How to make a cement floor screed in an apartment. Floor screed in the apartment: cement-sand screed technology

Do-it-yourself floor screed is a task that you can face if you decide to make a major overhaul in an apartment or a private house. It can be fine and rough, for wet and dry rooms, hard and floating, dry, semi-dry and traditional wet. A rough screed is understood as a leveling layer of cement-sand mortar on top of the floor slab, slight irregularities are allowed, since it involves additional leveling in the next step.

The final screed is the finishing layer of the floor finish, it must be perfectly even and can serve as an independent coating, or as a basis for laying floor coverings (linoleum, laminate, carpet, etc.), as a rule, self-leveling mixtures are used to create it. The main functions of the screeds are to level the surface, if necessary, to create slopes, to give the surface strength and rigidity, as well as heat and sound insulating properties. In this article we will tell you how to properly make a floor screed and what are its features for rooms for various purposes.

Types of screeds

Screeds are classified depending on the main material included in their composition. Do-it-yourself floor screed can be concrete, magnesite, anhydride, asphalt, mosaic, based on gypsum and epoxy resins. Currently, there are many different types of ready-made dry mixes on the building materials market with which you can make a floor screed with your own hands.

Screed for wet rooms

For wet rooms, the composition of the screed will be slightly different. Let's look at how to make a floor screed in the bathroom. A prerequisite is the creation of waterproofing. As a waterproofing layer, it is recommended to use a modern material - euroroofing material. This roll material is laid in 2 layers dry with overlapping joints.

Important! Bring the edges of the waterproofing onto the wall to a height of 5-7 cm. This will protect the joints between the walls and the floor from leaking.

After that, beacons from metal profiles are laid on a concrete solution strictly according to the level. Wet room mortar is made from three components: sand, cement and a dry waterproofing mixture, which is sold in bags. (for example manufacturer Ceresit). The video shows in detail the process of making a concrete screed in the bathroom:

Screed for underfloor heating

To install a warm floor, a cable or pipes (in the case of a water heated floor) are laid out on the surface, and then they are poured with a 1: 3 cement-sand mortar with the addition of reinforcing additives.

The video shows how to properly make a floor screed for water heating:

floating screed

This type takes place if the floor slab needs additional heat and sound insulation. The solution is laid on top of thermal insulation and sound insulation on a special layer (you can use a polyethylene film with a thickness of 0.1-0.15 mm). The layer performs the function of separating the solution and insulation. For a floating screed, a cement-sand or calcium-sulfate mortar is used.

It is recommended to use a damper tape, which is glued at the junction of walls and floor around the entire perimeter of the room, taking into account ledges and columns. It protects the surface from cracking during concrete shrinkage, and also increases the sound insulation of the room. The height of the overlap of the tape on the wall is taken in accordance with the total thickness of all layers of the future floor.

Video. floating floor. Types of solutions, pouring methods, nuances, subtleties:

Dry and semi-dry screeds

In the case when it is required to carry out repairs in an accelerated time and there is no time for the traditional wet screed to fully dry, it is possible to perform a rough screed using a semi-dry method. To do this, a small amount of water is added to the cement-sand mixture, sufficient to obtain a loose concrete mass after kneading. It is also necessary to perform reinforcement with the addition of fiberglass to the composition of the solution. After that, the mixture is applied to the base with the rule aligned with the beacons, and then the surface is polished. This technology is most quickly and efficiently performed by a mechanized method.

Dry screed is a backfill of dry filler - quartz sand or expanded clay, on top of which plywood, or chipboard, GVL is mounted. This technology provides good sound insulation, light weight of the structure, no wet work in the room, and therefore no dirt and the risk of fluid leakage from the solution into the ceiling. This type of screed is easy to do with your own hands, because. it is easy to manufacture, does not require machine mechanisms, special equipment and special care, however, it is afraid of moisture, and if it gets into the structure, swelling of the floor, deformation of the surface and the formation of irregularities can occur.

Video. Dry screed technology. This method is suitable if you need to meet a tight deadline and do not want to mess with a liquid solution:

Finishing screeds

Finishing screeds often use factory-made finishing self-levelling mixtures. They are cement and polymer based. Self-leveling floors are easy to care for, they form a durable, even and smooth surface that is easy to clean. Bulk floors are divided into types depending on the binder that is used in their composition. There are methyl methacrylic (MMA), polyurethane, polyurethane-cement, acrylic-cement and epoxy compounds.

Advice! The strength grade of the finish coating should not be higher than the grade of the rough screed solution on which it is laid. Otherwise, deformation and delamination will occur over time.

Video. Finishing screed device using a self-leveling mixture:

Screed laying technology

Let us consider in more detail the device of a traditional wet screed using concrete as an example. Do-it-yourself floor screed is performed using the following tools:

building level;
rule;
beacons (guides);
drill with a nozzle for mixing the solution;
putty knife.

