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What is the height of the heated floor. Screed for electric and water heated floors. Additional information about the minimum screed thickness parameters

Although there are no regulatory or regulatory documents, there are still certain rules associated with the work.

The installer must take into account the following:

1. The thickness of the screed under and above the heating cable.
2. Choosing a screed installation method.
3. Nuances associated with the preparation of the solution and the pouring process.

A properly made screed for a warm electric floor does not crack, ensures uniform heat distribution throughout the room, and retains its strength over a period of time. long term operation.

What layer of screed for electric heated floors

A screed under a warm electric floor is not mandatory. It is often poured to level the surface before laying the cable. In this case, the manufacturers' recommendations should be taken into account.

According to the requirements of most manufacturers of electric floors, a cement mortar screed cannot be thinner than 3 cm. When using special leveling mixtures, the thickness can be reduced to 2 cm.

The optimal thickness of the screed for electric heated floors is selected depending on the following factors:

• Base for pouring. The screed on the ground must be at least 10 cm. The thickness for the screed on the floor slabs depends on the unevenness of the surface. The resulting plane should be perfectly flat.
• Material. The cement-sand mixture is poured with a thickness of at least 3 cm, leveling solutions depending on the manufacturer’s instructions.

Laying the heated floor cable in the screed can be done strictly on a perfectly flat surface. Variations affect the uniformity of heating and often cause cable overheating.

What is the thickness of the screed above the electric floor?

Experts' opinions on this matter may vary. Therefore, it is best to refer to the recommendations of underfloor heating manufacturers. According to the instructions given in the operating instructions, the minimum layer of screed should be 4-5 cm.

But the thickness may vary depending on several factors:

1. Cable thickness.
2. Floor type.
3. Screed mortar used.

Thus, heating mats are laid out on the floor surface, after which they are immediately covered with floor covering. The cable in mats is attached to a reinforcing mesh. The design allows you to lay tiles using an adhesive composition without a screed.

The larger the cable volume, the greater the thickness concrete screed. To determine the minimum parameters, you should refer to the operating instructions. The minimum thickness of the screed over a warm electric floor cannot be less than 4 cm for cement mortar and 2 cm for special leveling mixtures.

The total height of the screed for an electric heated floor is from 5 to 8 cm. Provided that the installation is carried out on a flat base, the thickness of the cake can be reduced to 4 cm. Heating mats together with the floor covering, reduce the height of the room by no more than 2 cm.

Which screed to choose for pouring

In addition to the traditional sand-cement composition, there are other types of screed recommended for pouring heated floors.

Each of existing options has its advantages:

• Wet screed. For preparation, take cement, sand and plasticizer. Be sure to add fiber fiber to avoid the appearance of cracks and deformation during the drying process and during operation. The advantage of the solution is that you can make it yourself. The components are inexpensive, which somewhat reduces the final cost of the work.
  The disadvantage of a wet screed is that the floor takes a long time to dry (28 days), there is a high probability of cracks, and the inability to make a perfectly level base.
• Semi-dry screed method. A small amount of water is used for production. Ready-made mixtures are popular. But if necessary, you can prepare the solution yourself, based on - river sand 120-140l/fiber fiber 130g/cement 1 m/water 14-17 l. /plasticizer 0.5 l.
  The advantage of the semi-dry composition is the complete absence of cracks in the screed after drying. There is no need for additional leveling of the floors after drying.
• Dry method. The composition of the screed mortar may vary depending on the manufacturer, but most often fine perlite or quartz sand, fine-grained slag, etc. The advantages of the dry method include: quick installation and drying. TO further work You can start after 12 hours.

The tie must be done carefully to prevent possible damage to the cable. The rupture of protective insulation or conductive conductor during floor pouring is the most common cause of floor failure.

How to reinforce the screed

In order for the installation of the heating cable into the screed to be successful, it is imperative to prevent deformation and cracking of the floor during the drying process. Cracks cause cold zones to appear, uneven distribution heat over the entire surface of the stove.

What methods of screed reinforcement exist?

1. Additives. When preparing the solution, it is important to use fiberglass. This is a special additive based on polypropylene. After adding fiber fiber to the solution, it increases several times strength characteristics: resistance to mechanical damage, cracking, settling and spreading of the mixture. At the same time, frost resistance and fire resistance increases.
2. Reinforcing mesh. Recommendations for pouring screeds for heated floors indicate the need to use a plastic reinforcing layer. The manufacturer additionally provides special stands to raise the mesh off the floor.

