Concrete base gender is currently perhaps the most widespread in both residential and industrial construction. It is suitable for almost any finishing coating or can, after appropriate processing, be used independently. Its main advantages, subject to the filling technology, are high strength, resistance to destruction, and durability of use. It is not surprising that when conducting private construction or when renovating an apartment, in the vast majority of cases, homeowners opt for this particular flooring technology.

Is it worth inviting construction specialists, or is screeding a concrete floor with your own hands quite accessible process for the average home owner? This publication is devoted to answering these questions.

Types of concrete floor screeds

Concrete floor screeds may have different design, performed using slightly different technologies and intended for different purposes.

• Thus, they can serve exclusively for leveling the floor, which is carried out before installation. finishing coating. Powerful screeds serve as a reliable foundation in rooms where increased mechanical loads are expected. They can also perform the functions of ensuring the required thermal balance, acting, for example, as powerful heat accumulators in “warm floor” systems. Screeds are often used to cover communication systems. They can they are used and in order to create a certain slope in those rooms where it is necessary.
• Concrete screeds differ according to the number of layers:

— They can be single-layer, that is, poured simultaneously to the entire calculated height. This is usually used in industrial, utility or ancillary non-residential premises, where there are no increased requirements for the evenness of the floor.

— Multilayer screeds are poured in several stages. Usually the first layer serves as a rough base, and the top one creates flat surface for further flooring work. This approach is also used in cases where the total thickness necessary screed reaches too large sizes, and it is more expedient to do it in layers.

• Screeds also differ in the degree of adhesion to the base:

— Bound ties have direct contact with the base. Of course, with such a filling technology, maximum homogeneity of the materials and their high adhesion to each other must be ensured. Such coatings are characterized by good strength qualities in terms of withstanding high mechanical loads. However, the condition of the surface layer will largely depend on the moisture level of the base. Such screeds are mainly performed on dry floor slabs on the floors of buildings.

— In the case where the base does not have sufficient waterproofing, a sleep screed is used separation layer. A layer of waterproofing material (roofing felt, polymer film, coating composition) becomes a barrier to the penetration of moisture from below, and the screed itself has no contact with the base. With this technology, the layer of poured mortar cannot be less than 30 mm and, as a rule, requires reinforcement.

This technology is often used when constructing screeds on the ground, for example, in garages, sheds, basements, and on the first floors of houses without basements. They also use it in rooms with high humidity levels.

— Where enhanced thermal insulation of the floor is required or there is a need for sound insulation, floating screeds are used. In this case, the concrete solution is poured over a layer of insulation of one type or another. The screed turns into completely independent design- a slab that is not connected either to the base or to the walls of the room. Minimum thickness the fill in this case is at least 50 mm, and reinforcement of the screed becomes a prerequisite.

The humidity of such a screed is absolutely independent of the condition of the base, and a good insulating effect is achieved. Disadvantages - excessively large thickness, and therefore - load on the floor. Typically, such screeds are used only on the first floors of residential or ancillary buildings, especially if the filling is carried out on the ground.

• Screeds can be made with a homogeneous solution or include certain fillers:

— Additive with cement-sand mortar polystyrene foam chips significantly increases the thermal insulation qualities of the coating.

Typically, such screeds require a second, strengthening and leveling layer.

— Where ties are required large thickness or with increased thermal insulation qualities, expanded clay is added to the concrete solution.

Expanded clay concrete has sufficient strength, but for laying some coatings, you will also need to fill in the front layer from ordinary mortar. And here ceramic tiles It will be quite possible to lay directly on such a base.

Screeds with micro-reinforcement show good performance fiberglass. This technology allows you to dramatically increase the strength of the coating to mechanical loads, stretching, and bending.

Such screeds usually do not crack, are less susceptible to shrinkage during hardening, and have less dust formation. They are great for underfloor heating systems.

• flooring can be done using classic, “wet” technology, or using semi-dry technology. Semi-dry screed is a relatively new thing, and not all more ready to try it out in practice. In addition, it requires special professionalism in preparation. mortar mixture, in laying out, compacting and leveling the mortar. Most home builders prefer to use proven “wet” technology, which will be discussed later in the article. However, if you are limited in time, consider inviting a semi-dry screed installation specialist. When choosing a contractor, pay attention to the technology used - the presence of a mechanized supply of the composition will ensure cleanliness in the apartment. For example, laying a semi-dry screed along latest technology is carried out by the company "EUROSTROY 21 CENTURY" (company website www.prestigehouse.ru).

Solutions for pouring concrete screed

It is quite natural that if you need to pour a concrete screed, you will first need to decide on the type of solution. There are some options in this matter.

According to the existing SNiP canons, the minimum strength of conventional concrete screed, regardless of the type of further cladding, must be at least M-150 (the coating can withstand a force of 150 kg/cm²). If used self-leveling jellied composition, then here the requirements are even higher - from M-200. The solution should be selected in accordance with these requirements.

