Screed on a wooden floor under a tile: how to fill it. How to make a screed on a wooden floor and as far as possible Concrete floor over wooden beams

23.06.2020

Flooring made of wood is extremely rarely covered with a concrete mixture for leveling. Many experts argue that the use of heavy monolithic slab on a wooden platform there is no point. This is due to the incompatibility of the wooden base and concrete. Masters recommend using dry leveling methods. But if a floor screed is necessary for the further installation of tiles, it should be done on a wooden base, but some nuances should be taken into account.

Features of working with wood flooring

Wood is a material that has some negative properties. She is not static; even after the lumber is laid, they will exist according to their own laws. Changes in moisture and temperature levels cause the wood to change its volume, decrease or increase in height and shrink in linear measurement. For these reasons, having built a wooden house, they do not carry out fine finishing work in it for several more years.

Wood flooring in need of pouring

How to make a screed on a wood floor tile? It is important to remember that repairing the floor in a wooden house can be problematic. Indeed, after a certain period of time, the surface begins to creak and lose evenness. Various other damages are also possible. To reduce the time of repair work, you can leave the old coating on. But if you correctly understand how to make a screed on a wooden floor, then there will be no problems.

Before you perform such a coating, you need to know that there are several options:

standard pouring with concrete mixture;
dry method.

The second option has the following advantages:

light weight;
convenience during installation;
the ability to immediately correct deficiencies;
no "wet" effect;
cement dry screed does not need to dry.

You can also highlight among the pros and cons:

reducing the height of the room, as a greater thickness is required;
due to the significant thickness, more material is consumed compared to the conventional method.

Depending on what conditions exist, you can make a choice in favor of one of the options. The concrete screed is made using a technology that includes the so-called non-cohesive screed, which ensures the elimination of possible wood deformations.

Incoherent screed on wooden surface

Pour cement mortar recommended only when there is a need for flat surface with fixed hard floor materials. Such a screed can be used when constructing a warm floor, although the opinion of the masters on this matter differs. This is due to the fact that the tree can be deformed when exposed to moisture or different temperatures when the underfloor heating system is turned on or off.

Therefore, the question often arises whether it is possible to make a screed on a wooden floor. First you need to weigh all the pros and cons. If, nevertheless, a decision is made to perform a screed, then it is necessary to follow the recommendations for such work:

carefully inspect the condition of the base, cover it with a special primer containing moisture-proof components;
make a waterproofing layer using polyethylene film, laying it with an overlap;
install beacons;
prepare concrete mix for screed;
lay out the prepared solution to a height of at least 5 cm.

Styling features

Pouring screed on a wooden floor has the following features:

the weight of the solution must be sufficient so that the fit to the floor is tight;
the screed itself should not be tied to a wood surface (the film layer will prevent this);
it is not recommended to pour the solution on the wooden flooring, but only on the waterproofing layer;
it will be good to lay the DSP board first, prime it and only then mount it flooring;
during the preparation of the mixture, plasticizers should be used to ensure mobility, high strength and plasticity.

Screed by wooden lags can be practical in case of using tiles or underfloor heating. It can deform during solidification. Subsequently, no changes occur with such a surface.

The subtleties of the screed device

The essence of the concrete method on a wooden floor is that it is necessary to isolate each layer separately. Therefore, the concrete screed is separated from the walls in the room with a special damper tape, and from the base - with insulating material.

As an insulating material, you can use a polyethylene film, roofing felt or special bituminous mastic. Recently, there are also many roll materials or parchment.

Although polyethylene film creates the greenhouse effect, but it still has some advantages for concrete screed:

she has smooth surface, which does not cause adhesion to the concrete base;
in case of shrinkage or deformation, the screed that is not bonded to the film does not pull it along;
an undamaged insulation layer does not allow moisture to be absorbed from concrete that has not yet hardened;
in order to avoid the negative impact of polyethylene on a wooden surface, all elements should be coated with an antiseptic and it will not be superfluous to apply a water-repellent primer.

