How to heat roofs and gutters with an anti-icing system. How roof and gutter heating works Roof heating with an electric cable pros and cons

Everyone knows that the operation of the roof in the winter is much more problematic than in the summer. This is due to the fact that due to negative temperatures and a large amount of precipitation, ice, icicles and a snow cap form on some sections of the roof.

To prevent spontaneous slippage of ice and snow from the slopes, special snow retention structures are often not enough, so you have to resort to periodic mechanical cleaning.

Due to the low ambient temperature, as well as the alternation of frosts and thaws during the winter, it is often not possible to get rid of snow on roofs in a timely manner. This, in turn, causes the danger of falling snow masses and blocks of ice on people passing in the immediate vicinity of the house.

To minimize traumatic roofing mechanical cleaning and make the operation of the house safe, electric roof heating is used, the device of which we will discuss in this article.

As a rule, the roof of a private house is a pitched structure, consisting of two or more slopes located at an angle of 30-50 degrees to the base. The roof structure is specially designed in such a way that melt or rain water is drained as efficiently as possible, and snow melts better.

Experienced craftsmen note that the following types of roofing are more actively covered with ice and icicles:

Warm type roofs. Experts note that a warm roof, in which the slopes are thermally insulated and the attic floor is heated, is more prone to icing in the winter. This is due to the fact that due to the high temperature of the lower surface of the roofing material, the snow cap on the slope begins to melt, and during frost it becomes an ice crust.
Roofs with metal coatings. Roofing materials based on metal, for example, metal tiles or corrugated board, have a higher coefficient of thermal conductivity, therefore, due to temperature changes, they are more likely to be covered with ice than roofs covered with tiles, slates or shingles. For the same reason, ice formation occurs inside metal gutters.
Low slope roofs. From slopes with a slope of more than 45 degrees, snow masses easily slide off on their own, and on gentle slopes, snow accumulates, and an ice crust forms in places where it comes into contact with the roofing material.

Important! If the roof has at least one icing risk factor, a roof heating system is required. The use of this simple and inexpensive device will greatly simplify and secure the operation of the roof structure, as well as increase its service life.

Causes of the problem

With the right choice of the roof slope, the observance of the technology of its construction and the use of high-quality materials, neither on its surface, nor in the gutters and downpipes, ice should form, regardless of weather conditions.

Most often, the problem of ice formation occurs due to flaws during installation. Typically, roofers identify the following reasons for the formation of ice on the roof:

Poor thermal insulation. The most common cause of roof icing is insufficient or poor-quality thermal insulation of slopes. If the attic floor is heated, and the slopes are not insulated, the roof surface heats up, the snow melts on it even at low temperatures, and icicles form on the roof overhangs.
Daily temperature fluctuations. Even in winter, the sun shines, therefore, due to the heating of the sun's rays, the snow on the roof surface melts. In the evening, at lower temperatures, the water turns into ice.

Please note! If the problem of roof icing arises due to poor-quality thermal insulation of the slope, the most obvious way out is to additionally insulate it with thermal insulation material with a thickness of at least 150 mm. In other cases, in order to forever forget about putting on and icicles, electric heating of the roof is performed.

Icing Hazards

The problem with icing is solved by organizing the heating of the roof with the help of electric thermal cables. If icicles and frost are not dealt with, the following dangers arise:

Increasing the load on the truss frame. Raw snow, and especially ice, weighs quite a lot, so in winter the load on the truss frame of the structure increases. The valley, roof light and places of contact with vertical surfaces, where the bulk of the snow accumulates, suffer from this the most. It is necessary to get rid of snow so that the roof does not collapse.
Damage to roofing material. When the ice crust formed on the surface of the slope due to temperature changes begins to slide down, it scratches and damages the roofing. Each scratch from exposure to water becomes a hotbed of corrosion.
There is a danger of a spontaneous fall of snow mass from the slope. If the roof is not cleaned in time, snow and ice can fall from it at any time. This poses a threat to people passing by and parked cars.

Important! Heated roof with self-regulating wires is not covered with ice. Thermal cables, if necessary, heat the surface of the roofing material, gradually melting the snow cap, and then evacuating the melt water into a special drainage system.

Heating system and its functions

Roof heating is a system for maintaining a temperature on the surface of the roofing material, consisting of heating elements, water and precipitation sensors and control relays, which must be fixed along gutters, valleys and all areas where snow accumulates.

Cable heating of the roof maintains the desired temperature, ensuring uniform and gradual melting of snow, as well as directing it to the drainage system. The functions of electric roof heating are as follows:

Prevents the formation of icicles along the roof eaves.
It does not allow clogging of the drainage system, due to which the melt water is directed without loss through the gutters into the storm sewer.
Reduces the load on the truss frame of the structure, preventing deformation or collapse of the slope.
It completely replaces the mechanical cleaning of the roof surface, that is, the heating wires completely melt the snow cap.
Extends the service life of the roofing by minimizing the mechanical impact on its surface.
Automates operation. Thanks to sensors that record temperature, humidity and precipitation, the system automatically starts up without human intervention.

Note! If a metal roof is operated in areas with a cold climate, roof heating is necessary. Installation of the system solves the problem of icing of slopes, and prevents the growth of icicles. To determine the required number of heaters, the calculation of the heating power is used. The power of the system must correspond to the average annual temperatures in winter, the amount of precipitation and the area of roof slopes.

Device

Maintaining a constant temperature on the surface of the roofing can be carried out using a cable that is powered by the electrical network and transfers heat to the environment. The heating system consists of three parts:

heating. The heating part of the system includes an electric cable for heating, which is laid along gutters, funnels, valleys. One or two wavy lines of a thermal cable can completely melt the snow. During laying installation of heating wires from can be cut into pieces of the desired length, bent, give any shape. The resistive cable has the advantage of being more compact and easier to install.
distribution. The distributing part of the device consists of mounting elements, various sensors that record the state of the environment, as well as junction boxes. The task of such a system is to distribute its power, transfer power to the heating wire, ensure the transmission of signals from sensors to the control unit and vice versa.
manager. The device is controlled by thermostats, starting and safety systems, as well as a control panel. The self-regulating heating system is considered the most perfect, but installations of this design require special self-regulating cables.

