If you are reading this article, then you are probably thinking about installing a water-heated floor in your home. Now you are looking for information about what thickness of water heated flooring is needed for heated floors in your home.

In fact, you are probably interested in one of two questions:

• thickness of all layers of water heated floor;
• thickness of water heated floor screed.

We will analyze each question individually. Let us introduce the concept of not the thickness of a water heated floor, but .

A pie of water heated floor is called all the layers of water heated floor, connected together. It looks something like this:

The heated floor pie or the so-called thickness consists of the following elements:

1. , which is mounted along the edges of the walls and serves to compensate for the expansion of the concrete screed. Its height is 15-20 cm from the rough screed. It is not taken into account in thickness calculations.
2. , used more often in the form of polystyrene. It serves to cut off lower layers from heating by warm floors. Thus, you save on coolant consumption and warm water floors work as they should. The thickness of polystyrene on the ground floor in cold regions should be 10 cm. In regions with temperate climate a thickness of 5 cm will pass. But it’s still better to be overprotected than underprotected. Therefore, take a thickness of 10 cm as a basis.
3. Polyethylene. Mounted on thermal insulation to create an additional greenhouse effect. We will not take its thickness into account in general.
4. MAC mesh. It is mounted on thermal insulation and serves as a convenient way to lay pipes on it. Its thickness is ideally 4mm.
5. . Our main distributor of heat. The height of the 16th pipe is approximately 2cm.
6. Concrete screed. Today manufacturers recommend for filling concrete mixture brand M-300. From my experience, I recommend brands M-200, 250, 300. The thickness of the water heated floor screed is 5 cm from the top of the pipe! This is exactly what is needed for competent work water heated floor.
7. Finish coating. Parquet or tiles. A thickness of 2 cm is taken as a basis.

Thickness of water heated floor screed

As mentioned above, the thickness of a heated floor screed recommended by the manufacturer is approximately 5 cm. There are, of course, options when pouring a screed for a water heated floor to a thickness of 10 cm. Here the system begins to work on the principle of heat accumulation.

There is no rigid connection in the height of the screed. As practice shows, it is very rarely possible to achieve the recommended values. Therefore, the main thing is minimum thickness The screed above the heated floor pipes should be at least 5 cm. The maximum thickness of the screed should not exceed 10 cm. And then the size of the screed will be ideal for the operation of the heated floor.

The building structure will perform its functions without any complaints if preliminary calculations completed without errors. An accurately selected screed thickness for a water-heated floor will ensure sufficient strength and uniform heat distribution on the surface. To determine all the important parameters of the project, a detailed study of technologies, materials, and advice from specialized experts is necessary.

The figure above shows a typical screed diagram for a water heated floor, which is used in recommendations for creating heating systems built into the floor.

There are a few practical issues to note from this example:

• An ideal foundation is a rarity in domestic construction. Therefore, it is necessary to eliminate cracks and other defects in floor slabs. Creating a screed 4-6 cm thick will help solve the problem.
• The pipes of the water heated floor screed can be secured in different ways. Depending on the chosen option, the cost of the project, the speed of completion and the complexity of the work will change.
• One layer of thermal insulation is sufficient, but to obtain good results modern materials must be used.
• Experts recommend maintaining the surface temperature of the water heated floor screed at a level from +28°C to +30°C. But to fulfill this condition, it is necessary to take into account: laying step, type of main screed, type of finishing coating.

From this information we can conclude that the thickness of the screed over a water-heated floor depends on a variety of various factors. It cannot be considered separately. Coordination with other technical parameters of the heating system design is necessary.

If finishing coat The water-heated floor screed does not have sufficient strength (linoleum); it is necessary to install an additional layer of plywood underneath it.

How to determine the main characteristics

To figure out which screed is better for a warm water floor, you need to make a calculation. The table below shows surface temperature data for different finish coating options.

In all options, the following initial data are accepted:

• Pipe type: cross-linked polyethylene, diameter 20 mm, wall thickness 2 mm.
• Water temperature in the supply/return line: +50°C/ +40°C.
• From below on reinforced concrete floor Between the floors of the building there is thermal insulation made of foamed polystyrene foam 80 mm thick.
• The height of the main screed of a water heated floor is 7 cm.

Surface temperature for different types of screed

Heavy concrete filled with granite chips
Distance between lines, mm	100	150	200
Linoleum without insulation, °C	29	28	27
	26	25	25
Ceramic tiles, °C	33	31	30
Mixture of sand and cement
Distance between lines, mm	100	150	200
Linoleum without insulation, °C	28	27	26
Laminate on wooden base, °С	26	25	25
Ceramic tiles, °C	31	30	29
Semi-dry mortar
Distance between lines, mm	100	150	200
Linoleum without insulation, °C	25	24	23,8
Laminate on a wooden base, °C	24	23,5	23,2
Ceramic tiles, °C	27,3	26	25,5

From the data obtained it is clear that the fairly popular “dry” building mixtures are the worst option. They are easy to use. But the created covering of the water heated floor screed will have low thermal conductivity.

