Pour floors with expanded clay. Technology of wet floor screed with expanded clay

Leveling is an integral part of the overhaul of floors. For topcoats (parquet, laminate, floor tiles), perfectly flat floors are required. There are situations when the floor level needs to be raised to a height of 20 cm. If you fill this entire volume with concrete, the floors may not withstand such a load. In such situations, the ideal solution is to make a floor screed with expanded clay.

What is expanded clay

Expanded clay is an artificial building material obtained from clay or shale by firing in special kilns - drums. The size of the granules (fraction) of expanded clay is from 0.5 to 40 mm. Lightweight and porous, it is used not only in construction, but also as a decorative material.

Expanded clay granules have high strength and durability, they are insensitive to temperature extremes, have excellent sound-absorbing and heat-insulating properties.

That is why expanded clay is used as insulation for foundations and interfloor ceilings, especially the first floors.

Important ! For reliable floor insulation, the expanded clay layer should be at least 10 cm.

Preparation

Before making the floor screed with expanded clay directly, it is necessary to carry out some preparatory measures.

Stage one

The first step is to prepare the base, remove the old floor covering and remove the old cement screed (if any). It should be cleaned up to the floor slab. If there are wires laid on the floor, they should be corrugated. All joints, cracks and grooves should be sealed, for example, with polyurethane foam or plaster mix.

Stage two

Now you need to mark and install beacons in those rooms where the floor will be screed. The fastest and most convenient way to do this is with a laser level, but a hydro level is also suitable. The location of the lighthouses in each case is determined on the spot.

Exposing beacons by tags... The first beacon is set up at a short distance from the floor level, which is taken as the basis (zero level), and not too far from the wall. The material for the lighthouse can be pre-prepared wooden dies and other available material. Subsequent beacons should be installed taking into account the size of the rule that will be used for the screed. Beacons can be installed both on a gypsum solution and on an adhesive mixture. After installing the extreme beacons, the next ones can also be set using a level.

Some calculations

For sale in hardware stores, expanded clay is packed in bags. A typical bag of this material weighs about 20 kg, and 1 cubic meter weighs about 400 kg. It turns out, in one bag 0.05 m³ (20: 400). If you need to insulate the floor, for example, in a room of 15 m², you will need 15 × 0.1 = 1.5 m³ of insulation, which is 30 bags (1.5 / 0.05). Naturally, with an increase in the backfill layer, the required amount of expanded clay increases.

Cement screed on a layer of expanded clay

Now everything is ready for backfilling with expanded clay. It is necessary to evenly plan the material over the entire area so that a space of approximately 2.5 - 4 cm remains to the upper edge of the beacons.

After even distribution of the expanded clay layer, it should be spilled with a primary screed - cement milk made from water and cement. You can add some sand. The resulting mass should be liquid enough to spread freely, and at the same time thick enough not to seep through the expanded clay. This fill is done in order to hold the top layer together. Firstly, it will become possible to walk on it, and secondly, when pouring the solution, the water will not go deep, and will dry out properly.

Attention ! After pouring, work will have to be stopped for about 12 hours to allow the cement layer to dry.

Some masters do it a little differently. Gradually adding expanded clay, it is also gradually poured with milk.

After the cement milk has dried, it is recommended to lay a mesh netting on it for reinforcement. After that, you can proceed directly to the floor screed. You can use store-bought ready-made dry mixes, or you can make it yourself from cement and sand in a ratio of 1: 3.

Important ! To use for the preparation of a cement-sand mixture, cement of a grade of at least M 400 should be used.

You should start pouring the floor from the far corner, gradually moving towards the exit, leveling the screed with the rule of the beacons. After finishing work on the entire area, the solution must be given time to grab, at least a day. After that, it is advisable to periodically moisten the screed for a week, after which you can start finishing work.

It should be noted that the above method of floor screed with your own hands with expanded clay refers to semi-dry methods, and is not the only one.

Adding expanded clay to the solution

Consider another way - a wet floor screed with expanded clay.

The main difference between this method of floor pouring is that expanded clay is mixed with mortar, best of all, in a concrete mixer. This saves a lot of time. Let's figure it out in stages.

Stage one. The preparation of the base is no different from the previous method.

Stage two. This is where the differences begin, since waterproofing is required when using this method. Several options apply.

Hydroisol using a blowtorch.
Special liquid mastic with a brush. It is applied to the floor and wall slightly above the intended level of the screed. After drying, a second coat is applied.
The fastest and easiest method is to cover the floor with ordinary thick plastic wrap with a margin on the walls and an overlap between each other. The joints of the film should be sealed with wide tape.

Attention ! It should be remembered that any waterproofing work is carried out on a clean, dry surface!

Stage three. Marking with a laser level, installing beacons on marks and guides is no different from the usual screed method.

Stage four. Preparation of expanded clay concrete:

expanded clay is poured into a concrete mixer and filled with water, mixed thoroughly;
excess water is poured out;
a cement-sand mixture is poured into expanded clay and mixed until homogeneous.