Depending on the purpose of the room and the materials used, the technology will vary. Consider the stages of this process:

preparation of the base, primer;
thermal insulation (if necessary);
waterproofing (if necessary);
reinforcement (if necessary);
placement of beacons (guides) with leveling;
mixing the solution;
filling;
surface care.

The first step is to prepare the foundation. It must be dedusted, garbage removed, in the presence of dirt and stains of oil, bitumen, it is necessary to remove them. If there is an old dilapidated screed, it must be dismantled. After that, it is necessary to treat the surface of the floor slab with a primer using a roller or brush and allow to dry for 5 hours. If there are water and sewer pipes in the room, then you need to lay them out on the floor.

For thermal insulation of the room, you can use expanded clay or expanded polystyrene, the main thing is that the surface of the insulation is rigid. If the floor screed is done on a soil base with your own hands, then first you need to lay a layer of expanded clay, and then a layer of sand, with the obligatory compaction of each layer. For greater effect, it is recommended to moisten with water.

Waterproofing is usually carried out in wet areas (where there are connection points for plumbing and sewer systems). To protect against dampness, waterproofing is also sometimes arranged in the premises of the first floor, basements.

After that, reinforcement is performed. It is used in the event that the surface is planned to be subjected to heavy loads. To do this, use reinforcing bars, the cross section of which is selected depending on the planned load (diameter value in the range from 8 to 20 mm), or reinforcing mesh (bar diameter 6 mm). Sometimes plastic reinforcing meshes are used instead of metal ones. Reinforcing meshes will also help to avoid deformation of the concrete layer and cracking in case of shrinkage of the building. Concrete is a brittle material and does not work well in bending and tension, reinforcement allows you to eliminate these shortcomings and protect the surface from cracks.

After that, the placement of beacons (guides) is performed. They should be set clearly in accordance with the building level, tk. the subsequent flatness of the surface depends on this.

The next step is to pour the solution. When the screed is ready, it is left for a while until completely dry. Do not forget to take care of the screed during this time, periodically spraying it with water. Concrete slowly gains its strength (within 27 days), it must harden gradually. If it dries too quickly, cracks may form. Therefore, as a care, you need to moisten the finished screed with water 2 times a day for a week, and then cover it with plastic wrap and leave it for 2 weeks.

Regardless of the type of finished flooring, if the floor slabs are uneven or have a strong slope, then they will have to be leveled. Such a pouring of the floor screed is carried out with your own hands using a cement or gypsum mortar or various plate materials (GVL, chipboard, OSB). Making it yourself in an apartment or cottage is not so difficult. The main thing is to follow the building rules and the instructions below, as well as be ready to work.

Types of screed

The floor screed is a layer of rough finish. Below it is an interfloor overlap or soil, and above - a floor covering in the form of linoleum, parquet, ceramic tiles, etc.
A screed is made for:

concealment of communications (underfloor heating pipes or water supply, electrical wiring, etc.);
redistribution of loads from the upper decorative layer down to the base;
leveling the surface and / or giving it the desired slope;
hardening the base for finishing flooring;
providing sound, hydro and thermal insulation.

You can make a screed yourself in several ways. And the choice of method largely depends here on the requirements for the loads that will then arise on the floor. This is when deciding how to connect the drain of the washing machine to the sewer, you just have to follow the instructions for the plumbing fixture.

In the case of a screed, everything is an order of magnitude more complicated. Each technology has its own pros and cons. First, you need to clearly define the existing needs.

There are three main types of floor screeds:

Dry team.
Wet (classic version).
Semi-dry.

The first technology involves laying wood and gypsum boards. This method eliminates the use of a liquid mortar of gypsum or cement and is characterized by a high speed of screed installation. Plus, due to the low weight of materials, it exerts the least load among analogues on the overlap from below. However, in terms of price, this option is the most expensive. And he is afraid of moisture.

Features of expanded clay screed with insulation

The second method is based on pouring liquid concrete from cement and sand. This screed is characterized by the greatest strength, durability and resistance to moisture. However, due to the large mass, it is not allowed to use it everywhere. If the floor is leveled in an apartment in a new building, then this option is quite acceptable. Only too thick a layer of concrete should not be poured. But for an old house with wooden floors, this technology is not suitable.

Wet screed

The third method is an improved variation of the second. A cement-sand mixture is also used here. However, the amount of water used for its mixing is several times less than in the preparation of conventional concrete. As a result, the hardening time of the floor screed and the volumes of construction dirt formed during the work are significantly reduced. But you have to pay for this by the need to use the technique for grinding and the strict observance of the technology.

Semi-dry screed

In addition, ties are:

related;
floating;
on the separating layer.

The first ones are the most durable and imply a rigid adhesion of the poured solution to the underlying base. The latter have a heat and sound insulating substrate made of mineral wool, expanded polystyrene, wood or cork boards. They do not come into contact with the floor and are not rigidly bonded to it, like screeds of the associated variety.

The third option also has a separating substrate. But in this case, it is thin and performs the functions of exclusively waterproofing. Usually it is oiled or bituminous paper or polyethylene. Unlike the floating counterpart, this floor screed in the apartment can be made in a thinner layer. Plus, it's also more durable.