It should be noted not only the first position in the comparative table, but also the high strength of heavy concrete. Fiber fibers can be used instead of gravel and other traditional fillers.

The data from the table also shows how losses change when installing different finishing coatings. Linoleum, laminate, and natural parquet conduct heat poorly. Even with high supply line temperatures, it will not be possible to approach the ideal surface heat. The best option is ceramic tiles.

This image was taken using a thermal imager. Areas of water heated floor screed with more high temperature. You can see what happens if the distance between the lines is too large. A similar result will occur when the water temperature is insufficient, or the pipes are installed too close to the surface. By moving them lower, you can achieve even heat distribution. But this will increase the inertia of the system. We will have to increase the layer of concrete and reduce the height of the ceilings.

For residential premises, the main screed for a heated floor is from 6 to 8 cm. If it is planned to install a piano or other heavy products, double reinforcement is installed under the corresponding area.

Project preparation

A high-quality water heated floor consists of the following layers:

• Rough screed 5-6 cm thick. It is poured with pre-installation damper tape around the perimeter of the room.
• Insulation of water heated floor screed. It is better to use factory-produced polypropylene foam with a density of 40 kg or more. m cubic and above. The greater the thickness, the less heat loss. It is convenient to work if there are special cutouts at the ends of the products. They simplify precise joining and ensure tight connections.
• A polyethylene film (125-150 microns) is installed over the insulation boards. It prevents the penetration of moisture from the screed. If high-quality polypropylene slabs with interlocking joints and taped are used, additional waterproofing is not needed.
• The reinforcement not only strengthens the screed. It is convenient to fix pipes on such a frame. Instead of traditional metal ones, they are beginning to use composite and polymer products in construction. They weigh less and are not destroyed by corrosion processes.
• To speed up the work you need to purchase required quantity plastic clamps. Use 3-4 products for each linear meter lines.
• Where the water-heated floor screed pipe passes through the expansion joints, a protective corrugation is put on it.
• When the entire structure is assembled, pour it on top cement-sand mixture with fillers.
• Next, the finishing coating is installed.

The structure of the structure is selected taking into account the characteristics of the installation site and the structure itself. It is easier to install a heated water floor on a special substrate with protrusions. The corresponding sets are offered with edge and connecting elements. Some mats have IR reflective layers built into the bottom of them to improve the efficiency of the heating system.

When choosing a water heated floor, you need to check its technical parameters according to the manufacturer’s accompanying documentation. The numbers in the names do not necessarily indicate density.

Using the data of the selected project, they make a list of necessary things, consumables, tools. When determining the thickness of the screed, the load capacity of the load-bearing structures of the property must be taken into account. Layer 1 sq. m. concrete 6-7 cm thick weighs from 300 to 340 kg.

Execution of work operations

The exact sequence of actions depends on which screed for a particular warm water floor is ultimately chosen. However, the following expert advice will be useful when reproducing specific technological processes with your own hands.

Before pouring the rough screed for a water heated floor, it is necessary to install power cables and other utility lines. The walls and ceiling are leveled with plaster mortar. If you do the work in reverse order, you will have to wait until the screed hardens. Next, you will need to clean it of new contaminants.

When forming these building structures control the perpendicularity of the corners to ensure the tightness of the joints with the insulation boards. On a well-created surface, differences of more than 5-6 mm in height for one contour are not allowed. This will prevent the formation of “plugs” of air.

When choosing polystyrene foam boards with sufficient density, no special precautions are needed. This product will withstand the weight of an adult without deformation or damage. However, you should check the cleanliness of your shoes and remove potentially dangerous contaminants from the soles and surfaces. It is better to install ladders from boards for movement. It should be remembered that when pouring construction mixtures you will have to move heavy loads.

If the screed area of ​​a water heated floor is large, it is necessary to install expansion joints every 20-25 square meters. area. They will prevent cracks from appearing when the temperature increases/decreases. A tape made of foamed polymer (polyethylene) with a width of 100-130 mm and a thickness of 7 to 12 mm is suitable. Such elements are installed only in the main screed.

At this stage, high-quality wall plaster will be useful (at least to a level of up to 40 cm from the floor). Some types of specialized damper tapes are coated with an adhesive layer on one side. They attach to smooth surfaces quickly and firmly.

At the stage of preparing drawings for a water heated floor screed, it is necessary to accurately determine the intersection of pipes expansion joints. They are located only at the intersection of the supply and return lines. On open areas pipelines (from the screed to the collector and back) install insulation.

