In early spring and late fall, all homeowners are faced with the problem of freezing of roof slopes and freezing inside gutters of melt water. If it is not resolved in a timely manner, the safety of people, as well as the safety of their property, will be threatened by large icicles and frozen clods of snow falling from the roof.
A good solution is the heating of the gutters, which will prevent the formation of ice. In this material we will talk about why you need to equip the drainage system with heating. We will also talk about what materials will be required for this and describe in detail the essence of the process.
Is it worth it to warm the drain?
In the winter months, frost and heavy rainfall prevail in most regions of our country. As a result, large masses of snow accumulate on the roof. An increase in temperature provokes their first thawing, and later active melting.
During the day, the melted water escapes to the edges of the roof and into the gutters. At night, it freezes, which leads to the gradual destruction of the elements of the roof and gutters.
This picture is typical for the offseason. If no action is taken, ice and snow will fall to the ground. In this case, the facade, gutters parked at the bottom of the machine may be damaged.
Icicles and conglomerate from frozen snow and ice accumulate on the edges of the roof. From time to time, they break down, threatening the safety of the people below and their property, the integrity of the drainage system and decoration elements of the facade.
All these troubles can be prevented only by ensuring unhindered drainage of melted water. This is possible only if the edges of the roof and the drainage system are heated.
It happens that in order to reduce the cost of the heating system, it is laid only on the roof surface. The owner is fully confident that this will be enough.
However, it is not. Water will flow into gutters and pipes, where it will freeze at the end of the day, since there is no heating there. Drains will be clogged with ice, so they will not be able to take melt water. In addition, there is a danger of mechanical damage.
Thus, in order to get a good result, it is necessary to equip the heating of the roof and the gutters surrounding it. In most cases, the heating cable is mounted on the roof cornices, inside the gutters of the drain and in the funnels, at the joints of the roof fragments, along the lines of the valleys.
In addition, heating must be present along the entire length of the drainpipes, in the water collectors and drainage trays.
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The heating cable laid in the gutter system does not have to be activated continuously. It can be turned on as precipitation occurs, in situations that threaten the appearance of ice plugs in the system
The heating cable in the elements of the drainage system is laid in straight parallel lines, a snake or a zigzag. Mounting is made by metal mounting tapes, fixed to the system elements at several points
A heating cable that prevents icing of the drainage system and its breakthrough by ice formations equips both external and internal drainage systems
Around the riser of the internal drainage, the heating cable is laid so as to maximize cover the area arranged with a slope to the funnel
Laying a heating cable near the drainage funnel should ensure complete snow melting on a 1 m² area
In the case of a characteristic formation of snow drifts on structures adjacent to the roof, it is equipped with a heating cable. The formation of ice blocks capable of causing damage to the home and owners should be excluded
a cable heating system is laid throughout the gutter, including drainpipes. The growing ice jam inside the riser can damage it
An important factor in protecting the roof, facade and owners of the house from the formation of ice is the arrangement with a heating cable of all places of snow accumulation, for example, in valleys
Inoperative heating in the winter
Laying the heating cable in the gutter
Outdoor gutter system
Heating cable around the internal drain
The device of the heating system at the external funnel
Cable fittings
Gutter cable
Cable routing in the roof valley
Features of arranging a heating system
Methods of heating roofs of different types may vary. We are talking about the so-called "cold" and "warm" roofs. We will analyze the features of each option.
Cold Roof Heating
This is the name of a roof without thermal insulation along slopes with good ventilation. Most often, such roofs are located above non-residential attic rooms. They do not let heat out, so the snow cover on them does not thaw throughout the winter.
For such structures, a gutter heating installation will suffice. The linear power of the laid cable should gradually increase. Start with 20-30 watts per meter and finish 60-70 watts for each meter of the drain.
How to warm a warm roof?
A roof with thermal insulation is considered warm. They let heat out, so that even at low temperatures on the surface of a warm roof, the snow cover can thaw. The resulting water flows onto the cold fragments of the roof and freezes, and ice forms. For this reason, it is necessary to equip the heating of the edge of the roof.