Remember! The heated part of the roof must be roof overhangs, valleys, drain funnels, gutters. The length of the wire should be enough to lay it in wide loops in 1 or 2 rows.

Video instruction

From the article you will learn what cable heating of roofs and gutters with the help of anti-icing systems is, the main components, installation rules, types and structures of cables, the scheme and principle of laying, how to connect, control and protection equipment, ready-made solutions and much more.

The main tasks of anti-icing systems

Anti-icing systems - a set of devices whose task is to prevent the formation of frost on the eaves, as well as ice plugs in drains for draining water.

Timely and correct installation of heating of the roof and gutters allows you to protect building structures from dangerous contact with water, snow blockages or the formation of icicles.

The main difficulty is the correct arrangement of the system, because the quality of heating and the efficiency of the system as a whole depend on it.

What is a roof and gutter heating system

An anti-icing system is also called a cable heating system for gutters and roofs.

Its work is based on laying a group of cables that heat up and help thaw the snow, as well as protect against the formation of ice on the roof and in the building's drainpipe.

The peculiarity of the system lies in the possibility of its inclusion in the most dangerous periods, when the probability of water freezing on the roof is most likely.

It is known that the main cause of damage to roofs, gutters and gutters is precisely the ice that accumulates on the surface and carries its destructive effect.

With proper installation, the cable system eliminates the fall of icicles near the house, which allows it to be attributed to one of the elements of the building's security system.

In 2004, the Moscow Committee for Architecture published a document that provided recommendations on the arrangement of such systems on the roofs of buildings equipped with internal and external drains. Such recommendations applied to both residential buildings and industrial facilities.

Today heating of a roof and drains is in the greatest demand in Moscow and St. Petersburg. In these cities, anti-icing systems are installed on several thousand buildings, and this number is only growing.

During the period of installation work, companies that specialize in this work have managed to accumulate considerable experience and eliminate serious mistakes that were made before.

With proper design and compliance with the installation rules, the cable heating system eliminates the appearance of ice on the surface and guarantees the timely removal of water through the devices intended for this.

Due to this, the service life of the roof is significantly increased, "punching" and deformation of the gutters are excluded.

In addition, the risk of icicles falling on people passing by buildings is reduced.

Causes of roof icing

Experts identify two reasons for the formation of ice on the roof of structures:

How frost affects the roof and roofing material?

If the angle of inclination of the roof is less than 45 degrees, in winter a “cap” of snow mass forms on it.

In some cases, the weight of snow can reach 100 kg per square meter. The load increases even more if the roof has a slope of 30 degrees.

In such cases, deformation of the rafters under the weight of snow is possible. To avoid this problem, it is important to periodically clear the roof of snow and remove icicles. In solving this issue, heating of the roof and gutters helps.

If you save on an anti-icing system, the consequences can be as follows:

Roof deformation. During the period of snow melting, the ice crust that forms on the surface is heated from below, moves and damages the roofing material. Subsequently, corrosion processes begin with these scratches.
Drainage damage. Weather conditions are unpredictable. In nature, there are situations when, after a short thaw, frost comes again. As a result, the water accumulated in the drains freezes, which leads to deformation or rupture of these systems.
Icicle collapse, snow mass gathering. If you do not provide for the heating of the roof and gutters, it is impossible to predict the time of fall of the accumulated mass of snow or icicles. As a result, there is a high risk of injury to passing people, including damage that is not comparable to life.

What are the types of roofs?

Taking into account the thermal regime, all roofs can be divided into several types:

The heating system of the roof and gutters will get rid of the problem, but its installation is associated with many difficulties, and its operation is associated with high costs of electrical energy.

For this reason, the work is best done in several stages. First, the amount of “extraneous” heat is reduced by insulating the upper floors, and then an anti-icing system is installed.

If there are heating systems under the roof, they must be additionally insulated.

The main components of the anti-icing system

The device for heating the roof and drain consists of the following elements:

One or more heating cable branches. The laying pattern is determined taking into account the type of roof structure required, the level of complexity of the surface, and the presence or absence of a structure for draining water.

General installation rules

Before installing the icing system, it is important to draw up a project in advance, and then proceed with the installation work.

Documentation should take into account the following points:

PUE requirements;
Recommendations of the manufacturer of the system and its elements;
Decree on the implementation of fire prevention measures;
Other documents.

The best results when installing an anti-icing system can be obtained by observing the following rules:

Work on a fine day when precipitation is not expected;
The arrangement of the icing system must be carried out only at positive temperatures;
The area intended for laying the heating element must be clean and dry.

Remember that most of the sealants and adhesives that are used during the installation process work at positive temperatures.

The same conditions apply to various models of power and heating cables.

During the installation process, consider a number of recommendations:

For the greatest efficiency of the anti-icing system, work in the warm season.
Installation of roof heating and gutters is best done on roofs where an organized drainage system is provided.
The task of such a system is to exclude the freezing of melt water and ensure the discharge of accumulated moisture into the drainage system.
Before starting work, the roof surface must be cleaned and dried.

The ideal option is when the anti-icing system is designed at the design stage of the building.

In this case, it is worth considering in advance the path of laying the power cable from the roof structure node to the energy distribution point.

If a heating system for the roof and gutters has not been provided, during the construction process it is required to install horizontal and vertical embedded parts.

When arranging the anti-icing circuit, the cable power supply should be closed using rigid boxes or corrugated channels.

Types and structures of heating cables

When arranging the circuits, two types of heating products are used, the total power of which is equal to or greater than 20 W per square meter.

Laying, as a rule, is carried out in an open way, so the cables must have a reliable sheath that protects against UV rays and atmospheric moisture.

During operation, the heating elements should not touch materials containing bitumen - euro-roofing material, shingles and other coatings. If the laying is carried out on a bituminous roof, the cable sheath must be made using a photopolymer.

A big plus is the presence of an armored braid that will protect the product from mechanical damage.

On sale you can find power cables that are made in the form of a spring and exclude rupture during expansion or physical impact.

Resistive cable - types and structure

When installing the anti-icing system, two types of resistive cables can be used - one and two-core.

In general, the product is a metal conductive core that generates heat, a shielded braid, insulation, and an outer PVC sheath.