Concrete grades from 150 to 300 are suitable for creating a building mixture. This range is indicated in reference books to provide for different intended purpose surfaces. More durable ties (M300) are needed in commercial facilities, warehouses, production workshops. In residential and office premises concrete is created from 1 part M150/200 cement and three parts sand.

The composition of the water heated floor screed is strengthened using fine granite chips. Since it is expected to operate in a temperature changing mode, it is necessary to increase the ductility of the screed. There is no point in experimenting with PVA and adhesives from other series. The corresponding “free recipes” can be found on the Internet, but their actual benefits are difficult to confirm.

In order for the screed for water heated floors to be reliable, it is necessary to use specialized additives. They are subject to official guarantees. IN detailed descriptions Manufacturers provide instructions for proper use.

To fill the main screed of a water heated floor, the following algorithm is used:

• Work is carried out at room temperature not lower than 0°C.
• First, check the tightness of the system and eliminate any identified leaks. To do this, raise the pressure (up to 4 atm.) for one day. Next, set the nominal pressure (from 1.5 to 2.5 atm.). Monitor the values ​​using a pressure gauge.
• Markings are applied to the walls indicating the surface level of the future layer. To create smooth screed, mounds (“beacons”) of the required height are created in the room.
• To move a long rule, support guides are installed. The device is moved along them, removing surface irregularities.
• Pouring the solution begins from the far section, moving towards the entrance. Gas bubbles are removed from it using a tamper. The simple method, repeated blows with a metal rake, is labor intensive. A specialized floor vibrator for building mixtures will help you perform the necessary processing faster.
• During work operations, check the height of the screed using the marks applied to the walls.
• The amount of solution is created such that a portion of the mixture can be laid in a few hours, no more. It is necessary to calculate the technology so that one room is completely flooded in a day. To speed up processes, mixers and other means of mechanization with electric drives should be used. You don't have to buy this equipment. It can be rented.
• No later than 3 days later, the guides (beacons) are removed. The recesses of the water heated floor screed are leveled with mortar.
• To prevent the hardening of the screed from being accompanied by the formation of defects, it is moistened 2-3 times a day.
• After three days, a film is rolled out on the surface to prevent moisture from evaporating too quickly.
• In normal temperature conditions The screed will be ready for laying the final floor covering in 25-30 days. The coolant should not be heated above +28°C during this period.

Piece parquet and some other products made from valuable wood species are installed when relative humidity screeds below 55-65%. If this level is not achieved, extend the drying period.

Video: cement screed for water heated floors

Even the minimum thickness of the screed (5-6 cm) is an effective heat accumulator. Whenever emergency situation V winter period it will prevent pipes from freezing within 2-3 days. Correct installation of the system deep in the concrete layer will ensure uniform temperature distribution on the surface. This design is well protected from external influences. It remains operational for decades. The listed benefits can be fully enjoyed if you take into account the above tips when implementing the project.

Every builder and finisher should know what thickness of a heated floor is optimal, the fact is that only correct execution such a floor will allow him to work effectively.

The same floor, which is too thick, simply will not be able to perform its functions, since the air in the room will not warm up because of this.

Heated floor installation

In order to have an idea of ​​how thick a warm water floor should be, you need to know its structure. It is the excellent knowledge of the installation technology of such a heating system that allows you to correctly install all systems, as well as adjust the temperature in the room so that the level of comfort in it is optimal. It is worth keeping in mind that the thickness of the insulated coating layer used to make a warm water floor is usually indicated in the instructions for it.

Important! By general rule Warm floors of all types have a layered structure, that is, a kind of “pie” of concrete is formed in the room with a filling in the form of a heating element.

It can be electric or water. As a result, there is an opportunity for additional heating of one or another premises under the conditions reliable protection all elements of a warm floor.

If we take directly all the layers of the heated floor separately, then it consists of:

• insulation;
• polyethylene film;
• reinforcement mesh, which may be missing, but with it the floor will be stronger;
• pipeline;
• concrete screed.

Each layer plays its role, therefore, what thickness of the heated floor pouring should be in a given case can only be found out by adding up the thickness of each layer of such a cake. At the same time, it is always worth remembering that each layer has its own functional purpose For example, insulation allows you to save on heating water, as well as more efficiently distribute heat throughout the building. If you make a mistake with its installation, then it will become very difficult to understand what thickness of a warm water floor will be optimal.

In any case, before starting work, you should consult with a specialist who has experience in carrying out work. The fact is that the correct installation of the described “pie” is a rather delicate matter, and if it is done incorrectly at any stage, you can inadvertently ruin the entire work, and this is an extra waste of time and money. If you don’t have a specialist you know, carefully study the instructions for this or that type of heating system. This will help you determine what thickness of underfloor heating will be optimal in this particular room.

