Roof heating from snow. Heating of roofs and gutters: calculation, design and installation of anti-icing cable systems
The article provides information on the correct choice of a reliable roof and gutters heating system for your home or cottage. After reading the article, you will receive a lot of useful and important information that will be useful during the construction process and will help you ask the right questions when ordering roof heating. in a construction company and be sure to do right choice, based on the advice and recommendations received in my article.
The roof heating system helps protect the roof from the effects of bad weather in the winter. Source goldkryshi.ru
Roof heating and its functions
Now this innovation is just coming into wide use. Many people neglect roof de-icing work because they are afraid of wasting electricity and money to create the system itself. However, it is worth considering that such an approach can lead to an accelerated failure of the roofing pie. This will entail unscheduled repairs, and, consequently, unnecessary financial costs. Let's see how roof heating protects the roof.
So, the use of this system allows you to get rid of systematic ice, which causes significant damage to the structure, violating its waterproofing. By the way, do not hope that timely cleaning will solve the problem. It will not cope with all the moisture that accumulates on the roof and gutters. In addition, when the roof is heated, you get rid of falling icicles and snow, thereby increasing safety.
There are other ways to deal with icing. For example, setting up a special ventilation system attic or roof treatment with anti-icing emulsions. However, all these methods are imperfect, require constant financial costs and take you a lot of time, and also lower the temperature inside the building. Therefore, the best option is the correct heating of the roof.
Installation of an icing channel will help get rid of many problems Source eurohouse.ua
What is a roof heating system
It is called differently: snow melting system, heating system or anti-ice. Such a device consists of a large number of sensors, wires, executive and instrumentation, as well as heating elements. Such a complex prevents the formation of icing on the roof surface and prevents excess snow from accumulating.
It is not necessary to heat the entire surface of the roof, therefore, for the installation of heaters, certain places are selected that are most prone to the accumulation of ice and snow, as well as places that can let moisture into the roofing pie. So the system must necessarily cover the edges of the slopes and the surface of the valley, and also cover the entire length of the gutters.
Important! The roof heating system must be located below the snow guards. Firstly, this will allow you not to spend too much electricity on heating sections of the roof that do not require it. Secondly, the melting of the snow cap on the roof increases the thermal conductivity of the roofing pie, which leads to accelerated heat loss.
It is also convenient that the cables can be mounted even after construction is completed at any free time, because the system is most often located on the surface of the roofing material.
Roof heating cable can be installed at any time Source kryshadoma.com
If the roof heating system of your house is done correctly and competently, then you can forget about the snow falling from the roof. This device also eases the burden on truss system, which contributes to greater durability of the roofing cake. Additionally you will receive good protection drain. After all, there are frequent cases when it cracks from the icy accumulated water inside.
By the way, the anti-icing system relieves the owners of the house from regular manual cleaning of the roofing material.
roofing works of any complexity on a turnkey basis. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".
How does the roof heating system work?
Let's figure out what are the main elements that make up the system and how they should be located.
Approximate scheme for laying a heating system on the roof Source dom-electro.ru
The whole complex of heating equipment usually consists of three main components.
The heating unit includes a network of single or double heating wires. It is also worth pointing out at this point that a special film can also be used as a heating element. It is important that the heating elements meet certain requirements. They must be adapted to sudden changes in temperature, as well as to power surges. The system must also be resistant to excess moisture. If you plan to walk on the roof, then resistance to mechanical damage is a mandatory requirement for a heating unit.
The information and distribution block is designed to control the transfer of electricity from the network to the heaters. This part of the system provides information in the form of sensor readings and feeds all the components of the anti-icing complex. It is better to install all sensors and elements of this block in places where moisture does not get. For example, in the attic or under the roof overhang.
The control unit includes temperature controllers, weather sensors, as well as devices that allow you to change the temperature of the roof and the power supply manually. A variant with a self-adjusting control system is possible. There is no need to constantly adjust the operation of the heating complex, and the necessary changes are introduced automatically. In this case, the mini-computer makes decisions based on readings from weather sensors.
The icing cable is also laid in the drain channel Source eximtec-plus.com.ua
On our site you can find contacts of construction companies that offer the service of completing the construction of unfinished houses. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".
How to choose the right heating system
Such systems differ primarily in the type of heating element. There are options with the use of cable or film heaters. The second method has much in common with the "warm floor" system. An important difference is that the film should be located inside the roofing pie, because it is not designed for serious loads and is poorly adapted to mechanical damage. But the cable, on the contrary, can be on the surface of the roofing material. But the wire can fit inside. This is usually used when installing a heating system. flat roofs, and even during the construction of high-rise buildings. Cables are used exclusively for heating gutters and pipes.