1. "Classic" concrete mortar, used for pouring a regular floor screed, is considered to be a cement-sand mixture in a ratio of 1:3. This “recipe” is time-tested and fully justifies itself. However, there are several nuances, without taking into account which you can easily ruin the future screed:

• To prepare concrete, you cannot use ordinary “washed” river sand that has not undergone special treatment. The frozen surface will not be durable and will begin to crumble, crumble and crack over time. The fact is that grains of sand have smoothed outlines due to prolonged exposure to water, not providing adequate clutch. In this regard, quarry sand is much better than its faceted grains of sand irregular shape. True, when choosing, you need to look carefully so that you don’t come across large quantity clay inclusions - this will also reduce the strength of the screed.

The presence of a small amount of fine gravel component will not affect the strength properties of the screed. However, if a smooth surface is required, it will be necessary to sift the sand through a sieve.

• A very important condition for the strength and durability of the screed being poured is the optimally selected amount of water. It is no secret that some novice home builders, in an effort to make the work of pouring and leveling concrete easier, use excessive amounts of water, getting semi-liquid, easy spreading solution. By doing this, they are laying a “time bomb” - at the end, the screed will not have the required qualities.

Firstly, an excessively liquid solution will definitely cause severe shrinkage when hardening. In this case, one cannot expect a flat surface in accordance with the set level. And secondly, a violation of the cement-water balance will certainly reduce the strength qualities of hardened concrete. The surface is loose, unbound, with increased dust formation.

There are, of course, special amounts of water in concrete mortar, but they are usually adhered to by the technologists of production enterprises. reinforced concrete structures and large mortar units. In home construction, they often rely on their own experience, intuition and common sense. In addition, it is very difficult to accurately calculate the amount of water due to the fact that it largely depends on the moisture content of the filler. The sand can be wet and heavy - and this is also water, which will participate in the process of preparing the solution.

Ideally, the concrete solution should be dense, but sufficiently plastic, so that when it is poured and leveled, there are no air voids left in the thickness of the floor. You can roughly focus on the following ratio - a liter of water per five kilograms of cement-sand dry mixture.

It is important to choose the right golden mean"so that the solution is both dense and plastic

It is very difficult to mix the screed solution by hand using a shovel. It is better to use a concrete mixer or construction mixer of sufficiently high power for this. First, mix the dry ingredients in the required ratio (maybe with a little moisture), and then add water very carefully, portionwise.

An important condition for the quality of the future concrete screed is the purity of water. It is prohibited to use process water containing fats, oils, petroleum product residues, etc. Also, dirty, oily containers should not be used to carry water to the concrete mixing site.

2. The modern range of building materials on sale can significantly simplify the process of pouring screed. For these purposes, ready-made dry construction mixtures can be used.

Compared to using the usual cement-sand mixture, this technology has whole line advantages:

• In terms of strength and other performance indicators, screeds made from ready-mixes are in no way inferior to ordinary concrete, and can even surpass it in a number of parameters.
• To prepare the solution, you do not need powerful equipment or heavy manual labor - a mixer or even a powerful electric drill (perforator) with an appropriate attachment is enough.
• In principle, there are no problems with the dosage of components - everything is already provided by the manufacturer, and the master can only strictly follow the instructions for preparing the solution.
• Many solutions prepared from such mixtures are much lighter, which reduces the load on the floor, reduces transportation costs and makes it easier to lift materials to floors.

• It is possible to select the desired composition for specific operating conditions. Thus, there are solutions for rough or leveling screeds, for underfloor heating systems and for rooms with high humidity. Special plasticizers or microfibers added to their composition not only increase the strength characteristics of the coating, but also reduce the time it takes for the screed to completely harden, reducing the overall duration of construction work.
• What is very important for beginners is that working with such compositions is simple and does not require particularly high skills. The main thing is to follow the recommendations for pouring technology, which are necessarily attached to any batch of material.

All this will be true only if a high-quality dry mixture is purchased. Alas, there are a lot of fakes or low-quality mixtures on the building materials market in this segment. It is best to choose formulations from reputable manufacturers, be sure to check the certificate so as not to run into counterfeit products. It is also important to check the shelf life of the material - it is limited, and an expired mixture can significantly lose its quality.

The only drawback of this approach to pouring screed is that the price may be slightly higher than with self-production solution. Well, you have to pay for convenience and quality.

Prices for various types of screeds and self-leveling floors

Screeds and self-leveling floors

Preparing the surface for pouring concrete screed

The surface for pouring the screed is prepared in different ways, based on the conditions:

• If the floor will be laid on the ground, for example, in a private house without a basement or basement, then the work is carried out in next sequence:

— The soil is selected to a depth of 500 mm.

A sand cushion 100 mm thick is poured and carefully compacted. A gravel layer is poured on top of it in the same way.

— Rough pouring of concrete with the addition of expanded clay is done to a height of 150 — 200 mm – for insulating the floor surface.