Let's take a closer look at the types:

Resistive cables allow you to save on heating the roof and gutters at the stage of purchasing the material. As for installation, it is more expensive, because a longer length is required. The number of fasteners is also increasing.

The disadvantage of resistive cables is that they have a fixed length of sections, while the main elements of the roof, trays and gutters are made in various lengths.

The problem can be solved in only one way - by selecting products with different resistance. In addition, the operating conditions of different sections of the cable may vary, which is why roof heating is not always effective.

Self-regulating cable - types, structure and typical layouts

Unlike a resistive product, a self-regulating cable adjusts the resistance at each section or along the entire length. If desired, it can be cut into pieces of suitable length.

Structurally, a self-regulating cable is an electric-type tape heater, inside of which there are parallel conductors.

The latter are separated by a semiconductor-type heat-generating polymer matrix.

In turn, the conductive material of the central part plays the role of a heating element, which allows you to cut the cable in any necessary place.

As a result, the appearance of cold areas is eliminated and heat production is regulated taking into account the characteristics of the environment.

In fact, each section of a self-regulating product quickly adapts to external conditions.

This type of cable can be of two types - with or without a copper braid. Otherwise, the structural elements are identical:

Copper conductors;
Self-adjusting matrix;
Polyolefin shell;
Outer shell polyolefin type.

As noted above, resistive cable costs less, but electricity costs are higher.

At the same time, the use of a self-regulating "competitor" allows you to reduce costs, which is explained by competent adjustment to weather conditions.

Due to the design features, such a cable can heat up differently in different parts of the roof - in the shade or on the illuminated side.

The ability to cut anywhere eliminates a large number of surpluses.

Definition of heating zones

When determining the working areas and places for laying the cable for heating gutters and roofs, the efficiency of the flow of melted water is taken into account.

To achieve the greatest efficiency, the cable is laid in downpipes, gutters and other places where there is a high risk of ice formation.

The total length of the anti-icing system is determined by summing up the main elements of the roof that need to be heated.

With a steep slope, when there is a risk of a mass of snow and ice coming off, it is required to mount a snow retention system.

In such situations, it is worth laying the cable in the area between the protective device and the edge of the roof. The height of the snake is selected taking into account the width of the eaves.

If there is no risk of collapse, only drains and gutters can be heated. Depending on the diameter of the latter, the power and quantity of the self-regulating cable is selected.

Scheme and features of laying heating cables

The choice of a scheme for laying heating elements for roofs and gutters is made taking into account the angle of inclination of the roof slopes, as well as its configuration.

The greater the slope and the simpler the shape, the fewer meters of the product will be required to equip the surface.

Principles of laying and fixing the heating cable

Anti-icing systems, as a rule, are concentrated in places of the greatest accumulation of winter precipitation and ice formation.

These should include:

In a pitched roof, you can do without heating the cornices. If the angle of inclination is more than 45 degrees, the snow mass will be removed without additional help. In this case, the heating cable should only be laid in the elements of the drainage system.

If ice builds up near the roof windows, the heating filament is laid near them towards the drain.

If the building does not provide for a drainage system, the heating line goes through the drip and along the extreme part of the slope.

Here, it is necessary to mount a device for retaining snow above the cable installation site and equipping a dropper on the eaves.

The fastening of the anti-icing system elements deserves special attention. Here you should adhere to the following rules:

Flat roof icing system

On a flat roof, the heating cable is laid along the perimeter of the water drain line.

In addition, the heating circuit must be led into an internal drain funnel about 40 cm or more (for an internal drain). If the trays are external, a dripping loop is made.

In places where the roof touches the parapet, laying is carried out near a receiving tray with a power of 60-80 W per "square" with access to the tray and laying in a pipe for water drainage.

Connecting the power cable

The anti-icing system is connected using a power cable to a single-phase or three-phase network.

When connected to a network with a voltage of 380V, phase imbalance is possible in the range of 10-15%. To avoid the problem, it is desirable to use anti-icing systems with a total power of up to 6 kW.

If this parameter is higher, the connection is made evenly to the three phases of a 3-phase circuit.

When choosing a cable section, it is worth focusing on the power consumption and the total length of the heating section. In turn, the power depends on the resistance of the branches and the length of the heating line.

During the installation process, it is important to take into account the regulations of the PUE. The power and heating cable must be combined in a junction box, instead of which a heat shrink sleeve can be used. The latter guarantees tightness at the joints.

The device of the heating system of the internal drain

The internal drain deserves special attention, the heating of which is carried out according to a separate scheme.

The structure includes a funnel roof, waterproofing, thermal insulation and mounting tape.

The elements of the system also include a temperature sensor, a heating section, a junction box, a power cable, a casing, a clamp and a rivet.

If the roof has a flat design and the drain funnels are built-in type, the heating cable is laid on the path of collecting water, as well as in areas near the funnels.

After that, it is discharged into the funnel and into the pipe until it enters the heated room.

If the product does not go through a warm area, the heating cable is lowered to the foundation of the structure or to the level of the blind area. In the presence of a drainage system, laying is carried out to the freezing depth.

Control and protection of the anti-icing system

The purpose of the control system is to create conditions for automatic or semi-automatic operation of heating the roof and gutters, and the protection system is to quickly eliminate emergency situations (short circuits, leaks or overloads) in the circuit.

Let's consider these points in more detail.

Control equipment

The task of the control equipment is to activate the heating cables, as well as to turn off the power when the operating temperatures are exceeded.

Today, two types of equipment are used:

The first option is more affordable, but in regions with high humidity, a large error and ice may appear on the roof surface.

In this regard, the weather station is more sensitive and responds more accurately to changes in humidity. In addition, the greater accuracy of the weather station allows you to save money on electricity.

If the region is dominated by low humidity and the arrangement requires a low-power anti-icing system, a thermostat will suffice.

Interestingly, self-regulating cables are able to work without automatic control, thanks to the ability to independently regulate their power, taking into account the temperature outside and the presence of precipitation.

But it is still better to use special thermostats.

Here you can use the following devices:

Of the weather stations, IS-11 showed itself well, which is characterized by increased efficiency and does not require cleaning during operation.

Protection equipment

The control and protection panel for the roof and drain heating system includes the following elements:

Introductory circuit breaker;
Thermostat circuit breaker (weather station);
Magnetic switch;
RCD (30 mA);
Circuit breaker heating;
Alarm.