How to determine the thickness of each layer in the “pie”?

As we have already written, how thick a warm water floor should be can be determined by adding up the thickness of all its layers. First you will need to calculate and perform rough screed. She gets a job finishing field and is usually tied to the edge of the foundation base or the foundation itself. If the floor is being installed on the ground floor of buildings, then the rough screed will have to be done on the ground or the bonton floor of the first floor.

So, if you are doing work on the floor, then you do not need to prepare for this in any special way, just sweep the floor and wash it off the dirt. In the same case, when there is a soil base, you will have to prepare it especially, namely, level the soil and compact it. It is worth remembering that the soil foundation is usually made on the basis sand and gravel mixture, and therefore it can rightfully be called a “pillow” - it is it that makes up the first layer of the warm floor in this case, which is worth considering when deciding how thick the warm water floor should be.

By the way, there are building codes and regulations that regulate the thickness of each layer of a warm water floor. For example, when pouring a rough screed over the described “pillow”, you must proceed from its thickness of approximately 50 mm. At the same time, the thickness of the warm floor will further depend on the material that you chose as insulation.

The fact is that the same polystyrene foam can be different types and varieties, each with its own thickness. As a result, you have the opportunity to choose the “pie” that suits you, taking into account the size of the same doorways. If this is not done, the heated floor will have to be redone, wasting time and money.

To be more specific, how thick polystyrene foam for a heated floor should be, then a slab of this material measuring 100-115 mm is quite suitable. Its minimum thickness should be the same 50 mm. In addition, if you answer another question about what thickness of penofol should be for a warm floor, it will also be necessary to take into account the density of this material. It should be on average 30...35 kg/m3, this will allow you to significantly reduce the level of heat loss passing through the insulation.

Thickness of other underfloor heating elements

After you have laid the insulation, you will need to cover it plastic film 150-200 microns thick. Lay out on top of the spread polyethylene reinforcing mesh from rods with a diameter not thinner than 4 mm. After installing the fittings, it will be necessary to begin laying and assembling the pipeline. Here the thickness of the pipe will be 16 mm, however, if you take a pipe made of polyethylene, its diameter may be smaller.

When deciding how thick to fill the heated floor, you will need to add another 20 mm to the reinforcing mesh, which will cover the pipeline from above. The heated floor installed on top is covered with a screed with a minimum thickness of 50 mm; you can also add about 10 mm to be sure.

This screed has the function of not only the base of the finished floor, but also a heat accumulator. As a result, answering the question of what thickness of a warm water floor is optimal, it is necessary to provide a screed size that would allow the floor to remain as warm as possible long time. In any case, it is not recommended to make it thicker than 80 mm; it is best to use concrete grade M200 and higher.

These are, in principle, all the layers of the “pie” of a layered floor. However, there is still more to do fine coating, consisting of porcelain stoneware, tiles and other floor coverings. Moreover, each material has its own thickness, for example, for tiles you will need 20 mm of free space, and for parquet - 40.

In addition, sometimes the question arises as to what thickness of drywall for a warm lightweight floor is appropriate. The fact is that drywall is very sensitive to wear, so it must be taken with a reserve. It’s best to simply ask the store to provide you with this finishing material, indicating that you are going to use it to finish the floor.

Important! It is also worth remembering that all the dimensions given above are not strictly defined and may change in one direction or another.

This is due both to the unevenness of the floor itself and to the features used in the construction of heated floor materials. For example, can be used instead of polystyrene foam mineral wool, having a different thickness.

Calculating the thickness of underfloor heating layers

With the listed numbers on hand, it will be possible to calculate the thickness of the entire floor, but it is worth keeping in mind that the “pie” in any case must have a thickness of at least 140 mm, counting from the top of the base to the surface of the rough screed. It will also be necessary to make adjustments for the thickness of the gravel “pillow” and the overlap of the first floor.

It is worth taking into account the purpose of a particular room, for example, the same screed in residential premises should not exceed 100 mm, as for warehouses, shopping pavilions, as well as car centers, it should not exceed more than 200 mm. If you need to heat an aircraft hangar, you will already need a 300 mm screed.

It will be necessary to check that all underfloor heating systems are covered with concrete during installation. To do this, the minimum thickness of the screed must be 65 mm. It is imperative to remember that a warm water floor screed differs from a conventional screed by the presence of expansion joints in them.

Other points mandatory verification Warm floor systems before starting operation are:

• checking the functionality before laying the pipeline screed;
• checking the pipeline for hydraulic density;
• checking the heat-reflecting layer placed under the pipeline system in order to avoid losses.

In order for the screed to be of high quality, the choice of materials for it must be made responsibly, only in this case the warm floor will work for a long time and effectively. At the same time, you need to not overdo it with its thickness so that the heat can function normally in the room.