— After the base has hardened, it must waterproofed– roofing felt or dense plastic film to prevent the entry of ground moisture from below. Waterproofing material must definitely go out on the walls on height, slightly greater than the height of the planned screed. If necessary, another layer of insulation can be poured on top, and then a reinforced finishing screed can be poured.

• In apartments, first of all, it is necessary to remove the old screed. This is done for several reasons:

— Firstly, the old screed does not guarantee integrity, since it can peel off, crack, and these deformations will be transferred to the newly poured layer.

— Secondly, do not forget about the maximum permissible loads on floor slabs. So, in serial high-rise buildings old building permissible load about 400 kg per square meter - static and 150 kg - dynamic. And the news is one square meter concrete screed, 50 mm thick, approaches 100 kg. Therefore, all work related to thickening the screed will have to be coordinated with design organizations. And it is far from a fact that such permission will be obtained.

- And thirdly, the height of the ceilings in apartments is usually not so significant that you can afford to significantly raise the floor level.

The old screed is dismantled with a hammer drill, but very carefully to prevent destruction or damage to the floor slab. The remains of the chipped concrete are removed, and then the surface is thoroughly cleaned and dust-free.

• If a bonded screed is planned, then it is necessary to thoroughly clean the existing recesses, cut cracks or crevices to a width of at least 5 mm so that the concrete solution can freely penetrate into them when pouring.
• If the screed is floating or on a separating layer, then all defects must be repaired immediately. You should not leave voids under the waterproofing layer - condensation can accumulate there, and these areas of high humidity are likely to become a “problem area”.

Defects are sealed using a repair compound, epoxy putty or ordinary concrete mortar. In case of large defects, polyurethane foam can sometimes be used.

The corners between the walls and the floor are especially carefully checked and repaired - water from the concrete solution when pouring the screed can penetrate deep into the ceiling or even leak to the neighbors below.

• Then, in any case, the surface of the ceiling should be treated with a penetrating primer. This measure will additionally remove dust from the surface of the slab and improve its adhesion to the concrete being poured. In addition, the ceiling will not actively absorb moisture from the solution. This is extremely important. A lack of water in the layer of wet concrete adjacent to the base will lead to incomplete maturation of the cement stone, and the screed will peel off or collapse under even minor loads.

The soil is poured over the surface in strips and distributed evenly with a roller. In hard-to-reach places, for example in corners, it is better to use a brush.

• An elastic damper tape is glued along the perimeter of the walls. It will become a compensator for the expansion of the concrete screed, which will prevent its deformation or cracking. In addition, under no circumstances should the screed come into contact with vertical structures, be it walls, partitions or columns.

• If the screed is on a separating layer, then first the entire surface of the ceiling is covered with a dense polyethylene film, at least 0.2 mm thick. The strips are overlapped by at least 100 mm. The joints must be taped with waterproof construction tape. You need to try to very carefully lay the film in the corners so that strong wrinkles and folds do not form - air “pockets” may remain there. The edges of the film on the walls should be 5 ÷ 10 mm higher than the planned screed - it will be easy to trim them later.

Schematically - waterproofing film and damper tape for screed on the separating layer

After the polyethylene is laid, the damper tape is glued - just as mentioned above.

Beacon system and reinforcement

To achieve horizontal screed and its required height, it is necessary to create a system of beacons along which the concrete mortar will be leveled.

Definition of zero level

It is very successful if the farm has it or if it is possible to take it from friends. In this case, the work will be significantly simplified - to beat off horizontal stripes on the walls and it will be much easier to control the level of guides.

If this is not possible, then you can set up beacons just as well using a water level and a regular building level.

The water level consists of two cylindrical transparent vessels with the same scale applied, connected by a long elastic thin hose. According to the physical law of communicating vessels, the liquid level in them is always at the same height from the horizon. Thus, having made one mark at a certain level, you can high precision transfer it to other surfaces within the length of the flexible hose.

Marking begins by determining the zero level of the future screed. To do this, first of all, you need to draw a basic horizontal line. This is done as follows:

• The estimated highest corner of the room is visually determined. A mark is made on the wall in this corner at an arbitrary height. It is better, of course, to make it so that it is as convenient as possible to work, for example, one and a half meters from the floor.

• Using a water level, this mark is transferred to all walls of the room. The distance between the marks should allow you to connect them with a line using an existing ruler (you can use a long building level or pure rule).
• The drawn line should run along the entire perimeter of the room and close at one point - this will indicate the correctness of the measurements.
• Measurements are taken from the applied baseline to the floor surface. Measurement points are usually every 0, 5 m. It is imperative to ensure that the measurement is carried out strictly vertically. The obtained values ​​​​need to be written down (on a piece of paper or even on the wall with a pencil).

The measurement point that gives the minimum height of this distance will correspond to the highest section of the base.

