Do-it-yourself clean floor screed. DIY floor screed: recommendations for beginners. The composition of cement mortars for concrete floor screed

The concrete and cement floor serves for decades, does not creak and, in general, does not cause any problems for residents. Of course, if all the work is technically correct. Therefore, we offer you a comprehensive instruction on how to fill the floor screed with sand concrete mixtures for different types of coatings with your own hands.

The essence of leveling the floor with a screed

There are three typical circumstances when a screed becomes almost the only way to arrange an even and reliable base for the subsequent laying of a finished floor.

The first option is concrete floors and ceilings with significant irregularities and defects. First of all, this is typical for apartments in panel houses, where the gaps between the "voids" and casting defects do not allow the surface to be used as a subfloor. Cast ceilings can be seriously overwhelmed in the general plane, especially in new buildings. In such cases, the screed is performed using the standard method.

It's another matter if the floor level needs to be raised by 15-20 cm, when pouring with concrete is extremely unprofitable financially. A classic example is ground flooring on the first floor. In this case, the screed is poured over a bed of crushed stone or expanded clay. This is called a screed on a fill layer, the technology of work has significant differences.

The third option is the most exotic. If the mechanical characteristics of the subfloor do not allow the desired type of coating to be laid, a so-called preparatory screed is poured over it. The most common example is bathroom floors in wooden houses.

Keep in mind: the screed has its goals both to correct the general plane of the floor and to level out local irregularities when covering the entire floor with a common layer of small thickness. On the practical side, sand concrete screed is the most acceptable and affordable way to prepare almost any floor for popular types of coatings: linoleum, laminate, vinyl type or self-leveling floor.

What formulations to use

Traditionally, sand concrete is used for screed in residential premises in a ratio of 3.5 parts of sand to one part of grade 300 cement. In technical premises, the binder should be replaced with Portland cement grade 400. With a screed layer of up to 50 mm, this composition is optimal.

Thicker layers may require coarser filler. It is allowed to use granite screenings and chips, expanded clay and fine crushed stone. It is not recommended to use filler larger than 15 mm.

To improve some characteristics, frost-resistant additives, plasticizers and modifiers can be added to the mixture. To increase the fluidity of the mixture and for easier leveling, you can add about a tablespoon of dish detergent for 20-25 liters of water.

Conventionally, it can be called a screed and a self-leveling floor that does not require alignment with beacons. With a minimum layer of 10 mm, such a screed can cost a pretty penny, especially if the difference between the lowest and highest points exceeds 35-50 mm. It will be easier if you level the subfloor with ordinary sand concrete to eliminate the general drop, and after 2-3 days fill the self-leveling floor with the minimum possible layer.

Do you need reinforcement and insulation

The operating conditions of the floor can be completely different. If the layer thickness exceeds 40-50 mm, the coating may not withstand thermal expansion and seasonal fluctuations in the building. Cracking is practically guaranteed at 70-80 mm screed. If this is quite tolerable for linoleum and type-setting coatings, then the bulk formulations will reflect all the defects of the screed on themselves.

To reinforce the screed, use nylon or steel mesh with a mesh of 30-60 mm and reinforced (welded) intersections. The synthetic mesh is stretched on self-tapping screws screwed into the prep floor, or on thin knitting wire needles fixed in the bedding. It is also possible to lay the mesh in a freshly poured mixture. Steel reinforcing nets, due to their own high rigidity, can be placed on spaced "chairs".

Cement floor insulation is also widely practiced. First of all, when the screed is used as an accumulation layer for a warm floor. Thermal insulation is made with materials that are resistant to uniform compression: foamed polystyrene and polyurethane boards. In this case, the thickness of the screed must be at least 30 mm with mandatory synthetic reinforcement. When laying the insulation on the backfill, preliminary leveling with washed sand is required at a layer of 50-70 mm.

Work order

The first step before pouring is to eliminate absolutely all gaps and crevices through which water can seep. Hollow floor slabs promise another danger: water can flow into them and not flow out from below. A damp ceiling and a swelling floor are guaranteed in the next six months, damage to the electrical network laid inside the voids is possible.

Waterproofing needs to be done even by a private developer: the rapid outflow of water from the mass prevents the hydration of the cement in the mixture from completing, which is why the floor will not gain the required strength. The controversial issue of screed over the fill layer: how, in this case, to prevent seepage? Here it is necessary to fill in two layers with a time interval of at least a day. The first layer is poured directly onto the backfill, although more and more often it is first covered with geotextiles so that the water does not carry the cement along with it. The upper layer will then have time to form normally, and the residual flow of cement laitance will strengthen the underlying masses. The second version is also suitable for a wooden floor: the cavity to be poured is covered with a polyethylene film, hermetically sealed at the seams.

After the floor is sealed and waterproofed, we lay out the reinforcing mesh on the spacer props. Next, we give a zero mark on the walls and install beacons. You should not use pure alabaster here, it will shrink. The installation of beacons can be carried out promptly by mixing plaster of paris in the solution of the just prepared batch. After applying small bumps on the floor, we lay the first strip of the lighthouse 10-15 cm from the wall and align with the lacing. The second and subsequent strips are set at a rack or laser level, after laying every third beacon, the general plane is checked by the rule.