Types of screed

A separate line are self-leveling mixtures of the "self-leveling floor" type. They are cement and gypsum, but all have polymer plasticizers for quick hardening.

Their main purpose is to create a perfectly flat surface up to 10 mm thick without much effort on the part of the performer. Often this option is used in conjunction with other types of floor screed as an upper leveling layer. Then the general design of the rough coating is called a combined two-layer.

What you may need, materials

To make a floor screed, you will need the following tools:

beacons for horizontal alignment;
building level;
concrete mixer-mixer;
rule;
trowel and / or shovel;
grinder (for semi-dry screed);
roller (for self-leveling mixture);
bucket and drill with a nozzle for mixing the solution;
tape measure and pencil.

Materials and tools for screed

It is best to take a mixture for making a mortar for a floor screed immediately ready with the required proportions of the components. So there is less chance of making a mistake when mixing cement, sand and other components. But you can also purchase these components separately and do the kneading yourself. Only for a self-leveling composition, this is not worth doing, it is extremely difficult to prepare it yourself with the proper ratio of ingredients.

Features of surface preparation

When preparing the surface for the screed, it is necessary to remove the existing skirting boards, old flooring and logs (if used). As a result, a wooden or concrete floor should remain without any extraneous construction debris.

Further, the cleaned base is repaired in case of deep cracks or ragged potholes and primed. The sealing of defects is done with concrete mortar after preliminary priming of repair areas. Leaving flaws unsealed is not worth it. If you make a floor screed over such weak spots, then they will continue to collapse. As a result, inevitable damage to the new top layer will occur.

Preparing the floor before screed

If there is an old screed on the floor, then it should be carefully checked for integrity and reliability. In most cases, such concrete is recommended to be completely removed. But if it is still strong and does not peel off from the base, then it is quite acceptable to pour a new leveling layer on it.

Step by step instructions - how to make a floor screed

The general step-by-step instruction for the correct durable screed is as follows:

Foundation preparation.
Laying or filling of underlying materials.
Setting up beacons and laying out the edge damper tape.
Reinforcement with a mesh (if necessary) and mixing the mortar.
Pouring and leveling the prepared mixture.

If a dry floor screed is being made in an apartment or a private house, then the last two points come down to laying and fixing wood or gypsum fiber boards. There are no special difficulties. Figuring out how to connect a toilet is often more problematic than leveling under the floor.

The main stages of work on the implementation of floor screed

Dry

A prefabricated structure made of OSB, chipboard or GVL sheets is not particularly durable and is prone to delamination during a flood. But on the other hand, these disadvantages are offset by the speed of installation, as well as excellent heat and sound insulation.

A floor screed is made using this technology, usually on top of a backfill of perlite or expanded clay. Then the waterproofing is spread. Direct adhesion of the stacked sheets to each other is carried out on glue and self-tapping screws. At the same time, the latter should be carefully selected in length so that, when screwing in, they do not rest against a dense base and do not lift the floor covering.

Backfilling is done with a height of 3-5 cm. If more is required (for example, to hide pipes), then the screed should be made with plates in two overlapping layers. One will not be enough to provide the required strength standards.

How to make a dry floor screed with beacons inside

Wet

When performing a wet screed, the main thing is to pour the entire volume of the solution in one go. It is impossible to allow one layer to solidify and pour another on top of it, they will inevitably disperse later.

It takes about one week to strengthen 1 cm of concrete in the screed. In this case, the screed is usually made in 3–5 cm - as a result, until it is fully ready for further work, you will have to wait at least a month. This is the main disadvantage of this technology.

The second important point is the lighthouses. They are easiest to make from drywall profiles. You can also use tripod pins. The more precisely these horizontal guides are set, the smoother the surface will be.

Today, the requirements for finishing work are much higher than a couple of decades ago. Almost all floor coverings require a base, if not perfectly even, then with a very small difference - no more than a few millimeters. Therefore, almost every repair means leveling the floor, and they do it with a screed. The process is lengthy and requires significant financial investments. Everything will be cheaper if you do most of the work yourself. Even if there are no skills, do-it-yourself floor screed is not such a difficult task. Technology is the key to success.

Screed is an intermediate layer between the base (floor) and floor finishing materials. They can be divided into two groups - leveling and leveling-thermal insulation. A screed with a thermal insulation function is used on the ground floor, above a basement or unheated room. It is also made under a warm floor - to reduce heating costs.

There are two technologies for the screed device:

Monolithic. For laying a monolithic screed, various grades of concrete are used. Both heavy (DSP, with crushed stone) and lightweight (foam concrete, with polystyrene, expanded clay concrete and other light fillers). They can be liquid and semi-dry - depending on the amount of water in the solution.
Combined screed. This is when there are many layers, they can be from different materials. This includes dry screeds, along the logs, with insulation, soundproofing.