Device Technology

If a screed on the floor along the logs will be used, you need to know that the process technology consists of several stages. Fulfilled first preparatory work which should include:

removal and inspection of the board;
replacement of damaged or cracked ones;
inspect the logs, if there are unreliable - replace new ones;
it is important to check the distance between the lags, it should be no more than 40 cm;
if the interval is greater than necessary, additional beams must be applied to increase bearing capacity flooring;
fix the floorboards in place;
if the board is damaged only on one side, it can be turned over to the other side;
fill the gaps between the boards with sealant;
after hardening of this agent, you can treat the surface with a primer and give time for impregnation;
make marks on the wall of the room using a laser level.

When determining the height of the screed, it is important to consider that each centimeter of the concrete layer presses on wood weighing 100 kg. If necessary, make a thick screed beams need additional reinforcement. It can be made from a metal channel.

Installation of insulation

At this stage, you should make a waterproof container from special material under poured concrete. Therefore, you need to do the following:

around the perimeter of the entire room along the walls, attach a damper tape or replace it with a strip of foamed polystyrene;
double-sided tape can serve as a fixative for this material, or you can fix it with a construction stapler;
it should be fixed a few centimeters above the screed, it will serve as a soundproof barrier, except for deformation movements;
the ends of the tape sticking out to the sides should be cut off;
lay a plastic film with an overlap of 10 cm on top of each other;
fasten the joints of the parts of the film with adhesive tape;
lay the films in such a way that the edges go onto a wall 15 cm high;
the prepared screed solution can be poured into the resulting container.

Implementation of the waterproofing layer

The film in this case should not be damaged or contain holes. If such are observed, they must be sealed or soldered.

Execution of beacons

Guide beacons should be laid on the floor. It is strictly forbidden to fix them with nails or self-tapping screws to the surface. They should be attached to a solution laid on the floor in rows or small cakes. From the wall, the first beacon should be at a distance of 20 cm, the guides relative to each other should be located at intervals of no more than 1 m, the main thing is that the size of the rule is not exceeded.

Installation of beacons

Metal plasterboard profiles can be used as beacons. If they are placed on mortar cakes, this will greatly facilitate the installation of a clean floor. The lighthouse must be pressed to the floor so that it sinks into concrete mix, and then check with a level to refine evenness.

It is important to achieve the required mark. To make the solution harden faster, you can add alabaster to it.

Reinforcement of concrete screed

So that a floating screed arranged on wooden floor, was of high quality, additional reinforcement should be performed. This is especially necessary when the screed exceeds a height of 5 cm. Most often, you can see that the reinforcement is made using thick wire, reinforcement or metal mesh.

Reinforcement screed on a wooden surface

But if the floors are installed on logs, then you need to use a slightly lighter material that does not additionally load the screed. Metallic materials may break through the insulation layer when pouring occurs. For this reason, it is best to use fiber as a reinforcement material. It must be added to the solution during mixing. Fiber fibers, randomly located along the screed, make it strong in all directions.

Filling the mixture

Concrete pouring can be done in two ways.

If the filling should be done in a large room, then it is better to divide the entire area into small squares. Separate them with formwork and pour each card separately. In this case, breaks in work can be allowed. Pour in several approaches.

Pouring a wooden floor in parts

Fill in small room can be done in one go. The process should start from the far corner. During work, it is not allowed to take a break to get a smooth and beautiful surface. This job is best done by two people. While one is leveling the poured solution, the second is preparing the next portion.

Each portion of the solution must be laid a little higher than the lighthouse, and then level it with the help of the rule. Lay the rule on the guide strips and pull it while moving it sideways to even out the mixture.

Filling the mixture

Lighthouses the next day can be removed from the solution, and the traces of them can be treated with a primer and filled with a freshly prepared solution. For the first week, the surface of such a screed must be sprayed with water and covered with a film so that the moisture evaporates evenly. After that, you can apply a floor covering or some kind of coloring composition.

