0		Ø 220 mm stainless steel waterproofing crimp flange for roof drains.
HL 84.CU		Waterproofing flange with copper sheet 500x500mm, for roof drains.
HL 84.E		Waterproofing flange with galvanized steel sheet 500x500mm for roof drains.
Leaf catchers for funnels series HL 62
HL 160		Drainage flange for receiving water flow from waterproofing on an inverted roof. Ø 170 mm.
HL 161		Drainage flange HL 160 complete with adapter Ø145 mm to Ø125 mm.
HL 170		Flat leaf catcher for roof outlets of the HL 62 and HL 64 series. Ø 170 mm.
HL 175		Stainless steel leaf catcher for HL 62 and HL 64 series roof drains. Ø 145 mm.
Fire couplings for HL 62 series funnels
HL 850		Fire coupling for funnels of the HL 62 (DN 75) series, fire resistance rating EI 120, consisting of a metal body with expanding material and a yoke, with a mounting plug. Applies to DN 75 outlets only.
HL 870		Fire coupling for roof outlets of the HL 62 (DN 110) series, fire resistance EI 45, consisting of a metal body with expanding material and a yoke, with a mounting plug. Applies to DN 110 outlets only.

One of the most destructive factors that shorten the life of a roof is water. However, no matter what the design of the roof, there are quite reliable methods that can effectively withstand precipitation and melt water. In this article, we will talk about what drain funnels are for a flat roof, and how to properly install them.

It is worth noting that the slopes of the roofs make it easy to cope with the problem of intense precipitation, since water simply flows off them. But in those cases when the roof is absolutely flat, puddles form on it, since the moisture does not have time to evaporate. As a result, the waterproofing is subject to gradual destruction, and a layer of dirt accumulates on the roof surface.

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

What is a drainage system

The term "drainage system" implies a set of devices through which the collection, transportation and removal of melt and rainwater from the surface takes place. flat roof.

There are such types of drains:

Disorganized, 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.
External. It includes a set of pipes and gutters for the outflow of water, mounted on rafter legs or wind boards. Precipitation falls into such drains by gravity and is discharged outside into storm sewer. For flat roofs, this type of construction is applicable only in buildings of a small area.
Interior. This type of drain is laid in the thickness roofing cake. It is most preferred for flat roofs.

Gutters internal type for flat roofs

The structure of the internal drainage system offers 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;
vertical sewers - they transport sediments from horizontal pipes into the storm.

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

The structure of the catchment funnel

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

the lower section, which is laid in the base of the roofing cake;
sealing gasket sealing the joint between the upper and lower sections of the funnel;
the upper section that passes through the layer of waterproofing and insulation;
grate - serves to prevent large debris from entering the downpipe.

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

Varieties of roof funnels

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

According to the structure, the following types of products are distinguished:

Flat. Such products are mounted flush with the roof surface, covered with asphalt or tiles.
Kolpakova. This funnel is necessarily equipped with a protective grill that prevents debris and dirt from entering the pipe. The product rises above the surface, resembling a glass or cap.
With horizontal or vertical type of release.
With heating elements. A heating cable is mounted 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 correct installation funnel on a soft roof:

Installation of the device must be carried out in such places, the level of which is lower than the main surface of the roof. Minimum slope between the funnel and the main roof can be 2º, and in a segment of 50 cm it should increase to 5º. The necessary slope is created by plates of insulating material, concrete screed or expanded clay backfill.
The number of funnels on the surface of a flat roof is determined on the basis of one unit for every 25 m of length.
Whatever the area of the roof, it must have at least two drain funnels. They will allow you to quickly withdraw a large number of water from the roof 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 out, divided into equal geometric figures. In the central part of each of them with the help of expanded clay, a layer of insulation and concrete screed, organize a deepening. The lower part of the funnel joins with a downpipe laid horizontally and is mounted at the base of the roofing pie.
Upon completion of waterproofing and insulation work, a 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 also mounted.
To make sure that the water intake funnel is installed correctly and tightly, a bucket of water is poured onto the roof two meters from it and they check how quickly all the liquid will move into the drain.

It is worth noting that the drainage system, in particular roof funnels, needs periodic diagnostics and cleaning. This will significantly extend the life of your roof, as well as provide you with rainwater to water your garden plants.