The so-called warm roof lets heat out. Therefore, snow over the “warm” areas melts, melt water falls on the “cold” fragments and freezes
It is implemented in the form of heating sections laid along the edge of the roof. They are put in the form of loops 0.3-0.5 m wide. In this case, the specific power of the resulting heating system should be from 200 to 250 W per square meter. Arrangement of heating gutters is implemented similarly to that used for cold roofing.
The device of the drainage heating system
For heating the roof and gutters, the system with a heating cable is most often used. Consider its main elements.
Distribution block and sensors
The distribution block is designed for switching power (cold) and heating cables.
The node consists of the following elements:
- signal cable that connects the sensors to the control unit;
- power cable;
- special couplings used to ensure the tightness of the system;
- mounting box.
The unit can be installed directly on the roof, so it should be well protected from moisture.
Three types of detectors can be used in the system: water, precipitation, and temperature. They are located on the roof, in gutters and drains. Their main task is to collect information for automatic heating control.
The collected data goes to the controller, which analyzes it, decides to turn off / on the equipment and selects the optimal mode of operation.
Controller and control panel
The controller is the brain of the entire system responsible for its operation. In the most simplified version, this may be some kind of thermoregulatory device. In this case, the minimum operating range of the device should be in the range from +3 to -8 degrees C. In this case, the control and switching of the system cannot be fully automated, human intervention will be required.
For full automation of the heating system, a controller is required. This device collects and analyzes information from sensors, and not on its basis, corrects the system
A more convenient option for operation is the use of a sophisticated electronic control device with the possibility of programming. Such equipment is able to independently control the process of precipitation melting, their amount, monitor the temperature.
The controller quickly responds to ongoing changes and makes optimal decisions by choosing the best operating mode for heating equipment in existing conditions.
The control panel is designed to control the entire system and ensure safety during its operation.
To equip a node, the following elements are usually used:
- three-phase input automatic machine;
- RCD (it is also a residual current device);
- four-pole contactor;
- signal lamp.
In addition, it will be necessary to supply single-pole circuit breakers for each phase, as well as thermostat circuit protection.
In addition, during the installation process you will need parts for fastening: roofing nails, screws, rivets. You will need shrink tubes and a special mounting tape.
How to choose a heating cable?
Perhaps the most important element of the system can be considered a heating cable. In practice, choose between two types of devices: self-regulating and resistive cable. Consider all the pros and cons of using both options.
Features of resistive cable
It is characterized by the simplicity of the principle of operation. Inside such a cable is a metal conductive core with high resistance. When electricity is supplied, it begins to warm up quickly and gives off heat to the heated object. The resistive cable system is very easy to use and does not cost much.
The installation of a heating resistive cable is very simple. The main “working” element is a heating core. When current flows through it, it heats up very quickly
The main advantages of using this type of cable are the absence of starting currents at startup, the low cost of the resistive wire and the presence of constant power.
The last statement can be classified as controversial. Since in some cases, constant power will be rather a disadvantage. This will happen if parts of the system need different amounts of heat. Some of them may overheat, while the rest, on the contrary, will receive less heat.
To regulate the degree of heating of a system with a resistive cable, temperature controllers or other devices are necessarily used.
The effectiveness and efficiency of the functioning of such a system depends on the correctness of their settings, so the reality is often far from desired. In this, the resistive cable is significantly inferior to the self-regulating one.
If possible, experts recommend laying a zone resistive cable. This variety is distinguished by the presence of a heating thread of nichrome. Its linear power does not depend on size; if necessary, the cable can be cut.
Also, the advantages of the heating cable include the ease of installation and long-term operation.
The cable is self-regulating and the nuances of its work
It features a more complex device. Inside such a cable there are two heating conductors, around which there is a special matrix. It “adjusts” the cable resistance depending on what the ambient temperature is. The higher it is, the less the cable heats up, and vice versa, the colder it is around, the better it heats up.