How to make your own screed on a wooden floor, you can see in this video:

Wooden floors, if the right materials are used for their installation and if they are properly installed, can maintain their strength and stability for decades. Sometimes the question arises of laying concrete screeds directly on such floors. Why is there such a need? They think about a concrete screed in cases where they strive to perfectly level the floor in order to lay some kind of coating on it ( ceramic tiles, layer polymer materials). The same method is used when a complete wooden floor is too expensive.

Wood, which has a lot of technological advantages, is also known for one significant drawback that should be taken into account when working with it. This disadvantage is that it does not have static nature: even after the construction is completed, the wooden elements continue to “live” guided only by their own laws. Changes in humidity levels and temperature regime cause:

increase or decrease in volume wooden parts and elements;
their shrinkage in height;
increase or decrease in their linear dimensions.

This feature of the tree determined the rule that builders involved in the construction of wooden structures are always guided by: fine finishing of log cabins should be carried out no earlier than two years after their construction. As applied to our topic, this rule should be interpreted as follows:

It is strictly forbidden to pour concrete mortar on a new concrete floor. Concrete screed can be laid only after 3-4 years after the completion of the floor installation.

The mobility of wooden floor structures increases when any heating systems are laid under them. Each start-up and shutdown of such a system will cause them to move slightly.

When comparing mobility wooden structures with mobility concrete slab, which is formed when laying the screed, it should be noted that the geometric dimensions of the latter change only during hydration. When the hardening of concrete ends, the dimensions of the monolith practically do not change. Such a difference in the behavior of wood and concrete in the event of their tight contact can cause cracks in the screed. Moreover, in such a case, it may even crumble completely.

The technology of leveling, produced without connection with walls and with a wooden floor, which we will discuss below, allows each of the elements - floor boards and screed concrete - to exist, obeying only its own principles and without harming its neighbor.

Materials required for work

If an assessment of the condition of the wooden floor and other related conditions has led you to the conclusion that a concrete screed is really necessary and that it is quite possible to make it, it is necessary to prepare in advance the materials that will be required during the work.

When preparing, it must be remembered that the mass of the fill must be sufficient to guarantee the tightness of the junction of the screed to the boards. but big weight the concrete used can cause subsidence of the floor, bending, and then the destruction of the laid screed.

If the condition of the floor tells you that this course of events is quite possible, when preparing the concrete mix, you should use a plasticizer that will give the concrete some mobility while maintaining its integrity. An additional advantage of plasticizers is that these substances can have a positive effect on increasing the water resistance of the screed, which will be an additional protection for wooden structures.

And so, the list of materials required for laying the screed includes:

cement and the required amount of plasticizers;
the film needed to separate the concrete from the surface of the wooden floor;
sand;
any suitable sealant;
epoxy or other suitable putty;
primer with a water-repellent effect;
metal mesh for reinforcement.

During preparation, you need to make sure that there are no breaks on the purchased film. Since the film should be laid overlapping, and its edges should rise slightly to the plane of the walls, when calculating its amount, at least 15% should be added to the area of the room.

You should also remember about the tools that will be needed in the course of work. In particular, you will need:

spatula with which putty and sealant will be applied to the floor;
hammer and screwdriver to strengthen the floor with nails or self-tapping screws.

Preparing the surface of wooden floors

A concrete screed can be applied to the floor only if its surface is completely ready for this. When preparing it, you should carefully examine each floorboard to make sure that they are free of rot and cracks. All boards must be securely fastened, there should be no gaps between them. Boards with major damage are removed and replaced with new ones. If it becomes necessary to interrupt the floor, then the nail heads should be recessed. The resulting recesses must be carefully puttied.

When preparing the floor surface, you must:

fill with putty and, if necessary, mounting foam all the gaps on the floor;
process wooden elements using sealants;
after drying all the substances applied to the floor, clean it of debris and treat it with a moisture-resistant primer;

when the primer dries, roll out the film with an overlap, so that it goes fifteen centimeters onto the plane of the walls. Excess film must be cut off. Fixing the film, if necessary, should be done with adhesive tape. The use of nails to fix it is unacceptable. To achieve a better result, a reinforcing mesh can be laid on top of the film.

