What will happen if the screed is made 2.5 cm. How to make a floor screed - a step-by-step self-filling technology

The screed is an intermediate layer between the subfloor and the finished floor covering. It is designed to level the subfloor. Without pouring this layer, major repairs in a private house or apartment will be of poor quality. If you need to know how a floor screed is made, the technology will be presented below.

The laying of the presented layer should be done only after you decide on its type. The screed can be classified as follows:

By production method:

Wet. For its manufacture requires a cement mortar with the addition of sand. You can cook it yourself or buy a ready-made mixture. In this case, the layer must be further strengthened with a reinforcing mesh. Optimal Thickness screed is about 10 cm;
Dry. It can be produced using special large-format sheets, 1.5-3 cm thick.

By type of connection:

floating. It is usually laid if a waterproofing film is used during the repair. This screed is about 3.5 cm thick or more;
Solid. It is firmly fixed on the base.

According to the materials of manufacture:

cement layer. It can be used both in an apartment and in a private house. The most optimal mixing ratio of cement and sand is 1:3;
Sand concrete screed. Fitting is done using ready mix, which can be purchased at a hardware store. The biggest disadvantage of this floor leveling method is the rapid shrinkage of the material. While working with the mixture, you need to monitor the thickness of the screed, as well as the uniform distribution of the solution. To maintain the integrity of the layer, it is necessary to strengthen it with reinforcement or fiberglass. To achieve maximum quality, the filling must be sprayed with water for 2 weeks. It will take at least 20 days to completely dry the layer;
Gypsum floor screed in the apartment. In installation, it is very simple, does not allow shrinkage, has good plasticity. A layer of small thickness is laid. At the same time, the plaster dries very quickly. The only drawback of this material is the impossibility of its installation in those rooms where high humidity is observed;
Screed using concrete mix. It is laid in the same way as cement. But a cellular concrete solution is added to the finished mixture;
. Since it is not difficult to make a screed of this type, it is becoming increasingly popular, especially in a private house. This layer is from 0.5 to 3 cm thick. But if the horizontal differences in the base are very large, then to use the mixture, you need to additionally make a rough screed (you can use a concrete mortar);
Plasterboard. In this case, rectangular sheets are used, which are laid with a slight overlap. Please note that such a screed does not require a long time to dry, and is equipped quite simply.

What will be needed for work?

The most common and frequently used material for pouring is concrete mortar. Before you make a floor screed, you need to collect all the necessary fixtures and materials. You will need:

Container for mixing concrete.
Drill with a special nozzle or construction mixer.
Hydraulic level.
Rule.
Master OK.
Roulette and marker for marking the area.

Some tools needed for pouring floor screed

Features of the preparation of the base

The floor screed device is not a very complicated process that you can handle on your own. However, first you need to prepare the foundation. First, the old is dismantled flooring. If the subfloor has already been filled with a cement or concrete screed, then it should be carefully examined. If there is no significant damage, then you can apply for pouring.

Small flaws are eliminated with a cement or concrete mixture. Convexity is better to grind off with a grinder or perforator. Further, the base should be cleaned of debris, remnants of the adhesive substance of the concrete mixture.

Priming improves adhesion between the screed and the floor surface. It is carried out in two layers with a primer for highly absorbent surfaces.

The thickness of the screed is important not only in the apartment, but also in a private house, especially if you decide to insulate. This indicative may vary depending on the selected materials and parameters of the room. However, it must also be borne in mind that a screed with an incorrectly selected thickness may be of poor quality.

Installation of lighthouses

Before you make a floor screed in a private house or apartment, beacons must be set. They will help to pour the solution as evenly as possible. Their installation involves the following actions:

Determination of the highest point of the floor using a hydraulic level. Please note that a small horizontal difference can be "winned" without additional pouring of a layer of concrete mortar. If it is too large and exceeds 8 cm, then an additional screed will only increase the load on the floors.
. Most often, for this purpose, a metal profile is used in a private house or apartment, although there is another option - oak slats;
Installation of elements. The distance between them depends on the width of the rule with which you will level the solution. The alignment of the beacons must be constantly monitored with a level. Further, the elements are fixed with a small amount of solution;

Please note that even if an additional substrate is needed under the profile, wooden bars cannot be used, as they are able to change shape under the influence of moisture. The following video will tell you in more detail and clearly about this stage:

Features of the preparation of the solution

If you use, then the mixture is prepared very simply. Combine 1 part cement grade M400 and above with 3 parts sand. You can also add expanded clay, which will achieve additional insulation. Next, all the ingredients are well mixed with a construction mixer. Water is added gradually. In this case, the mixture must continue to stir so that no lumps remain. The liquid is added as needed, that is, the solution should not spread quickly or be very thick.

If you choose a ready-made dry mix for work in a private house, then it is prepared in accordance with the description drawn up by the manufacturer. However, the standard preparation procedure involves the following actions:

V large capacity pour water at the rate of 1 liter per 5 kg of the mixture.
Pour the purchased material into a bucket and mix thoroughly. If you pour liquid into the mixture, you are unlikely to achieve High Quality solution.
Leave the resulting substance for a few minutes to infuse, and then mix thoroughly again.

Foundation pouring technology

The main stages of arranging a single-layer cement-sand screed for lighthouses

After all preparatory work you can proceed to the most important thing - filling. How to make a screed step by step:

Start work from the far corner, gradually moving towards the doorway.
The mixture just needs to be poured onto the area that is enclosed between the two beacons. At the same time, constantly try to control the level of the layer. At this point, the rule is applied.
After processing by the rule, the surface is rubbed with a trowel. Please note that the movements should be light, circular.

Note! The screed should be poured so that the work is completed in 1 day.

1 - Preparation of the base; 2 - Installation of beacons and damper tape; 3 - Preparation of the solution; 4, 5, 6 - Filling and distribution of the mixture; 7 - Removal of beacons from the screed layer; 8 - Filling voids with mortar; 9 - Finished floor screed

Naturally, after the completion of the pouring of the solution, it must be given time to dry. At a temperature of + 20 ° C, the mixture will be solid after 24 hours. However, this does not mean that it is ready for operation. In the first few days of drying, the concrete must be periodically moistened with water so that its surface does not crack. Lighthouses can be removed already on the third day. In this case, the formed pits are filled with a solution prepared in advance.

Now lay cellophane on the resulting base, pour sand on it, and water it periodically for 14 days. Then the film is removed, and the base is again wetted with liquid. The surface must then dry completely. That is, it will be ready for loading in a week.

Now you know how to make a floor screed. This process requires special attention and patience. Many factors must be taken into account, in particular the thickness of the layer. Leave your opinion about the article in the comments or share your experience of installing a screed in your home. And finally, a couple of very useful videos.

The arrangement of the floor screed is a process that, with a good repair, and even more so construction, no one can avoid. And in this process, a lot of dusty, dirty and wet work is usually done. After them, the screed should be left to “ripen”, “helpfully” moisten for several days and not walk on the floor for quite a long time. Not to mention the money spent.

To make the result pleasing to the eye, and the process to take place in an organized and fast manner, we suggest that you read this article, which will tell readers how to make a floor screed yourself. Moreover, there is nothing supernatural and prohibitively difficult in this, which we intend to convince our readers of.

Floor screed is an intermediate layer that is organized between any base and the floor finish. Why do you need a screed?

To give floors the required rigidity and strength according to expected loads.
To level the floor horizontally, or, conversely, to give the desired slope in some areas, for example, in showers.

No matter how funny it sounds, but the screed is sometimes made for thermal insulation, as some of its types are capable of this.
The screed in underfloor heating plays the role of a large radiator, therefore, we can say that it is needed for the necessary heat absorption and distribution.
For hiding items engineering systems: electrical wiring, heating pipes and floor heating coils, sewer pipes.

For shelter and protection of the thermal insulation layer from mechanical stress.

In some cases, the screed itself is already the floor finish. For example, in garages, any technical or industrial premises, where another coating will not be laid in the future. Then, we can say that such a screed - single layer .

In many other cases, ties do two-layer .

The first layer levels the surface horizontally, or gives the desired slopes. Usually it is performed from a cement-sand mixture or concrete. It is customary to say that the first layer is rough screed . On it in the future, you can lay tiles or porcelain tiles.
The second layer is called finishing screed . It already makes the surface perfectly flat, under top coat floors, for example, under a laminate, parquet, carpet. Very often, a finishing screed is performed , giving an ideal surface at correct application.

The screed can be laid on different grounds: compacted soil, concrete or even wood. Depending on the connection with the bases of the screed, you can divided into the following kinds:

Linked screed , which is characterized by the fact that it is firmly bonded to the previous layer. More often it is a concrete screed on a concrete floor slab. The necessary adhesion and uniformity of this design provide excellent mechanical strength. Such screeds can only be done in those rooms where the humidity of the base will not be high. They are used on the second and subsequent floors of various buildings.