Usually, the filling is carried out by two workers: one prepares the batch, and the other installs the next 2-3 beacons on the remains of the previously mixed mass.

Post-processing the subfloor

When talking about the thickness of the screed, we always mean the final value after surface treatment. Depending on the floor covering, the floor can be processed in different ways, while the thickness can either decrease or increase within 0.5 mm.

The two most well-known processing methods are grinding and ironing. The first is to get rid of the top layer formed by the fine fraction of sand and rare milk, which will wipe unevenly, creak and dust. Sanding is carried out after the screed has dried for two weeks. Ironing, on the contrary, is carried out immediately after the setting of sand concrete and its purpose is exactly the opposite - to strengthen the top layer.

If the surface of the screed will not be exploited, it is allowed not to carry out such processing. For laminate, parquet and other type-setting coatings, it is better to saturate the screed with a primer and then wash thoroughly. The difference here is linoleum - under it the screed is impregnated with diluted 1: 1 polyvinyl glue.

In order to lay the tiles efficiently and evenly, grouting with an adhesive composition is performed over the primed screed, which will be used for tiling. This helps to smooth out the remaining irregularities, reduce the screed layer above the insulation to 20 mm using fiberglass facade mesh, and improve adhesion. After drying, the surface is processed with a grinding wheel to remove the "glaze", which prevents the deep absorption of the tile adhesive.

An uneven floor can ruin the appearance of the room, lead to tile splitting, deformation of linoleum, and a decrease in the life of the laminate. Therefore, to level the surface, before laying the flooring, a dry screed is used. Screed is an intermediate layer between the finishing coating and the floor base. The service life of the floor depends on the quality of the screed. There are solid monolithic screeds (seamless or they are also called "self-leveling floor") and prefabricated (dry).

The purpose of the screed

In addition to the main function of leveling, the screed also performs several others:

• strengthening the concrete base;
• increase of heat, hydro and noise insulation of the room;
• hiding wiring and pipes located on the floor;
• load distribution during floor operation;
• providing the necessary slope for the drainage of water in the bathroom, kitchen;
• lifting to the desired level of the sub-floor.

Screed requirements

The screed used must meet certain requirements:

• thickness not less than 20 mm - when using a polymer-cement mixture with reinforcing fibers, 30 mm - cement-sand mortar, 40 mm - if there is an insulating layer under the screed;
• when laying the screed for sound insulation, leave 20-50 mm from the wall (fill this space with sound-insulating material);
• when laying the screed on pipes, its thickness should be 15-20 mm more than the diameter of the pipe;
• the density of the mixture should be the same along the entire perimeter;
• the strength indicator must be at least 15 MPa (20 MPa when using polyurethane material);
• when using liquid mixtures, it is necessary to use a waterproofing barrier;
• with a screed thickness of more than 50 mm, reinforcement is recommended to prevent splits and increase strength.

Types of mixtures

There are 2 types of floor screed mixtures:

• Self-leveling

Ready mix, applied in a thin layer (20-30 mm). During application, it spreads itself evenly over the floor surface. It can be used for any type of coating.

• Requiring leveling with a trowel

They are used when there are strong irregularities on the floor surface, the need to create a slope or make a warm floor.

Classification of screeds by the type of materials used:

• Wet

It is the most common, inexpensive screed method. The composition includes cement, sand and water. With its help, you can level the floor surface even with significant defects.

It takes a long time for such a solution to dry (about 4 weeks), while the coating may crack during drying.

There are several types of cement-based liquid mixtures:

• concrete, contains concrete and fillers (crushed stone, gravel or sand). It is best suited for the primary formation of the base, as it has a coarse fraction and helps to level any surfaces;
• a cement-sand mortar is similar in composition to a concrete mixture, but it does not contain crushed stone. The absence of this component leads to an increase in price, a decrease in the strength of the screed.
• lightweight concrete contains, instead of the classic filler (crushed stone), granules or crumbs of expanded polystyrene. Such a solution provides good thermal insulation, minimal load on the floor, but has less strength;

• polymer-cement ready-mix is ​​used as a finishing layer (thickness not more than 15 mm), on a flat surface for subsequent laying of the floor covering. It contains Portland cement, fractional quartz sand, polymer additives. The components that make up the composition provide additional strength, reduce the likelihood of settling, and contribute to a fine distribution of the mixture.

• Semi-dry

A common type of screed. To prepare the mixture, less water is used, but more sand. Less moisture in the composition determines lower strength and faster drying (you can start laying the final coating after 15 days, but put heavy objects only after 4 weeks).

• Dry

Due to the absence of "wet" processes, the use of such a screed allows you to immediately start installing the floor covering.