In the video below, you can see how the film is properly laid on the surface of a wooden floor:

Having completed all these operations, you should start applying the preparatory markup. One of original ways markup is presented in the following video:

Directly on the film covering the floor, with the help of concrete, rack beacons are strengthened, the distance between which should not exceed the size of the rules used when leveling the concrete solution.

Concrete screed and the process of pouring it

Pouring is preceded by the manufacture of concrete mix. For its preparation, clean sand and cement grade 400 are taken in a ratio of 3: 1. The solution is prepared on the basis of water with the addition of special plasticizers or similar substances. For mixing, you can use plastic container big size and a drill with a mixing attachment. After mixing the solution, it is necessary to let it settle, and then mix it again.

If the thickness of the screed does not exceed 1 cm, then the consumption of the concrete mixture will be about 15 kg / m 2. Pouring the solution should be done, focusing on the beacons. Filling the entire floor must be done at the same time. Partitioning is not allowed. During the pouring process, air bubbles present there must be removed from the cement mortar using a spiked roller. Leveling the mixture poured onto the floor so that concrete screed turned out to be even, carried out using a wide spatula or rule.

The techniques for leveling the screed on wood and concrete floors are similar, so the following video can be used to learn more about the techniques used:

The drying time of the laid screed is 28 days. During the first two days after laying, it should be moistened with water three times a day. After that, the beacons are removed, and the surface is primed and rubbed. After a month, the concrete screed is completely ready for full operation.

In the video below, although it is not in Russian, you can perfectly see all the schematically presented steps for laying a concrete screed on a wooden floor.

Screed on a wooden floor under a tile can serve good decision for those who want to equip a bathroom or kitchen, and will also be appropriate for underfloor heating equipment.

Screed on wooden floor – not the best building solution, but with the right approach and certain conditions, you can successfully use such a connection in a wooden house.

What are the screeds?

The screed is upper layer on wood or concrete floor, which is further finished with a floor covering.

There are the following types:

Dry.
Cement.

In the first case, when using this type of screed, the surface becomes resistant to various loads and becomes high-strength.

It is made of drywall, moisture-resistant plywood or PVC sheets by laying on expanded clay or quartz sand. This type of flooring is the most suitable for a wooden floor.

A cement or concrete screed on a wooden floor is used as a base for a polymer coating or ceramic tiles.

Thanks to her, the process of leveling the floor from wood takes place. The owner of the premises can fill it himself.

Pros and cons of screed

Dry screed will correct mistakes

Dry screed has several advantages:

simple manufacturing;
if it is available, it is convenient to lay communications;
easy to fix mistakes;
no need to wait for drying.

However, it has some imperfections:

sometimes a significant thickness is necessary, while the height of the room decreases;
there is an increase in material costs.

With a poured concrete screed, the material consumption is small, but it takes a long time to wait for it to dry.

In any case, it is worth making a choice in the direction of one or another material. The right decision will avoid further problems with other coatings.

Working conditions

How to make a screed correctly and follow all the stages of its construction? Concrete pouring under ceramics on wooden floors must be constructed in the correct sequence.

Characteristic steps before pouring

Before pouring the screed, check the wooden floors, repair defective places

An indispensable condition for the manufacture cement screed on the floor and applying tiles is to identify the life of the tree, which should be at least three years.

The reason for this is the ability of wood to dry out and deform over time. It will take from 2.5 to 3 years to “calm down” it. Movement can occur after this period, but not so clearly.

The option, if the floor is not new, provides for:

a thorough inspection of the floors and the floor itself;
identifying weaknesses and major faults;
selective replacement of damaged parts;
sealing cracks and crevices with special means;
removing the plinth and replacing it with wooden slats;
floor sanding and debris removal.

After pouring an ordinary screed and drying it becomes a monolith, which cannot be said about concrete on wooden floors. It will be possible to remove irregularities and increase the strength of the floor, but it will not work to get rid of the main flaws.

What is the best way to apply?