Screed on the separating layer . Such a design should be at the contact of two various materials. For example, when a concrete screed is made on the ground. Or in the case when a gypsum or dry screed is laid on concrete. And also the use of a separating layer is mandatory if the humidity of the underlying layer is above the norm. Various delimiters can be used. roll materials based on bitumen (roofing material), polymer films or coating compositions. It is obvious that the screed will already be separate design, so it is desirable to reinforce it and make it at least 3-5 cm thick.
floating floor screed is a continuation of the previous one. It is necessarily arranged if any insulation is required. The floating screed is separated from the base by a layer of insulation along with waterproofing. It is also necessarily separated from the walls. It can be a heater, but of a smaller thickness or a special damper tape. Warm water floors are necessarily accompanied by a floating screed, since in addition to mechanical loads, such a screed will still change in size due to temperature effects. Working in such conditions forces the use of reinforcement and has a thickness of at least 5 cm.
Prefabricated or dry floor screed. In our country, this is a relatively new phenomenon, but in Europe it has been used for a long time. On the prepared and insulated base of such a screed, filler is poured in the form of dry bulk material. Most often used granular, which is a good heat and sound insulator. Sheets are laid on top of it gypsum fiber plates attached to each other. Such a screed is equipped very quickly and this is its main advantage. However, dry screeding can only be done in rooms with guaranteed low humidity and with a low or medium load on the floor.

Screeds can also vary in laying methods. Let's list them:

Solid floor screed, performed by a "wet" method . This is the most common, you can even say the classic way. The solution, closed with water, is applied to the prepared base and leveled along the beacons by the rule. Since the main binder for wet process 95% is cement, then such screeds gain full strength only after 28 days, which is a big drawback.
Solid floor screed, performed in a "semi-dry" way . This direction began to develop relatively recently. The meaning of this approach is that exactly the amount of water that is necessary for cement hydration is added to the working solution. Such screeds dry out faster - the next day you can already walk, and lay the tiles in a week. A plasticizer is introduced into the solution, which improves mobility and plasticity during laying. In addition, semi-dry screeds often use micro-reinforcement with fiber (polypropylene or basalt). The screed with fiber is better in terms of strength, wear resistance, stretching and bending than with classic wire mesh reinforcement. The technology of laying semi-dry screeds is more complicated, the preparation of the solution requires precise adherence to the recipes.

Laying, leveling and sanding semi-dry screed - all in one day

Solid floor screed with self-leveling compounds . This method also applies to "wet". As we noted in this way, it is very convenient to make a finishing screed. Such screeds are made with a thin layer of 0.5-20 mm, first of all for economic reasons, since dry mixes for the preparation of solutions are very expensive. But the laying technology and the result observed later are above all praise. The working solution is simply poured over the surface in stripes, rolled with a spiked roller to remove bubbles, and, in fact, that's it.
Dry or prefabricated floor screeds. We have already mentioned them before. You can read more about them on our website.

All floor screeds, with the exception of prefabricated (dry), are made on based on two main binders component - cement or gypsum. There are also others - magnesia, bituminous, anhydride - but for housing construction they do not apply and therefore will not be considered. We note the strengths and weaknesses of these two basic materials.

cement screed prices

cement strainer

Cement based screeds have high strength, durability and most importantly - resistance to water. Weaknesses such screeds are prone to shrinkage when dried and a long maturation time.
Gypsum based screeds strong enough and durable. The solutions are very plastic and do not shrink when dried. They have good thermal insulation properties. Can be applied to any substrate, including wood. The maturation period is several times less than that of cement screeds. But there is one main disadvantage - this is the "fear" of water.

Naturally, in addition to the binder component, which is the main one, the composition of any modern solution or dry mixture also includes other components: fillers and modifiers, both of natural origin and obtained in chemical industries. Therefore, modern mixtures cannot be called only cement or gypsum. It's more correct to speak cement-polymer or gypsum-polymer .

In cement screeds, polystyrene chips are often used as one of the fillers, which gives the coating thermal insulation properties. The bearing capacity and rigidity of such screeds is less, this must be taken into account. At the same time, a second leveling and strengthening layer with more durable fillers is also required.

If you want to create a screed with thermal insulation properties of great thickness, then another material comes to the rescue - expanded clay, obtained by firing clay. This is an excellent filler that has good thermal insulation properties, it is inert, does not decompose with water and is quite durable. Another plus of the use of expanded clay as a filler is a significant saving of cement and a reduction in the labor intensity of laying the screed.

With the help of fillers and modifiers, modern cement screeds dry faster and shrink less, while gypsum screeds partially overcome the “fear of water”. But it must be said that hereditary diseases still remain in one form or another. Therefore, cement-based screeds are still the most versatile. There is also a place for gypsum-polymer, but only in dry rooms, where exposure to water in any form is excluded.

Let's move on to the practical part of the implementation of the floor screed. To do this, we will divide this process into stages, each of which will be considered separately. What are these stages?

Foundation preparation;
Displaying lighthouses;
Solution preparation;
Floor screed device.

At each stage, we will try to explain the whole process in detail, accompanying with photos and videos. So let's start.

Preparation of the base for floor screed

We will consider only three types of foundations: soil, old floor screed and concrete surface. We will not deliberately consider a wooden base, since we believe that it is easier to equip floors on it without a screed using other levelers: plywood or OSB sheets.

The basis of the screed - soil

Most the best time equipping rough floor screeds on the ground is the stage of building the foundation. Then all earthwork and other work is much easier to carry out. And in modern construction they do just that. If this is done in an existing house, then, of course, the task is greatly complicated, but it is not fundamentally different. Let's note the main stages of preparation.

The first thing to do is to choose the soil to a depth of at least 50 cm. In each case, the depth may be different. The bottom of the pit is cleaned and compacted.
If the soil is clayey or loamy soil, then it is necessary to take care of drainage so that moisture does not “prop up” the floors from below.
Next, the creation of the so-called filtration or drainage layer begins. To do this, sand is poured with a layer of at least 100 mm. More is possible, but note that 100 mm is the lower limit. The sand is then rammed with a manual rammer or with an electric or petrol rammer.

It should be noted that the maximum allowable layer of sand you need to tamp - this is 200 mm. If a larger layer is planned, then the ramming work is divided into stages, but no more than 200 mm at a time. In the process of tamping, it is necessary to periodically water the sand with water from a hose.
A layer of crushed stone or gravel of a large fraction is poured onto the sand. The minimum thickness is also 100 mm. This layer is compacted manually or mechanically. Crushed stone or gravel helps to better compact the sand layer and give the filter layer a rigid base.

The next step depends on how much more space is left to the level from which the future floor screed on the ground will already be formed.

Prices for vibrating plates

vibrating plates

If there is still 150-200 mm available, then a layer of concrete with the addition of expanded clay can be laid on a gravel-sand cushion. This will be the first stage of thermal insulation, but it will still not be enough for most regions of Russia. per layer expanded clay concrete then a layer of 40-100 cm of “lean” concrete is laid and compacted. It is called "skinny" because it has a low content of a binder - cement. Lean concrete usually has grades M 100 (B7.5) or M 150 (B10). The task of such a layer is not to carry the main load, but to fill in the irregularities of the underlying layer, level the surface and prepare it for waterproofing.
Another case in the preparation of soil floors for a screed is the absence of 150-200 mm for the expanded clay concrete layer. Then lean concrete comes to the rescue again. It is laid directly on the rubble, and the concrete layer should also not exceed 100 mm, 40-60 mm is more than enough. When laying, be sure to ram it so that the solution penetrates into the space between the rubble stones. With the help of a trowel, a rule and a grater, it is necessary to form a flat outer surface, which will be the basis for the future floor screed.

The next steps are the same for both cases. After drying the "laying" of lean concrete, it is necessary to carry out waterproofing measures. For this, bituminous mastics are used, with which the entire surface is coated with at least two layers. Do not forget about the fact that mastic must be coated with walls to a height not less than the height of the floor screed. In regions with high level groundwater after mastic will not be superfluous at all and rolled on the basis of bitumen or dense polyethylene film, overlapped.

Screed base - old screed

Those who got this option should not be envied, since in most cases the old screed will have to be dismantled. Even if it gives the impression of reliability and impeccability. Even if it does not “blow” when tapped and has a flat surface without cracks. Let's give the arguments.

a new screed, the "perfection" of the old one can easily be broken. Under new conditions, delamination from the base can occur, cracks that will affect the top layer as well.