The proportions of expanded clay and cement mixture are determined on the spot empirically. The finished solution should be sufficiently "greasy", homogeneous and free of lumps.

Concrete prepared in this way is poured onto the prepared surface and leveled in the same way, not reaching 2 - 3 cm to the upper edge of the lighthouses. The advantage of this technology of floor screed with expanded clay is the fact that concrete can be poured in small areas, and immediately on top of it, make a "clean" screed with mortar. This significantly saves the total time to complete the work.

Important ! It is necessary to tighten the finishing screed carefully and several times, until the surface is perfectly smooth, without puddles, pits and other defects.

If you do everything carefully and responsibly, you will end up with a surface that is ready for any topcoat.

Dry screed

Expanded clay is also used for dry floor screed. Such a screed is made by experienced craftsmen in a matter of hours. The simplicity of the styling method will allow you to do it yourself as soon as possible. In addition to the simplicity and speed of installation, this method has other advantages.

When laying a dry screed, no water is used, which eliminates dirt in the apartment, heaps of sand and puddles of water with the risk of flooding the neighbors.
Maximum ease of construction. Since no cement mortar is used, such a screed weighs a little, which becomes important when insulating floors in old houses with wooden floors.
Hidden communications. The use of expanded clay as a dry backfill is ideal for hiding various pipes under the floor, both water supply and sewerage systems.

However, with all this, there were some drawbacks of this method of floor insulation. This design is recommended for laying in dry rooms, since the fear of moisture is the main disadvantage of a dry screed.

You can learn more about the stages of laying a dry screed with expanded clay from the video.

Expanded clay is a material widely used in the construction industry, both in the industrial sector and in the private sector. In many cases, for the installation of floors in residential and non-residential premises, expanded clay concrete screed is used.

In our article, we will analyze in detail how to competently and with our own hands make a floor consisting of expanded clay concrete screed and intended for a warm water floor. As an example, consider a kitchen plank floor in a private home.

Arrangement of rough expanded clay concrete floor

We dismantle the old floor, prepare the base

We will remove the old plank covering along with the logs, for this we use the tools at hand: a hammer, an electric saw, a nail puller.

For this particular case, a warm water floor device will include:

Screed with a water heating pipe;
Multifalg;
Sub-floor with expanded clay;
Leveling sand bed.

In the first part, we will analyze how to properly make a sand bed and make a rough expanded clay concrete floor.

After installing the floor boards, it is necessary to take out the logs.
After that we will get the floor from the compacted soil.... It is necessary to accurately calculate the level at which the corresponding layers will be located. All remnants of broken brick and mortar remain in place, backfilling will be carried out directly on them.
A special laser level is used to determine the floor level.

Two marks are made on the wall, one for a screed for a warm floor of at least 6 cm, and the second for an expanded clay insulation 5-10 cm.
After that, you need to walk around the room and put marks on the level of the finished floor.... The marks will be needed for additional verification when the beacon profiles are installed.
After marking, we proceed to backfilling the floor with sand, which will be the base... When filling in sand, the reference point will be the lower mark.
We distribute the sand evenly over the entire floor area and tamp it, properly using a hand-made homemade tamper.
Then the floor is waterproofed.... For this purpose, you can use the usual high density polyethylene film. The edges of the film should go over the side walls at least 30 cm. In some cases, special waterproofing materials are used for this purpose.

Installation of beacons

For the installation of metal beacons, cut cubes of foam blocks can serve as a base.

The initial cubes are set at a distance of at least 1 m from each other. Based on the width of the room and the length of the rule, three or more lines of lighthouse profiles will be required.

A metal lighthouse with a height of 1 cm is installed on the cube. A cube is also installed at the joints of the lighthouses. Trimming the lighthouses is necessary for docking.

For correct docking, the lighthouse profiles are superimposed on each other in the direction of the future movement of the rule. And now let's start leveling the beacons by level, for this we use a long level, direct it to the mark, which means the beginning with pipes.

To accurately level the beacons, we will use small plywood pads. It is worth noting that it is convenient to use long levels in order to level three beacons at once. But if the width of the room is narrow, then each pair of beacons can be aligned sequentially.

If you need to slightly lower the beacon, then you need to move a little and deepen the stand until the required level is obtained. When the beginning of all three beacons are level, we can proceed to their fastening.

Fasteners are made with ordinary self-tapping screws. In places where a wooden backing was used, we also tighten the self-tapping screw.

Now we can move on to the longitudinal alignment of the first line of beacons. According to the concept of a water-heated floor, we need to make a rough floor with a slight slope.

The difference should be up to 5 mm per 1m of length. Next, we perform leveling, as before, using special pads and slightly sinking the cubes into the sand if necessary.

We consistently carry out these operations with three lines of beacons. Note that high-quality alignment will take no more than 1 hour.

This proposed method of installing lighthouses is well suited for the installation of expanded clay floor. At the end of the alignment, we install additional cubes in the gap between the main cubes.

Note: Cutting reinforced concrete with diamond wheels is performed using a special powerful machine with carbide nozzles.