The cable is used for external heating of the roof Source domsireni.ru
Characteristics different types heating elements:
This is a matrix with polymer insulation and two strands of wires inside. It also includes a metal braid and an additional layer of insulating material. If it gets warmer outside, then the number of conductive paths inside the matrix decreases and, as a result, the temperature of the heater decreases. There are many advantages to this type of heater. Firstly, cable installation is quick and does not require much experience. Secondly, the matrix itself is resistant to overlaps and spot heating, thanks to the temperature self-regulation system. Thirdly, such a cable can be used in combination with absolutely any roofing materials. An important plus is that the system selects the optimal temperature and thereby prevents the consumption of excess electricity. It is possible to install such heaters without the use of weather sensors, and also with the help of a self-regulating cable it is possible to heat gutters.
Self-adjusting wire most easily mounted on the roof Source raychemfutokabel.hu
resistive wire
Heating occurs due to the resistance of the conductor. Such a cable can be two-core and single-core. The insulation is made from a layer of polymer, and on higher quality models a nichrome core is used. When installing such a cable, you need to pay attention to the fact that both the beginning and the end of each wire must necessarily converge at one point. There is one rather serious disadvantage of such a heating system: in the event of a point damage, the entire anti-icing complex fails. Installation is inconvenient, because the resistive cable cannot be cut. This method is suitable for heating large areas of the roof.
The resistive system is more complex, it is better to entrust it to an experienced master Source teploobogrev.ru
Film heater
Represents a flexible film, with veins from a carbonic conductor. It heats such material with the entire surface, since conductive strips are often located over the entire area of the heater. It is very convenient to transport and store, because such a film is sold in small rolls. This material is attached only under the roofing, so it can only be used in the case of roof reconstruction or during the construction process. Installation of such a heater should be entrusted to specialists. In the event of local damage, the heating system does not fail, but loses efficiency. During the repair process, it is always possible to replace the damaged section of the film heater. I would like to note that the film is very safe, it does not self-ignite. Uniform heating of the surface gives good energy savings.
Film heater mounted on the inside of the roof Source liquidsystems.ru
When choosing materials, you should pay attention to their cost. The most expensive is to use a film heater. Self-regulating cable costs a little less, and the most a budget option is a resistive wire. But I would like to note that roof heating using a self-regulating cable is more economical and will provide good benefits in the future. Also note that the installation of an anti-icing system on the roof surface is possible only if there are snow retainers. Otherwise, the entire network will simply be torn down during heavy snowfall. Various improvements and options make the whole complex more expensive, but the choice is always yours. Remember to order heating system for the roof follows, based on the characteristics of your particular roof.
The heating system is selected based on the type and characteristics of the roof Source ms.decorexpro.com
Installation of a roof heating system
First you need to figure out which area of \u200b\u200bthe roof requires heating. As already mentioned, these are valleys, overhangs and places of accumulation of a large amount of snow and ice, as well as drains. It is worth noting that the benefits of partial heating in areas that need it are much lower than from heating the roof in all problem areas. After you have decided on the area to be heated, you need to calculate the required amount of materials and purchase them.
So, after all the materials are selected and purchased, you can proceed with the installation. Below you will find information on how to correctly install the entire system.
Experienced hands will not make mistakes when installing a roof heating cable system Source: promalp-moskva.ru
The first step is to completely clean the entire surface of the roof, as well as gutters from debris or leaves. Next, a mounting tape is installed in the required places. The next step is to install the junction box. It is worth bringing to it and fixing the “cold” end of the cable, previously threaded into the corrugated tube. After completing this procedure, the cable should be laid out inside the gutters, fixing it with the antennae of the fastening tape. Now you need to fix the wire inside the drainpipe. To do this, the cable is attached to the chain, for example, with plastic ties, and this entire system is threaded into the pipe. After that, it is worth fixing the upper segment. The bottom edge can be fixed using metal ties. Next, you need to lay out the loops on the surface of the roof and secure them using the antennae of the tape for this. If the roof slopes are too steep, then it would be better to add plastic ties. Now you can install the weather sensors. They should be located on the north side of the building next to the junction box. The next step is to check the entire wiring system. The quality of the system can be determined by measuring the resistance in the circuit and comparing the readings obtained with the data indicated in the product data sheet. It remains only to fix the control panel inside the room. After installation is complete, the temperature of the system must be measured to compare it with the data you entered.
The structure of the heating system on the roof Source liderbudowlany.pl
Video description
You can familiarize yourself with the procedure for installing roof heating, gutters and gutters by watching the video:
If the test showed the correct result, then the installation of the anti-icing system was carried out correctly. In this case, you get good reliable heating of the roof and gutters. Such a system will increase the life of the roof, as well as eliminate the inconvenience associated with the fall of icicles and snow from overhangs.
Conclusion
A competent choice and high-quality installation of a roof anti-icing system will avoid the problem of clogging the drain channels and the destruction of the entire drainage system when snow melts from the roof. But it is better to entrust the design and installation of roof heating to professionals, because otherwise you can get a system that consumes too much electricity or does not cope with its duties.
What problems will cable solve?
The main task that cable heating of the roof / roof solves is to prevent the formation of frost and ensure continuous removal of melt water from the roof / roof under any (even the most unfavorable) natural conditions.