According to the method of connection with the base, there are two types:

Ordinary. This is if the solution is poured over the floor slab, for example. What is the downside? The fact is that if the house starts to “lead”, the floor will crack along with the base.
floating. When the base and screed are separated by an intermediate layer. For example, if a polyethylene film, thermal insulation (polystyrene foam boards), waterproofing or any other separator that separates the screed and base material is laid under the concrete layer.

All requirements and norms are spelled out in regulations. SNiP 3.03.01-87 "Bearing and enclosing structures", SNiP 2.03.13-88 "Floors",. To accurately navigate in what and how to do, study these rules. Then do-it-yourself floor screed or control over the work of the team will not be a problem.

How to choose the type of screed and what layers are needed

Making a floor screed with your own hands is not such a problem. The problem is to choose the type, not to make a mistake with layers, mass, to choose the right materials and calculate their quantity. And the best screed for each case has its own. It is one thing to repair a new building, another thing is a major overhaul in the housing stock. In addition, everyone has their own requirements and ideas about the “best”. But there are technical points that define the boundaries of your desires. These moments must be monitored.

The weight

When creating the floor and foundation, a certain load is laid that the floor can bear. It must be looked at in the project or clarified with the operating organization (usually the chief engineer). The average design load is 300-400 kg / m², but it can be more or less.

If the floor is wooden, it will not withstand a large load. The specific value depends on the section of the lag and the step of their installation. But on wooden floors, most often, they make a dry screed along the logs. The gaps between the lags are filled with heat and soundproofing material, and a floor board or sheet materials are placed on top. To improve sound insulation, sound-absorbing pads are used when assembling the screed.

If the load capacity of the ceiling allows, it is possible to make a cement-bonded particle board (DSP) screed, with or without gravel filler. But on top of concrete with gravel, a leveling layer is needed. Although, it is almost always needed. The floor screed rarely comes out perfectly flat, you still have to pour a layer of leveling agent on top.

Don't want to load the structure too much? Use lightweight concrete with lightweight aggregate. Any one you like best. I like wooden floors - do not make a wet screed, put logs, lay the floor from boards. Everything that fits within the limits of the load capacity can be done.

Waterproofing

In residential premises from 2 floors and above, waterproofing is not needed. This layer is required on the ground floor if there is no basement in the house, as well as in all "wet" areas on any floor. These include shower, toilet, bathroom, kitchen, balcony and loggia. Sometimes, for reliability, they can capture the corridor. Do-it-yourself floor screed in a bathroom or toilet is a good experience to start with.

Waterproofing materials are rolled, there are liquid compositions - mastics, rubber paints, compositions based on copolymers. In basements or on the first floors of houses without a basement, a waterproofing layer is laid under the screed. In wet rooms - under and over the screed, under the floor covering (regardless of the number of storeys). Most often, waterproofing is placed in two layers - to increase the level of reliability. You can combine different materials, for example, roll + mastic.

Noise isolation

Residents of apartments are well aware of how poor sound insulation interferes with life. Especially in the presence of violent or inadequate neighbors. Moreover, the noise from above interferes no less than from the side. Sometimes even more. So that the neighbors are not aware of all your affairs, you have to be quiet. And all because the screed is made ordinary, without sound insulation.

There are two ways to reduce noise levels - absorption and decoupling of the structure. With absorption it is easier - in the screed and not only it is necessary to use porous materials of low density. This task is best handled by carpets, from building materials - polystyrene foam / polystyrene foam and low-density mineral wool.

The second way to reduce the level of noise transmitted through the ceiling is the decoupling of the structure. In simple words, in a screed it is the use of layers of different densities, the use of porous gaskets that exclude direct contact of the screed with rigid structures. In our case, these are walls. That is, if you do not want to tiptoe so as not to disturb the neighbors, it is better to make a floating screed. Under the concrete layer, lay not a plastic film (or not only it), but a layer of mineral wool or polystyrene. And along the perimeter lay porous materials that will separate the concrete from the walls. Density - the minimum allowable for the estimated mass of concrete laid on top.

If you are going to do a dry screed, soundproof pads are also placed under the logs. They must also be placed at the junction with the walls. And the gaps between the lags should be filled with a material with good insulating characteristics. Do-it-yourself floor screed is good for what you do for yourself and you can spend more time to get the best result.

thermal insulation

A layer of thermal insulation in the screed is not needed by the inhabitants of high-rise buildings. Except for underfloor heating. In this case, it is better to make thermal insulation - so as not to heat the neighbors from below and reduce heating costs. The most common materials for this layer are expanded polystyrene foam and mineral wool. Their density depends on the type of screed. More dense ones are laid under the concrete layer (polystyrene foam with a density of at least 25 kg / m³, mineral wool - 160-190 kg / m³). In floors on logs, the density may be less - everything is decided by heat-insulating and sound-proofing characteristics.

Expanded clay used as a heater is ineffective. Compared to the above materials, its thermal insulation characteristics, to put it mildly, are not impressive. They are 3-4 times lower. In practice, this means that 35 cm of expanded polystyrene can replace 10 cm of expanded polystyrene.