A new screed over the old one is an additional load on the base. This is especially true for ceilings on the upper floors. A slab with an area of 1 m² of a cement-sand screed 5 cm thick has a mass of 110 kg.

Each screed “eats up” at least 5 cm of space, which is already very significant in standard housing. In addition, there may be problems with radiators, pipes suitable for them, thresholds and door leaf.

Ties are never made so that they cannot be dismantled. It seems to be logical sometimes to connect two layers with reinforcing bars or wire, but no. Even connected concrete screeds are held together only by adhesion and will delaminate quite easily under mechanical stress.

To dismantle the screed, it is best to call a team of workers who specialize in this. From experience, it will be much cheaper this way. You should not even try to do it alone, as both the owners and neighbors will be exhausted if the screed is removed in apartment building. A professional team immediately arrives with all the necessary mortising and stone-cutting equipment, shovels, garbage bags, and a vacuum cleaner. They immediately take away all the garbage collected during mortising work and the owner does not have to worry about calling a separate car. The work of professionals goes on in a continuous mode: one or two people hammer, another one or two immediately collect garbage in bags, and the rest take it out and load it into the car.

The main task of the owners is to negotiate with everyone who may be uncomfortable with noise. V panel houses is the whole house. And, of course, make sure that after the departure of the brigade, there are no traces left on the site and in the entrance from the presence of “noisy guys” and dust from the old screed.

In private houses, everything is simpler, you don’t have to negotiate with neighbors. You can try it yourself, but you still can’t do without helpers. To dismantle the old screed, you will definitely need a powerful puncher with a cartridge not SDS +, not SDS-Max. The puncher will also need chisels. Jackhammers are sometimes used, but this step can only be taken if this tool is in the hands of a professional. Misuse a powerful jackhammer can easily break a reinforced concrete slab.

In addition to a puncher, a 230 mm grinder with a stone-cutting disc, a construction vacuum cleaner, shovels, brooms, and a large number of durable bags can be very useful. Work must be carried out in working clothes made of dense fabric and in a headdress, gloves, mask or glasses. Since there will be a lot of dust, a respirator is required. It is better to protect your hearing organs with headphones, as there will be a lot of noise. Not every master has such a set of tools in his arsenal, but all this is rented in any region. In order not to overpay for rent, it is better to fit all the work in one day, so assistants are definitely needed. Let's describe the main stages of dismantling the old screed.

If there are electrical wiring routes, heating or water supply pipes in the room under the screed, then a circuit is desirable, which should remain after installation. If it is not there, then you will have to use a special device - a hidden wire and metal detector, which needs to examine the entire area of \u200b\u200bthe room and mark these places on the surface with a bright marker.
It is better to start dismantling the screed from the entrance to the room and further move deeper into it. So it will be easier to immediately remove the exfoliated pieces of the old screed. But before starting the dismantling, it is necessary to carry out "exploratory drilling". To do this, in a small area, cuts are made with a grinder with a stone-cutting disc, and then small pieces of the screed are broken off with a puncher with a spatula or a jackhammer to get to the next “cultural layer”. If that layer is the desired carrier plate, then you need to measure the thickness of the removed screed with a tape measure in order to know the landmark.
It is necessary to start to beat off the old screed with small revolutions of the perforator engine and first chip off in small pieces. Further, when the degree of adhesion of the screed to the base is already clear, it is possible to increase the speed and break off in large pieces. Intuitively everything will be clear. When working, always take a stable body position and hold the tool with only two hands. It is not necessary to press hard on the puncher or jackhammer, this does not affect the force from the blow, but the hands will get tired faster.
It is better to remove pieces of a broken screed immediately with shovels, load them into strong bags and take them out to a certain place for subsequent removal. This is another argument in favor of the need for helpers.

Breaks are required during work. This is necessary both for resting the hands and for cooling the instrument. After 15 minutes of work - rest 5 minutes. And it is also desirable that their operators also change behind the perforator or jackhammer. But this can only be done if others have good skills in working with the instrument.
If the old screed is reinforced with wire mesh, then before dismantling with a grinder with a stone-cutting disc, cuts must be made to a depth that would ensure cutting of the reinforcing mesh. The work of the grinder must be combined with the work of a vacuum cleaner, since there were a lot from cutting concrete. The surface is “shredded” into rectangles, such that it is convenient to carry them away in bags, and only then chiselling is performed.
Those places where pipes or hidden wiring pass a large puncher or jackhammer should bypass. In these areas, then after the "heavy artillery" it is better to let a small hammer drill or even a hand chisel and hammer work. And you also need to be careful in the corners and near the partitions, especially if they are made of drywall or cellular concrete.
After dismantling and removing all debris, the surface of the base is cleaned with a perforator with a wide spatula from the remnants of the old screed. Then the room is swept, the floor and air are sprayed with water from the sprayer and 15-20 minutes are given for all the dust to settle. The vacuum cleaner removes the remaining dirt.

Prices for polystyrene concrete

polystyrene concrete

It happens that after dismantling the screed, a “cultural layer” with ceramic tiles laid on the floor is exposed. And it happens that this tile was laid back in the 50-60s of the last century. On construction and repair forums, the question often arises of what to do with this tile? Repulse her or not? Opinions on this issue vary. Our opinion is unequivocal - beat off!

The tile, laid in the days of developed socialism in the USSR, has two extremes when it is dismantled. Either she literally "jumps" from the base herself, or "stands to the last." And It happens that tiles behave differently in one area. And all because before it was not in the arsenal of the masters tile adhesives with predictable properties. Therefore, they glued who on what much. It was used just cement, and cement with PVA, and Bustilat glue, and even epoxy resin and some other "brutal" compositions with ammonia. Moreover, they were glued without any mineral base in the form of sand, chalk or lime. Therefore, dismantling old tiles can be a problem.

Some home craftsmen mistakenly believe that the stronger the impact of the perforator, the more likely the tile will lag behind the base. However, practice shows that a small hammer drill with a sharp blade can handle old tiles better than "monster", but with a more blunt shoulder blade. That is, when dismantling an old tiled coating, it is not the strength that is more important, but the place of its application.

After dismantling the old screed and thorough cleaning, preparing the surface for a new screed will be practically no different from what will be described in the next chapter.

The basis of the screed is a concrete slab

It is most pleasant to make a screed on such a surface when you do not have to do earthworks or dismantle old coatings. Nevertheless, the surface must be prepared. What steps should surface preparation include?

First of all, you need to ensure workplace good lighting, in which the slightest flaws in the surface will be visible.
All joints reinforced concrete slabs(if any) are cleaned, processed, and then sealed with a cement-sand mortar of the same formulation as will be used for the future screed. And also with this solution, you can close up the junction of walls and floors, in which there may be gaps.
All dried mortar splashes, lime and others on the surface, as well as everything that lends itself to a spatula and a hammer, is beaten off and cleaned.
If there are large depressions on the upper surface of the plates, then they can also be smeared with the same solution as the joints between the plates.
If there are cracks, they are cut to a width of at least 5 mm, and then filled with special repair compounds for concrete.

After all the solutions have dried, the room is thoroughly cleaned, and then a deep penetration primer is applied with a roller. After the first layer has dried, the second one is applied. Primer treatment is mandatory in any case, even if a screed is made on the separating layer.
If the screed is tied, then it is recommended for use special compound- "Betonkontakt", which incorporates a complex of polymers, cement and quartz sand. After treatment with this primer, the surface becomes rough, to which everything sticks with pleasure. Construction Materials. However, we advise you to apply " Betonkontakt"After setting up the beacons, in order to exclude damage to the surface created by this soil.

If the screed is with a separating layer, then a dense polyethylene film is laid on the floor. The joint of the strips should be with an overlap of at least 100 mm, and the entrance to the walls should be the thickness of the future screed plus 20 mm.
A damper tape is glued to the walls along the perimeter of the room, which serves to compensate for thermal expansion.

At this stage, the preliminary preparation of the surface can be considered completed.

Prices for "Betonkontakt"

betonkontakt

Setting beacons for floor screed

The floor surface intended for screeding is rarely completely flat. In addition to the unevenness of the relief and the profile of the floor slabs themselves, in most cases the rough surface has a slope in one direction. If in a separate room a slope of 3 mm per 1 meter is imperceptible, then on the scale of the house it can already turn into several centimeters, which is unacceptable. It is always necessary to ensure that the floor in the entire apartment or floor of a private house is on the same level. The exception is bathrooms, which should be 15-20 mm lower. Therefore, with proper repairs, it cannot be that in each individual room the screed is made only in its interests. In no case! You can make a screed in a room, but taking into account the whole apartment or the whole house.

In order for the floor level in an apartment or house not to “dance” as it pleases, it is necessary to beat off the zero level in all rooms. It is very easy to do this if you have a laser plane builder at your disposal, which has long ceased to be a luxury. Let's describe the methodology.