In the case when the described heating system will operate in a non-residential premises, you need to pay special attention to the strength of the heated floor covering. For this purpose, it is imperative to carry out the reinforcement procedure. It is the reinforcing mesh that will help you make the floor durable and at the same time highly functional.

Choosing a floor covering

Once the “pie” is formed, all you have to do is finish your floor. To do this, you need to choose the flooring material taking into account its thickness. If you make a mistake, you will have to redo the floor again, since during the work there is a possibility of damaging the screed.

As for the direct choice of the material itself, it is better to select for heated floors those materials that are not afraid of exposure to moisture or temperature. These include ceramic tiles and porcelain stoneware. The use of laminate must be approached with great care, as it tends to deform when exposed to moisture and high temperatures.

Important! When choosing a particular material for flooring, you need to pay special attention to its thickness.

For example, laminate is available in different options, from which you can choose the one that suits your price. As a result, you get the opportunity to meet the thickness requirements of the water floor and at the same time decorate it beautifully.

By the way, some manufacturers produce kits for heated floors with the addition of a ready-made floor covering. As a result, you save time on searching for it, and in this case your floor will form a single, complete complex. Likewise You can achieve very significant savings in your money.

To lay an electric heated floor, it is important to perform the screed correctly, since the uniformity of heat distribution in the room, structural strength and heating efficiency depend on it. Arrangement of the screed is the most labor-intensive stage of laying a heated floor.

Its functions are as follows:

• protection of heating elements from mechanical influences and negative influence air;
• uniform heat distribution over the surface of the floor radiator to heat the entire space of the room;
• Creation level base under the finishing coat.

Please note the following during installation:

• the thickness of the entire screed, as well as the upper and lower layers around the heating element;
• what manufacturing method to choose;
• taking into account the peculiarities of solution preparation and cable pouring technology.

The most common is wet screed, although dry screed is beginning to be widely used, which allows you to avoid wasting time on drying the solution, during which time the heating cannot be turned on.

Despite the apparent simplicity of the composition, the screed is made in several versions:

• Sandy cement mortar with a component ratio of 3:1 it is suitable for electric heated floors.
• Concrete based on fine-grained filler is used in water floor systems. The slab is durable and does not crack.
• Self-leveling mixture is well suited for pouring electric heated floors when it is necessary to obtain a thin layer.
• Mixtures for heated floors, produced in a wide range.
• used as a thin screed for electric heated floors.

The strength of the screed increases significantly if you use reinforcement mesh or microfiber.

Compositions are obtained with high durability and plasticity if plasticizers are added to them.

Thermal insulation

To prevent heat loss through the ceilings, thermal insulation is used. When choosing it, take into account the heat-shielding properties, on which the overall thickness of the screed depends. On the ground floor, slabs 5 cm thick are used as thermal insulation; if there is an apartment below with heating, insulating layers no more than 2-3 cm can be used.

The heat insulator is taken with a metallized coating. Aluminum foil does not withstand prolonged contact with the screed and is destroyed. It is necessary to use metallized coatings in the form of spraying with lavsan, etc.

The slabs are laid without gaps. The resulting gaps are filled polyurethane foam, all joints are taped with adhesive tape.

Laying heated floors

The best way to install an electric heated floor depends on the type of heating elements. For any heated floor it is important to ensure that heating elements did not touch the thermal insulation. To do this, they are separated from it by reinforcing mesh.

Cabling

The location of the thermostat is selected. It is mounted at a height of more than 30 cm from the floor. If the device is a hidden type, grooves are made in the wall for it, as well as for the power and temperature sensor wires. In places with high humidity Thermostats are not installed. They are taken to adjacent rooms.

Mounting tape is attached to the base at intervals of 50-100 cm and at a distance of 30 cm from the walls. Markings are made on the floor, taking into account the distances from the furniture. The distance from the walls is 10 cm, and from pipes and radiators - 15 cm. Then heating cable It is connected to the power one using a coupling, and then attached to the mounting tape.

The power cable is routed through a groove prepared in the wall to the thermostat, and the heating cable is laid according to the diagram. In this case, the radius at the bending points should not be less than 5 cm. The bends are made smooth, without unnecessary tension. Fixation is done with staples or mounting tape. Contacting or crossing of turns is not allowed. The convergence should not be less than 8 cm. All indents are strictly observed according to the scheme, which is developed in advance.

The temperature sensor fits freely inside the corrugated pipe along with the supply wires. The corrugation at one end is hermetically sealed with a plug to prevent cement mortar from getting inside. The pipe with the temperature sensor is located between the turns of the cable at a distance of at least 50 cm from the wall and is placed in the prepared groove, after which the wires are connected to the thermostat.