IN large rooms Floor cracking may occur due to the lack of expansion pockets. Therefore, a mandatory measure is to install a compensating damper tape along the walls, as well as between sections of the slab.

How to pour screed correctly

The technology for pouring screeds for electric heated floors is practically no different from that used when installing a conventional cement base. After execution preparatory work and laying out the cable for further installation in the concrete screed, proceed to the following steps:

1. Displaying beacons. The surface must be extremely flat. In this regard, the step between the beacons is no more than 0.8 m. Although you can find recommendations that the distance between the beacon level should depend on the length of the rule, practice shows that the longer the step, the more irregularities appear during the stretching of the solution.
   Initially, we place the beacons along the edges of the room, so that there is 10-15 cm left to the wall running parallel to the plank. The fishing line is stretched, the remaining guides are placed under it. If the recommendations are followed, the result is a perfectly flat surface, leveled along the beacons, even when using ordinary cement-sand mortar.
2. Filling the screed. After the solution used to attach the beacons has dried, you can begin pouring the screed. If the floor thickness exceeds 5 cm, the work is carried out in several stages. First, apply the first layer of 2-3 cm. A day later, the second, finishing layer is pulled along the beacons. It is important to ensure that the rule does not scrape excess solution from the surface and that pits do not form after drying.
3. Drying the solution. Care should be taken to ensure that direct Sun rays. The screed is covered with film and watered at regular intervals during the first 5-7 days.

Warm floors built into the screed can be turned on no earlier than 28 days after pouring the solution. According to SNiP, at the same time you can begin laying the flooring.

How to make an electric heated floor without screed

It is possible to lay the underfloor heating cable without a screed. The following two methods are popular:

1. Grooving screeds for underfloor heating cables. Grooves about 2 cm deep are cut into the slab or concrete screed. To avoid a lot of dust, use special tool with dust bags. The cable is laid in grooves. The top is laid with a solution with the addition of fiberglass or adhesive composition for tiles.
2. Laying heating mats- this method is also popular due to its ease of implementation installation work. The design of the mats is quite simple. To connect, you need to spread them over the surface and plug them into a power outlet.

Many nuances and features that must be taken into account when installing an electric heated floor in a screed lead to the fact that more and more buyers prefer heating mats.

This work requires responsibility from the master, since the quality of the work determines how the floor will look externally, as well as how well the system will cope with its main heating functions.

Screed functions

The underfloor heating system is constructed of several layers, each of which has its own purpose. The screed for warm electric and water floors is an integral, connecting link of the entire system, on which the efficiency of heating will depend. Therefore, you need to know how to properly pour screed under a heated floor.

Find out the price and buy heating equipment and related products you can find here. Write, call and come to one of the stores in your city. Delivery throughout the Russian Federation and CIS countries.

The screed performs a number of functions:

1. Firstly, it acts as protection against any mechanical damage, and if we are talking about electrical heat field, then here it also does not allow air to penetrate into the system;
2. Secondly, the screed acts as a kind of floor radiator, sufficiently large in area, it is responsible for the uniform distribution of heat not only over the floor surface, but throughout the entire room;
3. Thirdly, it is a flat surface, so the main coating will lie on it well, without any protrusions or dents.

Screed for heated floors

By and large, a screed under a warm floor is a layer of concrete that is applied on top of the rough floor covering. A standard screed involves its repeated installation, with each layer having its own purpose:

1. The first layer is applied to the rough surface ( rough screed). It is necessary to level the floor. This point cannot be skipped; leveling is carried out on any surface.
2. The second layer is done on thermal insulation. It is necessary to create a base on which the floor heating cable will be installed in the future.
3. Last layer covers the heated floor and ensures heat distribution over the surface. Plus, the top coat is the basis for the final coat.

The screed under the heated floor plays a big role. True, it makes the coating thicker and the height of the room smaller, which often becomes the reason for failure to install a water system. The electric floor does not reduce the already usable space so much.

Mixture composition

Opinions differ as to what type of screed for heated floors is best to use, so there is no definite answer. Some prefer, it contains dry materials. You don't have to wait for the solution to dry. Others choose wet screed, and such users are the majority.

To install a heated floor, you can choose one of the proposed mixtures:

1. A solution of sand and cement is mixed in a ratio of 1:3, respectively. This solution can be used for screeding water and electric floors.
2. A concrete solution containing fine-grained filler. Experts say that such a screed is the most suitable option for water structures, the surface will not crack.
3. Self-leveling mixtures have found their active use in pouring electric heated floors; they are very easy to work with when screeding a heated floor with your own hands.
4. There are also special mixtures that are suitable only for heated floors and no other heating systems. They vary in composition; in specialized stores you will find many different mixtures. Tile adhesive is used during installation.