In a certain place, a laser level is installed on a tripod so that it can capture the maximum number of rooms with its beam. It is better to install it at a height that is comfortable for work - about 140-150 cm. On the walls of the premises, marks of the position of the beam are made with a marker.

The level is transferred to some room where there is already a mark and is set on her . Further, the position of this label is transferred to all walls. With the help of a masking cord, a horizontal base line is beaten off.
Similar actions are carried out in all rooms. As a result, it should turn out that a horizontal base line is drawn on all the walls, relative to which the floor level and the thickness of the screed will be calculated.
Measurement points are marked on the baseline with a certain frequency (1.5-2 meters). Then the distance from the measurement points to the floor level is measured vertically and written with a marker or pencil directly on the wall.

The minimum and maximum distance from the baseline to the floor surface is found. In the example shown, the minimum distance is 1420 mm and the maximum distance is 1445 mm. The height difference is 25 mm.
For example, the recommended minimum screed thickness for sand concrete of any brand is 30 mm. This means that from the highest point it is necessary to set aside 30 mm and get that the zero level will be 1420 - 30 = 1390 mm from the baseline. The thickness of the screed in this case will vary from 30 mm to 55 mm. This is perfectly acceptable.

These calculations are very appropriate to put on the plan of the house. Such a document will be very useful in the future, since the screed is usually not done immediately in the entire apartment or floor of the house, but gradually, moving from one room to another.

It's time to learn how to properly arrange beacons. These actions cannot be called heavy physical labor, but a lot depends on the correct placement of beacons. It is they who set the surface of the floor and from the slightest mistake all further work can lead, at worst, to further elimination of deficiencies, and at best, to banal overexpenditure of the dry mix from which the screed solution will be prepared.

Let's take an example. Let's say there is an apartment of 100 m² in which you need. For this, sand concrete M 300 will be used, in which the minimum layer size is 30 mm. When beating the zero level, it turned out that the thickness of the screed can be from 30 mm to 55 mm (we gave this example earlier). This means that the average thickness of the screed will be approximately (30 + 55) / 2 = 42.5 mm or 4.25 cm. The average consumption of sand concrete M 300 is 20 kg per 1 cm of thickness and an area of 1 m². It turns out that there will be an expense for the whole apartment: 4.25 * 100 * 20 \u003d 8500 kg of dry mix, which will be 212.5 bags of 40 kg.

Now imagine that when installing beacons, the master, instead of the minimum 3 cm at the highest point, set 4 cm with an “iron” argument “the pocket does not pull the stock”. We recalculate: an extra 1 cm added to the screed over the entire area of 100 m² will result in 20 * 100 \u003d 2000 kg, which will be an additional 50 bags in 40 kg bags. It turns out that the stock still "pulled the pocket." And the point here is not so much about money, but about the extra load on the floor. The extra 2 tons will lie on the base of the floor. The extra 2 tons will have to be dragged to prepare the mortar and lay it down.

All readers probably know that the most inconvenient load during transportation and especially lifting to the floors is a piano. Loaders shy away from it "like fire" and calculate at a special rate. The average weight of one piano is 250 kg. It turns out that plus 1 cm of the tie in the considered example is equal in weight to approximately 8 conventional pianos or one conventional Lexus RX 400 SUV.

There are too many ways to set up beacons to describe them all in one article. Each master has his own favorite way, which does not have to be similar to others. Basically, what difference does it make if different ways exhibiting beacons, two masters get an equally good result. We propose to consider a method that will be understandable to everyone and even a beginner can reproduce it.

Completely different objects and devices are used as beacons for floor screed. Someone prefers to make lighthouses from a solution, someone uses pipe segments. The ceiling guide profile is very widely used, " borrowed» in drywall systems, which we know as PN 28*27 or UD 28*27. Its shape and sufficient rigidity allow it to be used for lighthouses. For example, as it is done in the figure.

In the method of placing beacons we are describing, we will use the PM-10 beacon profile, originally conceived for plaster, but successfully used in screeds. It is made of galvanized sheet steel and has a shape that also provides it with good rigidity. The side shelves of PM-10 are perforated to facilitate its attachment to the leveling surface in various ways.

Very often beacon profiles are fixed with mortars. To do this, on a pre-marked line, on which the lighthouse should be located, at the beginning and at the end of it, self-tapping screws are screwed into the previously installed dowels. Then, using a laser level or other measuring tool, the self-tapping screws are set so that their upper plane is in the plane of the future screed. Along the line of the beacon, with a certain frequency, slides are made of cement-sand or other mortar, and then the beacon profile is placed on them and pressed in with a rule that is pressed against the caps of the self-tapping screws.

When the beacon profile is pressed into the mortar pad, make sure that it is pressed against the rule along its entire length. Excess protruding above the lighthouse is cleaned. When the solution dries, you can begin the main work on the screed. For a cement-sand mortar, at least 1-2 days must pass for the lighthouse to be fixed, therefore, to speed up the process, some craftsmen use adhesive gypsum mortars or even alabaster. The beacon in this case is fixed almost instantly and work on laying the screed can be started immediately. Everything seems to be fine, but it turns out that there will be foreign inclusions from other materials in the body of the screed. During the operation of the screed, in those places where there are “strangers”, cracks will most likely form, since the coefficients of linear thermal expansion for different materials are different. Therefore, beacons should be installed only on the solution with which the screed will be made.

The method of installing beacons on the solution has a major drawback - it is the impossibility of correcting the position in case of an error. Only the dismantling of the beacon and re-assembly can correct the situation. Therefore, it is better to use a method that will allow you to easily mount, dismantle the beacon and adjust its position. This is easily implemented using self-tapping screws with dowels and a special fastener - a plastic clip for fastening beacons.

This clip consists of two parts - the clip itself and the lock that fixes the beacon. This type of fastening of the beacon is good because the clip itself can be mounted on the head of the self-tapping screw after it is screwed in and adjusted in height. For this there is a special groove. Later, already after the beacon is put into the clip, the final fixation with the lock is in progress. It turns out a very reliable mount, which can still be adjusted in height. The price for such clips is cheap - 100 pieces cost 250-300 rubles.

Consider the process placing beacons with plastic clips. For convenience of perception, we present it in the form of a table.

Image	Process description
	On the prepared floor surface, the position of the beacons is marked, which should be installed in the direction of pouring the screed from the far wall of the room to front door parallel to the side walls (if the room is rectangular). From the side walls, to the guides closest to them, an interval of 200-300 mm should be maintained. The distance between neighboring beacons is 1-1.5 meters. The rule laid down for neighboring beacons must still have a margin of at least 200 mm on both sides.
	On the position lines of the beacons, with an interval of 500 mm, holes are drilled with a perforator, into which dowels are immediately hammered.
	In the room where the beacons are placed, there is the highest point, according to previously made calculations. At the corresponding point, the dowel is screwed in, but not completely. The laser level is set and set according to the baseline previously drawn on the walls.
	On a straight wooden block, a mark is made on the position of the screw head relative to the baseline, but taking into account the height of the beacon (10 mm) and the clip (2 mm). That is, 12 mm is added to the previously calculated screed level relative to the baseline. The bar is installed vertically on the head of the screw and the position of the mark is controlled.
	By screwing or unscrewing the self-tapping screw with a screwdriver, the mark on the bar and the laser level beam are matched. The self-tapping screw at this point can be considered set, and all the rest must be set on the same level with it.
	The laser level is installed on the floor and its beam should be above the cap of the exposed screw. A long bit is clamped into a screwdriver. Then the bit is inserted vertically into the slots of the exposed self-tapping screw and it is controlled that the laser beam is on it.
	A strip of white masking tape is glued onto the bit in a circle, then it is again placed vertically in the slots of the self-tapping screw and the position of the laser beam is marked with a marker.
	Self-tapping screws are baited into all previously mounted dowels.
	A screwdriver sequentially tightens all the screws to the level determined by the mark on the bit and the laser beam.
	Clips are put on the heads of the self-tapping screws, and the neighboring ones should be oriented opposite to each other.
	The position of the clips is checked with a rule, a level and a laser beam. The rule must lie on all clips strictly horizontally.
	Beacon profiles are inserted into the grooves of the clips. All profile joints should fall only on clips.
	Profiles in clips are fixed with latches.
	The room is cleaned with a vacuum cleaner.
	The surface of the floor is primed with a deep penetration compound.
	After the primer dries, a semi-dry sand concrete solution is mixed and all beacons are reinforced with it. The same solution can fix the position of the damper tape.

The proposed method is also good because the level can be set without the beacons themselves, and they can be put on immediately before laying the solution. This is very useful when the screed is being reinforced.