In more complex systems, a number of additional devices can be mounted, such as a time delay relay, a current transformer, controllers, a soft starter, and other systems.

The protection equipment must guarantee:

Protection of the supply circuit (single-phase or three-phase) against short circuit in the heating line, power cable or in any of the equipment elements;
Overload current protection;
Shutdown of the system or one of its sections when a leakage current exceeds 30 mA.

In the first two cases, the protection function takes over, and in the last - the RCD. You can combine two devices in one -.

Material Calculation Example

To represent the level of costs for the installation of an anti-icing system, we will give an approximate calculation of materials.

Imagine that the hanging chute has a width of 12 cm and a semicircular shape. Its length is 20 meters, and along the edges of the gutter there is a pair of downspouts, having a height of 14 meters and a diameter of 10 cm.

In the process of calculations, it is taken into account that laying is carried out in three lines:

As a result, the installation of the system requires:

The total power of the anti-icing system (with a supply voltage of 220 V) is 2.9 kW.

The next step is the choice of protective automation. Here you will need a single-phase RCD for 30 mA of leakage and 25A of rated current, as well as a single-phase machine for 16 A.

Fastening is carried out in pipes and gutter using special clamps. The calculation is carried out taking into account 3-4 fasteners per meter of gutter or pipe.

The total length of the mentioned elements is multiplied by 4 and the total number of fasteners is obtained.

For our case, this is 14 m + 14 m + 20 m = 48 m. The final number is multiplied by 4 and we get 192 mounts.

You will also need a cable to fix the cable in the water drains. Here the formula is as follows - (Hcable + 1 m) * 2 = (14 + 1) * 2 = 30 m.

As a result, from additional equipment you will need:

Cable in a plastic sheath - 30 m;
Cable clamp - 2 units;
The number of clamps - (14 m + 14 m) * 4 = 112 units.

Features of cable fastening depending on the type of roof are listed below.

How much electricity is consumed?

One of the key factors when choosing an anti-icing system is the amount of electricity consumed. Please note that the power reserve of the equipment may not be enough to lay the equipment.

Operating costs are determined taking into account the cost of electrical energy consumed during the operation of all elements of the system.

The formula has the following form - C year = Pн*h*s.

Its terms:

Year - the price that the system costs during the year, r.;
Pn - rated power of the system, kW;
S - the price of 1 kW / hour of electrical energy, rubles;
h is the number of hours the system operates during the year.

In order to calculate the approximate cost of maintaining the heating of the roof and gutters, it is important to determine the number of hours of its operation.

For this, it is taken into account that the system is active somewhere from November 15 to April 15, that is, 151 days or 3624 hours.

On average, 20% of this time the system is turned off automatically due to lack of precipitation or out of the operating temperature range.

It turns out that the total number of hours of work is lower. We multiply 3624 by a factor of 0.8 and get 2900 hours.

Below is an example of the annual cost of maintenance, subject to the connection of resistive cables with a total length of 100 meters and a power of 3000 watts.

Cyear \u003d 3 kW * 2900 h * 1.05 rubles / kW * hour \u003d 9.135 thousand rubles.

In the case of using self-regulating cables, the consumption of electrical energy will be lower by an average of 12-15%.

Rules for the operation of the anti-icing system

To ensure trouble-free and long-term operation of the roof and gutter heating system, it is important to strictly follow the installation instructions and entrust the work to experienced workers. The latter must undergo the necessary training.

If you do the work yourself in the absence of the necessary knowledge, there is a high risk of not having the expected result.

The main rules of operation should include:

Installation of the anti-icing system should be carried out while still warm, before the onset of cold weather;
The roof and gutters must be cleaned of debris, and the system should be inspected twice a month. If a breakdown is detected, it can be fixed on its own or involve specialists;
Cleaning must be done with extreme care to avoid damage to the insulation. Please note that if the integrity of the cable is violated as a result of mechanical stress, the warranty is lost;
The settings are already made on site, taking into account climatic factors. When independently determining the boundaries of turning on / off the system, you should focus on the manufacturer's recommendations.

Ready solutions on the market

Below we will consider ready-made solutions for anti-icing systems.

Gutter heating kit with Hemstedt cable, 28 meters.

The anti-icing system has a power of 23 W per linear meter. The advantages are UV resistance and ease of installation.

The kit includes 28 meters of cable, which is enough to warm up the drain and gutter, having a total length of 14 meters.

The total power is 700 watts. An alternative application of the anti-icing system is the heating of platforms, steps and paths, pipes and tanks.

Heating cable 104 meters long from the manufacturer Hemstedt (Germany).

The kit is useful for heating the drain and gutter with a total length of 52 meters.

Laying is carried out in two tracks (between spacer tracks). In the set, in addition to 104 meters of cable, there is a mounting tape.

The total power is 2.388 watts. It is used for heating tanks and pipes, drains and roofs, platforms and paths.

Heating cable from Germany (manufactured by Hemstedt), 44 m.

The anti-icing system has a total length of 44 meters and a power of 23 W/rm.

The product is resistant to UV rays, fits in two routes and has a total power of 2.2 kW.

Scope of application - heating of platforms, paths and steps, gutters and roofs, tanks and pipes.

FS 10 - heating cable from Hemstedt with a length of 10 meters.

This model of the device is ready for use and turns on automatically when the positive temperature is reached.

The heating cable consists of the following elements - a temperature sensor, a heating "cold" and "hot" conductor, and a plug.

Fastening is carried out with the help of clamps to the pipe with subsequent inclusion in the supply network.

The rated voltage of the product is 230 Volts, the length of the "cold" cable is 2 meters, the power is 10 W / m.

Of the characteristics, it is also worth highlighting an outer diameter of 9 mm, a nominal temperature of 65 degrees Celsius, as well as a minimum bending radius of 5 times the diameter.

The FS10 cable is excellent for small diameter pipes and can be run in plastic pipes.

Heating cable Thermo.

It is one of the main elements of the heating system of the roof and gutters.

The kit also includes a mounting tape for attaching to a concrete base, an insulating corrugated tube, as well as instructions in Russian. The cross section of the cable is 6.7 mm.