It's time to prepare expanded clay. We will use the wet method of laying the expanded clay sub-floor. For this, expanded clay granules are mixed with a small amount of cement-sand mortar.

This method allows you to get a more uniform and strong floor, which is more suitable for our purposes. After all, we have to pour over a concrete slab with water heating pipes.

The structure of expanded clay concrete for the floor includes concrete and expanded clay itself. The proportions of expanded clay concrete for the floor are as follows: 1 bucket of sand, 2 kg of cement and 2-3 liters of water are mixed into a bag of expanded clay.

Using a concrete mixer allows you to thoroughly mix expanded clay with mortar. The prepared solution with expanded clay is somewhat reminiscent of kazinaki and after drying it will be difficult to push through.

Backfill of expanded clay

We spread the prepared solution with expanded clay on the base and smooth it, starting from the corners. We fall asleep with expanded clay and smooth the strip up to 1 m wide.

Please note that about 1.5 cm remains to the upper level of the lighthouses, this space must be filled with prepared cement-sand mortar. Put it on top of expanded clay.

For these purposes, you can use dry ready-made mixtures or make a solution yourself. We distribute the solution with a trowel over the entire surface.

Now we will use the rule and stretch the screed well along the lighthouses. At this stage, it is important to prevent irregularities, for example, protruding tubercles.

Note that at this stage we do not need perfect evenness, the floor should be just flat, that is, correspond to the height of the beacons.

So, the screed on the expanded clay floor has been completed.

On a note!
Diamond drilling of holes in concrete is performed using metal bits of different diameters made of hard alloy.

Please note that the line of beacons is cleared of mortar, this is necessary in order to remove the beacons from the screed without problems.

As mentioned earlier, according to the concept, it was necessary to provide a slight slope of the floor from the side of the battery to the return pipe. After a couple of days, when the screed has dried, you can start dismantling the beacons, for this it is enough to unscrew the screws to which they were fixed.

Note that along with the lighthouses, you must also remove the wooden linings. Further, the cracks that remained after dismantling the lighthouses must be cleaned with a brush and sealed with a cement-sand mortar.

The operation to seal the cracks is reduced to a thorough smoothing of the solution. This method allows you to maintain the uniformity of the screed and reuse metal beacons.

When the cracks are plastered over, we give it an opportunity to dry, it will take at least a week. The rough expanded clay concrete floor is ready, as you can see, it was not difficult to do it yourself.

We hope you find our step-by-step tutorial helpful. As an illustrative example, you can watch the video in this article, which just describes all the steps for arranging the floor in question.

It is impossible to imagine a quality repair without an impeccably even floor - a guarantee of the subsequent technically correct laying of the coating. In turn, with gross mistakes of builders and significant differences in the levels of the lower surfaces, it is difficult to install door structures and plasterboard partitions, and various tricks are required when decorating the walls. How to create a flat surface and get rid of possible errors? The answer to this question will be a floor screed with expanded clay, which allows to achieve not only perfect alignment, but also an increase in insulating characteristics. Expanded clay reduces sound vibrations and perfectly protects against heat loss, which allows you to reduce costs in the winter season and do without an air conditioner in the summer.

When a floor screed with expanded clay is used

It is rational to use a floor screed with expanded clay in such cases:

The difference in floor level in the room exceeding 10 cm.
reinforced concrete or concrete slabs lying in the base for laying the floor.
The presence of a floor covering that does not allow the flaws of the subfloor, from which its appearance and quality suffer (floating floors made of natural materials, ceramic tiles, parquet or even practical linoleum).
Installation of an infrared or electrical heating system.
The need to reduce the consumption of cement slurry.
Improving sound insulation.
Placement of communications in the lower floor slab.

Screed with expanded clay perfectly combines lightness and strength. Expanded clay granules, crushed stone, sand and their combination minimizes the load on the floors. Due to the low specific weight of the material, the floor withstands static and dynamic loads with dignity, so that during many years of intensive use, its quality does not suffer at all.

The priority of expanded clay is due to the specifics of its production. Its material is low-melting, finely dispersed clay, foamed in a special way, and subjected to high-temperature firing. The result is the production of light edges with a strong outer shell that does not allow moisture to pass through. Low thermal conductivity and excellent thermal insulation properties are due to the presence of cavities and air bubbles. By the way, they also explain the low specific weight.

According to the criteria of the fractional size and the presence of acute-angled elements, expanded clay is presented:

sand, the particles of which are up to 5 mm, obtained after the fired amorphous mass is sieved;
gravel with its round and oval particles up to 40 mm in diameter;
crushed stone with angular particles up to 40 mm in diameter.

Often a fractional mixture is used for such a screed, due to which the insulating-leveling layer increases its density. And since usually the expanded clay layer covers the self-leveling floor, gypsum fiber sheets or other material for leveling, the size and configuration of the particles are completely unimportant. True, to minimize the weight of the structure, you should not use expanded clay sand, since if the density of the material is increased, the weight also increases. But in some cases, for example, when block parquet is laid, only fine-grained material is required.