The composition of the floor screed

As you understand, the composition of the floor screed can be different even in two apartments located on the same floor. It all depends on what the owner wants to achieve. Let's give some examples.

In either case, the result is a relatively even concrete base. With different characteristics and properties, but externally - the same. On such a base, you can lay tiles, parquet. All flaws will be leveled when laying the tiles. But even here the differences should not be too large. According to the technology of laying tiles, differences of 2-3 mm are permissible.

Some coatings require a perfectly flat surface. These are laminate, carpet, linoleum, art vinyl and other soft floor coverings. Under such materials, one more layer is needed - from the finishing or leveling mixture. It is poured on top of the already finished floor screed. For this, self-levelling compounds are usually used. Just do not think that they just need to be closed and poured onto the floor, and then they will spread on their own. Not at all. They also need to be distributed over the surface, but just do not need to be so carefully aligned. After the distribution, the composition itself will “become the horizon”.

Stages of work

To make a screed with your own hands, you need to know when and how to do it. In the process of repair, the screed is poured before the start of finishing work. That is, first level the ceiling, walls, put windows. Only then pour the screed. Not earlier. Because all leveling compounds, plasters, putties weigh a lot. For work, ladders and other equipment are needed. All this leaves marks on the floor. And the screed matures for at least 28 days. During this time, it is gaining design strength (subject to certain conditions). It is unlikely that you will wait so long before leveling the ceiling or walls. So all heavy and dirty work must be completed before pouring the screed.

Painting the ceiling, gluing wallpaper, applying decorative plaster - these works are no longer so dirty, they do not require heavy materials. They can be started when the concrete gains 50% strength. At a temperature of +20°C and sufficient humidity, this occurs a week after pouring.

Floor screed laying technology

We are talking about the procedure for pouring concrete mortar. It can be any loaf - from heavy to light. Maybe a semi-dry screed - a solution with a minimum amount of water.

This is a step-by-step instruction on how to make a screed with your own hands in a general way. There are still moments that depend on the specific composition of the screed and the selected materials, but in general, the sequence of work is just that.

Care after pouring

Do not think that after pouring and leveling the concrete, the work is already finished. In order for concrete to “ripen” and not dry out, it needs certain conditions. First, you need a temperature not lower than + 17 ° C. Secondly, a certain humidity is required. And these conditions must be created and maintained.

If you poured the screed in the winter in an unheated room, you will either need:

more time for aging;
special additives in the mortar, which make it possible for the mortar to normally gain strength at lower temperatures;
heating.

At low temperatures, but not in frost, it is easiest to add a certain amount of additives and cover the laid mortar. First with a film, then with something that retains heat.

Screed covered with foil

If the temperature is above +25°C, care must be taken to ensure that the solution does not dry out. To protect against evaporation, it is necessary to curtain the windows - so that there are no zones of local overheating, cover the surface with a film. And, every two or three days, wet the concrete abundantly. Abundant - until the appearance of puddles. At the same time, it is necessary to ensure that the surface does not blur. Such hydration is desirable for at least two to three weeks.

What materials are needed for floor screed

The basis of a wet or semi-dry screed is a solution. Use as a simple cement-sand mixture (CPS), and with aggregates. You can add plasticizers that accelerate the maturation of concrete, make it more plastic. For screeds take cement brand M400 or M500. Concrete for screed class M150 or M200 (do not confuse with cement brands).

Higher grades of concrete (with a high cement content) can also be used. The surface will be more durable, but shrinkage and the likelihood of cracks during drying are too great. A floor screed made of M150 concrete for an apartment or house is more than sufficient in terms of strength. You will not drive a car ... Any other load is not terrible for such a floor.

Proportions of concrete for screed, mixing order

To obtain a cement-sand mixture for M150 concrete, take 1 part of sand and 3 parts of cement (M400 or M500). Water - 0.48-0.55 liters per kilogram of cement. You can add gravel of medium or fine fraction. The proportions are given in the table.

When kneading, first dry dry mix the bulk components until smooth, then water is added in parts. Its exact amount is difficult to determine - it depends on the moisture content of sand and gravel. Therefore, it is added in small portions, constantly stirring. It is more convenient for a screed if the solution is low-plastic - it slides off an inclined shovel.

Plasticizers can be added to the composition, which make the solution more plastic. A solution with increased plasticity is easier to distribute. The cheapest additive of such a plan is PVA glue, but there are specialized ones. Not more than 1% by weight of additives is added to the solution. Fiberglass can also be helpful. These are short fibers that prevent the development of cracks during the shrinkage of the screed itself and small deformations during the shrinkage of the foundation. There are other additives that change the properties of the solution, but they increase the cost, and there is no particular need for them to fill the screed in an apartment or house.

How much concrete and cement is needed

How to determine how much concrete is needed? Can be roughly calculated. You know the area to be poured, you know the thickness of the layer. All values are converted to meters and multiplied. We get cubic meters - this will be the required volume of concrete.