1. Problem: Poor water drainage from the so-called “warm roof / roof”, the formation and further accumulation of ice in horizontal gutters and trays, blockage of vertical drainpipes with ice. This leads to the breakdown of even the highest quality drainage system.
Decision: Heating of the drainage system of horizontal gutters and trays, as well as vertical drainpipes. Increases the service life of the drainage system, provides a constant removal of water from the "warm roof" or the roof/roof on which electrical heating elements are installed.
2. Problem: The formation of ice and large snow masses on the edge of "cold" cornices and overhangs. As a rule, this occurs in areas behind snow-retaining structures or standing gutters of seam metal roofs. The possibility of large snow and ice masses falling off the edges of the roof poses a threat to people's lives and possible damage to property.
Decision: Roof/roof eaves heating. Proper laying of the heating cable on the problem areas of the cornices helps prevent the accumulation of snow and ice masses and timely drain the melt water without further freezing.
3. Problem: Accumulation of snow masses in difficult areas of the roof / roof - in valleys, around various roof structures, near funnels of internal drains, which leads to damage to the roofing.
Decision: Heating of sections of a roof/roof. This part of the heating system minimizes the chance of leaks. It also reduces the mechanical load on the roof/roof elements and increases its service life.
Please remember that control elements (thermostats, thermostats or weather stations) are required in a roof/roof heating system, even if a self-regulating cable is used! If the system is not turned on in time, the problems associated with the formation of ice can be exacerbated.
Components of a cable heating system for roofs/roofs and gutters
Technical characteristics of the heating cable for heating the roof/roof and gutter system
Rated voltage 220 V
The smallest bend status is 45mm.
Rated temperature 65 o (max)
Power consumption 30 W/m at 10 o С
Cable thickness 12 mm.
Resistance disconnection tolerance -5% +10%
Minimum laying temperature -20 o С
Heating of the roof / roof and gutters in the diagram
Roof/roof heating in photos
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Examples of some proven technical solutions for the installation of cable heating of the roof / roof and drain
Heating of gutters and drains
Double laying of the heating element in the gutter on the roof of the hospital. In total, there are 8 such gutters, which required about 300 m of self-regulating cable with a power of 18 V/m.
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The heating element is made in the form of a double laying of a self-regulating heating cable with access to the bitumen roof.
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Roof/roof and gutter heating
Self-adhesive aluminum tape was used as fasteners. Temperature and precipitation sensors ensure fully automated and cost-effective operation of the system.
Roof/roof and gutter heating
Roof panel heating was installed in May 2013 on the metal sheets of the office building eaves. Thanks to the use of zinc fasteners, the heating elements are reliably protected from wind gusts and are firmly fixed in place. Approximately 900 m of the heating main was laid out in the form of a meander (in the form of loop-shaped bends) at a distance of 100 mm from each other. On the courtyard side, the gutters and pipes were also equipped with heating systems. Both systems were equipped with digital sensors for temperature and precipitation with two-zone adjustment (2 sensors for drains).
Electric heating of the roof/roof and gutters
For safety reasons, the roof slope and gutter with a total width of approximately three meters up to the fire barrier were equipped with a heating system. This special situation arose as a result of the expansion of an existing building (side extension), the modernization of the old roof structure was not possible. For the most economical use of the system, temperature and precipitation sensors were installed.
After the unusually snowy winter of 2010/2011. problems arose with this building in Moscow - snow and ice fell from the eaves of the building. To solve this problem, we installed heating elements on the edge of the cornices. The pigeon protection system installed earlier was used as the main fastener. For the most economical application of the heating cable system with a total length of 60 m, we installed a digital temperature and precipitation sensor.
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Movable roof/roof and gutter heating system (400 m2) with plastic-covered 400-volt heating cable (overpressure from the building kept the roof covering elements in motion). The distance between the heating cables is 100 mm, resulting in an output power of 300 W/m2. This system allows you to safely and reliably melt snow and ice drifts up to 2 m high (without additional heating). Thanks to its high power, the system is able to prevent the accumulation of snow and ice on the roof even in the most severe frosts. Fasteners are fixed with a special adhesive that provides lightning protection of the heating system.
The arrangement of the roof heating system and preventing the formation of icicles and ice, functions thanks to the heat generated by the electric cable laid on the roof in gutters and pipes. The system ensures the melting of ice and snow, which leads to a timely outflow of water. Having provided heating of a roof, it is possible to solve the following problems:
- preventing clogging of drains;
- reduction of roof loads;
- increase in the operational life of the roof;
- automation of the heating system.
The composition of the heating system
The main system is an electric cable fixed with fasteners. Electricity is supplied through a switchboard equipped with a three-phase protective input circuit breaker and a four-pole contactor.
There is a device that provides a protective shutdown, as well as single-pole circuit breakers for each of the phases. There is a signal lamp and a machine that provides protection for the thermostat. Distribution network consists of several components:
- power cable;
- mounting box;
- couplings for cable - terminal, signal;
- signal cable.