• The thickness of the future screed is subtracted from the obtained value at the highest point (minimum 30 mm). For example, minimum height– 1420 mm. We subtract the thickness of the screed (30 mm) and get 1390 mm. This is the distance from the drawn reference line to the zero level.
• Now it will not be difficult to draw the entire zero level line around the perimeter of the room - to do this, you need to measure the resulting value from the base down, mark the points and connect them with a straight line. To simplify your work, you can make a template and quickly move the marks from the base line. After connecting them, you get the main line of the zero level.
• In construction practice, it is rare, but it still happens, when in the center of the room the floor level is slightly higher than at the walls. This must be checked by pulling the cord at the zero level between opposite walls and measuring the height from it to the floor. A similar check should be carried out in several places. If it is determined that there is a hill in the center, it will be necessary to shift the zero level up to ensure a minimum permissible thickness screeds throughout the entire area of ​​the room.

Marking for beacon system

It is advisable to mark the beacons and guides immediately after hitting the zero level, guided by the following principles:

• The orientation of the guides should correspond to the intended direction of the most convenient pouring of the screed. This is usually done along the room, from the far wall to the exit.
• It happens that due to the complexity of the room configuration, it will be necessary to change the direction of pouring in a certain area. This should also be immediately taken into account when marking beacon lines.
• The distance between the wall and the parallel guide closest to it is usually maintained no more than 250 - 300 mm. If you leave it large, a poorly leveled area or even a failure may form along the wall, which will require additional intervention later.

• The distances between adjacent guides are not particularly regulated. The main thing is that the leveling rule installed on them protrudes on both sides by about 200 mm. The guides should not be spaced too far apart - quite large gaps may appear in the center between them after the hardening concrete shrinks.
• I distribute the guide lines across the width of the room, usually at the same distance from one another.

How to set beacons and zero level guides

Previously, various available materials were used as guides for the beacon system, for example, wooden blocks or unnecessary pipes. Today, metal profiles are mainly used for these purposes.

• Thus, galvanized U-shaped profiles from plasterboard systems perform very well. They are resistant to deflections and create a reliable “rail” for working as a rule.
• Plaster profiles are very popular, although they are not without some disadvantages. They have a stiffener, however, on long sections when working as a rule, they can still sag. Therefore, when using them, the number of support points must be increased.
• In some cases, you can do without using profiles altogether.

There are many ways to install a beacon, and it is impossible to consider everything. Let's look at just a few of them.

• One of the most accurate and simplest is using self-tapping screws.

— At the far end of the room, at a distance of 250 - 300 mm from the corner between opposite walls, a strong cord (for example, a fishing line or a thick nylon thread) is pulled strictly at the zero level. It is important to tighten it as much as possible so that there is no sagging in the center.

- At the intersection of the line of the extended cord with the line closest to the wall, directing in the floor is drilled a hole into which a plastic dowel is driven and a self-tapping screw is screwed in. Using a screwdriver, it is screwed in so that the upper edge of its cap exactly coincides with the zero level.

— A similar operation is repeated on the opposite side of the room, closest to the exit.

— Two self-tapping screws defining the guide line are connected to each other with a tightly stretched cord, so that it runs along the top of their heads.

— On this segment, mark and drill holes for dowels, distributing them evenly so that an interval of 350 ÷ 400 mm is maintained between them.

— Self-tapping screws are screwed into dowels until their heads coincide with the tensioned cord. A check must be carried out using a building level - if necessary, the required adjustments can be made.

— In the same way, a line of screws is made on the opposite guide, and then on the intermediate ones. In this case, the check must be carried out in all directions - longitudinal, transverse and diagonal.

— Once the same zero level has been reached along all lines, the stretched cords are removed. Prepare a thick concrete solution. It is laid out in small slides along the line of screwed-in screws. Then a U-shaped profile is put on top and pressed into the solution. The transverse flange of the profile should rest against the head of the screw. It is important that the profile “sits” evenly on both sides, without distortions.

Installation and fixation metal profiles— guides

— After the solution has set and securely fixed the profiles in the installed position, you can proceed to pouring the screed.

With plaster profiles it turns out to be somewhat more complicated - it is more difficult to fix them using the heads of the screws. For these purposes, special fastening elements can be used - “eared”, which are placed on self-tapping screws, and their petals are used to crimp the side flanges of the profile.

Video: placing beacons using screws and fasteners -“ Ushastiki»

Another subtlety is that plaster profiles also have their own height, and this must also be taken into account when setting the screws to the zero level.

In addition, much more solution for fixing is required - to the point that I even resort to laying out a solid shaft into which the profile is embedded with emphasis on the screw heads.

• Some craftsmen are accustomed to doing without metal profiles altogether.

— The exposed self-tapping beacons are tied with thin wire, thereby creating a kind of reinforcement cage. Then the solution is laid out along the entire line in a slightly excess quantity, so that the resulting shaft is slightly above the zero level.

— When the solution begins to set, a guide plane is formed. Using the rule, the upper edge of this shaft is compared and smoothed down to the screw heads.