There are other proportions; they are used depending on the type of floor that is planned to be made. When, after the screed has hardened, the laying of parquet, tiles or laminate begins, then for one share of cement it is necessary to add five shares of sand, as well as water (0.7 shares).

If you plan to use soft materials as a floor covering, for example, carpet or linoleum, then the composition of concrete for screeding a warm water floor can correspond to the following values: cement 1 part, sand - four and water - 0.7 parts.

The addition of crushed stone implies the following proportions: cement - 1 part, sand - 3 parts, crushed stone - 5 parts. As a rule, water is added to half the cement weight.

To reduce time costs, ready-made mixtures are used. How to use them is written in the instructions included.

To flooring was as durable as possible, use reinforcing mesh, and to make the compositions more resistant, microfiber can be added to them.

Whatever mixture you choose, in any case, when screeding a heated floor, strictly observe all proportions.

Thickness

During the work process, many users ask the question: what should be the thickness of the screed for a heated floor?

And this parameter is very important; there are clearly described rules in this regard, the observance of which is beyond doubt:

1. The thickness of the screed over the entire area of ​​the room should be identical. Only in this way will uniform heating and high heat transfer be achieved. Under no circumstances should screed be poured under a heated floor until all bulges, holes and folds on the subfloor have been eliminated.
2. It is important that the coating is not too thin. Insufficient thickness will affect the uneven heating of the floor, the amount of accumulated heat will be negligible and the surface will cool down very quickly. Also, a thin layer can cause the material to crack.
3. It is also unacceptable to use too much thick layer, since in such a situation the heat, on the contrary, will be retained inside the structure.

Only maintaining balance and exact proportions will allow you to achieve high efficiency heating

What is the optimal screed thickness for a warm water floor? Fill at least 5 cm from the thermal insulation layer. Otherwise, cracks will appear in the first operating season. For electric cable system this is 2.5 cm, for - 1 cm.

How to make a screed under a warm floor with your own hands

In order for the procedure to be successful, just adhering to the styling technology is not enough. The organizational stages also deserve special attention, so initially you need to prepare the foundation well.

This can be done in several ways:

1. The base is made of floor slabs. Initially, it is necessary to dispose of all unnecessary items from the surface and clean it thoroughly. After this, you need to lay soil on the surface of the slab. deep penetration or concrete contact. For processing, use a regular paint roller.
2. Base made of heating elements. Here you also need to clear the surface of everything unnecessary and get rid of any contaminants.
3. The base is made of earth. The first thing to do is cover the ground with sand, 100-150 mm thick. Next you need to spread waterproofing material, most often preference is given plastic film. Already on the film you need to place a reinforcing mesh. And the finish line is pouring the concrete mixture.

Many users do not know which mesh to use for underfloor heating. Everything is simple here - for a water heated floor you need to choose a special metal one (reinforced) with a cell size from 50x50 to 100x100 mm. For electric, you need a polymer mesh (cell size - 20x20 mm).

Next we move on to the stage of installing beacons. You need to pay special attention to this process and be extremely careful, since the evenness of the floor in the horizontal plane will depend on your care and accuracy in installation.

But it is not necessary to install beacons.

Laying technology without the use of beacons is popular in situations where cement-sand screed is poured in small rooms.

It is simply aligned by the insertion rule. Laying the screed starts from the far corner. The finished mixture must be poured onto the floor and leveled. Once it is hard, a thin layer of self-leveling flooring is poured. They spread over the surface, and as a result you get an even and durable final coating.

Beacons are installed for pouring floors in large houses or apartments, where it is very difficult to determine the horizon level by eye. The beacons are a profile with an edge size of 10 mm. During the installation process, a step of 500-700 mm should be maintained.

It is fixed on the solution. Initially, you need to mark the room along long wall need to be positioned laser level, and only then mark the installation horizon line on it.

After all the above steps have been completed, the first beacon profile is placed on the solution.

It is aligned along the line on the wall. The remaining beacons are installed according to the specified step. The horizon from the first profile is transferred using building level. At the end, you need to make sure that all the beacons are present and let them stand for a day, during which time the solution will harden.

The next stage is pouring the screed.

At this stage, we begin to frame the room around the perimeter. To do this you need to get one. This is a special polymer; you need to glue the walls at floor level. The tape forms a buffer section between the screed and the enclosing structures.