After installation and connections it is checked electrical resistance heating cable and sensor. The values ​​must differ from the passport values ​​by less than 10%.

The grooves are sealed with mortar or putty, and after hardening, the functionality of the heated floor system is checked.

Laying the heating mat

Heating mats are easier to install because the cable is already attached to a mesh base, which only needs to be spread on the base. At turning points, the mesh is carefully cut without compromising the integrity of the cable. Where obstacles are located, the mesh is removed and the cable is laid maintaining a distance of 6-8 cm from adjacent turns.

An important advantage of the heating mat is its small thickness, which makes it possible to pour a thin screed or lay heating elements in a layer of tile adhesive. Then the thickness of the fill will be only 8-10 cm, which will allow you not to take up excess space in the room.

Laying the core floor

Rod infrared heaters look like rope ladder. They contain transverse heaters and 2 longitudinal connecting wires through which power is supplied.

The core roll rolls out across the floor, starting from the thermostat. At the turning points, the connecting wire is cut, after which it is necessary to reconnect the ends with a piece of wire. This reduces the reliability of the heated floor. It is advisable to select rolls of suitable length. Then you won't have to cut anything.

After laying in the insulation, windows are cut out in checkerboard pattern for better adhesion of the screed to the base. All connections must be carefully insulated.

Compositions and types of screed

A concrete screed for an electric heated floor will turn out to be of high quality if you select the correct proportions of materials and mix them thoroughly.

Cement and sand alone are not enough to prepare a screed. It requires plasticizers and additives that increase the plasticity and uniformity of the mass.

Dry screed

Advantages of dry screed over wet screed:

• no special equipment is required: mixers, containers for solution, etc.;
• less effort is spent on delivering the material;
• speed of work completion (in 1-2 days);
• there is no need to wait for the screed to mature;
• opportunity step-by-step installation heated floors divided into zones;
• absence of dirt and excess moisture;
• small specific gravity screeds;
• the floor acquires sound absorption and thermal insulation properties without the use of special materials, the price of which is sometimes high;
• the possibility of laying communications in the thickness of the material;
• the surface is smooth and ready for finishing floor coverings.

With all the advantages, the coating is quite light and durable. It will not withstand the load from interior partition from gypsum boards or brick, but frame structures plasterboard can be installed on it.

Dry screed is not used in the following cases:

• if there is a slope in the room;
• in the presence of large dynamic loads (vibration effects or high intensity of human flow);
• in rooms with high humidity or with the possibility of water spills on the floor;
• in cramped spaces where it is not possible to compact and level the composition efficiently.

When preparing dry screed, the following materials are used:

• Waterproofing film.
• Damper tape around the perimeter to compensate for temperature deformation.
• Dry backfill made of fine gravel, expanded clay, slag pumice, perlite. Instead, high-density insulation boards can be used, for example, etc.
• The top layer is sheets of moisture-resistant plywood, asbestos cement, chipboard, OSB. They are also used for large thicknesses. The best option is the use of waterproof gypsum fiber sheets suitable for any floor finish.

Manufacturers building materials produce special complete and balanced systems dry floor. For indoors different types a whole line of dry screeds “Knayf” is produced. Among them, two-layer gypsum fiber boards with the possibility of assembly with locks are popular. For housing, “Vega” compositions are produced based on small expanded clay screenings in bags and other components.

When using industrial waste, for example, solid expanded clay or slag, for dry screed, the fraction size should not exceed 5 mm. Otherwise, the floor will begin to sag and creak.

The thickness of the backfill must be more than 30 mm, otherwise the required quality cannot be achieved. If the upper limit is higher than 60 mm, intermediate spacer sheets will be required. The top of the screed is additionally covered with a sheet covering, the thickness of which is about 20 mm.

The base for backfilling must be level.

Semi-dry screed

The screed is a cement-sand mixture with the addition of fiber fiber and plasticizers, but with a low water content. Distinctive feature is a large layer thickness of 70-100 mm. If the thickness is less, the layer may crack.

The advantages of semi-dry screed are its heat and sound insulation properties due to its porous structure.

The disadvantage is the need to use construction equipment, but in small spaces the screed can be laid manually.

The ratio of components, which include cement, sand and water, is 1:3:0.4, respectively. Fiber fiber is added to them in an amount of 600-800 g/m 3.

The screed is laid along the beacons, similarly wet method. A special machine is used for grouting, which can be rented. It is difficult to compact the screed manually.

Wet screed

A screed is a layer of mortar or concrete applied to the surface of the base.

It is laid in several layers, the functions of which differ:

• Leveling the base. The first layer is always used for uneven surfaces. It is necessary even when a dry screed is placed on top.
• A layer on top of thermal insulation for laying heating elements. If the cable touches the insulation, it may overheat at this point.
• The third layer covers the heated floor, evens out the temperature field and keeps flooring. It is often combined with a second layer, if the thermal insulation is covered with a waterproofing film on top.