System installation diagram
The heating cable is laid outside the gutters, trays, valleys, as well as pipes and weirs. The information and distribution segment of the system transmits power and ensures the exchange of signals transmitted by sensors that control the heating process in the direction of the control cabinet. The command block consists of several elements:
- thermal air sensors;
- thermostats;
- starting devices;
- protective system.
Installation of the heating system begins with checking the heating sections for compliance with the zonal dimensions. Sections are cut into segments of the desired length, couplings are mounted on them, and then laid out and fixed. The electric cable is laid in the gutters and fixed with mounting tape in the transverse plane.
Important!
The mounting pitch for resistor cables is 0.25m, and in the case of self-regulating wiring it reaches 0.5m. It is required to fix the tape with rivets, additionally using sealing compounds.Cable laying in the drain is carried out using a heat-shrinkable tube. If the downpipe is more than 6 meters high, then the cable is fixed with an insulated metal cable, which helps to reduce the bearing loads. The cable is fixed to the roofing surface by means of a sealant and a mounting tape.
The installation of mounting boxes is accompanied by measurements of the insulating resistance of the heat-generating sections. The wiring of power and signal cables is carried out together with the installation of thermostat sensors, after which a cabinet is mounted, through which the system is controlled. The final step is to carry out control measurements regarding signal and power wiring. Along the way, checking automatic system off and the thermostat is adjusted.
System design
The roof heating system is designed in the following order:
- identification of areas in need of heating;
- appointment of places for mounting junction boxes;
- carrying out calculations - determining the power, characteristics of the protective system, phases;
- writing project documentation.
The main task is to determine the heating zones. It is necessary to lay the cable in places of the greatest accumulation of snow and intensive formation of ice. It is preferable to simultaneously provide heating for overhangs, valleys and drains, which will certainly prevent the formation of blockages in pipes and gutters.
Important!
If the roof has steep slopes, then avalanche-like gatherings are possible there. Therefore, it is required to create a snow retention system and lay the cable along a zigzag line between the edge and the fence.Types of cables
The roof will be heated by a cable, the choice of which is an important stage of work. There are several types of wiring:
- resistor - a metal insulated core with constant resistance, stable temperature, fixed power. The vein warms up due to internal resistance. Such wiring is ideal for maintaining the desired temperature in large areas and around drains;
- self-regulating - an insulated matrix with a braid and an outer sheath. The heating element is a matrix that independently regulates the degree of heating depending on the ambient temperature;
- mixed - a combination of resistor and self-regulating cables, laid in the most favored places.
Control system installation and power calculation
The control unit is of two types. Traditionally, a thermostat is used, which activates the operation of the system in a predetermined temperature range. However, a profitable alternative is a weather station that records the amount of precipitation and the process of their melting. The station consists of sensors that determine the level of humidity and a temperature sensor.
To establish effective heating of the roof and gutters, you can only correctly calculate the power of the equipped system. When choosing wiring, it must be taken into account that resistor cables have a power of up to 22 W / m, and a self-regulating system needs 30 W / m.
Important!
If the drain is made of polymeric materials, then cables with a power exceeding 17 W / m should not be used, since it is possible to damage the pipes as a result of overheating.It is required to trace the supply cable in accordance with the provisions of the PUE, taking into account external conditions. It is necessary to carry out the installation of RCD blocks that prevent electric shock to people. Having foreseen all the nuances and fulfilled all the conditions, it is possible to provide high-quality and full heating of the roof, in accordance with the norms and state standards. A reliable heating system will ideally protect the roof from ice formation.
VIDEO:
The cable heating system for roofs and gutters is an anti-icing system based on the use of electric heating cables to melt snow and ice on the roof and in the drainage system of the building during periods of danger - at a time when daily temperature fluctuations occur and ice formation is most likely.
In turn, it is ice that causes roof leaks in the autumn-spring period, as well as the cause of deformation of gutters and gutters due to ice and snow accumulated in them.
Since the roof anti-icing cable system does not allow the formation and, accordingly, the fall of icicles on the adjacent territory, it is classified as a security system.
It is quite natural that in 2004 a document of the Moscow Committee for Architecture “Recommendations for the use of anti-icing devices on roofs with external and internal drains for residential and public buildings under construction and reconstruction” appeared, which directly recommends the installation of such systems on all new buildings.
Currently, several thousand buildings are equipped with cable roof heating systems in Moscow and St. Petersburg. Significant experience in design, installation and operation has been accumulated.
A properly designed and properly installed roof heating cable system based on high-quality components does not allow ice accumulation and ensures the removal of melt water along the entire route. As a result, the roof itself lasts longer, the gutters do not sag, the gutters do not deform, and people and cars in the vicinity of the building are not threatened by falling icicles.
Roof heating in photos
Warm and cold roof heating
- In the case of a cold roof (having minimal heat loss), it is enough to revise the drainage system and install heating cables in gutters and gutters.