Damper tape is a very important component; it does not allow heat to escape through the walls, and also acts as protection for the screed from cracking in case of temperature changes.

After the reinforcing mesh is laid, you need to make sure that the entire system is functioning. Especially when it comes to a water field. If there are leaks in it, then the floor covering urgently needs to be redone.

Next you can fill cement-sand composition on a warm floor. It is important that at this moment the room temperature is between +5-25°C. The mixture must be poured from the far corner. Once the solution is on the surface, you need to level it well.

Once the filling is completed, you need to wait several weeks until the screed is completely dry. You can cover the floor with film.

Another important stage is the installation of expansion joints. They are needed to level out changes in screed size due to temperature fluctuations. They should be cut a day after pouring the screed in increments of 1500-2000 mm or with a room area of ​​no more than 25 m². After this, the seams need to be filled with sealant and sealed with mortar.

A day after the main work is completed, you need to remove the beacons and seal the seams using a cement-sand mixture.

The screed is ready and already on such a strong and reliable base you can lay any finishing coating.

By following all the requirements and laying the screed accurately and without errors, you will receive effective source heating If you are not sure that you are able to cope with this process yourself, you can always use the services of professionals who will quickly and efficiently complete the work.

A warm floor cannot do without a high-quality concrete screed, which performs a large number of functions during operation. But to do this, you should familiarize yourself with the general structure of a heated water floor, and also find out what the minimum thickness of the screed above the heated floor should be so that it meets all the requirements and technology.

Purpose

Underfloor heating will affect the performance characteristics of the entire system, as well as its ability to operate effectively under external loads. It should be understood that the layer must be optimal and comply with the manufacturers’ recommendations if a ready-made construction dry mixture is used.

If a very thin one is installed on the base of the floor, then it will not be able to last long. In addition, there will be a very rapid heating of the surface and a rapid cooling process. She won't be able to bring any benefit. Taking this into account, especially if the room constantly has loads not only from movement, but also from the furniture located, then the minimum underfloor heating will very quickly crack and lose its appearance. This will also lead to damage to the floor covering that will be laid on top.

Thick fill layer concrete mortar it will also not be able to demonstrate all the qualities of a warm water floor system. Warming up such a design will be very difficult and problematic. There is a high probability of failure in some areas. All this will cause large financial investments to pay for heating. After all, a large amount of energy will be required for the heat to pass through the thick layer of screed and warm the base of the floor in the room.

It cannot be said that there are universal indicators for installing a heated floor system. The fact is that here it is worth taking into account some factors, such as the type of base, the configuration and area of ​​the room where the work is being carried out, as well as its purpose. After all, the load in residential premises will be significantly less than in industrial ones. Therefore, in the latter case it should be somewhat larger.

Difference from a regular screed

A regular screed is somewhat different from a screed for a warm water floor. The fact is that in its latest form it is mandatory to arrange expansion joints. Even in rooms with a small area of ​​up to 10 m2 they should be present. In addition, a depreciation strip should be installed, which is laid along the bottom of the wall. This is all necessary to compensate for thermal expansion during operation of the warm water floor system.

For larger rooms, additional seams are also made. Here, the compensation function is performed, in addition to the tape, by thermal insulation for the walls. In this case, the thermal insulation must have a heat-repellent foil.

Number of screeds for heated floors

At first glance, a very strange question is about how many ties should be installed for the system. In addition to the rough screed, optimal screed for heated floors over pipes. The last layer will serve as the basis for finishing floor in the room. An alternative to a rough screed is a floor slab. But in this case, it should be almost perfectly smooth and without defects. Otherwise, you will have to arrange a layer for leveling.

It must be mounted on the base without errors. It should be smooth. This is necessary so that the pipeline is subsequently evenly distributed in the concrete screed for finishing.

Components of a heated floor

The entire underfloor heating system, together with the screed, has a certain thickness, which must have optimal parameters. In this case, you should first decide what is included in the subfloor heating system and how thick each layer can be.

Pouring composition

First, you need to decide on the brand of cement for the mortar. It should be M200-M300, depending on the purpose of the room itself. In addition, the composition can be included to avoid the appearance of cracks on the surface after pouring, as well as for better distribution over the base. When installing a screed under a warm floor, the thickness must meet all requirements and recommendations. Usually it is 50-70 mm. The start of the fill level comes from the top of the system pipeline. Manufacturers of dry mixes for preparing concrete mortar can also advise on optimal parameters. This should also be followed during installation.