- After hardening, you will get excellent guides along which you can work as a rule, and then they will enter the structure of the poured screed.

• If the screed is carried out on the floor, then the self-tapping method becomes inapplicable - the tightness of the film cannot be broken, and in addition, there should be no rigid adhesion of the new screed to the base. In this case, you will have to tinker more, laying out piles of mortar and accurately inserting the guides at the zero level along the stretched cords.

To speed up the readiness of the beacon system, tile adhesive is often used instead of conventional mortar - its hardening time is much shorter. But gypsum compositions are unacceptable. Firstly, they practically do not shrink, unlike cement ones. Secondly, gypsum compositions have completely different indicators of water absorption, adhesion, strength, ductility, etc. We can say with 100% certainty that cracks will appear on the screed where the beacons are located.

Nuances of screed reinforcement

Of course, this measure is useful, especially with thick ties. Most often used for this metal grid made of galvanized steel wire with cells from 50 to 100 mm - it can be purchased at finished form in shops. Only when placing it, many people make a serious mistake.

If you look at numerous photographs on the Internet, you can see a mesh laid directly on the floor slab or on a layer of waterproofing. There are many doubts about the usefulness of such reinforcement. Ideally, for the reinforcing belt to play its role, it should be placed in the thickness of the mortar being poured, approximately in the middle of the height of the screed.

To do this, you can purchase special polymer stands. However, it will not be difficult to make supports from wire or even to raise the mesh on linings from pieces of broken tiles or fragments of old concrete screed. Wooden pads should not be used under any circumstances.

Obviously, it is necessary to install the reinforcing grid before setting the guides. Most often, the installation of the beacon system and reinforcement is carried out in parallel, and the mesh can also be fixed on those piles of cement into which metal profiles are embedded.

Filling the screed

Oddly enough, the process of pouring the screed itself looks like a series of technological operations probably the easiest one. If all preparatory work done correctly, this stage will not present any difficulties.

• For normal pouring and hardening of the screed, the optimal temperature is from 15 to 25 degrees. It is allowed to carry out work even with more low temperatures(but not lower than +5), but the maturation period of concrete will increase significantly. In too hot weather, it is also better to refrain from pouring - = the top layer can quickly dry out and crack. Does not like screeds and drafts, although there is full access fresh air cannot be blocked.
• It is best, of course, to work together - one is preparing the concrete solution, and the second is directly pouring and leveling the screed. The technology for mixing the solution has already been described above.
• Work is carried out from the far corner of the room, gradually moving towards the exit. You should try to complete the pouring within one working day - this way the screed will be as uniform and durable as possible. If for some reason this is not possible, then the floor surface is divided in advance into sections (they are called fill maps) with jumpers installed between them.
• spread in excess quantities between the guides, so that its layer is 15 - 20 mm above the zero level. Initial distribution is carried out using a trowel or shovel. It is imperative to ensure that there is no unfilled places- this happens often under the guides, under the bars fittings or at corners. It is necessary to achieve maximum compaction of the concrete solution and release of air bubbles from it. To do this, you can carry out “bayoneting” - the solution is pierced with a shovel or trowel before leveling.
• Next, on on the rulers set the rule. Using forward and transverse zigzag movements, the solution is leveled to the level of the guides, so that a flat, smooth surface is obtained.

If the sand has not been sifted and large fragments (pebbles or shells) remain in it, then certain difficulties may arise - these inclusions can leave grooves and you will have to suffer a lot, removing them and smoothing out unevenness in order to bring the surface to an ideal state.

Concrete mortar is added as needed so that work continues uninterrupted. Excess mortar is carefully removed at the end of filling the room.

Video: a visual example of pouring screed along beacons

After the filling is completed, it is necessary provide measures, excluding accidental entry of people or pets into the premises during the first 5 - 7 days. In order for the maturation process to proceed effectively, the surface must be moistened with water daily (starting from the second day), keeping it moist. In extreme heat, it makes sense to cover it with film after initial setting to avoid drying out.

If a regular sand-cement mortar was used, then the readiness of the screed with the operational one can be said no earlier than after 3 weeks. When using dry building mixtures, the timing may be different - they must be indicated in the attached instructions.

After the screed is ready, it is checked for evenness and surface quality. To do this, set a rule on the embedded guides and measure the resulting gap in the center. There is no escape from concrete shrinkage, and if the gap does not exceed 1 - 2 mm, then this will be within normal limits.

Often a thin layer of compound is poured over the screed to make the surface perfectly smooth. However, this is a topic for separate consideration.

Using the traditional method of leveling bases for future floor coverings. The technology of its device is quite simple, and the price is one of the lowest among all types of screeds. On a perfectly flat base obtained after installing a wet screed, you can lay polymer floors or floor coverings (tiles, laminate, linoleum, etc.).

Application features and types of wet screed

To make a choice - wet or dry screed, you need to know the features and area where the wet screed is used.