Between the tree and the monolith, it is necessary to lay a moisture-proof layer

For greater reliability, the method of "incoherent" screed for a wooden floor is used. At the same time, its isolation from the floor covering and walls is observed.

The floor is leveled first. A moisture-proof barrier is created between the moving part of the floor and the monolith.

For this it is used:

thick polyethylene film;
material in the form of a damper tape, which is fixed at the bottom of the wall and floor;
expanded polystyrene;
ruberoid;
material impregnated with bitumen.

Related article: Installation of fixtures in plasterboard ceiling

Wood must be treated with an antiseptic and a layer of waterproofing, preferably from bituminous mastic. Then you can lay the film, leaving a ledge of 20 cm on the walls and be sure to make overlaps. They are glued with adhesive tape, they achieve a complete absence of joints, holes and wrinkles. About how to make a screed on wooden base see in this video:

The advantages of a "non-cohesive" screed

Similar moisture barrier board:

is floating;
cut off from the plank base;
makes the screed independent of changes in temperature and humidity.

What should be the solution?

Use brand M 400 for screed

Self-leveling compounds must be included in the concrete mortar for screeding on a wooden floor. But the basis, of course, is cement and sand of the M400 brand.

Fill preparation steps:

Pour 25 kg of dry mixture with 6 liters of water;
mix by hand or with a mixer;
to achieve a homogeneous mass;
follow desired temperature solution, it should be at least 10-15 degrees;
can be used warm water if the room is cold;

To achieve the strength and water resistance of the solution, you can add special plasticizers to it in the proportions indicated on the package. The option with the addition of a simple washing powder one handful per 100 liters of water.

The process of implementing a cement screed on wooden logs

Sometimes in wooden houses or old apartments, a concrete screed over wooden logs may be necessary.

Due to the fragility of the tree, the structures need to be strengthened.

This is done by setting metal frame or mesh, as well as a channel.

Before the construction of the frame, a heater made of expanded clay, perlite or other materials with low thermal conductivity is poured into the space between the lags.

Sufficient density and elasticity of the solution must be achieved by adding polystyrene, vegetable fibers and other necessary components. Such additives will also perform the role of sound insulation.

When repairing a house or apartment, the master may encounter the problem of a wooden floor. Over time, such coatings become creaky, lose evenness. It is also possible the appearance of various damage. To shorten the duration repair work, it is best to lay the new floor without removing the old wood floor.

To level the base, a screed on a wooden floor, laid under the tile, is perfect. It is important to consider this option, since installing tiles is the most difficult task for a wooden floor. The material is characterized by high density and has a strong effect on the underlying structures. If you understand how to make a screed for tiles, there will be no problems with the rest of the coatings.

How to make a screed

There are two work options:

The second option is more suitable for a wooden floor, as it has the following advantages:

But you can also highlight the disadvantages for use in the house:

Depending on the conditions, requirements and wishes, you can choose between two options when laying the material under the tiles.

Work production technology

To do a coupler under a tile on wooden floors follows in strictly established order. When repairing a house, you first need to inspect the structures of the ceiling and floor. Identify weak points, make sure that there are no serious damages. If traces of decay, mold, fungus and other microorganisms are found, it is better to selectively replace the wooden floor elements.

Scheme of preparing a wooden floor before laying tiles, part 1

Scheme of preparing a wooden floor before laying tiles, part 2

Using a screed can eliminate irregularities and strengthen the surface before fixing the floor covering, but it will not work to get rid of serious defects. The base for the tile must be even and strong, as it will have to withstand heavy loads. To prevent problems during operation, it is better to do timely replacement and removal of old boards in the house.

After inspecting the old floor, you can proceed to the main task. It is recommended to fill a classic wet screed in the following order:

If earlier there was a cement screed on the floor, it is removed by grinding or milling.

Checking the reliability of fixing the floorboards to the joists. If they do not have a secure fixation, a creak will appear during operation. To prevent this, all elements of the old floor must be securely attached to each other.