The advantages of the product include protection of the cores with a special screen made of aluminum foil, the presence of additional insulation and cable reinforcement using fiberglass.

The upper temperature limit is 90 degrees Celsius. Power - 20 W per running meter.

The outer shell is made of PVC. The length of the "cold" wire for connection is 3 meters, and the cross section is 1.5 square meters. meters.

The entire range of products is shown below.

Thermostat ET-02-4550.

This is an excellent solution for managing the anti-icing system. It can be used to control electric and water heating devices.

The main options include the presence of two control zones, low energy consumption, convenient programming and the presence of an alarm relay.

The device accurately captures the parameters of temperature and humidity. The operating temperature range is from 0 to 5 degrees Celsius. Rated current - 16 A.

Thermostat ETR/F-1447A.

This is a reliable thermostat, which is installed in the shields using a DIN rail.

The device is used to melt snow and ice on gutters and roofs of small structures.

It has a remote sensor that monitors the air temperature. Operating temperature range from -15 to +10 degrees Celsius.

Installation can be done manually. The upper load limit is 3.6 kW. Rated current - 16 Amps.

Thermostat ETV 1991.

A model that is mounted in panels on a special DIN rail. Application is possible for heating the entire room or floor heating.

One of the areas of application is the provision of ice and snow melting on roofs, heating of pipelines and protection of external areas.

Features - load up to 3.6 kW, as well as the ability to connect a remote temperature sensor.

The operating range is from 0 to +40 degrees Celsius. Rated current - 16 A.

Heating cable from Germany Hemstedt with a length of 16 m.

The product is intended for heating a drain or gutter having a length of up to 8 meters.

Capacity is 25 "square" per linear meter. The features include resistance to UV rays and the possibility of laying in two routes.

The total power of the kit is 380 watts. The system is controlled manually. Temperature range - from +5 to +40 degrees Celsius.

Two-core cable DEVIsafe 20T.

The product is designed for heating roofs, gutters and gutters. It is UV and weather resistant.

Structurally, it has two cores with a screen made of foil and copper braid.

The upper temperature limit is 65 degrees Celsius. The length of the "cold" cable - 2.3 m. Product type - resistive. The cable has a diameter of 6.9 mm.

Cable FS10 36 meters.

It is intended for heating of drains. The heating element consists of a plug, a temperature sensor, an electrical cold and hot cable, and a 2 meter long cold connection cable.

The cable is easy to install. Its fastening is carried out using clamps, and the operating temperature range is from -15 to +5 degrees Celsius.

The system is controlled automatically. Food is carried out from a household network of 220-240 Volts.

ProfiTherm cable.

Designed for heating drainpipes and roofs with one core and power from 23 to 140 watts.

This is a product of Ukrainian production, which is supplied with two couplings for each of the sections.

The product is used (except for the already mentioned purpose) for heating steps, parking lots, paths and other structures.

The upper and lower ambient temperatures are +75 and -20 degrees, respectively. Management is performed automatically. Supply voltage - 220 V.

Cable with thermal limiter, 22 meters long.

The product is based on two cores with photopolymer insulation. The bimetallic thermostat ensures operation at temperatures up to +5 degrees Celsius. Shutdown is made at +15 degrees Celsius.

The main scope of application is the heating of water supply pipes. Diameter - 8.2 mm. The maximum operating temperature is + 65 degrees Celsius. The length of the "cold" section is 2 meters. The total power of the set is 220 watts.

Cable SMCT-FE 30W/m with two cores and a power of 4 kW from Thermopads (UK).

Power is 30 watts per sq. meter. The main scope of application is roof insulation, as well as providing street heating.

The total length is 134 m and its thickness is 6 mm. The advantages include minimal losses and optimal use of heat. The average service life (under warranty) is 10 years.

Two-core cable TXLP/2 R.

It is intended for heating of a roof and downpipes with a power of 28 W/meter.

The manufacturer of the product is Norway, the company Nexans. Scope of application - heating of steps, platforms, gutters, roofs, tanks and pipes.

This type of product is reliably protected from moisture, overheating and UV rays. It is equipped with a jointless connection, which guarantees trouble-free operation of the cable at the junction of the power and heating parts of the cable.

The work is carried out automatically. The upper temperature limit is 65 degrees Celsius. Warranty - 2 years.

Hemsted heating cable 19 m long.

Anti-icing system designed for 9 m gutter and downspout. The features include resistance to UV rays and a total power of 460 watts.

Cable laying is carried out in two routes. The maximum temperature should be 40 degrees Celsius. Management is carried out in manual mode. The power of the product is 25 W/m.

The benefits of roof and gutter heating systems can hardly be overestimated. They contribute to the extension of the life of the roof, eliminate frost, protect against the formation of icicles, improve the operation of the drain and reduce the risk of leaks.

In the absence of experience in such work, it is better to involve specialists who know the installation schemes, strictly follow the work technology and configure the system to meet modern requirements.

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A group of people with shovels on the roof and an attentive duty officer below, carefully warning passers-by with the phrase: “you don’t go there, you go here” - this is a very funny scene if you watch it in your favorite movie. In life, this is not such a fun sight, especially if you have to wield a shovel. You can get rid of hard work, as well as protect yourself and others with the help of an anti-icing system for the roof, which will become the subject of our conversation.

The need for underfloor heating

Snow, as you know, not only “circles, flies and melts”, but also creates a lot of problems:

With its weight, it can damage the roof or gutter system up to the formation of leaks.
Having overcome the critical mass, a snowdrift can slide off the roof slope and fall down, injuring people or animals near the house.
Soft and loose snow very easily turns into solid dangerous ice: during the day, under the rays of the sun, melting occurs, and at night the water formed during this freezes. Ice not only blocks the drainage system and creates a danger of its collapse with its weight, but also in the form of icicles threatens the lives of passers-by.

Note that snow melting can also be observed in frost if the roof is poorly insulated (“warm roof”). This time, the cause of the melting is the warmth of the interior space of the house. Flowing down to the colder cornice and drain, the melt water freezes, forming ice and icicles.

Such "decorations" turn the roof of the house into a source of danger to others.

The problem of ice and snow on the roof cannot be ignored. But instead of removing them mechanically, you can apply a simpler and more modern solution: fix heaters on the roof and drain. This is the essence of the anti-icing system.