Let's count on an example. We will fill in an area of 45 square meters, a layer of 5 cm. We translate 5 cm into meters. This is 0.05 m. Now we multiply 45 m² * 0.05 m = 2.25 m³. Approximately you will need 2.2-2.5 cubic meters of cement mortar. Knowing the required volume of mortar and the brand of concrete, it is possible to determine the consumption of cement. It can be taken from the table.

Please note that the table shows the consumption of cement for the CPS, that is, without crushed stone. Having decided on the volume of concrete, you can calculate the mass of sand. It needs 3 times more. It is better to take building sand, not river sand. Quarry sand has sharp edges, and river sand is smooth. It seems that the difference is small, but it is not - concrete is stronger with quarry sand.

Filling the screed with step-by-step photos

The first self-made screed will add confidence to you. It's not too difficult, and physically hard work, even if there is a concrete mixer. And if you also interfere with your hands, it will be very difficult. Try it on a small volume first. It may well be that you then decide to order concrete in a mixer.

Look at the example of a floating screed, an industrial dense film serves as a separator. The following tools are required for pouring:

The most expensive tool is the laser level. If the floor screed will not be the only type of work done on your own, this tool will be very useful to you. So it is better to buy it, and you should choose good quality.

How to calculate the minimum layer, where to do the zero level

If the base were even, the screed would be a very simple matter - they poured the solution, leveled it with an even layer. All. But the thing is, this is extremely rare. Usually there are humps somewhere, hollows somewhere, a few corners can be higher, a little lower. Since the minimum screed layer is 30 mm, it is necessary to find the most protruding part of the base and, relative to it (plus these 3 cm), display the zero level.

To work, you need a laser level with the ability to build planes. Expand the horizontal plane at any distance from the floor. Let it be 10 cm. Next, take a ruler or tape measure and move along the perimeter of the room, measuring at what distance from the floor we “catch” the laser beam. It is displayed with a bright strip around the perimeter, so you can immediately see how things are with the corners. If in each of the corners there are 10 cm to the beam, you are incredibly lucky. But usually the picture is different.

If the floor screed is done in the whole apartment, you need to check all the rooms and look for the highest point of the apartment. The zero level should be beaten off in the whole apartment the same, however, taking into account the characteristics of the flooring. For example, floor tiles are thicker than art vinyl, and this must be taken into account when pouring the screed. In rooms intended for laying tiles, the level should be slightly lower - then you will not have differences in floor level in the apartment.

When we find the point at which the smallest distance to the beam, this will be the highest point of the base. It will become decisive in applying the zero level. This is the level at which the screed will end. To this point we add the planned thickness of the screed (but not less than 3 cm). At this level, we deploy the laser plane. Rays are displayed on the walls that display the level of the screed. We take a ruler, a pencil and transfer the line. Now we determine the average thickness of the screed - again we pass around the room, checking what distance is obtained to the zero level. Now it is already possible to more accurately determine the consumption of the solution and the required amount of cement.

Not all models of laser levels allow you to change the height of the deployable plane. If you can’t set it at the right level, you have to work a little. It is necessary to calculate how much higher the plane passes, put this distance down from the laser line, and draw a straight line.

Foundation preparation

If there are gaps, we close them up, we clean off everything superfluous from the walls (we leave the lines). We remove the garbage, it is advisable to vacuum it, but when using a film this is not critical, you can just sweep it. We spread the film. She must climb the walls. The overlap height is 3-5 cm above the zero level. If the width of one web is not enough, one piece of film overlaps the other by at least 15 cm. For reliability, the joints can be glued with double-sided tape.

The film can be glued to the walls with adhesive tape, but such a fastening is unreliable - it constantly falls off. It is better to take a bar, press the film with it, nail it to the walls. Yes, they are plastered, but patching up small holes is not difficult.

We expose lighthouses

The concrete mortar will need to be leveled. Beacons serve as a guide - special strips that are set exactly on the same level with the zero mark. There are such special metal films that are called lighthouses in hardware stores. These are strips of a special profile, 3 meters long, the height of the protruding part is from 3 mm to 15 mm. For floor screed take 10-12 mm.

As beacons, you can use any even planks of any material. For example, pipes - round or profiled, a drywall profile, even wooden even planks. The only condition is that the material must be perfectly even. Any beacons can be put on the mortar, you can - on the screws. There are also special adjustable stands for placing beacons. But they are expensive, they are needed only for a while, because after gaining 50% strength, the beacons are removed from the concrete, and the stands remain.

The distance between the beacons is determined by the length of the rule - 30-50 cm less than its length. We expose the planks along the long side of the room, from one wall to the other. When installing the first beacon, we retreat from the wall about 30 cm. That is, the extreme strips should be approximately 30 cm from the walls. The rest of the space is divided into equal parts so that the distance is less than the length of the rule.