Floor screed reinforcement

The question often arises about the advisability of reinforcing the screed, because by its purpose it is often not a power element that carries the main load. And partly this is true. But the absence of reinforcement can only be justified in bonded screeds laid on a reliable concrete base, and in all other cases it will not be superfluous. Consider cases where reinforcement is required.

Screeds in the underfloor heating system are necessarily reinforced, as they are subject to thermal expansion and contraction.
Floating screeds laid on insulation boards are also necessarily reinforced, since it has a much lower bearing capacity.
Ground screeds must be reinforced with reinforcement, as they are usually laid on a loose base. Another reason for reinforcement may be external factors, such as seasonal swelling.
If heavy objects are installed in the room or the screed is subject to any dynamic loads, then reinforcement is mandatory.
Screeds with a height of more than 5 cm are reinforced to avoid cracking during the drying process.

For reinforcement, various materials can be used. Let's consider what.

Reinforcement of the screed with metal meshes

The oldest proven method of reinforcing screeds are steel mesh rebar or wire. the former are used for power heavily loaded floors on the ground, for example, in garages, and the latter in all other cases. Grids for reinforcing screeds are made of VR-1 wire with a diameter of 2.5 mm to 6 mm. If earlier a frame was formed using a thin wire, which was used to twist the stacked rods, now meshes are offered, connected spot welding. Cells can be square or rectangular, ranging in size from 50 to 200 mm. It is obvious that what smaller size cells and the thicker the wire, the more reliable the screed will be. Grids made of thin wire (up to 3 mm in diameter) can be sold in rolls, and thicker ones in the form of cards 0.5 * 2, 1 * 2 and 2 * 3 meters in size.

A very important element in any wire mesh is the presence of notches on the bars, located in increments of 2-3 mm along the entire length. They significantly increase the area of adhesion of the frame to the concrete solution, which strengthens the finished screed. When buying wire mesh, you must strictly ensure that all wire intersections are welded, since not all manufacturers do this. And it is also worth checking the grids for the absence of strong foci of corrosion, which will expand in a highly alkaline concrete solution when it hardens.

There are a lot of sources on the Internet that tell how to “correctly” reinforce a floating screed with underfloor heating pipes. A wire mesh is placed on a layer of heat and waterproofing, and only then pipes of a warm floor are attached to it with plastic clamps. The deeds of such "craftsmen" can be seen in the photograph.

Such "reinforcement" is inherently possible - it is hiding expensive wire mesh under a layer of concrete. They do not perform any reinforcing function, since they will simply “roll” under the screed. In order for the reinforcement not to be useless, the meshes must be inside the concrete, while they must be separated from the base on a protective layer with a thickness of at least 15-20 mm. In thin screeds, the mesh will be located approximately in the middle, and in thick screeds it is better to place it in the lower third, so it will work better under various loads that occur.

When forming screed frame made of steel meshes be sure to overlap by 1 cell, but not less than 10 cm. For example, if a grid with a cell of 10 * 10 cm is used, then adjacent canvases should overlap exactly by 1 cell, and if 20 * 20 cm, then half of it is enough . In order for the grid to stand at the same distance from the base, several methods are used:

The grid is installed on the slides from the cement mortar - exactly the same as the screed will be poured. Sometimes this is combined with the installation of beacons. This is a perfectly acceptable method, but its main drawback is the non-simultaneous drying of the slides and the screed itself. This can lead to heterogeneity of its structure and delamination. The use of gypsum solutions is unacceptable!
The reinforcing mesh is installed on supports made of pieces of broken brick, fragments of concrete or other improvised materials. This method is also allowed, but it is quite difficult to set the grid at the same distance from the base. And further, when the screed is laid and moved along the grid, some homemade supports may fly out. The use of wooden blocks is unacceptable, as they will increase in volume from the water and “tear” the screed.
The most modern and best way to install reinforcing meshes is to use special reinforcement retainers. They are made of plastic, have calibrated dimensions and are selected for any type of reinforcing mesh, for any thickness of the protective layer and for any base. Such “implanted” racks do not in the least affect the concrete or cement-sand structure of the screed for the worse. These products can be easily found in any normal building materials store or market. The price for them is cheap: about 0.8-1.6 rubles per 1 piece, if you take packages of 1000 pieces. For 1 m², it is recommended to use at least 8-12 clamps. It depends on the diameter of the reinforcement or wire, the mesh pitch and the base material.

Rebar clamps - modern and the best solution for installation of reinforcing meshes

The most common cause, in which reinforcement of the screed is necessary in residential premises - this is a warm water floor. But placing a metal mesh on the base, and then attaching pipes to it, is a rather dubious task. The effectiveness of such "reinforcement" is close to zero. The most correct thing is to fasten the pipes to the thermal insulation, and on top of them already place steel meshes on the reinforcement clamps.

We note the advantages of using steel reinforcing mesh for screed:

Such ties have the highest strength: tensile strength, bending, for stretching and compression.
Excellent resistance to temperature extremes over a very wide range.
Steel grids laid on top of underfloor heating pipes make it possible to distribute temperature gradients more evenly, since metal has a thermal conductivity many times greater than concrete.
Properly mounted screeds with steel reinforcing elements have a long service life.

There are few disadvantages of steel reinforcement - this is a high price and the ability to corrode if stored and installed improperly.

Reinforcement of the screed with polymer and composite elements

Progress does not stand still, so to replace traditional reinforcing steel elements others come from various polymers or composite materials. For a long time there was no alternative to traditional steel reinforcement, but now a worthy “rival” has appeared - reinforcement and meshes made of polymer and composite materials. Let's briefly consider them and immediately note the advantages and disadvantages.

Composite reinforcement - these are rods of various diameters, which may have ribs similar topics, which is also on steel reinforcement, or for better adhesion, a sand coating is applied to them. The rods are formed from fibers and a polymer binder, which is why such reinforcement is called composite. Fibers use glass, basalt or carbon and therefore the reinforcement is called fiberglass, basalt-plastic or carbon fiber.

Composite reinforcement has a number of advantages, we list them:

We note the disadvantages of composite reinforcement:

Lower stiffness of composite reinforcement than steel.
Lack of plasticity - high brittleness.
The heat resistance of composite reinforcement is worse. Fiberglass loses its properties at 150 °C, carbon fiber at 300 °C, and steel only at 500 °C.
When cutting composite reinforcement, a large amount of dust harmful to health is generated. This is especially true for fiberglass reinforcement.

Work with composite reinforcement in the same way as metal. When knitting frames, wire or plastic clamps are also used, and for installation, clamps or mortar cushions. The correspondence between the diameters of steel and fiberglass reinforcement can be seen in the following table. At the price of composite reinforcement is not lower than traditional steel, however, if there are large logistics costs for delivery to the site, then in the end its use can be cheaper. True, when mounting the frame and pouring the screed, care must be taken, because composite reinforcement is much easier to break than steel reinforcement, since it works much worse for bending.

Prices for fiberglass reinforcement

fiberglass reinforcement

Plastic meshes are now widely used to reinforce screeds located on reliable foundations. They are made of polypropylene or fiberglass with a special impregnation that prevents exposure to alkaline environment inside concrete. Grids are produced in a very wide range, with different mesh sizes. For screeds, polypropylene meshes with a mesh size of 35 to 50 mm are most commonly used. The width of the canvas is from 50 cm to 4 meters, and the length of the mesh roll is from 10 to 50 meters. Of course, it is very convenient. Note the benefits plastic nets for reinforcing floor screed.

The only drawback of plastic nets is the impossibility of their use in rough screeds on the ground.

Fiber screed reinforcement

The reinforcement of the screed with microfibers (fiber) differs from all the others in that the frame itself is not visible. But the reinforcement in the concrete mixture is still in the form of thin fibers, evenly distributed in the solution, and after drying and in the thickness of the screed. It is they who reinforce the concrete in all planes, as they are randomly located. Their addition, even in small quantities, significantly increases the brand of concrete, impact resistance and strength. in fiber concrete (this is what concrete with the addition of fiber is called) there is also an almost complete absence of shrinkage cracks. Fiber can be made from different materials:

Steel fiber - is a piece of high-quality steel wire with a diameter of 0.2-1.2 mm and a length of 25-60 mm. For better adhesion to concrete, the ends of the wires are curved. Steel fiber is the strongest, but is not used in screeds. Its purpose is concrete for massive monolithic structures, mainly prefabricated.