The composition of the anti-icing system

This system consists of the following components:

The shield consists of several devices:

automatic switch (VA): if the system is 3-phase, then one for each phase;
contactor 4-pole or magnetic starter;
residual current device (RCD), triggered by current leakage from 30 mA;
signal lamp;
VA for thermostat control circuit;
thermostat: supplies power to the heating cable at a certain temperature, usually from -8 to +3 o C.

Types of heating cables

The main element of the anti-icing system is available in several variations.

Although the definition of "resistive" for this type of cable is firmly established, it is not entirely correct. It is more correct to call this version of the cable "unregulated", since all heating cables are inherently resistive.

An unregulated cable has the simplest device. This is a heating element made of a metal alloy with high electrical resistance (usually nichrome is used) extended into a long core, enclosed in a shielding sheath and insulation. Its advantages are the following:

Disadvantages:

It has a constant heat output. Because of this, those sections of the roof that currently need less heat are subject to overheating, and even at the expense of the user (overexpenditure of electricity). In addition, with insufficient heat dissipation, an unregulated cable can overheat and burn out. In particular, places where two cable lines overlap are subject to overheating.
It is impossible to reduce the length of the cable in an already installed system, since this will reduce its electrical resistance and, accordingly, increase the current in the circuit.
The power input also depends on the length.
If the heating core breaks, the entire cable becomes inoperative.

The non-adjustable resistive cable is available in two versions:

single core;
two-core.

In fact, one core is also used in a two-core cable, only it is folded in half. This allowed us to win in the following:

There was no need to close the circuit by pulling the other end to the connection point. Thus, a two-core cable is laid in one thread, and not in two, like a single-core cable, therefore, the danger of overlapping when large masses of snow converge is eliminated. It should also be noted that a system with such a cable is easier to design and install.
The currents flowing in the cable cores, and in fact - in two halves of one core, have opposite directions, therefore the magnetic fields generated by them cancel each other out. A single-core cable in close proximity to a person (for example, if the attic is residential) with its electromagnetic field can be harmful to health.

The heating conductor is also made of nichrome, but the cable is designed somewhat differently: it consists of two insulated conductive conductors (phase and zero), and the heating conductor is wound around them in the form of a spiral. In this case, the nichrome conductor is divided into segments, which are connected at their ends to current-carrying conductors. Thus, the zonal cable consists of many heating fragments connected to the mains in parallel. This provides the following benefits:

A zonal resistive cable costs, as you might guess, more expensive than usual.

Self-regulating cable

In this cable, as in the zonal one, there are two conductive cores, but the heating wire is made of a completely different material: it is a special polymer with semiconductor properties, called the "matrix". It is not laid around the conductive cores, but between them. The peculiarity of the matrix is that its electrical resistance depends on temperature: the stronger the heating, the smaller the number of conductive paths is active.

In the end, when heated to a certain temperature, the polymer generally turns into a dielectric, that is, it turns off, while the sections with an acceptable temperature continue to function. The advantages of a self-regulating cable are obvious:

But there are also negative aspects:

the cost of a self-regulating cable is 3 - 5 times higher than the cost of an unregulated one (240 - 660 rubles / running meter versus 90 - 150 rubles / running meter);
in a cold state, the matrix has a very low electrical resistance, therefore, when turned on, there is a high inrush current (you have to use more expensive protection devices).

Design and calculation of anti-icing system

Developing a roof heating system is far from an easy task, especially since an individual approach is required in each specific case. Design should be done by experts. But the future owner should still familiarize himself with the general provisions of the calculation. At least in order not to become a victim of an unscrupulous supplier trying to sell an unreasonably expensive system.

So, in general, do something like this:

Develop a scheme for laying the heating cable. If the roof is “cold” (that is, well insulated) and sloping, you can limit yourself to heating the drainage system. On a “warm” roof, the edge of the roof is also subject to heating, the boundary of which is determined as follows: 30 cm are laid up the slope from the line of intersection of the planes of the outer wall and the slope. On roofs with a significant slope, due to the high probability of collapse of the snow mass, this border should be carried even higher by 15–20 cm. If the roof is flat, then the cable is laid along the perimeter and at the drain funnels.

On sloping and well-insulated roofs, only the areas where the gutters of the gutter system adjoin
With a large angle of inclination of the slopes, it is also envisaged to lay the heating cable in a zigzag pattern between the edge of the roof and the snow retainer, which must be installed on such a roof without fail (due to the high probability of snow mass slipping). Particular attention should be paid to places where two parts of a slope with a different slope meet - these are valleys (drainage faces) on flat roofs and valleys on gable roofs. The same can be said about the place where the roof adjoins the wall. Here ice is formed especially often. The cable must be laid in the form of an elongated loop at 2/3 of the height of the valley or valley. If the roof is adjacent to the wall, the cable must be laid 5–8 cm from the latter, while the distance between the threads of the extended loop should be 10–15 cm.

At the junction of two slopes, the cable must be laid to a height of 2/3 of the length of the valley
If the roof is not equipped with a drain, the cable on its edge is placed according to the “dripping loop” (with a large slope) or “dripping edge” (with a small slope) scheme. The idea is as follows: the loop is suspended so that the water from it drips directly onto the ground. For laying according to the "drip loop" scheme, the cable must have an allowance of 5 - 8 cm.

If the roof is not equipped with gutters, the cable is laid so that water drips directly onto the ground.
One cable line is laid along the gutter up to 15 cm wide. The cable lying in the gutter must be led with a “drip loop” 30 - 40 cm long into the funnel of the downpipe. The same is true when installing the system on a flat roof.
One or two threads are also run into the downpipe, depending on its diameter. At the bottom of the drain pipe, the number of turns should be increased, since it is colder than the top. On the roof, the cable is laid in a zigzag pattern. The zigzag pitch is determined as follows: for a soft roof based on the required specific power (W / sq. M), for a hard one - in accordance with the pattern of the roofing.

The heating cable on the roof surface is placed in a zigzag pattern with a constant pitch
If there is not enough money to purchase a self-regulating cable in the right amount, you can use it only in part of the system. The use of such a cable for heating the drain can be considered the most appropriate, while the roofing part can be equipped with a cheap unregulated cable.
Next, choose the location of the mounting (junction) boxes so that they are accessible for maintenance. Most often they are located on the roof next to the heating cable. This element can be fixed somewhere under the visor or on the fence (on the parapet). If you have an attic, you can put the boxes there.