The figure shows the process of leveling the floor using expanded clay sand

If you have to deal with the most difficult area, it is better to use expanded clay sand as giving the least shrinkage.

In modern construction, repair and restoration work, three methods of screed are used:

leveling and insulation of the floor using expanded clay and cement-sand mortar;
installation of a self-leveling floor using expanded clay aggregate;
dry screed with expanded clay.

Let's consider each of them in more detail.

Leveling and insulation of the floor using expanded clay and cement-sand mortar

To level the subfloor, you can contact a construction and repair organization, or, without waiting for specialists, you can perform this simple but time-consuming process yourself by purchasing the required amount of materials. For this, it is important to correctly calculate the costs, based on the data given in the manufacturer's instructions. Knowing the technical information about the material and the area of the floor to be leveled, it is easy to calculate the need for the material and make an approximate estimate.

Floor leveling traditionally begins with dismantling the floor covering and preparing the area to be treated. The floor is dismantled to the ground, and then the debris is removed. The holes in the floor are thoroughly cleaned, and the cables and wires in it are wrapped in polyethylene. The joints of polyethylene insulation are tightly wrapped with tape, protecting them from crumbs, dust or mortar.

The next stage is waterproofing the base, which is also applicable when laying self-leveling floors. Here you can use a special mastic, but, as a rule, they use polyethylene film, izolan or waterproofing. Using waterproofing materials

a damper layer is created between the wall and the screed;
the adhesion of the mortar to building materials is prevented, often leading to cracking of the cement screed when it dries;
the transmission of sound waves from the screed to the partitions and supporting structures is reduced.

Waterproofing cannot be dispensed with if you have to cover thermal insulation with a screed, arrange parquet flooring, process ceilings in contact with the basement. The installation of rolled thermal insulation materials is 15 cm higher than the marked level of the screed. After the flooring work is completed, the materials are cut at the level of the upper plane.

At the last stage, beacons are set up - landmarks for leveling the surface at the same level. For this ueli, you can use ordinary self-tapping screws or special metal T-shaped devices, specially designed for arranging the screed. Correct marking is easily done using an inexpensive laser level or, at worst, an elementary homemade hydro level made from a transparent hose. Lighthouses are set in accordance with the marks left on the walls in the process of making markings.

A screed with expanded clay is poured in two ways:

first, there is backfilling, tamping and leveling of expanded clay aggregate, the surface of which should not reach the level of the floor marked by beacons. The distance from the expanded clay layer to the marks should not be more than 2 cm. Then the entire treated area is poured with cement "milk", which fixes the expanded clay granules. After they have hardened, you can fill them with a cement mortar that includes sifted sand and M-4 marking cement. To eliminate errors with proportions, you can also use a ready-made screed mixture;
first, expanded clay is introduced into the solution, mixing it with a construction mixer. To make it easier to apply the mixture, the floor is divided into segments with the help of beacons, which are sequentially processed. The laid out expanded clay mixture is leveled with a rule device, and cement is added to the places where pits and puddles form.

But in any case, the floor screed is carried out starting from any of the walls and moving towards the door opening. And both methods are suitable for arranging a sub-floor under any floor covering.

Installation of a self-leveling floor using expanded clay aggregate

With the help of self-leveling floors, you can form a perfectly flat surface due to the ability of the composition to spontaneous leveling. Completely such a floor hardens in a maximum of a week, which is two to three times faster than the previous method. Currently, a ready-made mixture with expanded clay for the installation of a self-leveling floor is being sold, which includes additives that improve the characteristics of the floor structure. In the absence of a ready-made composition, the screed begins with a uniform distribution of expanded clay scattered over the entire area. When laying expanded clay on a dry base, waterproofing is optional. Tamped and leveled as in the previous method, the material is covered with plastic wrap or new insulation. Everything is poured with a solution, from which excess air is expelled with a needle roller.

Dry screed with expanded clay

Such a screed is the fastest, cheapest and most practical. Work on it includes the following stages:

marking the future floor height;
laying a layer of waterproofing on the base;
fixing defimer film around the perimeter of the treated floor;
backfilling, tamping and leveling of expanded clay layer;
installation of gypsum fiber sheets on top of expanded clay, processing of butt joints with PVC glue and fixing the elements with self-tapping screws.

The work carried out on the basis of technological requirements and building standards allows the floor to serve for a long time, the communication systems under it and the floor covering. Such a floor will not need cosmetic and major repairs for a long time.

Video - expanded clay floor screed

Expanded clay for dry floor screed is an excellent material that allows you to significantly simplify the process of leveling it with a minimum budget, time and amount of labor. You will learn how to make a floor screed with your own hands from our article.

Floor screed is, in any case, a laborious process that requires time and effort. However, the characteristics of expanded clay make it possible to get the best result in a relatively short period of time.

Expanded clay itself is durable, reliable, lightweight, easy to use and completely environmentally friendly material. It has excellent sound and heat insulation performance. The material is fired clay, which is compacted and hardened due to the effect of high temperature.