This is followed by cleaning the surface from old contaminants. You will need to remove grease, traces of glue, old paintwork, various impregnations, dirt and dust.

If necessary, sand the surface of the old floor with a special machine. In this way, the top layer is removed, the base under the tile becomes smoother.

If irregularities with a height difference of more than 1 cm are detected on the floor, preliminary leveling under the tile must be done. To perform the work, you can use various leveling mixtures based on cement binder. The surface of the boards is covered with the composition, cracks can be repaired with putty. Water-soluble compounds for puttying cannot be used.

Instead of skirting boards, slats are mounted along the perimeter of the walls, which will cover the distance between the old floor and the wall. Thin slats are installed with subsequent puttying. This rail is removed after completion of work. With its help, a gap is provided that will allow air to enter the space under the floor. For wood flooring this is extremely important, because if you do not take measures for ventilation, the wood will rot and cause trouble during operation.
The leveled surface must be primed in accordance with the technology of this process.. For priming, buy a ready-made mixture. A layer of this material will not only increase adhesion, but also improve the spreadability of the mixture for pouring the subfloor over the surface during repair work. When processing, the floor must be dry, the work is performed twice.
Having finished with the previous stage, you need to lay a reinforcing mesh under the tile. The diameter of the elements is assumed to be 3-4 mm. The cell dimensions are 50 by 50 mm. This stage can be neglected, but it will provide greater reliability of the base and the ability to withstand higher loads.
When preparing the solution, the proportions must be observed. It is better not to make it yourself, but to buy a ready-made dry mix, for the preparation of which only water is required. This will avoid mistakes when choosing the proportions of the components and reduce the complexity of the process of pouring the screed.
The mixture must be applied in one go. If you perform work in several stages, the layer will not work as a whole, cracks, tears and irregularities will appear. Notched trowels are used for application. Control the thickness of the application using guide beacons or marks on the surface of the walls.
After completing the laying of the mortar, it is necessary to let the concrete suffice. This process at normal conditions takes several hours. After this time, you can carefully walk on the floor, but for full use it will be ready no earlier than in a couple of weeks (in the summer, for the winter season, the terms increase).
They take out the slats installed around the perimeter of the walls instead of skirting boards. After that, if necessary, grinding can be done (not earlier than 6 hours after pouring).

To reduce the repair time in a house or apartment, it is better to lay a new floor covering on top of the old one. It should be borne in mind that the old wooden floor is often uneven, and the surface is leveled before laying the tiles. To do this, you need to equip the screed. It is made using two technologies: standard concrete pouring and dry method. Let's consider them in more detail.

dry base

For several reasons, this technology is most preferable when working with a wooden floor:

ease of manufacture;
low weight of the structure;
good sound insulation;
ease of laying communications;
opportunity to correct mistakes;
no wet processes.

On a note! The last point means that when using the dry method, you do not have to wait for the floor to dry (unlike the process of creating a cement base).

This method also has several disadvantages. Such a screed on a wooden floor should be thicker than concrete (which reduces the height of the room). The consumption of materials will be higher than when creating a classic base for flooring. Dry base should not be done in rooms with high humidity, since the backfill draws in any vapors.

As a backfill, you can use:

expanded clay;
vermiculite;
perlite;
compavit.

Expanded clay is the most common filler. It must be clean (without dust and sand), otherwise the floor will start to creak very quickly. Suitable size grains - no more than 0.5 cm, they should be approximately the same size (otherwise, smaller granules will fall between large ones, this may cause the flooring to sag). The minimum thickness of the expanded clay layer is 3-4 cm.

On a note! If the material is not defective, the expanded clay granule in the section should be porous. To make sure of their quality, expanded clay granules should be bought in bulk, and not in closed bags.

Work production technology

Before starting work, evaluate the condition of the ceilings and the existing flooring. Weak and damaged areas, rotten and moldy elements must be replaced. To do this, it is worth using the most dried parts to avoid rotting wood in the future.

If the boards sag, this can be corrected by laying additional logs. Nail heads that stick out above the surface must be deepened with a punch. Large irregularities can be cut with a scraper or planer.