The knauf dry screed (plasterboard sandwich construction) is most popular for leveling floor surfaces. Depending on the purpose, 4 types of knauf screeds are classified:

• "Alpha" - used for floors with a flat surface;
• "Beta" - laying on a flat surface with a substrate of heat-insulating porous fiber materials;

• "Vega" - installation of the structure on a leveling, dry backfill layer;
• "Gamma" - laying on a combined substrate.

• Self-leveling floor

Thin-layer coating based on liquid-viscous oligomers (liquid rubbers and elastomers). The use of such a coating will not be able to even out significant differences. For this reason, the best option is to apply it in a thin layer on a pre-leveled surface.

Types of wet screeds

Depending on the base coating and its operation, there are 4 types of wet screed:

• knitted laying - carried out on floor slabs;
• with waterproofing - the most appropriate use of this screed is in rooms with high humidity or the possibility of a large amount of water getting on the floor (bath, kitchen). The screed mixture is laid on the waterproofing layer;
• with thermal insulation - a reinforced screed is placed on the thermal insulation layer;
• with a final self-leveling coating - for leveling the floor before using floor coverings that are sensitive to minor irregularities (linoleum, laminate).

Materials for floor screed in the apartment

What is needed to screed the floor in an apartment in addition to the ready-made mixture or components for its preparation?

To lay it, you may need:

• wire, plastic or steel mesh (for installing a reinforcing layer);
• to prevent the appearance of cracks on the screed during its drying;
• sound or heat insulating materials;
• The damper tape insulates the walls from contact with the screed mortar.

Initially, you need to dismantle the old screed to prevent the appearance of its defects on the new base. Remove debris and dust. Fill any cracks or depressions with concrete. Using a machine, grind the floor surface, get rid of dust, vacuum it. Place a damper tape between the wall and the floor. If desired, you can install waterproofing using plastic foil or bitumen mastic.

Before laying the screed, it is necessary at a distance of 1.5-2 m from each other.

The highest point of the floor will correspond to the level of the future screed. If the floor surface is not even enough, to place the lighthouses on the same level, underlays can be used.

Use a long building level to check the location of the lighthouses on the plane. To fix them, use a cement mixture every 30 cm.

Calculation of the number of components for concrete

To calculate the required amount of components, it is necessary to calculate the total volume of the mixture. To do this: multiply the average height of the screed by the length and width of the room.

If the floor width is 3 m, the length is 4 m, the lower point of the screed is 3 cm, the upper one is 4 cm, the average height of the screed is (3 + 4) / 2 = 3.5 cm, the required volume is 0.035 m * 3 m (width) * 4 m (length) = 0.42 m3.

To prepare a solution with a ratio of cement and sand of 1: 3, you need to take 0.105 m3 of cement and 0.315 sand. 1 m3 of cement has a mass of approximately 1500 kg, then its required amount is 0.105 * 1500 = 157.5 kg. 1m3 of sand - 1400 kg, then its required amount is 0.315 * 1400 = 441 kg.

High quality concrete mortar

To prepare a high-quality solution, it is necessary to mix all the components correctly:

• mix well dry ingredients (sand, cement). For this, it is better to use a drill with a nozzle or a construction mixer;
• add water (1/3 of the weight of cement) and plasticizers to another container (the required amount will be indicated on the package);
• to the liquid component, slowly, stirring, add the dry one. The finished solution will be similar in consistency to thick sour cream.

Concrete screed device

Not everyone knows how to make a floor screed in an apartment yourself. Before starting work, you should read the recommendations:

• pouring should be started from the far wall of the room;
• pour the solution between the guides, in one go;
• with a large thickness of the screed, make reinforcement;
• level the mixture towards you until the air is completely released and the voids are filled;
• after 24 hours, remove the guides and fill the space with the mixture.

After laying, it remains only to wait for drying. But ? After 4-5 days, you will be able to walk on the floor. Complete drying will take place only after a month.

When self-laying screed in an apartment, you should know:

• must be laid on protected pipes. For these purposes, you can use boards or shields. The pipes leading to the collector must be thermally insulated;
• with significant unevenness of the floor or its rise by more than 10 cm, an expanded clay concrete screed is suitable. Despite the fact that the installation process is quite laborious, it has good heat and sound insulation characteristics;
• before laying the covering (parquet, laminate), make sure that the screed is completely dry;
• for better drying, drafts in the room should be eliminated, the use of heaters should be excluded;
• before using the laying material (to prevent damage to it), put a special gasket on the screed.

It is not difficult to carry out a screed in an apartment. The main thing is to purchase quality materials and follow the instructions.

Concrete screed is the most famous and truly high-quality way of arranging floor foundations. It is very popular with home craftsmen. We will tell you about all the varieties and features of the screed, paying special attention to the technology of its implementation.

Screeds - for what tasks are they used?

Concrete floor screed (BSP) is in demand in both industrial and private construction. It guarantees a perfectly leveled base - durable, resistant to mechanical stress and destruction, high strength, which is suitable for mounting a variety of topcoats. Moreover, the screed in an apartment or a private house is easy to do yourself. The technology of its filling is accessible and understandable. For these reasons, BSP is so popular among craftsmen who are used to doing household repairs with their own hands.