- In the case of a warm roof, it is very likely that installation will be required in other areas: valleys, drips (cornices), skylights, junctions and overhangs.
- If the roof is completely iced over, then the installation of KSO may not be economically justified and the reconstruction of the roof suggests itself.
System Composition
The following classification seems to us the most successful:
1. Subsystem of heating elements
Heating cables for use on the roof are subject to increased requirements:
- linear power: not less than 20 W/m and not more than 60 W/m at 0°С;
- shell resistance to UV radiation;
- resistance to local overheating;
- reliable operation in wet conditions;
- the presence of a shielding braid;
- certification of compliance with TR TS 004/2011 "On the safety of low-voltage equipment";
- certificate of conformity TR CU 012/2011 "On the safety of equipment for operation in explosive environments" * (if the building is located in an explosive zone, for example, a gas station).
Roof and gutter heating systems use resistive cables and self-regulating cables.
The advantages of resistive cables include low cost and stability of power characteristics. The disadvantages are the impossibility of changing the lengths of the sections and the likelihood of overheating. On soft (welded) roofing, resistive cables cannot be used.
Resistive cables for roofing
Roof heating systems are still considered know-how, but many organizations and owners of private houses are already successfully using them. Today, not everyone understands the feasibility of installing a heating cable, most are sure that “heating the street” is unprofitable. In fact, roof heating allows you to save on maintenance and repair of the roof. How does it work? Let's figure it out.
How to avoid the formation of icicles and frost on the roof
AT winter time you will not surprise anyone with rows of icicles under the roof. But if children perceive them as decoration and entertainment, then for adults ice is a real disaster. Every year, many residents of high-rise buildings suffer from fallen icicles. In addition, due to ice, the waterproofing of the roof worsens, and the roofing material collapses faster. Even timely cleaning of the roof does not improve the situation, because during work it is inevitably damaged. outer layer roofs.
Icicles under the roof pose a real danger to passing people and cars parked nearby
There are several ways to avoid this unfortunate fate:
- Ensure proper attic ventilation. If the temperature of the roof is not higher than that of the air, the snow on it will not turn into ice and form icicles. You can cool the roof by adding ventilation holes on the gables or slopes so that cold air can freely enter the attic. This method is only used when good insulation ceilings, otherwise the heat from the room will quickly be lost through the ceiling. In addition, even properly equipped ventilation often does not bring the expected result.
- Carry out work on the insulation of the roof. Another way to keep the roof cold is not to let the heated attic air raise the temperature of the roofing material. To do this, the roof is sheathed from the inside with membranes, laying insulation between them. This path requires a significant investment of time and money, since good materials will be quite expensive. In addition, errors in the installation of a heat insulator and ventilation system can lead to mold in the attic and in the house. In a temperate climate proper insulation can almost completely eliminate the likelihood of ice formation, except for days with especially unfavorable weather. In colder regions, it is sometimes necessary to deliberately arrange heat leaks so that less snow accumulates on the roof.
- Treat the roofing material with a chemical agent - an anti-icing emulsion. Similar compositions are applied to the surface of aircraft so that ice does not accumulate on them at high altitude. The tool is effective, but too expensive. In addition, the protective film must be updated several times during the winter, and the technological process requires the involvement of experts. Because of these nuances chemicals de-icing on roofs are not commonly used.
- Equip an electric impulse anti-icing system. It was developed in the sixties of the last century for the needs of aviation. The heating block of the system consists of inductors (electromagnetic coils without a core) fixed under the roof overhangs. When a short pulse is applied to the coils, ring currents are created in them, which seem to hit the roofing material. As a result of such processing, the ice on the roof turns into crumbs and crumbles down. This system is not able to prevent the formation of frost, but does not require constant energy consumption. Unfortunately, due to the high cost of components, such systems are also rarely used.
- . Active heating is needed when the previous methods cannot give positive results due to the climate, the complex structure of the roof, high prices or other factors. Most often this happens in regions where the temperature often changes from positive to negative and vice versa. In addition, heating is the only way to prevent the formation of ice in the drains and thus reduce the likelihood of winter leaks.
The roof anti-icing system works by heating the cable as it passes through it. electric current, which is activated manually or by a signal from sensors installed on the roof
If you are sure that your roof is well insulated and has proper ventilation, but icicles continue to appear, active heating is the only solution. Of course, it will require a certain amount of electricity, but you won’t have to personally clear the snow and ice, as well as risk the rapid destruction of the roof and the health of others.
What is a roof heating system
A roof heating system, anti-ice or snowmelt system is a complex of heating elements, sensors and actuators that prevent the formation of ice and icicles on the roof. As a rule, the roof is not fully heated, but only in the most vulnerable places: along the edges of the slopes, along the valley, along the entire length of the drainage systems. It is not advisable to install heating above the snow retainers, as this will require too much energy, and will also reduce the effectiveness of roof insulation due to the snow cap. Cables are placed on top of the roofing, so you can add an anti-icing system at any convenient time after final finishing roofing, dismantling of its elements is not required.