Mounting boxes should be installed in places accessible for regular maintenance.
Determine the required linear and total power.

The approximate heating power for various roof elements is:

for a gutter up to 150 mm wide: on a "cold" roof - 30 - 60 W / m, on a "warm" - 100 W / m;
for gutter width over 150 mm: 200 W/sq. m;
on the roof (cornice overhang): on a "cold" roof - up to 150 W/sq. m, on the "warm" - 200 - 250 W / sq. m;
in valleys: 250 - 300 W/sq. m;
on flat roofs around drain trays located in the area of adjacency to the parapet: 40 - 80 W/sq. m.

If the drainage system is assembled from plastic parts, the cables heating it can have a total linear power of not more than 17 W/m. For roofs with soft roofing, the maximum power input is 20 W/m.

Next, the total length of the heating cable is calculated and the number of circuits is determined, taking into account the fact that the length of one circuit cannot exceed 120 - 150 m (depending on the brand of cable). Each circuit must be connected through a separate RCD.

Lastly, the control panel is designed taking into account the number of circuits and the electrical power they consume.

Installation of a roof heating system

Installing a roof anti-icing system requires certain knowledge and skills in working with power equipment. If you do not have experience with voltage, it is better to contact specialists or at least invite a practicing electrician as a partner.

Tools and materials needed to work with the roof anti-icing system

For installation you will need the following tools:

drill;
rivet pliers;
screwdriver;
hammer;
roulette;
multimeter;
megger.

To work at height, you need a ladder.

Of the materials, you may need a special adhesive, for example, GE Gray RTV 167. It is used on soft roofs, to which the heating cable retainer cannot be screwed with screws or nailed.

Preparing the cable for installation and connection

Work on the installation of the anti-icing system is carried out in the following order:

The installation step of the mounting tape depends on the cable material:

for resistive (unregulated) - 25 cm;
for self-regulating - 50 cm.

If several cable lines are laid side by side, then separators should be installed between them in increments of 25–30 cm to prevent the cable from tangling when snow melts or in strong winds.

To avoid damage to the cable, do not:

lay it on sharp edges;
pull with force;
walk on cable
squeeze or twist it;
place rough materials on top of it.

Fixing the heating cable to gutters

On drainpipes, the heating cable is installed in the same way: either it is simply inserted inside, or it is fastened from the outside with a mounting tape. Heat-shrinkable tubes can be used as fasteners. If the pipe has a length of more than 6 m, the cable must be fastened to a metal cable with a polymer sheath to avoid rupture from its own weight.

Inside the drainpipe and at the entrance to it, the cable is reinforced with special clamps or ties

When laying the cable in one thread, after forming a “drip loop” in the funnel, the end of the cable must be fixed with a tie. Fixing the cable in the funnel can be done with a bracket.

When laying several lines, each of them is attached with a separate bracket.

Video: installation of a drainage heating system

Cable installation on the roof

On the roof, the cable is fixed with a perforated tape, which can be screwed on with self-tapping screws or glued with special glue (on soft roofs). When installing a self-tapping screw, he himself and the hole in the roofing are treated with sealant. Excess sealant should not be removed, but coated with a hardware cap.

On the finished tiled roof, the fastening tape for the cable must be led 7.5 cm under the tile and glued there. If the tiles have not yet been laid, this tape is nailed to a continuous crate.

When using glue, its excess also does not need to be removed. Having come out through the holes of the perforated tape and dried, it strengthens the fastening, working like a nail or a self-tapping screw.

The installation step of the mounting tape is indicated in the instructions for the heating cable. Usually it is 15 - 25 cm.

Many manufacturers today supply clip-type clamps with the heating cable, in which the cable is fixed with pliers. Before this, the clamps must be screwed to the roof with self-tapping screws, nailed or put on glue.

Some types of cable are attached to the roofing with special clips that are included in the kit.

Another method is also used: the cable is fastened with clamps to a pre-laid mesh.

Video: laying the cable of the snowmelt system on a multi-pitched roof

Heating cable ringing

A megohmmeter is used to measure cable insulation resistance.

For a full check, measurements must be performed at a voltage of not only 500 and 1000 V, but also 2500 V, otherwise some defects may not be detected.

The first step is to measure the resistance between the conductive wires and the shielding metal braid. In the event that the cable is installed on a metal surface, then the resistance between the metal braid and this surface must also be measured.

The check is carried out in the following order:

Normally, all three resistances should have a value of at least 1000 MΩ, regardless of circuit length and voltage. In this case, the value of one resistance, for example, between one of the cores and the screen, must be constant at all three voltages, and all three resistances within the same circuit should not differ by more than 25%.

In the case of using a self-regulating cable, it is necessary to measure the resistance between the current-carrying cores at both ends. It should be 3 ohms. A value of more than 100 ohms indicates damage to the cores or a broken connection between sections of the circuit. After such a check, all elements with heat-shrinkable materials, for example, the end sleeve, must be replaced.

Connection and commissioning of the roof anti-icing system

After checking the insulation resistance, make the necessary connections:

Fine tuning of the thermostat is possible only in the cold season.

Upon completion of the installation, the owner must have the following documents in his hands:

passports of the anti-icing system, thermostat and control cabinet;
certificates for all components of the system;
protocol with data on the value of insulation resistance.

Roof anti-icing system maintenance

At least once a year (before the cold season) inspect the heating cable for mechanical damage.
Before turning on the roof heating, clean the gutters and pipes of the drainage system from leaves and other debris.
At the beginning of the winter season, check the value of the insulation resistance.
With the onset of cold weather, you should check the performance of the thermostat.
Periodically check the operability of the RCD with controlled current leakage.

The heating system of the roof and gutters not only saves the time of the owner of the house, but also prevents the residents from getting injured from falling icicles or snow. And since health and life are priceless, the cost of buying and installing the complex will be justified at any cost. You just need to remember that equipping the roof with heating is a rather serious project, and the best result will be guaranteed only if experienced specialists take part in it.

The main component in the heating system is the heating element, which forms a large part of its cost.