Instead of plasticizers, “folk” remedies in the form of PVA glue can also be used. Such methods were applicable 15-20 years ago, when technology was not so well developed. It is worth noting that the cost of various ones is currently not so significant and you can afford to purchase them. In addition, their consumption is not large per volume of concrete solution. In this case, the thickness of the screed above the heated floor pipes can even be slightly reduced due to improved strength characteristics.

Minimum parameters

Building codes and regulations provide minimum limits for pouring concrete screeds. This is stated in relevant documents. But not everyone knows how thick a screed for a warm water floor can be.

The minimum underfloor heating should be 20 mm if self-leveling mixtures without a reinforcement layer are used in the work. If this is a classic concrete screed, then at least 40-60 mm along with the reinforcement layer. True, metal mesh is not always laid on top of pipes. This is done if there is a desire to strengthen the entire structure and create reliable protection for the pipeline.

The minimum screed for can be considered for execution with a rough layer installed, when the base is leveled and adjusted to the horizontal level. In any case, the pipeline must be laid on a flat surface without errors or defects. You can talk about the minimum thickness of the screed over a warm floor if you completely forget about reinforcement. This layer should be skipped so that the distance from the ceiling to the floor is not affected. Currently there is alternative options metal mesh – . Adding a small amount of it to the prepared concrete solution will allow you to obtain the same characteristics without increasing the pouring layer.

The minimum layer of screed for a heated floor will not be suitable when loads occur during operation. This may be installed bulky furniture, Appliances etc. All this can damage the surface and render the floor covering unusable. So you should know what thickness of screed will be optimal for, and under what conditions it will be used.

Typically, a layer of underfloor heating screed of 60-70 mm will be sufficient along with any type of floor covering. This is where all the quality and efficiency in work will be evident. The floor will warm up in required quantity at minimum costs for heating.

Screed pouring limits

Above the water heated floor it can reach a certain height parameter while it performs its functions. Nothing is documented about this. No one advises choosing a screed thickness for a heated floor under tiles of no more than 15-17 cm. Otherwise, you will only waste money on purchasing the material, as well as time to complete the work.

The minimum thickness of the screed cannot be provided when creating monolithic design. That is, the screed above the heated floor pipes also serves as the foundation of the house. The situation is similar in specialized premises that are more of an industrial value (garage, warehouses, parking).

Since water heated floors are mainly installed in private buildings, this is where another problem arises - problematic soils in the base. If they are present, parameters such as minimum thickness screeds over water heated floors. The fact is that if a small fill level is created, over time it can collapse and affect all components of the structure, including the pipeline with the floor covering. The system is installed for years, therefore, care must be taken to create the necessary underfloor heating.

If there are significant surface unevennesses or large differences in heights, you should think about it to the necessary extent. All protrusions are knocked down, and the remaining areas are covered with dry material. Such manipulations are carried out before installing the heated floor.

Using a backfill layer allows you to reduce the cost of preparing a solution for a concrete screed. After all, every centimeter of pouring level requires a certain amount of concrete solution. The higher this figure, the higher the costs. One cubic meter for filling a room area of ​​10 m2 and a screed thickness for a heated floor of only 10 cm.

If the minimum screed of the heated floor did not work out, but reached the maximum limits, then it is worth remembering the difficulties and problems that will have to be encountered during the operation of the system. The floor surface in the room will heat up for a very long period. Funds will be spent on all this in order to “sink” the entire “pie”. Consequently, the efficiency of the heated floor will be reduced to a minimum or there will be nothing at all. So, when performed, the optimal thickness should be selected as far as possible.

Everyone wants an answer to which one over the water-heated floor will be the most suitable. In any case, it is impossible to get a definite answer here. To do this, the base of the floor, all requirements for pouring, as well as operational characteristics are studied. There are tips from experienced craftsmen who claim that compliance with the following conditions will achieve maximum effect from organized system warm floor.

The system of warm water floors involves installing a screed on top of heat exchanger pipes, which serves as the basis for laying floor materials. Many people are interested in what the minimum thickness of the floor screed should be so that heat transfer occurs as efficiently and quickly as possible, while the strength of the concrete base is sufficient to withstand the expected loads on the surface. To fully understand this issue, it is worth considering various options, both in terms of the characteristics of the heating system itself, and the materials used to construct the finished floor base. The recommendations set out in this regard in SNiP, as well as some video materials, will help with this.