Fiberglass fiber - significantly improves the quality of concrete, which allows you to reduce the amount of cement up to 15%, and water - up to 20%. It is not used in monolithic structures and screeds, since fibers from a special alkali resistant zirconia glass is very expensive. Therefore, fiberglass fiber has found his application in decorative and structural plasters.
Basalt fiber is a piece of basalt fiber with a diameter of 20 to 500 microns and a length of 1 to 150 mm. Reinforcement of concrete with basalt fiber increases its strength by 4-5 times, abrasion resistance - by 2-3 times, tensile strength - by 2-3 times, compressive strength - by 1.5-2 times, water resistance - by 2 times. This kind of fiber can partially dissolve in cement mortar, but from this it only gains strength. It turns out that reinforcement occurs both chemically and mechanically. Consumption - approximately 0.8-1.2 kg per 1 m³ of ready-made concrete solution.

Polypropylene fiber is the most common a type of micro-reinforcement of floor screeds, since along with the excellent characteristics of concrete (almost like with basalt fiber), its prices are lower. Polypropylene fiber does not enter into a chemical reaction with concrete mortar and does not change its properties during the entire service life of concrete. The consumption of polypropylene fiber is approximately 0.6-1 kg per 1 m³ of the finished solution.

Adding fiber to concrete mortar is very simple, there are two ways to do this - dry and wet. All types of fiber, except for basalt, can be kneaded in a dry way. This means that the basalt fiber is first soaked in water, and then the dry ingredients of the mixture are added. Steel fiber is added only in a dry way. That is, it is added to the sand, mixed, then cement is added, and then water.

It should be noted that the mixing of solutions with fiber will be of high quality only when it is done mechanically - using concrete mixer or mixer. The mixing time with the fiber must be increased by at least 30% so that it is as evenly distributed throughout the volume as possible.

Conclusions about the reinforcement of the floor screed

The opinion of the authors of the article about reinforcement is unequivocal - it is necessary in any case in one form or another. This is based primarily on personal experience, but also on the analysis of the opinions of professionals at numerous thematic construction forums. Here are the arguments:

Any properly made reinforcement makes the screed better.
Highly loaded screeds, as well as those made on the ground, must be reinforced with a reinforcing cage.
Composite rebar offers no advantage over steel rebar at current prices.
Any reinforcing frame must be inside the screed, and the thickness of the protective layer must be from 15 mm.
on a reliable basis, it is sufficient to use a polypropylene reinforcing mesh.
Reinforcement with polypropylene or basalt fiber is always best done, since the cost of this is disproportionately less than for all other components of the solution, and the result, if used correctly, is obvious.

Preparation of floor screed mortar

Question proper cooking solution in the arrangement of the floor screed is extremely important, since both the quality of installation and the period of further operation depend on it. If you “rewind” 20-30 years ago, then at the construction sites of private houses in the territory former USSR there were no issues with this. Either just on the floor surface, or in makeshift troughs, a solution consisting of cement, sand and water was kneaded with shovels, and then it was laid on the floor surface using wooden graters, slats, pieces of edged boards and other improvised means. And a lot of screeds, made then, are still serving. But this does not mean that we should continue to use these "grandfather" methods.

Modern screeds are often made on a layer of insulation, and warm floors are also no longer a luxury item. Accordingly, the requirements for which solution should be prepared also increase. Let's tell readers right away that mixing with shovels on the floor or in a trough, which some current sources can even talk about, is an outdated approach. A good screed should have a uniform structure, so the preparation of a solution for it is better compared with the craft of a pharmacist, which from various containerswith the help of beakers accurately measures right amount ingredients, and then mix them until smooth. It is clear that the volumes of the pharmacist and the builder are different, but the ratio should be similar. And, of course, the preparation of the solution should be carried out only using mechanisms - mixers or concrete mixers (concrete mixers).

A drill mixer is a very useful device that will come in handy in household not once

Floor screed solutions can be prepared in two ways, each with its own advantages and disadvantages.

The first way is self-preparation of the solution. At the same time, the necessary ingredients are purchased in the right volume, which are mixed in certain proportions. It should be noted that experience or clear instructions are desirable with this method, not to mention the quality of the individual components of the solution.
The second method is the use of ready-made dry building mixes, which are specially designed for floor screed. This simplifies the work, but costs more.

Let's consider these methods separately and in more detail.

Self-preparation of floor screed mortar

Modern SNiPs do not in the least interfere with self-preparation of the solution, but its grade must be no less than M -150, which means that each square centimeter of the screed must withstand a load of 150 kg. This is sufficient for simple screeds, but may not be enough for underfloor heating. In addition to the traditional screed components - cement and sand, it is also recommended to use a special additive - plasticizer . What does it give?

In order for cement to turn into stone, it needs a certain amount of water, approximately equal to a quarter of its mass. Approximately 25 liters of water are needed for 100 kg of cement. But such a ratio will not allow to obtain a plastic and fluid solution of cement with fillers, therefore, additional quantity water, which allows you to conveniently lay the solution. Plasticizers allow you to minimize the water-cement ratio, which has a beneficial effect on both the rate of solidification and the final strength of the structure or coating.

Plasticizers are not a luxury, but a necessity

The use of a plasticizer avoids the appearance of air bubbles in the body of the screed. This is especially true in the pouring of underfloor heating screeds. When laying the screed, due to the plasticity of the solution, the air freely exits itself, and the cement-sand mortar better “encloses” the underfloor heating pipeline.
The grade strength of the finished solution when using a plasticizer increases by 20-40%.
Solutions with a plasticizer have frost resistance 50% higher than without it.
The “life” time of the solution, in which it can be worked with when laying the screed, increases significantly. This allows you to make batches in a large volume and increase productivity.
The water resistance of screeds with a plasticizer is significantly higher than without it.

We hope that we have convinced our readers of the need to use a plasticizer for screed. It can be easily found on sale in liquid or powdered form. It can be called differently, but according to its chemical composition and in fact in 99% of cases it is a C-3 plasticizer. measured volume of water. All instructions for the use of the plasticizer are always indicated on the packages.

Now let's look at how to prepare a time-tested screed solution.

Portland cement must be used as a binder. widespread brand M 400. You can also use M 500, then the screed will be even stronger. Usually it is sold packaged in 50 kg bags, but for ease of transportation there are bags of 25 kg. Of course, it is necessary to check that the expiration date of the cement has not been exceeded.

As a filler, it is recommended to use quarry sand, in which grains of sand have an irregular shape with sharp edges. In a screed, such sand will adhere well by itself. with you, with cement and foundation. River sand with prolonged exposure to water takes on a smoother shape, which means it will more readily peel off the screed.
Water for the preparation of the solution should be used only clean, free of impurities of oil products, fats and other contaminants. Naturally, water containers should also be clean and intended only for her. It should be noted that the required amount of water does not need to be added immediately, since a solution with a very high content of it can be obtained. This will have a bad effect on the convenience of laying and the strength of the screed. The sand may already contain some water and the use of a plasticizer also greatly affects the water/cement ratio.

Now about the proportions of the ingredients of the screed solution. The “classic” proven over the years is one part cement to three parts sand. We propose to calculate the exact amount using a calculator.

Floor screed mortar ingredient calculator

The proposed calculator is very easy to use, requires a minimum amount of initial data, and produces results with good accuracy. The only explanation for its use is the paragraph on the height difference of the screed. This is nothing but the difference between the highest point of the base and the lowest, expressed in millimeters. We talked about this in our article when we considered the installation of beacons.

Modern decoration makes high demands on the correct geometry of all surfaces of your home, especially the floor. In order for the finish coating on the floor (tile, linoleum, laminate, parquet board, etc.) to be of high quality and look great, it is necessary that the base of the floor - the screed - be done professionally. The screed, of course, can be made independently, if you know exactly what type of screed you want to use specifically in the house, but for this you need to know the technology and features of the screeds. In this note, we will analyze the device of the most common - cement-sand screeds CPS.

The very first stage in carrying out work on the screed device is surface preparation. How long your screed will last depends on the quality of this stage. It is necessary to understand once and for all - the surface under the screed must be thoroughly cleaned of dust, dirt, various layers, etc. Ideally, of course, it is necessary to apply industrial vacuum cleaner, which will collect the smallest rubbish from the surface, but in the absence of such equipment, you can use old vacuum cleaner or carefully sweep the entire surface for 2-3 times. It is necessary to clean the slab to concrete, try to knock down all the uneven bumps.

Next preparatory stage- it's a primer. It is advisable for the first time to go through a deep penetration primer for floors, which will reliably remove dust from the surface and create a film. After two hours, the primer will dry and it is necessary to apply a second layer of primer on it - Betonkontakt, which includes quartz sand and other binders that will create a durable rough surface that can ideally interact with the screed, creating monolithic structure firmly attached to the plate. If, when cleaning the slab, you find cracks, they must first be repaired with the composition from which the screed will be. Naturally, cracks should be sealed along the primed surface.