The screed is poured for different purposes. Most often, it is used for high-quality leveling of the floor surface, creating a certain slope, masking engineering networks laid on the floor. BSP is usually divided into multilayer and single-layer. The first ones are poured not at once, but in several steps. In such situations, the lower layer of the mixture plays the role of the base, and the upper one is responsible for the formation of a perfectly flat surface. Single-layer screeds are poured over the entire treated area at once. With this approach, it is impossible to get a perfectly flat floor. Therefore, single-layer BSPs are usually used to perform work in non-residential (utility, utility) and industrial premises.

Screeds can be homogeneous or include special. additives. The latter are often used:

• Expanded clay. This additive provides an increase in the heat-shielding potential of the concrete solution and allows the creation of thick screeds.
• Expanded polystyrene crumb. It also increases the thermal insulation of the floor.
• Fiber fibers. They significantly increase the resistance of the base to bending, tensile and mechanical stress. Compositions with fiberglass are used in the arrangement of underfloor heating systems.

Next moment. Concrete screeds are made using semi-dry and wet technology. They have certain differences. Semi-dry technique involves the use of expanded clay crushed stone or other bulk material. Prepare it, lay it on the surface to be treated, ram it, level it according to a special scheme. Not every person is ready to study its features. The wet method is better known to self-taught craftsmen. It is used by them much more often. We'll talk about it in detail later.

Types of BSP according to the degree of contact with the base - choose the appropriate option

Also screeds are classified as different types depending on the level of their adhesion to the surface. From this point of view, they are:

1. 1. Connected.
2. 2. Floating.
3. 3. On a special layer (called separating).

The connected screeds are poured directly onto the working base, with which it is connected. No additional heat or waterproofing is provided between them. Such solutions are recommended for the following cases: a large area of ​​the base to be treated, an initially flat floor, the need to obtain a BSP with a minimum weight, a low floor level that cannot be raised.

The associated structures are highly durable. They can easily withstand perceptible mechanical pressures, but are susceptible to moisture. It is best to equip them on dry ceilings between the floors of an apartment building in rooms where household appliances, furniture, and so on stand in permanent places.

Floating bundles are mounted on a pre-made cushion made of hydro-, noise- and heat-insulating layers. The result is a kind of slab of concrete mortar, which is not tied to the walls of the room and to the floor. Such screeds must be reinforced without fail. And their minimum thickness should be 5 cm. Parquet boards, linoleum, laminated coverings and other finishing materials can be laid on the floating slab. It is advisable to organize such screeds exclusively in apartments on the first floors.

If the floor surface is characterized by high humidity, it is recommended to pour BSP on a separating layer. It is equipped with a polymer film, roofing material, a special coating composition, foil plates made of polystyrene foam. These waterproofers prevent water from eroding the screed and the floor base itself. A screed on a separating layer shows all its operational advantages when installed in private houses without basements, outbuildings, garages and other premises on the ground. It is also recommended to fill it in toilets and bathrooms.

Classic grouting solution - proven over the years

A sand-cement mixture is used to fill the traditional BSP. Its proportions are known to everyone. For one part of cement, we take three parts of sand. Fill them with water. We get a solution that can be poured into any base (floor slabs, soil). In this case, the screed mixture must be prepared correctly. One mistake in the choice of material for it, a little extra water, and the solution will turn out to be of poor quality. Let's figure out how to avoid such problems.

In order for the solution to have the required characteristics, we carefully select the sand for it. We use exclusively quarry material. It is characterized by irregular grains of sand. This ensures the required level of adhesion of the screed to the base. There should be no clay inclusions in the quarry sand.

River washed sand with grains of sand smoothed by water should not be used. The screed from it will turn out to be of poor quality. The hardened base will very quickly begin to crack and crumble. The volume of water with which the cement mixture is diluted is also of great importance. It is important not to overdo it here. If you add too much liquid, the solution will run out. It is quite convenient to work with him. But the strength of the screed, unfortunately, will be minimal. The poured surface will be loose and very loose. In concrete plants, water is topped up according to strict regulations. In everyday life, it makes no sense to adhere to them. We need to add so much water to the sand-cement composition so that the solution turns out to be plastic and at the same time dense.

On average, about 5 kg of mixture requires about 1 liter of liquid. In practice, this volume can vary, since both cement and sand have their own moisture values. Another important point. It is strictly forbidden to use water containing residues of oil products, particles of technical oils and fats, and other pollutants. The liquid must be clean. And the mixing of the solution itself should be done in well-cleaned containers.

Ready mixes - if you want to finish everything quickly

BSP mortar can also be made using a dry mix that is manufactured and packaged at the factory. This composition initially has the optimal ratio of the components included in it. Dry mixes are characterized by the following advantages:

1. 1. They can be used for pouring floor slabs in old apartment buildings and new buildings.
2. 2. In terms of operational and strength characteristics, they are similar to screeds, equipped with the classic composition described above.
3. 3. Ease of use. The BSP device using ready-made mixtures does not require special knowledge. The technology for carrying out all work is indicated in the instructions attached to the dry composition. It is enough to strictly adhere to the manual, and there will be no problems with the screed.