For example, the width of the room is 4.3 m, we will work with the rule of 1.5 m. We consider this: 4.3 meters - 0.6 m (two times 30 cm), it will be 3.7 m. They will divide the remaining space into three parts - 1.2 m + 1.3 m + 1.2 m. The distance can be equal, you can move the extreme profiles a little closer / further.

For solution

The arrangement of the screed begins with the placement of beacons. The final result will depend on how evenly they are exposed. First, consider how to put the beacons on the solution. We knead the solution from a standard DSP with the addition of one part of gypsum. This will make it more flexible. We mix a thick solution. It should lie in a "bunch" and not swim. Add a minimum of water.

Along the wall, in the right place, at a distance of 50 centimeters, lay out piles of mortar. In height, they must be above the zero mark. To make it easier, we turn on the laser level, we achieve the coincidence of the plane with the mark applied to the walls. We lay out the bar on the solution, press it so that it is in the same plane with the laser.

Doing this is not as easy as it seems. Either higher or lower than necessary. Even if the profile is filled up in only one place, you have to start all over again. It is a little easier if you press the beacon with the rule - attach it in length and gently press, following the laser beam. So efforts are easier to control and beacons are easier to set.

We leave the strips set according to the level alone for a day. During this time, the solution will seize, and it will be possible to continue.

For dowel screws

To put beacons on screws, take fasteners with a rod length greater than the height of the screed. The head is selected so that the selected type of beacon is well held on it. On the floor we draw a line along which we will put the lighthouse strips. We drill holes in the base, insert dowel plugs. We screw the screws so that the hats are at the same level. The height is determined taking into account the fact that another beacon bar rests on the screws.

This method seems to be more labor intensive. But believe me, it’s normal to set up a beacon on the solution - that’s another task. As a result, more time is spent. Checked. Especially if the floor screed is done for the first time with your own hands. In addition, immediately after the beacons are set, you can start pouring the screed.

Laying and leveling the solution

The solution is laid out between two beacons, slightly distributing it. After laying out a certain amount, they take the rule, they level and level the solution. It is moved slightly to the right and left, at the same time pulled towards you. Beacons are used as the basis. The bottom edge of the rule rests on them. The plank captures the excess solution, pushes them in front of him. Along the way, possible voids and pits are filled.

If, after passing the rule, dips form, add a solution with a trowel, level again. So until we get a flat surface. We knead a new batch of mortar, level it again.

To make it convenient to work, start pouring the screed from the wall farthest from the entrance. It is more convenient to completely fill one span between the lighthouses, leave the next empty, then fill the next one. Then - the third. With this technology, the screed can be poured in parts. This option is good for those who make repairs after work, have a couple of hours left.

Floor screed - as you know, the basis of everything. Leveling and concreting the floor is necessary, first of all, to create a base on which the final coating will be laid. In this article, you will receive all the necessary information about the do-it-yourself screed device.

Which is better? How to do it right? How to use beacons? You will receive comprehensive answers to all these questions, supplemented by photo and video materials.

The key to a perfectly even screed is the use of special rails-beacons in the work. They serve to ensure that the level of cement mortar over the entire surface of the room is the same.

That's why, installation of beacons for floor screed is the most important stage of the whole process. Treat it with the utmost care.

So, as you can see in the photo, metal beacons are fixed to the floor with the usual solution that you will use. But before that, make sure that you have all the necessary materials and tools available:

metal beacons, on the basis that the distance between them should be 100-150 centimeters;
special solution for screed;
masters for convenience;
a large basin and access to water (for stirring the solution) as in the video;
bubble levels of different sizes;
damper tape around the entire perimeter of the room;
rule - for leveling the screed with your own hands.

First of all, you need to mark the floor in order to understand where and at what distance to mount the beacons and how to make a screed in general. At the walls, the distance to the beacons should be 20-30 centimeters, the distance between the beacons may be different, depending on the length of your rule, for small spaces, small distances of 100-150 centimeters are most convenient. Beacons fit only in one plane.

In advance, it is worth attaching a damper tape to the wall, which will become a “layer” between the screed and the walls.

We expose beacons on the floor

In order to fix the beacon on the floor along the entire length of the intended installation, we make small tubercles from the finished screed solution. After that, until the solution has hardened, we sink the beacons in the solution and begin to level them using bubble levels.

Important! If the solution remains above the level after leveling the beacon, it must be leveled to the level of the beacon.

Very carefully it is necessary to measure the level of not only a single beacon, but all at once and in different planes. To do this, you can use both a thread stretched across, and any means at hand.

When all the strips of the lighthouses are installed and aligned, you need to wait until the mortar that fastens them to the walls hardens.

Preparing a screed solution

Today, hardware stores and markets offer a large variety of ready-made dry mixes for do-it-yourself floor screed. Which one to choose is up to you. The main thing is to carefully read the information on the bags and their areas of application before buying a batch of the mixture.

Ideally, choose well-known brands that have been proven over the years, but in some cases you can use lesser-known brands, but with good recommendations from familiar builders.