The roof heating cable is usually laid along the edges of the slope, while it can be attached to the snow retainers with plastic ties
A good heating system is capable of:
- prevent snow and ice from falling on people, cars, flower beds, etc.;
- reduce the load on the rafter system and floors, which usually increases due to ice;
- protect the drain from destruction, which often cracks after the accumulated water freezes;
- extend the life of the roofing material, saving it from adverse operating conditions;
- save the owners of the house from the need manual cleaning roofs from snow and ice.
A cable heating system can save warm roofs where snow melts at a temperature of -10 o C. If your roof is decorated with icicles in colder weather, cable installation is advisable only after good insulation.
Roof heating device
A standard roof heating system consists of three main components.
How to choose a roof heating system
Roof anti-icing systems primarily differ in the type of heating element - it can be a cable or a film (similarly warm floor). Specialists often divide such systems according to the method of installation - into equipment for hidden and outdoor installation. Outside, only a heating cable is mounted, the film will not withstand harsh conditions. But under the roofing material, you can place both a film and a cable. In particular, this is done when installing cable heating on flat, exploited roofs of high-rise buildings.
If the anti-icing system is installed under the roofing, then both a cable and a film can be used as its heating element, located according to a certain pattern.
Gutters and pipes are heated only with open-mounted cables, since it is impossible to ensure timely snowmelt otherwise.
Table: differences and features of the heating elements of the roof heating system
| Element | Device | Peculiarities |
| Self-regulating wire | It consists of a matrix (polymer with two wires inside), polymer insulation, metal braid and an additional layer of insulation. As the air temperature rises, the number of conductive paths in the matrix decreases, which reduces the heating temperature. |
|
| resistive wire | It consists of a heated metal core under a layer of insulation (single-core cable) or a heating and power core in insulation (two-core cable). The best and most expensive modifications have a nichrome core. Heats up due to internal resistance. |
|
| Film | Thin flexible film with conductive carbon strips. Due to the frequent arrangement of strips, heat is given off almost over the entire surface of the web. Supplied in small rolls for easy shipping and storage. |
|
If you don't want to spoil appearance roof or fear for the safety of the anti-icing cable system, mount the cable between the elements of the crate.
In addition to the structural features of the roof and the characteristics of the heaters, the cost of the anti-icing system should also be taken into account. The most expensive type is a film, in second place will be a self-regulating cable, in the third - resistive. But you should not use the latter option just because it is the cheapest. After all, with long-term operation, a self-regulating cable will be more profitable and will pay off its increased price due to significant savings in electricity consumption.
Do not use an open-mounted anti-ice system (cable) if there are no snow guards on the roof. Ignore the rule - the cable will be torn off the fasteners after the first descent of snow from the roof.
Installation and maintenance of roof heating systems
Before laying the cable, it is necessary to determine in which area of the roof heating is required. As a rule, these are places of maximum accumulation of snow and ice: valleys, roof overhangs and gutters. If you heat only one zone and ignore the other, the heating efficiency will decrease significantly, and the probability of destruction of unheated fragments will increase several times. For example, if you do not heat the drainpipes, the water that melted on the slopes will not be able to get into the storm sewer, it will collect in the pipes and break them. Having decided on the heated zones, you can calculate the length of the required cable, taking into account the margin for arcs, connections and allowable fragment sizes.
When calculating the required power of the roof heating system, use the rule: for a gutter with a diameter of 10–15 cm, a power of 30–60 W / m 2 is needed, for a larger diameter - 200 W / m2. It is impossible to mount a cable with a power of more than 17 W per linear meter in a polymer drain.
Power and others specifications heating cable is usually indicated on its insulation
The power standard for a roof heating system is 18–22 W/m for a resistive cable and 15–30 W/m for a self-regulating cable. The calculated specific power per unit area of the roof is 150–300 W / m 2.
- for the air temperature sensor - switching on at a temperature of 0 to +3 ° C, switching off - at a temperature of more than +3 ° C;
- for the air temperature and humidity sensor - switching on at a temperature from 0 to +3 ° C simultaneously with the presence of water in the control area.
The placement of weather sensors needs to be thought out so that they are located in the path of melt water.
What cable to put on roof heating
If you are determined to drop the foil heating option, you will have to choose between self-regulating and resistive cables. When buying a self-regulating cable, the main thing is to take into account the climatic conditions of your region. If your winters are not too cold, a medium temperature cable marked NTM, NTA, NTR will suffice. For colder places, a high-temperature wire under the BTC or BTX brand is suitable.
