How to correctly calculate the amount of expanded clay per square meter?

Application

Gravel

A person will not be able to look at the process of making gravel from expanded clay, since hot air will interfere, but the manufacturing process is very spectacular:

• Clay, which melts easily, is constantly rotated and exposed to high temperatures in pyrogenic furnaces.
• Further, the rock is fired.
• As a result, after these actions, rather large granules are obtained, about 0.2 - 0.4 cm.

To obtain other fractions, these granules are crushed into smaller particles.

Very good gravel is obtained from this material and it has such characteristics as:

• fire resistance;
• frost resistance;
• waterproofness.

There are no impurities in the composition that could damage the cement - this is important, since this material is often used as an aggregate for the manufacture of lightweight concrete -

Crushed stone

To obtain crushed stone, the largest parts of the material are crushed to obtain smaller fractions.

The size of crushed stone granules ranges from 0.05 to 0.4 centimeters. It is the same size as gravel. It can be distinguished from other materials by the shape of granules - they have an almost arbitrary, most often angular shape. The scope of application of crushed stone is the same as that of gravel; it is used to fill lightweight concrete structures.

Sand (fines)

In order to obtain sand, large fractions are crushed or fines from clay are fired. After the listed actions, expanded clay of fine fractions with a size of less than 0.05 centimeters is obtained. The purpose of this particular sand is to mix it into a variety of solutions, and lightweight concrete is also filled with it.

Also, expanded clay is perfect for making concrete. This is confirmed by the fact that it has resistance to frost, and it is also worth noting its excellent resistance to combustion and protection from decay processes. Due to the listed advantages, this material is very often used for the manufacture of foundations.

House

easy enough to build. Moreover, such construction is quite economical, and the house will have a number of remarkable properties.

Bath

Expanded clay has found application in the construction of various baths. It can also be used as thermal insulation for the walls of the bathhouse due to its properties: the required temperature is quickly established in the room and remains for a long time. For this purpose, it makes no difference which material to use: fine or coarse.

Laying of communications

For laying water pipes or, for example, heating systems, you need to purchase a material such as expanded clay. Then you will be calm that the warmth will reach your home. Another advantage of this material is that in the event of a leak, you do not need to dig out hard soil. And after eliminating the accident, fill it with the same material again.

Other application

This material finds its application not only in construction work, but also in other areas:

• you can make a path in the country,
• insulate the roots of garden plants, thereby increasing the yield of the site. For this, the material of the fraction 0.1-0.2 centimeters is perfect, since it will create a drainage system in the roots.
• for indoor plants, you can use the same advice. The only difference is that you need to choose a smaller fraction, about 0.05-0.1 centimeters.

Currently, many professional builders are no longer using just cement-sand screed as an outdated technology. When screed, the floor covering is covered with expanded clay, which significantly improves the quality. Even an inexperienced amateur builder will be able to do such a screed.

Due to such material properties as thermal insulation and mechanical characteristics, it can be used to solve a number of construction problems. Expanded clay with fractions of 0.1-0.2 centimeters is most widespread.

It is used as thermal insulation for a wide range of purposes:

• roofs,
• floor coverings,
• walls,
• basements,
• foundations.

Many people use it about the well masonry of a building. Also, expanded clay is perfect for equipping street water pipes, sewer systems and many other communications, plant growing.

Leveling layer

As already mentioned, the expanded clay concrete screed does not give a flat surface. Rather, a fairly flat surface can be made by craftsmen who are engaged in this particular type of screeds. And that's not all. Therefore, it is usually advised to lay out a layer of mortar on top or pour a self-leveling mixture (on a cement basis, not gypsum).

With DSP everything is clear, but about leveling mixtures there are several points about laying.

• It is better not to use completely cheap formulations. Look for strength. For the floor, it must clearly be more than 150 kg / cm².
• The base is cement, and choose the type according to the required layer thickness.

• Pour water strictly according to the instructions. No more, no less. If poured, the strength will be lower.