How to make a screed?

The technology looks like this:

Stretch a layer of insulation (film) over the entire area of \u200b\u200bthe room, it must necessarily have a slight overlap on the walls (above the level of the future coating);
Take the edge tape and create a damper seam around the perimeter of the room;
Fill the space with insulating and leveling dry material and evenly distribute it over the design thickness;
Lay a gypsum fiber sheet over the backfill (this should be done without creating cruciform joints);
Next, lay the second layer of GVLV so that the seams of the first layer do not overlap the seams of the top one.

Important! The quality of the dry backing is highly dependent on how the first fibrous sheet was laid. Avoid the slightest distortion and digging into the backfill. It is better if you do this with the help of an assistant.

Classic floor screed

If you decide to go the traditional route of pouring the concrete base for the tiles, you will need to do the same preparation as you would with dry tech. Check the overlap and the condition of the boards, eliminate weak elements and irregularities, cover the cracks with epoxy putty.

On a note! Large cavities can be blown out with self-expanding foam and covered with a moisture-resistant acrylic sealant. Ideally, after the putty and sealant have hardened, the entire floor area should be treated with a waterproofing compound.

Preparation for pouring

Cement screed on wood floor needs the same preparatory activities, as well as dry:

Spread a plastic film over the entire surface (with an overlap on the walls of at least 20 cm, you can fix it edging tape or tape), avoid wrinkles and bubbles;
Install beacons. To do this, lay slides of thick cement mortar on the film and fasten metal perforated slats on them;
Align the lighthouses with a level (add or remove mortar from the cement slides);
Make reinforcement. This can be done in two ways. The easiest is to add fiberglass or steel fiber to the solution (the strength of such a layer will increase as the cement hardens). Another method is associated with the installation of a continuous reinforcing mesh, which is laid on a layer of polyethylene under the supports of the lighthouse rails.

Important! In some cases, the thickness of the cement-sand layer may exceed 10 cm, which means that the logs and ceilings will be subjected to high loads. Before you build a tile cushion, consider reinforcing the floor further: residential buildings the lag laying step can reach 90 cm, it makes sense to reduce this distance to 40 cm.

Pouring and drying

The concrete base is poured onto a wooden deck according to the following algorithm:

knead the cement mortar (M400 cement and sand in a ratio of 1:3 or 1:4), or use a ready-made mixture (the main thing is to ensure sufficient fluidity of the composition);
fill, evenly distributing the solution between the beacons and avoiding the appearance of air voids;
take the rule and level the surface with the beacons;
leave the filling to dry for 48 hours;
remove the beacon rails and fill the voids left after them with fresh mortar;
perform the final leveling of the surface with wet half-tracks.

Filling must be done in one step. If we divide this process into stages, the screed will turn out to be heterogeneous, which can lead to the rapid appearance of cracks, gaps and irregularities.

Apply the solution to the surface with a notched trowel, control the thickness of the layer by beacons or marks on the walls.

On a note! Concrete must gain strength before final curing. Therefore, you should slow down the drying process. To do this, moisten the surface and cover it with polyethylene. The solution will gain brand strength within 3-4 weeks. During this period of time, it must be moistened at least once every two to three days.

Just a couple of weeks after filling concrete base you can walk carefully, but it is better not to rush with laying tiles. Keep in mind that in the cold season the solution will dry more slowly. When it has completely hardened, cut off the film protruding along the edges and finish the surface leveling with a grinder. After that, you can lay a new floor covering.

Summary

Even if you are planning to use a different flooring, it is important to screed the wooden floor under the tiles. It is a high density material and has a strong effect on structures below. Having dealt with the tile, you can easily cope with other materials.

Remember that screed is designed to eliminate relatively small irregularities and reinforce the surface before installing the tiles. To get rid of serious defects, you will have to replace the old boards or completely dismantle the old coating. Neither the concrete nor the dry base should move during operation. For a more complete picture of the technology of work, watch the video about the arrangement of the screed.