Cables with markings starting with the letter "H" are intended for standard operating conditions, and products whose designation begins with "B" makes sense to use in regions with frosty winters
With a resistive heating cable, things are not so simple. There are varieties that do not differ too much in price, but are noticeably different in structure and properties. Experts highlight:
- single core resistive cable. This is the cheapest variety. It is these conductors that need to be brought to one point during installation. The service life of the product is short, but the presence of a metal braid under the insulation guarantees the safety of people, even when a breakdown occurs. Select this option only for non-residential buildings or for roofs with a very large area;
Single core resistive cable is the cheapest and is used on the roofs of outbuildings or very large buildings.
- two-wire resistive cable. It has two equivalent cores or one heating (high resistance) and one supply (low resistance) wire. Since the circuit is completed by an additional wire, the end of the cable does not need to be brought to the beginning of laying, which greatly simplifies installation and preliminary calculations. The two-core cable also has reduced electromagnetic radiation, so it is better suited for residential buildings.. It costs more than a single-core one, but justifies the additional costs due to savings in length (no return loop is needed);
Due to the presence of two conductive cores, such a cable does not have a round, but an oval cross section.
- sectional or zone cable. The most advanced type of resistive heating elements. It consists of two parallel low-resistance conductors (only for current transmission) connected to a high-resistance coil (for heating). In this case, the spiral (usually nichrome wire) is connected pointwise to one or the other conductor. It turns out that the cable consists of sections connected in parallel (and not alternately like other cables). At the same time, the resistance and degree of heating of each zone is regulated independently. This is especially useful for complex roofs, where nearby areas are heated differently by the sun..
The zone resistive cable consists of two cores with low resistance, connected by a helix of nichrome wire.
The most effective and affordable anti-icing system consists of a combination of resistive cables for the roof, complemented by temperature sensors, and self-regulating cables for the gutters.
For complex roofs (water accumulates in some areas, leaves are difficult to clean in others, and others are warmed up by the sun even in winter), a single- and two-core resistive cable is not suitable. It is more expedient to use a zonal resistive or self-regulating cable. The system will cost more, but will last much longer.
Gutters should only be equipped with self-regulating cables, otherwise you run the risk of too high operating costs and a quick failure of the system.
Do not buy a resistive heating cable for a summer residence. It is not able to regulate heating and will either use electricity for nothing in any weather, or will not interfere with the formation of ice (when turned off). Resistive cables, not supplemented with weather sensors and a controller system, require your regular intervention, so use them only in buildings where you can control their operation.
Foreign manufacturers make cables designed to operate at a voltage of 240 V, and domestic ones - 220 V. Therefore, when buying foreign components, reduce the rated power by 10%, since it will not be able to give out the power indicated on the passport in our conditions.
Fixing the heating cable to the roof
You can fix the heating cable on the roof using:
- stretch marks;
- mounting plate;
- brackets with a chemical fastening system;
- special adhesive tape and sealant (for temporary fixation for the installation period).
To fix the cable at the bottom of the gutters and inside the downpipes made of tin, arched fasteners with rivets are used. If it is undesirable or impossible to break through the pipe wall, a heavy chain is placed in the drains, to the links of which the cable is attached with plastic ties.
Video: instructions for installing the cable on plastic clips
The sequence of laying the cable on the roof:
- Keep gutters and roof surfaces clear of leaves and debris. Install roof cable straps in the gutters and on the roof.
When installing a heating cable in a metal drain, it is convenient to use a cutter
- Mount the junction box on the wall under the overhang, put a protective corrugated tube on the cold end of the cable and fix the cable inside the box.
Cable installation on the wall is carried out in a protective corrugated pipe
- Lay the cable inside the gutters, using the movable antennae of the fastening tape to fix it.
When laying the cable, it is desirable to ensure that the fastening step is constant.
- Attach the cable fragment that will heat the downpipe to the chain with plastic ties. Lower the prepared cable into the pipe until a cable loop appears in the lower socket. Fasten the segment at the top and repeat the procedure for each vertical pipe.
If it is impossible to make holes in the downpipe, the heating cable is fixed to the chain with ties and lowered into the pipe
- Secure the bottom edge with two plastic or metal ties.
The lower loop is attached to the pipe with plastic or metal ties
- Lay out the loops of the heating cable on the selected roof fragment, fixing them with the antennae of the mounting tape. On steep slopes, you should additionally play it safe and add point plastic fasteners.
In no case do not use tape for underfloor heating, only special roofing tape can provide durable cable fixation
- Install the air temperature sensor on the north side of the building next to the junction box.
The air temperature sensor is installed on the north side of the building near the junction box
- Check the resistance of all wires used (the norm is indicated in the passport) and the operability of the sensors. Assemble the system, focusing on the manufacturer's instructions.
All wire connections must be laid in a sealed junction box and protected from direct contact with the environment.
- Inside the building to be heated, mount the electrical control panel of the system. Immediately after connecting, make sure that the system is working, set the operating temperature spread on the temperature sensor.