Inside the self-regulating cable there is a special matrix capable of changing the resistance of the heating core depending on the ambient temperature
The self-regulating cable has many advantages. First of all, for its normal operation, installation of a set of control devices: detectors and temperature regulators is not required. The system will configure itself, and overheating or insufficient heating, as can happen with a resistive cable, will not happen.
Self-regulating wire can be cut. The minimum length of the segment is 20 cm, its operational characteristics will not change from the length. During the installation process, if necessary, the cables can be crossed and even twisted, they will work in normal mode. Installation and operation of the self-regulating cable is very simple. It can be mounted outside or inside a heated object.
The system also has disadvantages. First of all, this is the cost. Self-regulating cable costs about 2-3 times more expensive than resistive. It should be borne in mind that it will be cheaper to operate. Another minus is the gradual aging of the self-regulating matrix, as a result of which the self-regulating cable fails over time.
Read more about the features of choosing a self-regulating cable read on.
Calculation of the heating system
Experts advise choosing cables with a capacity of at least 25-30 watts per meter for the heating system of the roof and gutters. You need to know that heating cables of both types are used for other purposes. For arranging warm floors, for example, but their power is much lower.
Before proceeding with power calculations, you need to decide how all the elements of the system will be heated. The figure shows examples of the possible organization of heating gutters and drains
Power consumption is evaluated in active mode. This is the period when the system is operating at maximum load. It lasts a total of 11 to 33% of the entire period of cold weather, which conditionally lasts from mid-November to mid-March. These are average values, for each area they are different. System power needs to be calculated.
To determine it, you need to know the parameters of the drainage system.
We give an example of calculations for a standard design with a cross section of a vertical drain of 80-100 mm, the diameter of the chute pipe is 120-150 mm.
- It is necessary to accurately measure the lengths of all the gutters for water flow and add up the resulting values.
- The result must be multiplied by two. This is the length of the cable that will be laid along the horizontal section of the heating system.
- The length of all vertical drains is measured. The obtained values add up.
- The length of the vertical section of the system is equal to the total length of the drains, since in this case one cable line will be enough.
- The calculated lengths of both sections of the heating system add up.
- The result is multiplied by 25. As a result, the power of electric heating in the active mode is obtained.
Such calculations are considered approximate. More precisely, everything can be calculated if you use a special calculator on one of the Internet sites. If independent calculations are difficult, it is worth inviting a specialist.
Choosing a place for cable laying
Actually, the heating system for drains is not so complicated, however, in order to work as efficiently as possible, you should lay the cable in all areas where ice forms and in places where the melted snow has melted.
In roofing valleys, the cable is mounted up and down, with a length of two-thirds of the valley. Minimum - 1 m from the beginning of the overhang. For each square meter of valley there should be 250-300 watts of power.
On flat sections of the roof, a fragment of the roof located immediately in front of the catchment is equipped with heating. So melt water will flow freely into the pipe
On the edge of the cornice, the wire is laid in the form of a snake. The snake pitch for soft roofs is 35-40 cm, on hard roofs it is made a multiple of the pattern. The length of the loops is selected so that no cold zones appear on the heated surface, otherwise ice will form here. The cable is laid on the drip line. It can be 1-3 threads, the choice is based on the design of the system.
The heating cable is mounted inside the gutters. Usually two threads are laid here, the power is selected depending on the diameter of the gutter.Inside the gutters, one heating core is laid. Particular attention should be given to pipe outlets and funnels. Usually, additional heating is required here.
Heating system arrangement technology
We propose to study the detailed instructions for installing the heating system of the roof and gutters with your own hands. The process of installing a heating system for drains includes a number of standard steps:
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Step 1: Installation of the heating cable according to the design
Step 2: Laying vertically oriented heating lines
Step 3: Installing the icing system sensors
Step 4: Install junction boxes and automation in the dashboard
First, we outline the places where the cable will be laid. It is important to take into account all the turns and their complexity. If the rotation angle is too steep, it is recommended to cut the cable into parts of the required length and then connect them using couplings.