In all cases, it is advisable to reinforce the layers to prevent cracking and maintain the integrity of the heated floor. At the same time, the thickness of the floor increases significantly, which leads to a decrease in the height of the premises. It can be reduced through the use of leveling compounds.

The classic screed is cement-sand. But the composition is not limited to only two components. Plasticizers are added to it, as well as crushed stone or expanded clay. A mixture of 3 parts sand, 1 part cement and PVA glue, added in an amount of 1 kg per bag of cement, works well.

When using ready-made mixtures, it is achieved high quality screeds. Each composition has its own preparation instructions.

Any heated floor must be installed on a flat surface. To obtain a level base, use regular cement-sand mortar, and leveling compounds are most often placed under the finishing coat. Their cost is high, but the filling is perfect.

The thickness of the tie depends on the diameter of the cable and is 3-5 cm. If it is made smaller, the required strength of the slab and uniform heating will not be ensured.

When cracks appear in the screed, the reliability of the heated floor decreases sharply. Due to the violation of the integrity of the layer, the heating of the floor becomes uneven. Areas with high temperatures appear, as a result of which the cable overheats and its service life is reduced.

The technology for laying the screed must be performed correctly. The strength of the cement takes 4 weeks; no work can be carried out during this period. It is important to ensure uniform fixation of the layer. To do this, cover it with film and keep the surface damp.

The main screed is installed after leveling the base and laying the cable. First, a damper tape 10 cm wide is rolled out along the perimeter of the walls from below and secured with tape in places adjacent to subfloor. It is also placed in places of transition to other rooms.

Cracks will not form in rooms larger than 40 m2 if they are divided into rectangular zones and T-shaped strips of porous material are laid between them. Damper tape is not suitable here because it is flexible. Thin foam sheets are usually used. Where the cable passes through expansion joints A short corrugated hose is put on the cable so that it does not break due to temperature deformations.

A reinforcing polymer mesh is placed under the cable. It should be rigid and located at a distance from the insulation.

The laid heated floor must be tested - apply voltage and check the uniformity of heating.

In order for the screed to be exactly horizontal, beacons should be installed at a given height. For this purpose it is used laser level. If it is not there, the usual one is used, but then the upper boundary of the fill should be drawn on the walls.

The first beacons are installed at a distance from the wall, and the next rows are made at a distance slightly shorter than the rule. Beacons are made using a solution, after which you need to wait for it to set.

The heated floor is poured with careful leveling and filling of all voids manually. The solution is poured 1 cm above the level of the beacons and compacted with a hand tamper. Then another layer of screed is applied on top and pulled out using the rule. After this, you should immediately rub the surface with a trowel, making circular movements. At the same time, the horizontal level is regularly checked by adding solution to the holes and removing excess.

The work of pouring the screed is done within one day with minimal interruptions during manual mixing.

The drying surface is covered with a film and moistened for a month until the concrete matures. If you hurry and turn on the heated floor earlier, it will will crack and all previous work will be done in vain. In addition, removing a frozen screed will not be easy.

Video: installation of heating cable

The screed is important element warm floor, on which its quality depends. At correct installation it will provide comfortable conditions and durability of the heating system. Great value has the thickness of the screed. If the surface is uneven, it can be improved with a leveling layer. The base must be strong and durable, since it is subject to constant alternating temperature influences. It should be built according to certain rules, maintaining the thickness, ratio of screed components and its maturation time.

A warm floor is a complex structure, each element of which must be assembled with very high quality. This requirement also applies to cement screed, poured over laid pipes. The service life of such a floor will directly depend on the durability of the poured screed. What are its main parameters? What is important is the composition of the mixture and quality preparatory work. These indicators are relevant for both water heated floors and its electric counterpart.

Fundamental Points

What determines the quality of the screed being poured and its service life? There are four main parameters.

It is important to place it correctly thermal insulation material. Its task is to direct heat into the room. Thermal insulation acts as a special barrier that does not allow heat to escape down into the floor slabs. The insulation layer is usually made up of two complementary materials: foam and reflective material are suitable for this purpose. A 3 cm layer of foam plastic protects the heating elements from the cold of the floor slabs, and the reflective material works to transfer heat into the room.

Surface reinforcement work also plays an important role. To do this, use a metal mesh, to which the pipes themselves are then attached. Sometimes a second layer of mesh is attached to them, which helps strengthen the future structure.

Why is reinforcement required? Under the screed is located soft material, which is easily deformed. If you skip reinforcement work, the screed will quickly crack during deformation processes in the lower layers.