For you, it will be needed primarily in order to raise the floor level to the desired height, insulate it and significantly strengthen it. Screed floor with expanded clay is much more effective than a solution of sand and cement. Mainly due to the fact that it is able to pass the required amount of steam and air.

Among the main advantages are the following:

resistance to high and low temperatures;
the ability to use in any residential or commercial premises;
expanded clay does not ignite, does not rot, weighs little;
the ability to level out even strong irregularities that other mixtures cannot cope with;
ease of screed performance even without additional skills.

When do you need to fill the floor with expanded clay?

There are often cases when no alternative other than expanded clay is simply not suitable:

It is necessary to process an area exceeding 15 centimeters in height. In this case, the cement mortar will cost much more, and its strength will be an order of magnitude lower.
When it is impossible for the screed to greatly add the weight of the building due to a weak foundation.
The presence of wooden floors (together with expanded clay, it is also recommended to use foam as a heat insulator with a low weight).
Unless you have a large renovation budget and want to spend less on the materials you use.

How does the floor screed with expanded clay do it yourself. Preparatory stage and calculation of materials

Instruments:

level;
construction mixer;
ruler;
rope;
slats and profiles;
rule.

Materials:

expanded clay;
sand;
cement;
water.

Initially, you need to get rid of the old coating and bring the base to the desired condition - remove construction debris, clean it of foreign objects.

disassemble the old floor;
vacuum or sweep small debris;
clean and cement any minor holes in the floor.

As with most modern construction work, it all starts with the markup. Initially, decide to what height you will raise the floor, install beacons around the perimeter. The step between the beacons should be up to a meter. All slats must be exactly level.

Important! If the screed will be carried out in all rooms, make sure that the level is the same.

First, you need to determine the highest point of the floor. To do this, you can use a laser level (it is more convenient and faster to work with it). If it is not there, you can replace it with a regular water one. But in this case, you will need to use a rope to mark the level accurately.

Place beacons starting from the top point. At the highest point, the width of your screed in most cases will not exceed 5-6 millimeters, gradually increasing in the lower parts of the room. Plaster or cement mortar can be used to fix the beacons. But the second implies the need to work quickly until the solution has frozen and begins to harden.

It is not difficult to calculate the required ratio of expanded clay to standard cement mortar. The more this material is used, the better thermal insulation the screed will provide. But if you overdo it, then its strength will deteriorate greatly. In the calculation, it is necessary to take into account the thickness of the base, the strength of the foundation, and thermal insulation characteristics. The optimal ratio of expanded clay and mortar is 1: 1.

Keep in mind that the density of the material of different fractions can vary within 250-600 kilograms per cubic meter.

The standard number of components per cubic meter of expanded clay concrete is as follows:

cement - up to 300 kg;
sand - 300 kg;
expanded clay - one cube (weight may differ due to different density, so when buying, focus on volume).

A more accurate calculation can be done using the following example:

As a reference, let's take a room with dimensions of 9 square meters and an average layer thickness of 60-65 mm. We make a calculation: 9 x 0.06 = 0.54 cubic meters. m., which is exactly 540 liters. screed solution.

There are several ways to make a floor screed. We offer two simplest and most effective options:

Screed option No. 1

After you take measurements and mark the level of the screed, you need to fill in small expanded clay throughout the entire area. A small fraction at this stage is needed so that the expanded clay is better compacted. The layer should be no higher than 2.3 centimeters to the top of the future screed. Using a level, make the expanded clay layer completely even and distribute it over the surface.
The resulting layer for better density can be filled with cement "milk".

To prepare it, you need to make a standard screed solution, but there should be twice as much water in it. By itself, the "milk" material will not hold together, but it forms a film on it, which will prevent the absorption of liquid by expanded clay. As a result, the consumption of the solution will decrease when pouring. It will take a day for such a film to form and harden. At this stage, finished. Now you just have to wait.

At the end of the day, you can proceed directly to the finishing screed. Fill in the required amount of expanded clay over the entire area and level again using a level. Now pour the finished solution onto the surface, level it with a rule and leave to dry for 2-3 days.
When the screed is dry, remove the beacons, and seal the holes formed with cement.

Screed option No. 2

In this case, expanded clay will also have to be put in two layers, but the whole process is noticeably faster than in the first option.

Prepare a screed solution. To make it suitable for use, you must first fill the expanded clay into a large container, fill it with water and mix with a construction mixer. Next, add cement and sand in the required amount to the container and also mix everything. There is no exact proportion in this case.
Gradually add sand and cement to the mortar until it becomes a homogeneous, viscous mass without lumps.
Pour the finished composition to a height of 2.5 cm from the floor. Please note that in this case, unlike the previous one, you do not have to wait a day, but you can immediately continue working.
When you start finishing pouring, do not reach the edge of the bottom a few centimeters.
Carefully level the top layer of the screed. There may still be bumps in some areas. They need to be found and eliminated in time. Avoid puddles, gouges, surface bubbles, etc.