The scope of application of wet floor screeds is very wide, compared to dry screeds, which can only be used in rooms where there is no risk of exposure to moisture. Wet screed can be used both in production and at home. This can be a self-leveling screed, which also belongs to the “wet” category, a traditional cement-sand screed or a concrete screed with fillers.

With the help of wet screeds, modern heated floors are installed when pipes or cables are laid under the screed layer.

Wet screeds can be single-layer or multi-layer. Single-layer screeds are convenient to use to eliminate defects in floors. But with significant differences in height, for rough leveling, it is better to use cement-sand mortar. After installing the first layer, you can apply it finishing layer from a self-leveling mixture.

The main advantage of wet screed is its relatively low cost due to the low cost of materials. This screed is durable, fire-resistant and moisture-resistant, it has a small thickness. There are, of course, disadvantages of wet screed. In particular, such a screed takes a long time to harden and dry; it has poor heat and sound insulation. Also, a disadvantage can be considered the high labor intensity of wet screed.

Wet screed technology

To install a wet screed, you can use a traditional cement-sand mortar, which is prepared immediately before starting work by mixing the components. Ready-made mixtures for screeds greatly simplify the procedure for preparing the solution. If concrete floors are installed in industrial premises, designed to withstand very heavy loads, a filler of gravel, expanded clay, screenings, etc. is added to the solution. The solution is distributed over the base area using a rule.

The thickness of the wet screed ranges from 10 to 80 mm. If the layer needs to be thicker, for example, to raise the floor level, then expanded clay is poured under the screed or expanded polystyrene is laid. In addition, these materials have heat and sound insulation properties.

The drying time of a wet screed is from 3 to 36 hours. It all depends on the composition of the solution and the thickness of the layer. But you can walk on the surface no earlier than in a week. Semi-dry floor screed hardens more quickly, which is installed with a minimum amount of water in the solution.

In order to give the wet screed greater strength and durability, you can use reinforcement - reinforcing mesh or fiberglass. In the second case, the duration technological process The cost of laying a wet screed is significantly reduced, since fiber can be added directly to the solution, while installing the reinforcing mesh will take a lot of time.

Material consumption and price of wet screed

The consumption of materials, which affects the price of a wet screed, is determined depending on the characteristics of the technology and the quality of the base. IN classic version To make a wet screed 6 cm thick, you will need an average of 15 kg of cement per 1 m2. The company’s specialists, after inspecting the premises, will be able to accurately calculate the cost of the wet screed. In any case, in the foreground is quality that matches the price.

Installing a floor screed is an important event during renovation and construction. However, which floor screed is better? After all, the reliability and ease of laying decorative flooring depends on its quality. Smoothness and evenness of the floor, the ability to withstand high mechanical loads, sound, heat, waterproofing - the screed performs many functions, and therefore requires a serious approach to its installation.

Today, there are two main types of floor screed: “semi-dry” and “wet” floor screed. Before choosing one of them, you need to figure out which floor screed will be better and what are the pros and cons of each option.

“Wet” and “semi-dry” screeds

The wet version of floor screed is older; the essence of this method is to create a liquid solution based on concrete or cement, which is directly poured onto the slab bases of the subfloor.

Due to the fact that the screed easily spread over the surface, it was practically characterized by self-leveling properties. However, in reality, to improve the quality of a wet screed it is necessary additional processing. First of all, the surface was rolled with a roller to remove air bubbles, and after hardening it was leveled with a spatula.

This technology has a significant drawback - the long drying time of the solution, which, as a rule, led to cracking of the surface, even if the floor screed was previously reinforced. Of course, all this slowed down renovation work. That is why a logical step in the development of technology was the creation of a more advanced semi-dry floor screed, which, depending on the material used, is divided into concrete and cement-sand screed.

Cement strainer

The distinctive characteristics of the mixture prepared for the installation of semi-dry cement screed are the addition of fiber fiber and plasticizer. These components make the screed more elastic and facilitate its installation. In addition, this reduces the amount of water, thereby eliminating the problem of wet screed - high moisture content in the mortar, which as a result makes the cement screed stronger and lighter.

By doing cement-sand screed in the “semi-dry” version, the drying period is reduced to 12 hours after installation, and after 4 days it will be possible to lay laminate or parquet board.

Of course, the process of installing a cement floor screed using the semi-dry method has its own specific nuances. In particular, to create a solution of the required consistency, you will need special equipment such as mortar pumps, trowels, with the help of which the procedure for installing the screed will be high-quality and fast.

Another pleasant advantage of cement screed prepared using the semi-dry method is its low cost. Use of inexpensive components and significantly reduced material consumption compared to wet cement screed determine the price for its installation.

Concrete screed

Another method of laying semi-dry screed can be done with concrete mortar. In reality, the technology differs little from cement technology. In addition, most building mixtures contain cement, so leveling the floor with a concrete screed can be safely classified as a type of concrete-cement screed. The only fundamental advantage is the lighter weight. This clear advantage of screeding concrete floors can be explained by the use of lighter aggregates in dry construction mixtures under the brand name "sand concrete".