In addition, ready-made mixtures make it possible to make a so-called lightweight screed. It is indispensable for cases when it is impossible to equip an ordinary concrete floor due to the high weight of the latter.

Lightweight mixture usually consists of cement and perlite, vermiculite or expanded clay. Such formulations have been used relatively recently. But they have already become quite popular, especially when apartments are being set up in new buildings. Their main advantage is that a light floor can be used within a day after laying the dry mix.

How to do the job - let's get down to the procedures

The screed in the apartment is done in several stages. First, dismantle the old concrete base. The operation will have to be performed with a puncher. We act carefully so as not to damage the integrity of the floor slabs.

We clean and dust the dismantled surface. We close up all flaws (voids, cracks) with concrete mortar or epoxy putty. After that:

1. 1. Apply a (penetrating) primer to the prepared surface using a brush or roller.
2. 2. We glue a damper elastic tape around the perimeter of the room. It will exclude the contact of the screed with the walls and will act as a compensator for the expansion of the concrete structure.
3. 3. We create a system of beacons. Using the building level (laser, water), we determine the zero level. We mark the floor. We install beacons (U-shaped metal profiles), attaching them to the base with self-tapping screws.
4. 4. We carry out, if necessary, the reinforcement of the future screed. Pre-fabricated zinc coated wire mesh is best suited for this purpose. We choose products with cells of 10 cm. Nuance. If the fill area is small, a 5 cm mesh is sufficient.

Everything is ready for pouring the concrete mixture. The screed is recommended to be done at a room temperature of 15 to 25 ° C. At the same time, there should be no drafts in the room. If the temperature in the room is less than 5 ° C is prohibited, from 5 to 14 is possible, but undesirable, since the concrete layer will harden for a very long time.

It is most convenient to fill the surface with two people. One person mixes the solution, the second immediately processes the floor with it and levels the resulting base. We always start the procedure from the far corner of the room and move towards the exit from it. Pour the solution between the previously installed guides. We take its layer 1.5-2 centimeters above the zero level. We distribute the screed with a shovel (as an option - with a trowel, if the room has a small area). We use the same tools to bayonet the concrete mixture, expelling air bubbles from it.

After the initial distribution of the composition, we put the rule on the metal guides and begin to carefully level the concrete. The procedure is performed in zigzag movements - first transverse, then translational (or vice versa). We will have to work hard, since the purpose of this operation is to get the smoothest and most even foundation. The finished screed must not be touched for a week. If it's hot outside, the coating will have to be moistened with water every day. The final solidification of BSP is observed in 3-4 weeks.

If a major renovation is planned in the apartment, instructions on how to how to make a floor screed with your own hands with a video on the topic would be extremely helpful. Leveling the floor is the most serious and crucial step in finishing it. The durability and appearance of the topcoat depend on the quality of the work performed.

What type of screed to choose?

The choice of a base for a coating of any material should be made taking into account the load on the made floor, the strength of the floors and the characteristics of the premises where alignment is required. Depending on this, one of the screed types is chosen:

1. The slab-bonded base is suitable for leveling the floor in the garage and in high traffic areas.
2. A screed on a separating layer, or floating, provides for the presence of an insulating material between it and the floor. This type is chosen for rooms where waterproofing, insulation or underfloor heating systems are needed.
3. Compared to concrete mortar, the mixture for a semi-dry screed has minimal shrinkage. It can be used under the same conditions as a concrete solution.
4. Dry screed is carried out according to the principle of using loose and light enough materials (expanded clay, "Knauf" bulk floor, etc.). The only drawback of this alignment is the impossibility of using it in rooms with high humidity.

Before starting repairs do-it-yourself floor in the apartment, you need to take care of cleaning the base from construction debris, dismantle the old screed. When redeveloping, it is best to first install the plasterboard partitions, carry out electrical work, complete the rough finish of the walls and ceiling. Only after the room is prepared, you can proceed to the screed device in one of the selected ways.

How to make a screed yourself?

If one of the "wet" methods is chosen (bonded, floating), then it should be taken into account that it takes about three weeks for concrete or cement-sand mixture to acquire full strength. Only after that it will be possible to continue the work related to the installation of the floor covering. When choosing a semi-dry screed, the curing time is reduced to two weeks, and you can walk on a new floor base in 2-3 days.

Deciding how to make a floor screed in an apartment, many people choose the dry method: leveling the fill layer and laying the slabs is done with less effort. The technology makes it possible to operate such a screed immediately after the completion of installation. The application of the top coat to the base can be started after finishing work in the room without waiting for the moment when the full strength of the concrete mortar is reached.