If there are wires and any communications under the screed, it is necessary to wrap them with plastic wrap and fix them in the desired position with tape or electrical tape.
It is best to put a layer of waterproofing under the expanded clay. For this purpose, you can use mastic, plastic wrap or hydrosol.
Profiles and slats are the best options for beacons.
The screed will take at least a month to dry completely at standard room temperature and humidity.
During the drying process, the surface should be regularly watered with a small amount of water to avoid cracking.
If a plasticizer is added to the solution, the likelihood of cracking is significantly reduced.
If you use expanded clay mainly to improve thermal insulation, its layer should be at least 10 cm.
Use expanded clay of different fractions to get a tighter screed.
Expanded clay can be effectively used together with self-leveling floors. By themselves, they perfectly level the surface due to a fairly liquid consistency. If expanded clay is mixed with such a solution, you can achieve higher strength and thermal insulation.
During the screed, work the building rule for yourself over the entire surface area.
Reinforcing the screed surface is an optional but useful step that can significantly strengthen it.

As you can see, filling the floor with expanded clay with your own hands is a fairly simple method that allows you to get a good result for little money. No expensive tools and materials.

Expanded clay concrete screed - one of the few bases with universal properties, used in buildings and structures for various purposes.

Advantages	disadvantages
Sufficient mechanical strength for all types of floor finishes. Taking into account their characteristics, it is possible to adjust the properties of the expanded clay concrete screed by changing the proportion of the components.	Quite high heights reduce the volume of the premises.
Low rates of thermal conductivity. Such screeds can be used both in underfloor heating systems and for conventional coatings. In all cases, a noticeable effect of lowering heat losses is achieved. Thermal conductivity is regulated by the percentage of expanded clay and the height of the screed.	During the preparation of expanded clay concrete screed, it is necessary to use bulk materials and water, as a result of which a rather large amount of construction waste is formed.
High fire safety. Such screeds are considered a reliable barrier to open fire and are allowed by state regulatory authorities for organization and use without restrictions.	The work is done manually and requires considerable physical effort.
Environmental friendliness. Expanded clay is a specially processed clay, completely safe material for human health.	It takes at least 2-3 days to solidify, which creates difficulties for the rhythm of construction work.
Low cost. Among all the technologies for insulating floors, expanded clay concrete screed is the cheapest.

Proportions and solution preparation

The process of preparing the material has its own characteristics, and the proportions have a great influence on the final properties. Depending on the amount of water, the solution can be liquid, semi-dry or dry.

Liquid solution. There is so much water that lightweight expanded clay floats; after hardening, the heat-insulating material is concentrated in the upper part of the screed. Advantages - the screed is self-leveling. Disadvantages - for finishing flooring, it is imperative to make a cement-sand screed, which increases the time of construction work and increases their cost. Another drawback is that a large amount of water significantly narrows the scope of application. Liquid expanded clay concrete screeds are recommended to be used for insulating attics and various outbuildings. It is desirable that the floor slabs are reinforced concrete.

Semi-dry solution. The most commonly used material, the consistency of the solution allows you to evenly distribute lightweight expanded clay throughout the volume. Such a screed for universal use can be made on all types of floors and under all floors. Disadvantage - it requires a lot of physical effort, installation of beacons, finishing grout.

Dry screed. Feature - expanded clay is not mixed with a cement-sand mixture, but is placed in a dry state on the base. A thin ordinary screed is made on top. Advantages - fast manufacturing. Disadvantages - relatively low parameters of physical strength.

Currently, there are ready-made dry cement-sand mixtures in sale, it is much more convenient to use them than to buy ingredients separately. For the price they are somewhat more expensive, but if you take into account all the losses on travel and transport, then there is no benefit in self-cooking. Saving ready-made mixtures is achieved due to the fact that it is impossible to accurately calculate the required amount of sand and cement, there will always be a surplus. And this is a direct loss of funds. The use of dry mixes eliminates the occurrence of large unproductive losses of materials.

How to prepare a solution

It is recommended to add 2–2.5 parts of expanded clay to one part of dry mixes. If there is a desire to prepare the solution on your own, then it is recommended to add three parts of sand and four expanded clay to a part of the cement. The amount of water, as we have already mentioned, depends on what kind of solution is being prepared.

You can mix the composition manually or using an electric concrete mixer.

It makes no sense to use a mixer for several reasons. First, he can only prepare a small amount of a solution. Small portions make styling much more difficult. Secondly, each portion of the mortar will have different proportions, which has a negative impact on the quality of the screed. Thirdly, the mixer cannot evenly distribute light expanded clay balls over the volume, most of them constantly end up in the upper part of the container.

The percentage of ingredients can be adjusted depending on the desired end values of the screed. If it is necessary to increase its strength, then the percentage of cement should increase and vice versa. To reduce thermal conductivity, more expanded clay should be given, but should not be overused. Otherwise, the strength of the base will sharply decrease. The solution can be prepared indoors or outdoors; a specific decision is made taking into account the characteristics of the building and the capabilities of the developers.

Practical recommendation. If you plan to prepare a solution using ready-made dry mixes, then it is better to do it indoors. Factory dry mixes cannot be stored outdoors, they react extremely negatively to direct contact with water.