The cheapest heating element is a resistive cable, the only advantage of which is the price. The principle of operation is similar to an electric heater: a current flows through the conductor, generating heat.

However, there are a number of significant disadvantages:

When resistive cables cross each other, they burn out
When in gutters with leaves and dirt, they burn out
The length of the resistive cable must not be changed during installation as it is only used in fixed lengths
Resistive cable needs three times more than self-regulating
Low energy efficiency

For the entire time of our engineering center, we have not installed a single meter of resistive heating cable, since the most important thing for our company is the reliability, quality and durability of heating elements and other components of the roof heating system, and this can only be achieved using a self-regulating heating cable. Raychem cable.

The principle of self-regulation is to change the power of the cable depending on the ambient temperature, thus ensuring high energy efficiency of the roof heating system. When melt water hits the heating cable, it starts to produce its maximum power, and after the water is removed, it goes into a standby state, reducing the power by half. Only high-quality heating elements can provide such a wide range of power changes, and Raychem cables provide it thanks to the radiation-crosslinked heating matrix used in them. When using this matrix, it is possible to reduce the aging effect (power loss) of the heating cable to 10-15% in 10 years, unlike cheap self-regulating cables, in which there is no power variation range and the aging effect reaches 30% per year.

Roof heating systems aimed at anti-icing of surfaces and ensuring unhindered flow of melt water have not yet received proper distribution in our country. Such as it should be, based on the characteristics of our climate.

In our time, when the trend towards energy saving has acquired, where due to poverty, where due to greed, almost pathological features, up to cutting out sections of radiators in the entrances of high-rise buildings, few are ready to bear the additional cost of heating the roof. However, among the owners of manor houses, the trend is gradually gaining momentum.

The logic of roof heating is very simple: no matter how you insulate the attic, part of the heat is still transferred to the roof, and its temperature will always be higher than the ambient temperature. As a result, ice is formed, which destroys the elements of the roof, clutters up the drains, threatens the premises of the house with leakage and forms icicles that are dangerous to life and health. Installation of an electric heating system for roofs and gutters is one of the main ways to solve the above problems.

Video: Roof and gutters heating

We make our own roof heating system, cable for roof heating

If you do not resort to the services of specialized companies, but do the installation yourself, you will have to attend to careful calculations of the upcoming work, or even draw up real design and estimate documentation. Otherwise, there is a significant risk of wasting money, effort, time, regularly paying increased electricity bills and not achieving the desired result. Considering that a heat cable is often sold in sections of a given length, measurements of the future working surface should be made especially carefully.

Roof heating does not make sense if you heat the entire roof - it is enough to focus on problem areas: the edge of the roof, catchment funnels, gutters, etc. When calculating power, one should proceed from standard indicators. Depending on the type of cable (which will be discussed later), the power is 15-30 W per 1 meter of cable.

When installing heating of polyethylene gutters, the maximum power should not exceed 17 W / m in order to avoid deformation of structures. When laying the cable in the downpipe, its diameter must be at least 7 cm, which corresponds to the minimum radius of the natural bend of the cable.

The heat cable is laid so that the water completely leaves the heated surface. Connection of fragments of a heat cable to each other - using couplings; on finished sections, they are already installed by the manufacturer. Connection to the power supply system - power three-phase cable.

Particular attention is paid to the edge of the roof and natural places where water flows. In all other respects, recommendations during installation are of the most general order: avoid cable breaks and excessive tension, mechanical stress. And, of course, do not forget about grounding!

How to choose a cable for roof heating

For the installation of electric heating systems, resistive, self-regulating cables, as well as their combination, are used. They are sold both in coils and in the form of assembled sections with couplings and connecting wire, ready for laying.

T2Blue resistive cable

There is a modified variety of resistive cables called zonal. Their feature is the presence of two additional conductive cores and a nichrome spiral wound around. In case of overheating, only a part of the working elements fail, the rest remain operational.

Self-regulating cables are distinguished by the presence of a semiconductor matrix connecting two conductive cores. In addition, self-regulating cables have a shielding sheath, most often made of foil. Due to the presence of two layers of insulation, the self-regulating cable has increased dielectric and mechanical strength. The cable matrix changes resistance depending on the ambient temperature. As the temperature rises, the resistance of the matrix increases, which leads to a decrease in cable heating. Self-regulating cable is easier to install, and its only but significant drawback is its much higher price. Therefore, in a number of cases, the system is mounted from different types of cables, depending on the place of installation.

Temperature controllers and weather stations

The heating control system consists of a thermostat and a control unit connected by signal wires. This device is equipped with temperature sensors on the heated surface. Installation is allowed both directly in the working area, and in nearby protected places - under the canopy, cornice, in the attic. Access to the control system is made as convenient as possible. It should be remembered that the remoteness of the temperature controller from the cable leads to a decrease in measurement accuracy and, accordingly, to a deterioration in the operation of the system.

More expensive, reliable and efficient equipment for thermal control is a weather station. In addition to the temperature sensor, it is equipped with sensors for precipitation and the presence of moisture on the surface. Installation principles are similar. All this allows you to more finely adjust the heating control in automatic mode. For a system assembled from self-regulating cables, the option with a weather station is appropriate.

The temperature regime of the control system is set by the user. It is recommended to turn on anti-icing at roof temperatures from +2 - +3 degrees. up to -7 - -8 deg. At lower temperatures, the operation of the system does not make much sense.

Fastening equipment for mounting

Roof fasteners consist of reinforcing mesh, anchor plates and self-adhesive tape. Sometimes cable strain reliefs are used. The distance between fixation points should not exceed 30 centimeters. When using metal fasteners, it is necessary to pay special attention to the presence of an anti-corrosion coating: due to the nature of the use, the iron parts of the structure quickly rust.

Of the additional elements of the mounting structure, we can note a cable for cable in drains (tracing is recommended if the length of the drain exceeds 6 meters); for flat roofs where there is no risk of sliding large masses of snow and where it is necessary to accelerate the flow of melt water - a device known as a "drip edge".

It is known that the best criterion of truth is practice. If, as a result of the measures taken, snow and icicles do not risk falling on your head, water does not flow into the attic, the roof and drainage elements are intact, and the electricity bill has increased insignificantly, then everything is done correctly.