Installation of screed from DSP and concrete

Before how to make a concrete floor screed, with a related method of performing work, the surface of the ceiling should be primed to improve the adhesion of the solution. When making a floating screed, this step is optional, but a number of other works are performed instead:

• laying a waterproofing membrane (polyethylene film);
• installation of a damper tape around the perimeter of the room;
• laying a layer of thermal insulation (expanded polystyrene, mineral wool, isolon, etc.);
• reinforcement.

Only after the base is prepared, the process of pouring the screed begins. In order for the floor to be flat, you need to install beacons. These are long slats or special metal products that need to be laid on supports from mortar. Check the levelness of each rail by level. Align the height of the adjacent beacon by placing the spirit level on both slats at the same time. If necessary, lower the beacon by pressing it into the solution.

While the solution grasps with the installed beacons, you can prepare equipment and materials for pouring the screed:

• cement, sand and crushed stone for concrete;
• the rule for stretching the mortar;
• shovel;
• a concrete mixer or a container for manual mixing.

If the overlap is even enough, then nothing is easier, how to make a cement floor screed... For its manufacture, you need to take 1 part of cement grade M400-M500 and 3 parts of seeded river sand. Add water as needed until a mass is obtained that will not spread on its own.

The concrete mixture is used to fill the base with height differences of more than 5 cm. To obtain concrete for 1 part of cement, you need to take 3 parts of sand and 4 parts of crushed stone. Water is added in a ratio of about 0.5 part to 1 part of the dry component mixture.

A thoroughly mixed solution should be laid out in the far corner of the room and distributed using a rule that should be based on 2 adjacent beacons. It is necessary to stretch a portion of the solution until it forms a layer, the thickness of which is equal to the height of the installed beacons. If they have been positioned correctly and accurately, the screed surface will be perfect. After the solution has grown stronger within 2-3 days, the wooden slats must be removed, and the grooves must be covered with the same substance, leveling it with a trowel. Metal beacons remain in the body of the screed.

Semi-dry screed

Therein, how to make a semi-dry floor screed with your own hands, there are practically no differences from the traditional wet method. The difference lies in the amount of water. According to the recommended technique, the finished mixture should, when squeezed in the hand, stick together into a lump that retains its shape. At the same time, no water is released from it.

The proportions of the components are the same as for the DSP. Dry components must be mixed, laid on a plywood sheet in the form of a slide with a depression on top. Gradually add water to the well and stir the mixture until a sticky lump is obtained. For work, you can also use a concrete mixer.

The setting time for such a mixture is about 45-50 minutes. Therefore, you need to quickly distribute part of the solution between the beacons by about 2/3 of the height of their installation, tamp. Apply the next layer, which must be stretched according to the rule of the beacons, as when installing a screed made of concrete or DSP. As the mixture is stretched, it is compacted.

The laid screed must be sanded immediately, rubbing with a more liquid solution. Cover the finished floor with plastic wrap and dry within 7-10 days. During this time, the semi-dry mixture will become stronger and stronger, reaching the hardness of a conventional DSP.

Dry floor screed

Despite the use of rather fragile materials in the installation (gypsum board, chipboard, gypsum fiber board, plywood, etc.), the strength of such a base is practically not inferior to concrete. The dry screed can be successfully used to repair the floor in a garage or public building lobby. The only limitation is the impossibility of using a dry installation method for flooring in wet rooms.

A dry screed is arranged according to the floating principle, that is, using a layer of material that insulates the backfill from walls and floors. If it is necessary to insulate the room, you can use various porous layers, which are also used in traditional methods of screed installation: mineral wool, EPS, penoizol, etc. Foam mats are also used for laying a water-heated floor. A dry screed cake is formed like this:

• waterproofing;
• damper tape;
• insulation or backfill;
• a compensating layer made of gypsum fiber board (only for floors with a high load);
• substrate;
• actually a screed made of 2 layers of sheet material (gypsum board, plywood, etc.).

Before how to make a dry floor screed, the plastic wrap must be spread on a rough base. Along the perimeter of the room, glue the edge tape to the walls (it can be replaced by the edges of the moisture insulation raised on the wall). Install beacons with a step of no more than 1.5 m, starting from the walls. Align the entire floor horizontally. After that, you can act in different ways:

1. Spread mineral wool or other porous material between the beacons. In this case, the lighthouse rail serves as a lag, so it must be made of a bar of the required thickness. After laying the insulation, lay out chipboard sheets or other material on the logs, fixing with self-tapping screws. The next layer of sheet material should be oriented so that the slab overlaps the joint of the lower floor elements.
2. A dry screed with backfill is performed along the beacons. They need to be laid on the poured material and set to a horizontal level. The bulk floor from the Knauf company, expanded clay, perlite, slag or other backfill should be stretched as a rule. Remove the beacons and start laying the leveling sheets, starting from the entrance to the room. You cannot step on the backfill. To move, you need to lay islands from the debris of GVL on it. Lay the sheets as described in paragraph 1. How to do this work yourself, the video instruction from Knauf will tell you.
3. If necessary, you can lay 1 layer of gypsum fiber board on the backfill, cover it with a porous material and make a screed according to general principles.
4. If the subfloor is not on the ground, you can pour perlite or vermiculite directly onto the floor. Lay the screed on top in 2 layers.