When marking, carefully inspect the base. There should be no sharp ledges or corners, otherwise the integrity of the cable will be in jeopardy.
The cable is fixed inside the gutters with a special mounting tape. It is fixed across the wire. It is advisable to choose the tape as strong as possible.
The resistive cable is fixed with a tape every 0.25 m, self-regulating - after 0.5 m. Each strip of tape is additionally fixed with rivets. Their installation locations are treated with sealant.
For cable installation use a special mounting tape. No other fasteners are recommended. Rivets, sealant or mounting foam are used to fix the tape.
Inside the gutters, the same mounting tape or heat shrink sleeve is used to secure the cable. For parts whose length exceeds 6 m, an additional metal cable is used. A cable is attached to it to remove the bearing load from the latter.
Inside the funnel, the heating cable is attached to the tape and rivets. On the roof - on a mounting tape glued to sealant, or on a mounting foam.
Important notice from experts. It may seem that the adhesion of the roofing material to the sealant or foam is not sufficient for a reliable connection. However, it is absolutely impossible to perform holes for rivets on the roofing material. Over time, this will inevitably lead to leaks, and the roof will become unusable.
We select a place for the junction boxes and install them. Then we call and accurately measure the insulation resistance of all the resulting sections. We put the thermostat sensors in place, put the power and signal wires. Each sensor is a small device with a wire, the length of the latter can be adjusted. Detectors are placed in strictly defined places.
In some parts of the system, increased heating is required. A larger amount of cable is mounted here. These areas include a drain funnel where ice can accumulate.
For example, a place on the roof of a house is selected for a snow sensor, and a water detector is selected at the bottom point of the gutter. All work is carried out according to the manufacturer's instructions. We connect the detectors to the controller. If the building is large, the sensors can be combined into groups that are subsequently connected in turn to a common controller.
Next, we prepare the place where the automatic control system will be installed. Most often this is a distribution panel located inside the building. The controller and protective group are installed here.
Depending on the type of controller, the nuances of its installation may vary slightly. However, in any case, it will have terminals for connecting detectors, heating cables and for supplying power.
The picture shows that the cable is fixed in a “suspended" state. Over time, a malfunction of the installation will inevitably lead to its breakage and breakdown of the heating system
We install a protective group, after which we measure the resistance of previously mounted cables. Now you need to test the automatic protective shutdown to find out how well it copes with its functions.
If everything is in order, we program the thermostat and start the system.
Typical system installation errors
Experienced installers highlight the typical mistakes that are often made by those who first set their own heating gutters:
- Design errors. The most common is ignoring the features of a particular roof. When designing, one does not pay attention to cold edges, warm areas, spillway zones, etc. As a result, ice continues to form in some areas of the roof.
- Errors in fixing the heating cable: a movable wire “hanging” on the mounting tape, holes in the roof for fasteners, the use of a tape that is designed to install a warm floor on the roof.
- Installation of plastic clamps for internal use as fasteners. Under the influence of ultraviolet light, they will become brittle and collapse in less than a year.
- Suspension of a heating cable into a drain without additional fastening on a cable. It leads to wire breakage due to temperature expansion and the severity of ice.
- Installation of power cables that are not intended for installation on the roof. As a result, a breakdown of insulation occurs, which threatens with electric shock.
Errors include connecting the heating cable in areas where its use is not required. His work will be useless, and the owner will have to pay for it.
Interesting information about heating cables and useful tips for their installation are presented in the following videos.
Features of the self-regulating heating cable:
How to assemble the gutter heating system yourself:
Installation of a heating system for an industrial assembly:
Practice shows that in cold weather it is necessary to heat gutters. This makes it possible to get rid of ice and guarantees protection against sudden snow melting. You can arrange such a system yourself.
The most difficult thing is to calculate it and select the areas where you need to lay the heating cable. This part of the work can be entrusted to professionals. Having received the calculations and the project, the subsequent installation is easy to implement independently.
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