As a rule, concrete floor screed is used to level surfaces with strong protrusions and slopes. After all, the relatively small weight of the concrete screed makes it possible to slightly compensate for the high thickness of its installation.

As you understand, the impressive thickness of the mortar when screeding a sand concrete floor requires additional measures aimed at ensuring the surface does not crack. These include the installation of an expanded clay concrete screed or a reinforced concrete screed. In both cases, the presence of porous material in the cement-concrete mortar layer increases the adhesion of the mortar to the base and improves the conditions for uniform drying of the screed.

Otherwise, laying a concrete screed is no different from a cement screed. It also dries in about 12 hours, after which you can already walk on it, and 3-4 days after laying it can be laid decorative coating: laminate, linoleum, parquet boards, and after 7-8 days, tiles.

In the case of concrete and cement screeds, it is necessary to take care of waterproofing if the pouring takes place in the kitchen, bathroom or other room where there is a possibility of water spillage.

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Every adult, even without special construction education, understands that in order to lay any covering on the floor in a room, you must first level its base, which is why you need a floor screed. What is a floor screed? This is a construction procedure for forming a flat surface on the floor.. Today there are a huge number of varieties of screeds. When renovating apartments, office and industrial premises, both wet and dry floor screed are often used. The screed solution, called wet, is used quite often and is prepared from sand, cement and water. Additional fillers can also be used. This is the simplest and most inexpensive way to level floors.

The main tasks of a wet screed:

• Smooth surface;
• strengthening the sexual foundation;
• additional sound insulation, thermal insulation of the room;
• hiding the structural elements of a heated floor.

Types of wet screed

According to the specifics of preparing the type of floor surface and making the final layer, wet screeds are divided into four types, which are presented below.

You can also make self-leveling floors by using a thinner mixture that can spread onto the floor without physical intervention. But it’s not worth using only self-leveling floors without creating a key screed.

Preparing the subfloor

Preparing the floor for wet screed involves rough repair work, which includes:

• dismantling the old screed;
• clearing debris from slabs;
• base primer.

Note: The primer must be allowed to dry for five hours!

If the base is soil, then it is first cleared of vegetation, then a layer of sand (at least 10 cm) is poured. When using expanded clay for this purpose, sand is also poured on top of it. The formed layer is carefully compacted. For better shrinkage, the embankment can be slightly moistened with water. With the use of expanded clay, a wet floor screed is much simpler and cheaper, since a minimal amount of solution will be used. If repair work is carried out in the bathroom or toilet, then the water pipes are laid at the same time.

Thermal insulation

As thermal insulation material Expanded clay and polystyrene foam boards are used. But the insulation must be sufficiently rigid. Expanded clay has worse thermal insulation and sound insulation characteristics, but is more reliable and has a longer service life. When performing a wet screed on the ground, insulation must be carried out, and on slabs in some cases (for example, if there is a basement below).

Waterproofing

Roofing material, a thick film, can be used as a material for waterproofing. Strips of material should overlap by up to 15 cm and overlap by 10 cm on the walls facing water pipes, which must be coated with sealant above the planned level of filling the solution. Waterproofing must be carried out in bathrooms, as well as in other rooms that are connected, for example, to the basement.

Reinforcement

When screeding on the ground, it is recommended to reinforce it with reinforcement. For this, a steel mesh welded from reinforcement can be used. You can also simply add a special fibrous metal (plastic) material - fibrin - to the cement mortar.

Installation of additional equipment

If it is planned to lay wiring, install a heated floor system, repair and construction work is also carried out at this stage, with mandatory consideration of all technological specifics.

Stages of performing a wet screed

Wet screed is carried out in several stages, which are given below.

Placement of beacons

To ensure that the wet floor screed is completely level, during its implementation a beacon system is used, which is formed on the floor from profile slats. To install the beacon strip, it is recommended to use a solution designed for screeding.

• First, screws are screwed into the base of the floor parallel to the wall at a distance of 20 cm; their heads should be at the same level (you can check using a special building level), but below 10 mm of the planned level of the screed (depending on the height of the slats used).
• It is worth maintaining a distance of up to 80 cm between the screws; this is no longer recommended, as the slats installed on them may bend.
• The next line with screws is placed every 1.5 meters from the previous line. Here you need to take into account the length of the rule planned to be used for alignment cement mortar. The rule should lie on two parallel slats.
• Next, the mortar is applied to the screws and the slats are mounted. During the installation process, it is necessary to check the evenness of the resulting plane using a level. After installing all the slats, you need to let the solution dry.

The use of beacons is used even in small areas. There should be at least two of them so that the solution can be leveled.

Solution used

After full preparation To perform a wet floor screed, you need to prepare a mixture. As a solution for floor screed, you can use ready-made mixtures specifically designed for leveling floor surfaces. Currently on the market building materials They are available in a fairly wide range and may differ from each other in some characteristics. To prepare them for use, you must strictly follow the manufacturer's instructions.