Preparation of beacons for expanded clay concrete screed

A very important point, the quality of the screed largely depends on the accuracy of the preparation of the beacons. It is better to make beacons under the laser level, if it is not there, then you can use the water level. The work in this case will take more time, but will almost eliminate the possibility of error. Why? Each mark is placed on the wall separately with a water level, if there was an error on the first, then at the expense of the rest it is leveled. The laser level works differently, it gives marks immediately around the entire perimeter of the room. Initially, an incorrectly set device becomes the reason that the entire screed will not be horizontal, but with a slope. Keep this in mind, correcting the mistake later is long, difficult and expensive.

How to expose beacons under the screed?

Step 1. Remove the building debris from the building, inspect the base. If there are large gaps on it, then they will have to be repaired, and work should be continued only after the repair mortars have solidified.

Step 2. Cover the overlap with plastic wrap or other waterproof material. If the screed is made in non-residential premises on a concrete floor, then waterproofing is optional.

Step 3. Set the laser level. We have already said that this operation must be approached very carefully, all actions must be performed in strict accordance with the instructions of the device manufacturer.

Step 4. Check the distances from the floor to the laser lines. The minimum thickness of the expanded clay concrete screed is about 5 cm. If it is made thinner, then the strength will not meet the current standards. The maximum thickness of the screed depends on the parameters of the room and the planned indicators of heat saving. The thicker the expanded clay screed, the better the body is preserved in the room. It is recommended to cut down small projections on the floor surface. This is much more profitable than significantly increasing the thickness of the screed due to such problems.

Practical advice. The process of installing beacons will be much faster if you do not constantly check the distance between the guides and the laser beam with a tape measure or a simple template, but make a corresponding mark on the rule. Thus, you will simultaneously set the metal profile at the horizon level and adjust the thickness of the expanded clay concrete screed. This device allows you to display beacons without a bubble level, all the necessary functions are performed by a laser beam.

Step 5. Decide on the specific location of the lighthouses. The distance between the lines should be 15–20 cm less than the length of the rule. Between the extreme beacons and the walls of the room, the gap is within 30-40 cm. The lines should be directed towards the exit from the room. The distance between the stops for metal profiles is about 20–40 cm, specific values depend on the parameters of the elements. It is necessary to fulfill one main condition: the profiles should not bend under the rule during the leveling of the screed, and during this process rather large forces can act on them.

Step 6. Prepare metal strips, cut off the missing pieces if necessary. Make a solution to fix the beacons. To accelerate the hardening, increase the amount of cement, the solution for lighthouses can be prepared in a 1: 2 ratio. There is another way to accelerate the curing of the lath mortar. After placing the beacons, carefully sprinkle the surface of the mounds with dry cement, it will quickly absorb moisture. Remove the wet cement with a trowel or spatula and repeat the operation. Due to these actions, you can start making the screed 15–20 minutes after installing the beacons.

To speed up the work, you can first prepare linings for the slats from various materials at hand. It is advisable to use pieces of bricks or pebbles of the appropriate size. It is not recommended to use pieces of gypsum plasterboard due to very low physical strength and moisture resistance.

Step 7. Put the pads in place, throw some mortar over them and place the metal strip on top. Pay attention to the previously made markings of the beacons.

Step 8. Put a metal rail on a hill, and on top of the rule with the marks made.

Step 9. Gently press in the metal profile until it is in the desired position. Keep an eye on the position of the laser beam on the rule by the marks. Hold the instrument horizontally and with a little force push the beacons down to the desired level. If the profile is too drowned during operation, then it should be raised, put an additional portion of the solution below and re-exposed.

Step 10. With a spatula or trowel, remove excess mortar from the surface of the planks. Use the same algorithm to expose all remaining beacons. If you have the slightest suspicion of correctness, check the position of the rails again. For a guarantee, it is recommended to put the rule on the adjacent slats, the laser beam should be located exactly according to the previously made marks on it.

This completes the work with the lighthouses, after a short pause, you can start making the expanded clay concrete screed.

Filling the screed

For example, we will take a classic screed - expanded clay is evenly distributed throughout the volume of the solution.

Practical advice. When purchasing expanded clay, pay attention to its quality.

What signs indicate bad material?

The balls are too different in size and have different weights. This indicates that during the production of the material, the recommended technology was grossly violated. The large weight of the balls indicates that there are no air pores inside them, the thermal conductivity does not correspond to the standardized parameters.
There are open pores on the surface. A very unpleasant marriage, do not buy such material. The fact is that water gets into these pores, it conducts heat perfectly, and dries for a long time in an enclosed space. Such a screed in terms of its performance will never meet expectations.

To prevent cracking of the screed along the perimeter of the walls, lay a damper tape approximately five millimeters thick.

Step 1. Calculate the approximate amount of materials. This is easy to do, knowing the area of the room and the average thickness of the screed. You don't need special accuracy, you still won't be able to determine the amount of materials up to a kilogram. Buy them with a small margin, the surplus will always come in handy at the construction site.