Layer-by-layer design of water heated floor

To do the right system underfloor heating, you need to create several successive layers. From bottom to top, the pie of a warm water floor should look like this:

• rough base;
• waterproofing;
• thermal insulation;
• complex reinforcement plus heating pipes;
• finishing screed;
• finishing floor material.

Thanks to the creation rough foundation Primary leveling occurs, which allows the finishing fill layer to be made uniform. Moreover, the rough screed should be used not only when laying the floor on the ground, but also on the floor slab in apartments. If basic leveling of the base is not done, the final layer of concrete may be very uneven, which will affect the quality of the floor heating. What a heated floor pie looks like is clearly demonstrated in this video

Functions of finishing screed for heated floors

The finishing base is created for the following purposes:

• reliable protection of pipes from mechanical influences;
• heat transfer to the surface and its uniform distribution.

To accomplish the first task, the screed must be thick enough, and therefore strong. However, if the finishing base is too high, the second function will not be fully fulfilled. Therefore, it is important to create a layer of optimal thickness.

How many centimeters should it be upper layer sand concrete depends on several factors, such as:

• type flooring material(tiles, laminate, parquet);
• diameter of underfloor heating pipes;
• underfloor heating tasks (main heating or addition to radiators);

At the same time, we should not forget about the requirements for the finishing base, which are indicated in SNiP and are recommended for mandatory implementation.

Minimum allowable thickness

What is the thinnest screed over underfloor heating pipes? It depends on some factors. Let’s say that SNiP indicates a thickness of 20 mm, but this is in the case of using a metal-cement composition when constructing the base. The document does not say anything about what to do with other solutions, sand concrete, or semi-dry material. However, SNiP contains another norm, which determines that the minimum layer of screed over pipe communications laid in the floor (refers to cement mortars, such as classic concrete, or semi-dry sand concrete) should be at least 4 centimeters. If you add the cross-section of the pipe to this, you get 6-7 centimeters. This is exactly what the optimal foundation should be, according to the requirements of SNiP. In practice, it is precisely this thickness that is used to make the finishing screed over the pipes. You can see how this happens in the following video.

When watching the video, you will notice that the screed is of uniform thickness (visually, about 6 cm) over the entire area of ​​the room.

Nowadays, sometimes the upper base of a heated floor pie is made using self-leveling mortars that have increased strength. When using such materials, the screed is made minimal, that is, so that it slightly covers the pipe communications. Typically, this method is used if the flooring material is intended to be tile. Tile laid on a layer of tile adhesive gives additional strength to the floor surface.

The thickness of the layer over an electric heated floor system is determined in a completely different way. The heating cable is much stronger than the pipes used in water circuits, therefore the top layer of the screed in this case carries much less protective function. Moreover, the heated floor, made electric cable or mats, in most cases it is used for subsequent laying of tiles. For these reasons, the thickness of the screed when installing electric heating floor does not exceed 1.5 centimeters.

Important! Whatever the thickness of the finished base, a deformation gap should be left between it and the wall, where the damper tape should be placed. At large areas In addition, expansion joints must be made when filling.

Maximum thickness of finishing base

SNiP says nothing about how many centimeters the maximum layer above a heated floor system can be. greatly exceed optimal thickness Screeds in residential premises (house or apartment) make no sense. This will lead to the following negative points:

• excessive consumption of materials, therefore, increased costs of measures associated with the installation of warm water floors;
• increasing the inertia of the surface heating process;
• reduction of useful living space.

Typically, an increase in the layer is associated with the need to level the surface or create a floor at the same level in adjacent rooms. It is better to do this using a rough screed. A top base of different thickness will result in uneven heating of the floor. Although this situation will not greatly affect energy costs, since the screed is floating, that is, independent of other structures. So it will give off as much heat as it receives from the heating pipes. The uneven thickness will only affect the inertia of heating of the floating subfloor.

Important! It is necessary to greatly exceed the layer of finishing screed over water underfloor heating pipes in those rooms where the load on the floor can be significantly increased (garages, other technical buildings). When installing the base in living rooms You should strive to create a uniform layer of optimal thickness.

Warm floor is complex design, 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 the quality of the 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 insulating layer is usually made up of two complementary materials: for these purposes Styrofoam will do and reflective material. Polystyrene foam protects with a layer of 3 cm 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. For this they use 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? Located under the screed 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 very difficult and labor-intensive 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 performs a protective function in relation to the pipes laid below, and therefore 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. The minimum height of the screed above the 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? Screed thickness ready mixture determined according to the instructions supplied 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 are laid on an exceptionally flat surface, so 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. Ready self-leveling mortar It 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.