After the dry screed is completely assembled, proceed to laying the floor covering (carpet, laminate, parquet or your own version).

If the type of screed laying is chosen correctly, the necessary materials have been successfully purchased and the installation technology has been followed, then the base for the floor in the garage or apartment will turn out to be durable and very even. It is very easy to lay any floor material on a properly made screed with your own hands.

Modern floor coverings must be installed on a completely flat surface. Correctly executed floor screed will allow you to make a securely fixed floor covering, will ensure its neat appearance.

To determine if a concrete screed is needed, you need to determine the purpose of its application:

• the formation of a monolithic base for the floor;
• leveling the floor base for decorative coating;
• the need to pour the floor directly onto the ground, for example, when building a basement;
• using a wooden base for the floor;
• sealing cracks, irregularities of an existing base;
• strengthening of the constructed structure;
• increasing the height of the base for the floor;
• if necessary, the formation of a small slope for carrying out specific technological operations;
• savings in major repairs.

According to the manufacturing method, the floor screed is divided into "wet" and "dry".

"Wet" screed is familiar to all developers and is used in most cases. To make it, you need to make a special solution by mixing cement with sand. Sometimes a mixture of cement and gypsum is used. The surface is poured with a solution, and then leveled. When using a classic cement and sand screed, additional reinforcement is required. If other dry mixes are used, the floor does not need additional reinforcement. "Wet" screed is widely used in private construction, so it is often chosen. The thickness can be several millimeters, sometimes it reaches a threshold of 10 cm.

"Dry" screed is formed from large sheets or large slabs. Their thickness varies between 20-30 mm marks. Fiberboard is often used. If the subfloor has an uneven surface and needs level adjustment, then a cement screed must be used. Sheet material is not able to correct irregularities, so it must be applied on a completely flat floor. Sometimes the dry screed is placed after wet pouring. It finally levels the floor and becomes a convenient base for attaching cladding materials.

Video - Floor screed and electrician

There is a classification of screeds by the number of layers.

Single layer screed it is poured at once, often in one day, and the multilayer one consists of several layers, which always take more than a day to lay.

Usually, when performing work, first, for a quick overlap, a rough screed is produced, which serves as an initial coating, it is necessary to ensure sufficient rigidity of the floor slabs. The next layer of screed is carried out during the cladding work. The concrete is poured over a few centimeters, forming a perfectly even surface. For the screed, a self-leveling mixture is often used, which facilitates the work, there is no need for additional manual leveling of the concrete screed. The thickness of the rough screed is always higher than 20 mm, and the finishing threshold starts from 3 mm.

The screed can be connected to the base in various ways. According to this principle, it is classified into "solid" and "floating". "Solid" adheres to the base as firmly as possible. Floating does not connect directly to the base and walls. It is used if it is necessary to use insulating material in the building. The screed layer is usually poured to a height of at least 3.5 cm.

Video - Types of screeds

What to make a screed from

When creating the mortar, cement and gypsum appear in the binder position with any of the components. Fills - sand, sometimes various additives from mineral or polymer materials are used, which improve the appearance and properties of the mixture. All components are diluted with water and mixed to obtain the final solution.

Cement screeds can be used for any structures, as they do not lose their basic qualities under the influence of moisture. A homogeneous mixture is made of cement and sand; for its correct composition, components are used in a ratio of 1: 3.

To speed up the cooking process, sand concrete is used. The ready-made mixture can be purchased at hardware stores. The mixture must be thoroughly mixed, as there is a possibility of significant shrinkage.

To avoid the appearance of cracks or non-uniform distribution of the composition, propylene fiber is added to the mixture.

If this component is not available, the floor screed must be reinforced. In order for the newly applied screed to harden evenly, it must be periodically moistened with water. Of the disadvantages of a cement screed, it can be noted that it hardens for a long time. Experts advise, after laying it, to stop construction work in contact with the surface for at least 15-20 days.

In a professional environment, they are called anhydride. They are quite simple to perform, dry quickly within 1-2 days, and are quite plastic when poured. They are not subject to shrinkage, so they can be laid out in a very thin layer, without fear of the formation of an inhomogeneous surface. Gypsum easily absorbs moisture, therefore, it is not recommended to install such a screed in a room where there is high humidity.

Plaster and cement screeds can be purchased as dry mixes. Often, components are added to their composition that can simplify the mixing procedure, increase the flow rate, simplify the laying and distribution of the finished mixture over the surface. There are additives that can prevent screed shrinkage, ensure rapid evaporation of moisture, which will allow the screed to harden in a shorter time. If the developer uses dry mixes, no reinforcement is required. You can lay out the solution manually or mechanically. Recommendations on the time and sequence of installation, the drying time of the solution should be specified on the packaging of the specific material.

plaster floor screed mix

Mixes for dry screed are made using a special filler, for example, perlite, expanded polystyrene. The use of such a screed will allow you to simultaneously level the surface, carry out waterproofing and thermal insulation, applying the mixture in one layer. To withstand heavy loads, it is made reinforced with a layer of classic screed.