Next stage - level detection future screed. This step requires the use special tools- hydraulic level, and better - a laser level. If the area of the room is small up to 20 square meters. m - you can use a hydraulic level, the level itself is accurate, but when marking reference points on the walls, the participation of two people is necessary - and here the notorious human factor interferes with the accuracy of the method, which always leads to an error that the laser level is deprived of.

To determine the level of the future screed, you need the so-called "zero level", i.e. a line drawn at an arbitrary height (1-1.5 from the level of the plate prepared for the screed). To apply the zero level, you need to mark a random point anywhere in the room on any section of the wall, and with the help of a laser level, this mark is transferred to all the walls of your house. All marks applied in this way on the walls must be connected with one solid line, which will be the same zero level for all rooms where the future screed will be cast. This level will be the same relative to the horizon, and not relative to the surfaces prepared for the screed - and this is what you need to determine the height of the future screed.

Next stage - thickness height determination screeds. In all rooms where there will be a screed, it is necessary to measure the distance from the zero level to various points on the floor surface - this is necessary to determine the highest point on the floor, the more measurements there are, the more accurate the result will be. On the walls it will be necessary to record the results of all measurements. The smallest height value from zero level to the floor will mean the highest point of the surface in this room, and the largest height value, on the contrary, will mean the lowest point on the floor surface. Summing up all these values - the largest and smallest - and, getting the difference, you will have an idea of the height difference and, accordingly, the ability to calculate the thickness of the future screed and, most importantly, the consumption of materials.

If you are planning to different rooms different coatings of your house or apartment - somewhere tile, somewhere laminate or parquet board, somewhere linoleum, then you will need to calculate the height of the screed for each coating, this is necessary so that your future floor, consisting of different types of coatings, is perfectly even. After all, if you cast the floor throughout the house at the same level, and then put tiles in the hallway, and parquet in the hall, then the height difference between these coatings will be visible to the naked eye and you can’t compensate for this difference with any sills, and you can knock down your legs very easily . Therefore, decide in advance what specific floor coverings will be in each room and, based on this, calculate the thickness of the screed for each floor so that the height difference in the floor coverings is compensated by the different thickness of the screed.

Next stage - wall preparation. To ensure that the screed does not come into contact with walls and partitions, they must be waterproofed. A plastic film is best suited for this, which is fixed along the perimeter of the walls with a stop of 10-15 cm above the level of the screed and under the screed.

Now you can proceed directly to the screed device. It must be said that the screed can be cement-sand and dry. Their differences, of course, are in the different amounts of water used. There are also ties monolithic and floating. Monolithic, of course, is poured directly onto the prepared base and is in close contact with it, and the floating screed is used if it is necessary to insulate or soundproof the floor, i.e. the floating screed is poured onto the pre-laid material and does not come into contact with the floor slab and walls.

If we consider the classic cement-sand screed (CPS), then it consists of a solution consisting of a mixture of sand and cement (3: 1), closed with water and a metal mesh that acts as reinforcement, a kind of reinforced concrete structure is obtained. The thickness of the classic DSP must be at least 50 mm (40 mm ties and 10 mm reinforcement) - these parameters are suitable for domestic use, i.e. for our apartments and houses. When such a layer is not enough or heat and sound insulation is required, expanded clay is used. The required thickness is covered with a mixture of expanded clay and cement. First, expanded clay is evenly poured, leveled and spilled with cement milk - this is necessary for strong adhesion of expanded clay to each other and monolithic slab. In modern conditions, as a heat and soundproofing material apply extruded polystyrene foam, which is lighter than expanded clay and more convenient to use.

After the expanded clay pillow is ready, it is necessary to lay metal mesh , which reliably reinforces the screed. It is desirable that the mesh cell be 10x10 cm in size and it must be laid with an overlap of 15-20 cm, and the meshes should also be tied together with a knitting wire. An important condition is the location of the mesh inside the screed - it must be right in the middle poured solution, only in this case the mesh will fulfill its reinforcing function. To do this, plastic supports or pieces of ceramic tiles are placed under the grid, but not wood. In places where the highest load is expected, a metal bar can be laid by tying it to the mesh.

The same mesh installation steps apply to extruded polystyrene foam. The expanded polystyrene itself must be primed with Betonkontakt before laying - it will give the best adhesion of the material to the future screed. If the slab is very bumpy and there are a lot of irregularities, you can level the bay with a screed and pass the problem areas as a rule, then the surface will be more even. All foam polystyrene mats must be securely fixed to the floor with the help of "fungi" - special fasteners for this material. There should not be any backlash when walking on polystyrene foam - this is a prerequisite.

Then you can proceed to the next stage of work on the screed device - the installation of beacons. This is a very important moment, since quality installation beacons depends on whether or not your screed will be flat. As lighthouses, a beacon profile made of galvanized metal with perforated edges 10 mm high is most often used.

Beacons are installed on the same solution from which the screed will be. Small heaps of solution are laid out along the entire length of the beacon at a distance of 20 cm, the beacon is laid on them, the distances between the heaps are filled with excess solution, and the beacon lies completely on the path of the solution. The distance between adjacent beacons should be 30-40 cm less than the rule by which the solution will be leveled. The optimal distance between the beacons is 2 m. But if you work together on leveling, you can also use a 4-meter rule.

It is most convenient to lay the beacon on a gypsum mortar, since there is time for its complete alignment to a given height, and the complete filling of the space between the beacon and the floor with the mixture will provide the necessary hardness and strength of the beacon profile. You don’t have to listen to craftsmen who suggest using metal pipes or drywall profiles instead of a special profile - this will affect the quality of the screed, it’s better not to be too lazy and buy beacon profiles specially designed for leveling the screed. Special beacons can not be removed after pouring, especially if a finishing coating (self-leveling floor) is subsequently applied, which will create a perfectly flat surface (experience is required for this).

There is another way to set beacons through metal string, which can be stretched between two dowel-nails to any length (width), and fill the distance between the string and the slab with a screed mortar or gypsum mixture to create a solid guide structure. This method will give the most even surface over the entire area (experience is also required for the construction of such beacons).

After setting the beacons and solidifying them, it is the turn of the screed device itself. The prepared solution is placed between two beacon guides, completely filling the space between them and is leveled with the help of a straightedge sliding along two parallel beacons. It is advisable to work with three of us - two on mixing and a tray of the finished solution, and one is directly involved in leveling the screed.

When mixing the finished mixture, it is necessary to strictly adhere to the manufacturer's instructions for the amount of addition of water and the mixture itself. If the proportions are not met, for example, there is too much water, then cracks will definitely appear, after drying and the effect of a "stone". i.e. the solidity of the screed will be lost. It is very important to remember that when the mixture is leveled, excess air remains in it, which must be helped to come to the surface; for this, special needle rollers or thin steel wire knitting needles are used to pierce the leveled surfaces.

Currently, when installing screeds in apartments and houses, only special modified building mixtures are used for rough and final alignment surfaces. The classic DSP is now poured only during construction and when the owners of the purchased apartments begin to repair such a screed, which has turned over time into a bubbling and uneven surface are usually removed and discarded.

In special mixtures, the composition is selected in such a way that when mixed with water and subsequent drying, as a result chemical reactions education is taking place monolithic stone effect designs. Such a screed dries within 24-48 hours, does not require soaking with water and cracks do not form on it. The only thing required is to cover the new screed with thick plastic wrap, which will not let it get dusty and protect it from excessive abrasion during further repairs and will allow it to "survive" to the finishing floor coverings, so to speak, in the best possible way.

I would like to draw attention to one more important point. When a screed is made, several goals are pursued: leveling, soundproofing, waterproofing. We all want us not to hear the "life activity" of our neighbors and, accordingly, so that the neighbors do not hear us. If the goal is to qualitatively soundproof your home, then in the screed you should apply unleashing the structure and absorption. You can use expanded polystyrene, low density mineral wool. For decoupling, materials of different density are used, the so-called low-density pads, which exclude the contact of dense materials with each other, respectively, the sound is lost in these decouplings.

V ideal improved sound insulation the design looks like this:

wooden crate installed on polyethylene foam pads under the logs

the crate is filled with low density mineral wool

a thick layer of high-density mineral wool is laid on top of the crate

on top of the mineral wool, a dense insulation is laid in one layer

a cement-sand screed is laid on the insulation

It is worth noting that when soundproofing the floor, one should not forget about the walls, since the sound, meeting an obstacle in the floor, spreads further and goes into the walls.

It is also worth mentioning the weight of the screed. In general, the floor slab itself is designed for a weight load in the range of 350-400 kg / sq.m (can be specified in the project). If you have a concrete or DSP screed 5-6 cm thick for thermal insulation with a finishing floor covering of tiles, then the weight of a square meter of such a "pie" will be 130-150 kg.