Proportion of standard solution: 1 part - cement, 3 parts - sand. To improve the strength characteristics, you can additionally add adhesive mass, which is used for tiling work, into the solution.

The finished mixture should not:

• spread too much;
• be dry.

It is recommended to order concrete in a ready-made state. It is made of much better quality. Besides, it’s much more profitable. Concrete is usually used for such work in private country cottages, as well as the premises of the first floors of buildings. Thick layer wet screed made of concrete mixture on the upper floors it is used only in certain cases.

Pouring the floor

Important! To obtain a high-quality screed, the area of ​​the room must be filled at once, since the cement solution tends to harden within an hour, after which it will be impossible to adjust it.

Grinding

If concrete was used as a liquid screed, then after it hardens, the surface is polished with special grinding equipment (a grinder with a special attachment can be used). This event will help remove noticeable irregularities and prepare the floor surface for laying any type of flooring.

Wet screed is traditional way leveling the floor in front final finishing floors Most often, a solution with a high water content is used to make screed - this explains the name of the technology.

Characteristics

Consumer properties

• the ability to level the surface of the ceiling or base;
• strength, resistance to mechanical, chemical, temperature loads;
• high rates of thermal insulation and sound insulation;
• the ability to hide pipes and other communications;
• reasonable price of wet floor screed;
• availability of materials;
• ease of installation.

Areas of use

Wet screed is used in the construction of the following objects:

• Living spaces;
• shopping malls, offices, administrative buildings;
• entertainment and sports facilities;
• garages, parking lots, auto repair shops;
• warehouses, hangars, loading and unloading areas, etc.

Compound

In most cases, a cement-sand mortar is used to create a wet screed. Modern additives (plasticizers) can improve the properties of the solution and reduce the thickness of the screed. Dry mixtures for self-leveling wet screeds - for example, based on gypsum - are becoming very popular.

Wet screeding is a classic method of leveling horizontal surfaces. It is used for all objects, which is not surprising, because wet floor screed is an inexpensive and common method of repair.

Advantages and disadvantages of the method

Often, when a wet floor screed is used, the price of floor installation work is significantly reduced. However, the delivery time for projects increases, since the installation of a wet floor screed requires a long drying time.

pros

The method has several undeniable advantages:

• high structural strength, which allows the technology to be used in the construction of most facilities, including production workshops;
• the ability to conduct hidden communications in the floor;
• availability of prices for materials and work.

Minuses

The main disadvantages of wet screed:

• It is extremely important to follow the installation technology. This includes the process of making the mixture, leveling the floor, approach to work;
• Screed drying time is from a month to six weeks;
• the importance of additional procedures, which include both preparing the room (removing cracks, nicks, gouges) and maintaining the desired microclimate while the screed is drying.

All this makes the work of installing floors using wet screed a very unpleasant procedure, especially if the room is large - the larger the square footage. m. has to be processed, the more labor-intensive the process will be.

Prices and terms

The cost of floor screed using the dry method depends on which composition is chosen as the main one:

• classic sand concrete mixture will cost less;
• a gypsum-based screed will be a little more expensive.

In addition, the manufacturer is important - a high-quality mixture from Knauf will not be cheap, but at the same time it will be easier to make a screed with it. The timing of the work depends primarily on the size of the room and the thickness of the screed. A layer of 10 cm under normal conditions dries in about 4 weeks. At the same time, the work itself on leveling the floor usually takes a day or two.

Laying wet cement screed

Allows you to take a fresh look at the general house arrangement of a wet screed in an apartment: often performing all operations in the usual multi-storey building turns out to be difficult. Some believe that wet floor screed in an apartment is unnecessary, although the technology is quite simple:

• using a level, beacons are placed along which the installation is carried out;
• the mixture is prepared with precise adherence to proportions;
• starting from the highest point, the screed is distributed over the floor surface. It is extremely important to complete the procedure in one go;
• When drying indoors, it is important to maintain heat, humidity, and avoid drafts.

It is quite difficult to obtain a flat surface using this method, so it is easier to transfer all the worries into the hands of specialists. For example, if a team is installing wet screeds on cement based This is not the first time, most likely, they will complete all the procedures quickly and professionally. You can order high-quality installation of a wet screed in Moscow; the cost of the work is usually low, but depends on specific conditions. In order to clarify the price, it is better to call a measurer.

Prices

• Wet screed from dry mortar mixture M150, M200 (thickness from 50 mm) 250r./m 2
• Wet screed made of sand concrete mixture M300 (thickness from 50 mm) 350r./m 2

Floor technology

“Wet” screeds made of cement-sand or gypsum mortar are made according to the following scheme:

1. preparation of the base (carried out regardless of whether the screed will be laid dry or wet);
2. preparing the solution;
3. display of beacons;
4. pouring and distributing the solution, leveling;
5. screed care.