A "dry" screed, if done correctly, can be completed very quickly. Fiberboard, gypsum fiber boards are used. Sometimes multilayer plates are used, the composition of which, in addition to drywall, includes a special film and reliable insulation material.

Mixtures requiring mixing with water are classified into several types. Leveling tools are suitable if the base needs to be leveled quickly, but there is no need to create an even coating. When diluted with water, their consistency remains quite dense. It is allowed to lay them up to 10 cm thick. An ideally flat surface is not created in this way, however, a relatively smooth base for the application of additional building materials can be obtained after leveling with a special rule.

Self-leveling mixtures used when it is necessary to establish a flat finishing surface. After making a screed from such a solution, the floor will be ready for the application of any, even the most problematic facing materials in the installation. The mixture is diluted with water until an even, homogeneous mass is obtained.

There are two types of such screeds: thin-layer, no more than 7 mm in thickness, and thick-layer, reaching 3 cm in thickness. If the base has many drops, grooves or other irregularities, you first need to make a rough screed, removing all abrupt transitions, and then apply a small screed, perfectly leveling it and preparing it for the topcoat.

Self-leveling mixture

Video - DIY self-leveling floors

It is necessary to calculate what height of the screed is needed. All elevation differences, if any, the estimated floor level are taken into account. The thickness of the screed is commensurate with the level of the surface drop. Usually it is at least 4 cm. All walls in the structure are marked at the estimated fill level.

The surface is cleaned of all contaminants, for this you need to completely wash it with warm water. If the screed is applied directly to concrete, care must be taken to improve the bond quality. For this, the concrete base is covered with a primer. If the screed is laid on the waterproofing material, then it is evenly bent over the adjacent supports. Then the screed is called "floating", so its height is always more than 4 cm.

It is desirable to reinforce the screed if it is made from a solution formed by mixing cement with other components. For this, a reinforcing mesh is laid over the entire length of the floor. To deepen it from all sides into the solution, and not leave it tight on the base, you need to put small pieces of ceramic tile under it.

In order for the screed to be poured correctly, beacons must be installed to control the level. The slats with the help of self-tapping screws are placed at the level where the mark of the finished floor is calculated. They are installed, maintaining a step of 1-1.5 m.If it is not possible to use self-tapping screws, for example, if their installation can damage the insulating layers, then using a fast-hardening adhesive, the slats are placed directly on the base, and then they are installed in the correct position with tools.

Video - Preparing the floor for pouring the screed

The composition of the mortar, the type of screed depends on certain factors, taking into account which you can choose the optimal coating.

1. Reinforced concrete floors created from a monolithic composition require sound insulation, which must be in the floor structure. A "floating" screed will be required. Under it will be a layer of thermal insulation, for example, made of mineral wool, it will be protected by a waterproofing film. It is possible to use materials made with the addition of liquid polymers.
2. Frequently ribbed ceilings do not need sound insulation, as they have the ability to eliminate loud sound. Directly on them, a rough screed is made, which does not give a smooth surface, and then a layer of a liquid mixture is used.
3. Wooden floors also need a screed. Logs are installed, a wooden flooring is applied to them. Initially, it is covered with layers of hydro and thermal insulation, then a screed is applied.
4. The overlap, located on the ground or over an unheated room, requires the obligatory laying of insulating layers. The insulation must be hermetically protected from moisture on both sides.

If you need to make a floor screed for an unheated room, then only waterproofing is applied under it, no insulation is needed.

Laying methods

Cement-sand mortar must be sufficiently plastic, liquid, crumbly. The dry mixture must be prepared exactly according to the instructions on the package. Work starts from the far wall, preferably on the opposite side of the exit. Often the composition is laid using an ordinary shovel, the mixture is placed on the slats not higher than their level. The top layer is carefully removed when all the work is finished.

If cavities are formed in the cement, then they are filled with removed excess cement or residues of the finished composition. To ensure the quality of the coating, work should be done quickly, and after laying the screed, immediately level the cement to the marked level. The slats are removed by detaching themselves against the wall. The resulting depressions are filled with a mixture. If only a rough screed is performed, and there is no need for a finishing one, then the floor is additionally leveled with a trowel.

When the screed is ready in the entire structure, you need to wait 24 hours. It is possible to walk freely on the screed the next day, but the floor covering can be installed after at least a week, provided that the thickness of the screed is minimal. If it is more than 5 cm, you can continue the repair after 15-20 days. Dry mix screeds dries out in 1-2 days, after this time you can apply facing layers.

A fine screed is made using self-leveling compounds. A liquid solution is obtained that spreads easily over the base. The poured screed must be leveled with a squeegee or comb. To displace air that may remain inside the coating, a needle roller is passed along the screed. Calculation of the level is not carried out, beacons do not need to be installed, since the thickness of the coating is small.