To prepare the solution, you will need a large container, water and a mixing tool. Usually, in the finished mixture, you just need to add water in the proportions indicated on the bag and mix thoroughly.

How to make a screed can be seen in the video below the article.

Note that it is better to measure the amount of water carefully, because. lack or excess of moisture in the screed can significantly affect its quality.

Some masters "in the old fashioned way" cook mortar for floor screed from cement-sand mortar. This is also appropriate, but more laborious, because. in this case, it is necessary to take into account the grade of concrete and the amount of sand to comply with the required proportions. Such a solution will ultimately cost a little cheaper than the finished mixture, so here are the proportions for the mixture:

In ordinary rooms, the concrete grade M150 is suitable, in rooms with increased load - M200. Which screed is better? It all depends on your preferences and operating conditions. If you want to do everything yourself, quickly and easily, use ready-made dry mixes.

Important point! The floor screed solution must be prepared gradually, because. its curing time is usually only a few hours. Therefore, it is better to knead the mixture in small volumes.

Do-it-yourself floor screed

When the beacons are installed, and the first portion of the solution is mixed, it's time to start pouring the screed. There are no special rules and tricks in this, anyone can handle it.

So, the whole point is to fill the space between the beacons with a screed solution for the floor with your own hands. Leveling is done using a rule, or in extreme cases, a flat board or bar. You can simply pour the solution onto the floor with a bucket, as shown in the video below.

By the way, if there is a need to strengthen the floor, it is recommended to lay a reinforced mesh in the screed.

So, guided by the beacons and gradually kneading all new portions of the solution, all voids are filled and leveled. It turns out a perfectly flat and durable surface.

How should the screed dry

Depending on which dry mix you use, the drying conditions for the screed may vary. In some cases, a few days will be enough for complete solidification. Sometimes (in the case of using cement-sand mixtures), you will have to “care” for the screed with your own hands, pouring plenty of water daily.

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

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

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

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

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

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

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

In many other cases, ties do two-layer .

The first layer levels the surface horizontally, or gives the desired slopes. Usually it is performed from a cement-sand mixture or concrete. It is customary to say that the first layer is rough screed . On it in the future, you can lay tiles or porcelain tiles.
The second layer is called finishing screed . It already makes the surface perfectly flat, under the floor finish, for example, under a laminate, parquet, carpet. Very often, a finishing screed is performed giving a perfect surface when properly applied.

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

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

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

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

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

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

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

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

cement screed prices

cement strainer

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

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

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

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

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

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

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

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

Preparation of the base for floor screed

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

The basis of the screed - soil

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

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

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

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

Prices for vibrating plates

vibrating plates

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

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

Screed base - old screed

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

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

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

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

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

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

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

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

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

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

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

Prices for polystyrene concrete

polystyrene concrete

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

The tile, laid in the days of developed socialism in the USSR, has two extremes when it is dismantled. Either she literally "jumps" from the base herself, or "stands to the last." And It happens that tiles behave differently in one area. And all because before there were no tile adhesives with predictable properties in the arsenal of masters. Therefore, they glued who on what much. Just cement was used, and cement with PVA, and Bustilat glue, and even epoxy resin and some other "brutal" compounds with ammonia. Moreover, they were glued without any mineral base in the form of sand, chalk or lime. Therefore, dismantling old tiles can be a problem.

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

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

The basis of the screed is a concrete slab

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

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

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

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

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

Prices for "Betonkontakt"

betonkontakt

Setting beacons for floor screed

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

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

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

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

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

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

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

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

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

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

There are too many ways to set up beacons to describe them all in one article. Each master has his own favorite way, which does not have to be similar to others. In principle, what's the difference if, with different methods of setting beacons, two masters get equally good results. We propose to consider a method that will be understandable to everyone and even a beginner can reproduce it.

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

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

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

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

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

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

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

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

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

Floor screed reinforcement

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

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

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

Reinforcement of the screed with metal meshes

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

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

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

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

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

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

Reinforcement clamps - a modern and best solution for installing reinforcing meshes

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

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

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

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

Reinforcement of the screed with polymer and composite elements

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

Composite rebars are bars of various diameters, which may have ribs similar to those found on steel rebar, or be coated with sand for better adhesion. The rods are formed from fibers and a polymer binder, which is why such reinforcement is called composite. Fibers use glass, basalt or carbon and therefore the reinforcement is called fiberglass, basalt-plastic or carbon fiber.

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

We note the disadvantages of composite reinforcement:

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

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

Prices for fiberglass reinforcement

fiberglass reinforcement

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

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

Fiber screed reinforcement

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

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

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

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

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

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

Conclusions about the reinforcement of the floor screed

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

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

Preparation of floor screed mortar

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

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

A drill mixer is a very useful device that will come in handy in the household more than once.

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

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

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

Self-preparation of floor screed mortar

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

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

Plasticizers are not a luxury, but a necessity

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

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

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

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

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

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

Floor screed mortar ingredient calculator

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