And in conclusion. If you are not indifferent to what kind of foundation will be under your floor covering, from what materials and what technology it is laid with, then you should familiarize yourself with the building codes and rules that were developed in construction laboratories by specialists in construction chemistry and physics. The results of the work of these people should not be neglected. SNiPs and GOSTs are documents in which everything technological subtleties and the rules are written in the most detailed way. As for the screeds themselves, it would not be superfluous to look at such documents as SNiP 2.03.13-88 "Floors", SNiP 3.04.01-87 "Insulating and finishing coatings", SNiP 3.03.01-87 "Bearing and enclosing structures" which are active.

The floor screed is the part of the base that is located between the ceiling and the finishing coating. Without it, it is impossible to make the floors perfectly even - such that even the most demanding finishing material in terms of installation conditions can be safely laid on them. You can’t do without it when building a house and even during the overhaul, but how to make a floor screed is a very difficult question for many. Let's try to figure out how to create it with your own hands.

The screed is not only a structural element of the floor, responsible for its leveling. It performs other equally important functions - for example, it takes over and redistributes all the loads experienced by the floor covering. But still, the most important function of the screed is precisely the alignment of the base. It is necessary in order to lay the floor covering without problems and correctly, some types of which are quite demanding on the evenness of the subfloor. For example, ceramic tiles, parquet and other materials will quickly become unusable if they are used lying on an uneven floor. They will begin to break and collapse, and when moving along the coating, it will emit an unpleasant creak.

Another function that the screed performs is increasing the heat, sound and waterproofing properties of floors. Also, due to it, it is easy to raise the level of the base to the required level if necessary.

What is the screed?

The floor screed can be divided according to several criteria into different types. For example, depending on the manufacturing method, it can be dry, wet, combined.

Table. The main types of screeds.

View	Description and characteristics
	This option is made without the use of heavy mortars. The technology is used to level floors with very large height differences (up to 11 cm), as well as in rooms where floors cannot experience significant load. In this case, a dry screed can be laid along the logs and be made of plywood or chipboard, or it can be made of sheets of gypsum fiber, which is laid on expanded clay bedding. The thickness of the screed can be quite large. Dry screed is easy to perform, does not require drying after production, is very light, does not exert a load on the floors and foundation of the building.
	This screed can also be called concrete or cement. The most familiar and most commonly used way of leveling and raising the floor. As a rule, it is used for the initial stage of leveling floors or subfloors. It is made on the basis of cement with the addition of fillers, it is laid in a layer of 3 cm or more. Difficult to work with, takes a long time to dry, but very strong and durable. Unfortunately, it exerts significant non-overlapping pressure due to its considerable weight, and therefore cannot be applied to all types of buildings. For 1 sq.m. accounts for at least 100-120 kg mortar- the mass is quite impressive.
	This type of screed combines the main advantages and, in some way, the technology of wet and self-leveling screeds.
	This method is good because there is no need to use beacons and somehow monitor the evenness of the finished base. The fact is that special mixtures are used for manufacturing, which tend to self-level on the surface of the subfloor. Such compounds are quite expensive, and they can be filled with floors with irregularities up to 2 cm. Often, due to this method, you can additionally level the usual cement screed.

Also, screeds are divided into different types depending on the number of layers. Thus, they are single layer(poured immediately at a time to the required thickness) and multilayer. The latter have the so-called rough and finish surfaces. As a rule, the rough base has a thickness of 2 cm or more, and the finishing one - 3-20 mm.

According to the type of connection with overlappings, screeds can be divided into solid and floating. The first has a reliable connection with the draft base, the second has no hitch with anything. For installation, hydro- and heat-insulating materials are used.

What can be used to create a screed?

Depending on the type of screed, they can be made of various materials. Yes, to create wet screed cement, water and sand are used. Cement in this case acts as a binding material, and sand becomes a filler. To improve the quality of building mixtures, various components can be added to them to improve strength and reduce drying time.

On a note! To prepare such a mixture, it is necessary to mix 1 part of cement with 3 parts of sand. The required amount of water is added to them. This is a fairly economical option.

To create a wet screed, ready-made sand concrete sold in stores can also be used. Its main disadvantage is the high shrinkage rate. Because of this, the thickness of the screed layer cannot be less than 3 cm, otherwise it will quickly become covered with cracks.

Advice! To reduce the risk of cracking of the screed, fiber fibers are added to the raw composition, or layers of reinforcing mesh are laid on the rough base.

Gypsum-based mixtures are used for wooden floors. This material can be laid in a thin layer, as it practically does not shrink. Drying time is also attractive - only 1-2 days. The only exception in terms of the use of such compounds is high humidity in the premises.

Self-levelling or usually used for the final leveling of conventional wet screed. The reason is the rather high cost of the material. Such a composition is used for leveling floors with an unevenness of 2-7 mm.

Required for manufacturing sheet materials type of drywall, as well as expanded clay of medium and small fractions for backfilling the base. The joints of individual sheets of material are treated with adhesives.

How to make a floor screed

Work on the installation of floor screed invariably raises questions from beginners. Below are instructions for creating a dry, wet and semi-dry screed. However, no matter which option is chosen by the masters, in any case, before starting work, it is important to prepare a rough foundation.

Features of the preparation of the base

To begin with, if the house was not built from scratch, you will need to get rid of old finish gender. Moreover, you will have to remove the old screed up to the overlap. It is especially important to repair any flaws on the base. It can be cracks, chips, any gaps. All this must be sealed with a sealant or cement composition after preliminary priming in order to avoid too much consumption of mixtures (relative to a wet screed) and to increase the adhesion of the compositions to the base.

Preparing the base for the screed - photo

On a note! Sometimes a new screed is poured directly on top of the old one, but this is only acceptable if the previous version of the base is strong enough. However, only an experienced specialist will be able to assess the condition of the old screed. Sometimes it is even enough to use just self-leveling compounds to make the old base perfectly even.

You can clean the floor from the old screed using a jackhammer. Further, the base is cleared of construction waste, which is placed in strong bags and taken to a landfill.

Small protrusions on old screed can be removed by arming grinder. After preparation, it is important to prime the base in order to increase adhesion.

Making a wet screed

Step 1. The first step is to prepare all the necessary tools and materials. This building level, slats that will act as beacons, self-tapping screws and dowels, building mixtures, sand and cement, as a rule, a perforator.

The price per square meter of floor screed seriously affects the cost of the entire repair, because. These works are quite laborious and costly. In this article, we will analyze the prices for the services of workers, as well as for average cost necessary materials for screed.

Based on our review, we can draw preliminary conclusions and calculations on the final amount.

As we already wrote in, the main material here will be a dry mix for floor screed. Prices different manufacturers do not differ significantly from each other, so we recommend choosing the options "by ear".

The price of a bag (25 kilograms) of a self-leveling floor will average 350 rubles. You can buy a mixture and much cheaper, but the quality of the mixture will be in question.

In addition to the mixture itself, you need to buy metal "beacons" that will help make the floor perfectly flat. Their standard size is 3 meters in length, and the price is about 35 rubles apiece.

The average cost of floor screed work

The price of a floor screed per m 2 depends heavily on the required layer thickness. Price of work at minimum thickness in 2-3 cm will be about 350 rubles per 1 sq.m.

In some cases, a thickness of 30 mm is enough, but if the rough surface is not even, it is better to increase the thickness to 4-5 centimeters, respectively, and the price of the fence will increase to about 500 rubles per 1 square meter. At the same time, prices in different companies and different regions may vary significantly, so we recommend that you familiarize yourself with the offers of several companies.

To save almost half of all funds for a floor screed, we recommend that you read the article on our website about self-filling the floor with your own hands.

Approximate calculation of the price of floor screed

Now, let's do some math. Take for example a room measuring 30 square meters (5 by 6 m), the required thickness of the screed is 3 centimeters.

The cost of beacons - you will need about 10 pieces of 3 m each. So their total cost will be - 350 rubles.

Now to the main calculation, to the mixture. The flow rate of the solution must be measured in cubic meters, which means: 30 sq.m. * 0.03 screed thickness = 0.9 cubic meters of solution.

Depending on the type of your dry sweep, the number of cubic meters of ready-made mortar from one bag can vary significantly, so check the information on the bag first. On average, about 0.016 cubic meters of the finished solution is obtained from one bag of the mixture.

That is, to fill a room of 30 sq.m., 3 centimeters thick, it will take about 55 bags of the mixture, or about 19,500 rubles.

The cost of work, if workers do the floor screed for you: 30 * 350 = 10,500 rubles.

Total expenses: 19500 + 10500 + 350 ~ 30,000 rubles.

The price of a floor screed per m 2 will be about 1000 rubles.