On the inside the door should be glued to the diagram according to which the system was assembled - this will facilitate further maintenance and repair
Features of working with a resistive cable
Laying a resistive cable has its own characteristics and nuances:
- Measure the resistance of each section, connecting them to the network in turn (check the diagram in the manufacturer's instructions). Make sure that the indicators correspond to the passport data. After laying, you will need to repeat the measurements. Differences in numbers will indicate damage to the cable during installation. Such a system cannot be put into operation.
- Draw up a detailed plan for laying the cable, taking into account each loop. Make sure the cable is long enough to bring the other end back to the starting point. Calculate the step and height of the loop so that the distance between the fragments is constant. If necessary, make a loop template out of cardboard and/or place the bags on the roof.
The pieces of resistive wire must not touch. Use separators to avoid contact. The distance between the separators should be 25–30 cm.
Features of laying a self-regulating cable
Just like laying a resistive cable, the installation of a self-regulating cable is due to certain features:
Laying heating cable in gutters
In drainpipes, cables of any kind are usually laid in one loop, in which the beginning and end converge in one place. For this, a piece of wire is taken, twice the length of the gutter / pipe, with a margin of 7–10%. The beginning and end of the loop should be placed in a place where fallen leaves, debris and water are least likely to accumulate. After all, it is there that the junction box is placed with the supply to the humidity and temperature sensors. The connection itself is always carefully waterproofed, but the correct selection of the installation site will help reduce possible risks for the equipment and increase its service life.
Video: do-it-yourself installation of a heating cable in a drain
How to install a roof heating control panel
Connecting the controllers is an even more important step than attaching the cable to the roof. Therefore, it is worth attracting a professional electrician to it. But if you are firmly confident in your abilities and have experience working with electrical appliances and shields, you can do the work yourself.
The control element of the system is a controller that turns the heating on or off depending on the readings of the sensors connected to it.
When assembling the shield, you will need:
- an input two-pole machine that can turn off the power to the system in an emergency (if the house has a three-phase input, the machine must also be three-phase);
- four-pole contactor;
- RCD (device protective shutdown) for heating with a power of 30 A or more (check the power of the entire system and select a device for it);
- separate single-pole RCDs for temperature and humidity sensors;
- 30 mA RCD for protection against leakage current;
- weather sensors for humidity and temperature. If necessary, you can add precipitation and melt sensors;
- thermostat (standard temperature range - from -8 - +30 ° C) with its own circuit breaker (RCD);
- signal diodes / bulbs.
You will also need power cables and signal wires to connect the elements of the shield, mounting boxes(the quantity depends on the complexity of the system and the number of slopes), couplings, end caps, insulating materials (duct tape, cambric tubes, heat shrink tubes) and sealants.
Malfunctions and repair of roof heating
In order not to have to do repairs, you need to properly care for the roof, which is equipped with an anti-icing system:
- roofs with resistive cables are especially afraid of clogging; in a place where debris accumulates, the cable can simply burn out. Therefore, during the period of leaf fall, especially carefully (but carefully) remove the foliage not only from the slopes, but also from the gutters;
- If one of the weather sensors fails, try to replace it as soon as possible. After all, humidity and heat sensors not only help save energy, but also prevent overheating and damage to the cable;
- at the end of autumn, be sure to check the performance of all elements of the system. If you have a self-regulating cable, check all RCDs especially carefully, as they can fail due to high inrush currents in the cables.
If you follow all the rules, the anti-ice system will last at least 15 years. But if problems have already occurred, you will have to deal with their causes.
Table: possible malfunctions of the anti-ice system and how to eliminate them
| Symptom | Cause | How to repair |
| Heating did not turn on even in test mode after laying the cable. |
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| The cable dangles from the edge of the roof, visibly swaying in the wind, or moving without your input. | Use of incorrect fasteners or insufficient number of fasteners. | Additionally secure the cable with special clamps (taking into account the type of cable and finishing material roofs). |
| Destruction of the cable or breakdown at the junction of the conductors. | Incorrect or insufficiently careful isolation of connections. | Dismantle the connecting elements and reconnect them, protecting the joint from moisture and heat. |
| The cable broke and partially fell out of the pipe. | The cable in the drain was mounted without a base - a cable or a chain, therefore it could not withstand its own weight and the load from the water. | Disconnect the damaged section of the cable and replace it with a new one using a cable. |
| The system began to spend noticeably more energy. | If the winter has not become more severe, the cause may be a failure in the weather sensors or the control unit. | Check the weather sensors and all elements of the control unit one by one, replace the broken one. |
| The system is ineffective, frost is not prevented. | Incorrect setting of the heating on mode or untimely switching on in manual mode. | Set the operating temperature range from +5 to -15 ° C. If frost is not prevented in this mode, expand the operating range. |
| Incorrect system calculation or use of a less powerful cable. | Such an error is solved by a complete replacement of the system; spot repairs are not possible. |
Still not sure if you need a roof heating system for your home? Then try to calculate how much time and money you spend on cleaning the roof from snow and repairing the coating, evaluate whether the temperature in the attic suits you. Perhaps it is the heating cable that can make your life easier and more comfortable.