Step 2. Prepare the mass. We have already mentioned that it is better to mix with a concrete mixer or a shovel in a large container. If you don't have either the first or the second, then prepare the solution in a bucket using an electric drill with a large whisk.

But be prepared for difficulties, the process is not that easy. Watch out for overheating of the drill motor, while mixing the thick mass, it works with critically high loads. As soon as the tool body is hot, immediately stop stirring, cool the stator and rotor windings. Overheating of their insulation becomes the cause of a short circuit, or, at best, significantly reduces the service life. After each overheating, the insulating properties of the special varnish decrease, the situation repeats on an increasing basis until a short circuit occurs.

Important. There is a common misconception among inexperienced builders that electrical cooling tools need to be turned off. This is not true. Of course, in this state they will cool down, but this will take a very long time. Professionals always cool electrical tools plugged in; the load is simply removed. All motors have an efficient air cooling system with built-in fans. No heat energy is released without load, and the powerful air jet quickly removes excess heat.

It is not necessary to take the cement out of the bag with a shovel, it takes a long time, the material will inevitably wake up a little. Experienced builders advise doing it differently.

Place the sealed bag over a piece of pipe or sturdy rail.
Cut through the top of the bag with a mounting knife.
Using a pipe, lift it up and place the two halves in a vertical position.
Break the uncut part of the package with a pipe.

Now you can effortlessly lift half of the cement bag and pour it into the container for preparing the solution.

Do not forget that water is always poured first, then sand should be added, mixed a little, and only after that cement and expanded clay are poured out. Water is added in such a way that the expanded clay balls do not float, but are distributed by weight.

Step 3. Step by step, throw the finished solution onto the floor, level it a little and level the plane with the rule. You will have to work in an uncomfortable position; for relief, use knee pads. Do not throw in too much solution at a time, you should easily get to the extreme point with the rule.

Practical advice. It is difficult to level a claydite-concrete screed with a rule, the balls are pushed by the bottom plane and leave deep grooves on the surface.

There are two ways to solve this problem.

Keep the rule not at right angles to the guide rails, but tilt it. During alignment, you need to pull it towards you and at the same time intensively move it left and right. Due to such movements, expanded clay balls are sunk into the solution, the surface, as a rule, remains flat.
On the surface, make a finishing screed with a cement-sand mortar.

Make a specific decision depending on the type of finish flooring you choose. There is no need to level anything for attic rooms. If in the future you cover the screed with mineral wool, and lay the floor along the logs, then in this case, the screed surface may have small indentations or protrusions. Fix the screed will have to fruit laminate floors, parquet and all types of soft surfaces.

To improve adhesion between a thin cement-sand screed and hardened expanded clay, the latter should be abundantly moistened with water before work. The fact is that concrete quickly absorbs moisture, an insufficient amount of it will not allow the upper screed to gain the required strength. Professionals advise to pour dry cement on a richly wetted screed and mix it well with the liquid with a broom. This technique perfectly replaces modern primers.

The quality of the screed will significantly improve if the leveling of the surface is done not after the expanded clay concrete has hardened, but immediately after it has been leveled. The new mortar will tighten all grooves and grooves, material consumption will be significantly reduced, and work will be accelerated. In addition, this technology ensures complete solidity of the screed layers, despite the fact that it is made with two different mixtures.

Final leveling of expanded clay concrete screed

If you have little practical experience in the production of this kind of work, then the next day you will have to correct the shortcomings of the screed.

Important. Be sure to check if the material holds the weight of a person. If not, then you need to wait another day.

The surface should be leveled with a rule and a float. The metal slats of the beacons can be pulled out or left in bulk, make the decision yourself, the quality of the screed hardly changes.

Step 1. Remove the metal slats from the solution. He has not yet gained maximum strength, the elements can be removed without difficulty.

Step 2. Press the rule firmly to the surface and scrape off the bumps with back and forth movements. Make sure that no grooves appear. As soon as tool marks appear on most of the surface, the base is considered level. Work the rule not only parallel to the lighthouses, but also diagonally.

Step 3. Remove the dry mortar, moisten the surface, level the screed with a float. If the depressions are too large, then they should be filled with mass. Never use the old mass for leveling, the cement has already lost its ability to gain strength, it is useless to dilute it with water. Check the condition of the screed with a level or rule, you do not need to finish off the ideal indicators. The maximum allowable height difference for the most capricious coatings is 2 mm per running meter, such parameters are easily achieved after several passes with a float. Start grouting from the far corner of the room and gradually move towards the exit.

This completes the work. Further arrangement of the floor can be started only after the screed is set at least 50% of the maximum strength, the cement mortar gains such parameters in 10-14 days, the specific time depends on the microclimate in the room. If it is very warm and dry in it, then the screed should be watered every day. Keep in mind that concrete hardening does not occur due to the evaporation of water, on the contrary, it is needed for the optimal course of chemical reactions, as a result, their solution turns into solid concrete.

Prices for expanded clay in screed bags

expanded clay in bags

Video - Leveling the floor with expanded clay concrete screed