An obligatory component of the preparatory work is the laying of a damper tape, the purpose of which is to resist deformations of the screed caused by temperature conditions. Due to deformation of the cement coating, heating elements may be damaged. Since their repair seems to be a very complex and time-consuming process, it is not recommended to neglect the work of laying the damper tape.

Installation of damper tape.

The composition of the mixture for pouring the screed is more important. The solution must be prepared in strict accordance with the instructions: all components must be added in certain proportions. Depends on the thickness of the screed mechanical strength the entire floor heating system, as well as the main parameters of its performance. The height of the cement layer should be optimal for a particular room: here it is important to take into account the required level of heat transfer, efficiency and ability to respond to temperature changes. The thicker the screed, the greater the heat capacity it has - this is logical. But there is one drawback here, which is that when the screed is too thick, it becomes problematic to regulate the temperature.

You can make a cement screed yourself, but if you make it too high, it will take a very long time to heat up. Such a floor will also give off heat longer, but in everything you need to look for the “golden mean”.

A thin screed will heat up quickly. But this ability is not her strength. The thinner the cement layer, the higher the likelihood of overheating. And if the screed overheats, the coating will simply crack and all your work will be in vain.

Defects in thin screed due to overheating.

The thickness of the screed also serves protective function in relation to the pipes laid below, so it must completely cover them. If the size of the cement layer is selected correctly, the heated floor will warm up evenly and serve you for many years.

The recommended thickness of the heated floor in the apartment should not be more than 10 cm. non-residential premises it may be more: the norm for warehouses, shopping pavilions and other similar rooms is 20 cm. The total thickness of the screed should hide all heating elements; its height may vary depending on the diameter of the pipes used. Experts call the figure 6.5 cm as a minimum guideline.

The thickness of the screed in a residential area should be between 6.5 and 10 cm.

If we consider the thickness of the screed directly from the pipeline, then this value can be within 2-5 cm. Provided that thermal insulation was previously laid between the base of the floor and the pipes, and a reinforcing mesh was used, you should aim for a minimum of 3.5 cm.

If you haven't used metal structures, then the thickness of the top layer of the screed should be increased by 1-1.5 cm. Minimum height screed over pipes automatically increases to 4.5 cm. A screed of this thickness is the best option, since it will warm up evenly over the entire surface of the floor.

Pouring the solution

The solution that is poured over the heated floor pipes can be prepared in two ways. The first option is a ready-made special mixture, purchased at a building materials store. It is not difficult to prepare a solution for pouring from it, and installation also does not cause any particular difficulties. The mixture is not recommended for use in rooms with high humidity, since the gypsum included in its composition is not resistant to such conditions.

Ready-made self-leveling mixtures can be used for water heated floors.

What layer is the mixture laid out? The thickness of the ready-mixed screed is determined according to the instructions included with the building material. It is most often used for electric heated floors, not water ones.

For a water floor, a cement-sand mortar is best suited, which includes: M-300 cement, sand, water, fiber (if there is no reinforcement stack) and a plasticizer. A plasticizer is a special additive necessary to improve the quality and plasticity of the mixture.

The volume of solution required for pouring is calculated by multiplying the estimated height of the screed and the area of ​​the room where the water-heated floor is installed. It makes no sense to save on such a parameter as the thickness of the screed. If you are installing a heated floor, this should be done according to all the rules. Having saved on screed mortar, you will then have to incur additional costs for a new floor.

The optimal height of the cement layer ensures that the new heated floor will withstand unexpected loads of various types.

If you initially plan to place heavy furniture in the room, then when installing the floor, be sure to install a metal mesh. Fiber is added to the mixture when preparing the solution for the same reason: it helps strengthen the screed.

The screed is usually poured from the corner, and then the solution is leveled using a rule. Here you should also take into account the future floor covering. Almost everything decorative materials fit exclusively flat surface, therefore, leveling the solution must be taken as responsibly as possible. When laying the screed, it is important to prevent the formation of voids, as they will subsequently affect the heat transfer performance of the floor.

When installing the screed, it is important to follow the technology.

After pouring, the screed is left to dry. This requires 1-1.5 months depending on the thickness of the layer. All further finishing work can only be carried out after the solution has completely dried. The finished self-leveling mortar will dry less, but even here you will need to wait the time specified in the manufacturer's instructions.

What other rules should not be ignored? Before pouring the solution heating system pipes are checked under operating pressure conditions. There should be no defects. All defects must be eliminated before pouring cement: repairing a finished floor will be very difficult. The rules for laying the insulating layer must not be violated, otherwise all the heat from the pipes will go into the floors between the floors of the house, and not into the apartment.

The screed for a warm water floor should be made from quality materials. If the cement is caked, then you should not add it to the solution. The quality of cement as the main element of the screed should be at high level. The durability and performance of a warm water floor directly depends on the quality of the materials used in its installation.