• Under the equalizers, the surface is primed in at least two layers. Since the surface is bumpy, you have to work with a brush. It is necessary not to pour too much - so that there are no puddles, but also not to allow omissions. They lead to the rapid absorption of water into expanded clay, which reduces the strength of the screed. In place of the puddles, a dense crust forms, which worsens the adhesion of the compounds, which is also bad and threatens with delamination.

• Mix the entire volume of the leveler immediately. You can calculate by the area and thickness of the layer (there is an example above). It is better to cook a little more than less. The remains can be poured somewhere else, in extreme cases, thrown away. And it is difficult to “get” an insufficient level. Only with thin equalizers, and their cost is high.

• The mixture is laid out throughout the room. Not in one place, but so that it is convenient to distribute it. Do not think that "it will spread by itself." You need a needle roller, marks in the form of beacons / screws, set on the level and lines along the walls. Before setting, we actively work with a needle roller, distributing the composition.
• After setting, cover with foil and leave for at least 3-4 days. Better - for a week or two.

A few more points. When pouring the roving, it is better to walk in shoes with a spike soles. Of course, no one will specifically buy it, but you can make something similar from scrap materials (boards with screws). Yet. It makes no sense to align with beacons with a rule. It will be worse than with a roller. As a rule, you can disperse at the beginning when the entire composition has been poured. It's easier to distribute it this way. Then "roll" with a needle roller.

Features of expanded clay concrete

Expanded clay concrete differs from ordinary concrete mixture by the type of filler: instead of crushed stone, expanded clay is put in it - a loose material obtained from fired clay. It gives the solution special properties.

A few words about expanded clay

Made from natural raw materials, expanded clay is an environmentally friendly material. Thanks to a special production technology, it has a light weight, a porous structure and has high thermal and sound insulation properties.

Expanded clay - the most inexpensive and convenient insulation for laying

At the same time, it does not rot, does not corrode and does not contribute to the development of microorganisms, therefore, unlike other heaters, it can be used for screeding on the ground.

The material is classified according to the shape and size of the fractions. A concrete screed with expanded clay of different fractions has a different purpose.

The bulk density of the material in kilograms per cubic meter depends on the grain size, and as a result, the weight of the expanded clay concrete screed. Bulk weight is reflected in the expanded clay grade (from 150 to 800).

The smaller the fraction, the higher the bulk density and grade of expanded clay

The price of expanded clay is higher than that of crushed stone. But it also gives a lot of advantages in the composition of the concrete mixture. And not only in the mixture. Lightweight and free-flowing, it allows you to level surfaces with a large difference in height, without creating a serious load on the floors.

Advantages and disadvantages of expanded clay concrete

The main advantages of expanded clay concrete include:

• Relatively light weight;
• High sound and heat insulation characteristics;
• Durability and fire resistance (unlike most other heaters).

Expanded clay concrete for floor screed is easier to prepare and install due to the lower weight of the mortar. But this material itself is quite fragile, therefore, the expanded clay concrete floor screed is performed only in rooms with a small load.

For example, it is not suitable for coating workshops with heavy equipment. But for residential and public buildings, garages and outbuildings, this is a great option.

Expanded clay concrete coating in the garage

The disadvantages of the material include the fact that light granules in the composition of the solution float to the surface when pouring, making it uneven. Therefore, it has to be sanded or an additional sand concrete screed is made.

Expanded clay screed when drying has a rough surface

However, there is a technology for arranging a screed made of expanded clay concrete, which makes it possible to avoid time-consuming additional work. But it is worth talking about this and other methods in detail.

Application area

Fine expanded clay sand has found its application in different areas:

• in construction - for pouring screeds, which need to be given additional thermal insulation qualities, for the manufacture of various forms used in the construction of buildings;
• in plant growing - for arranging the drainage layer;
• to create hydroponic systems.

Also, a fraction of 5-10 mm is used for installing a warm floor according to German technology. This material is used as a backfill for plywood sheets or gypsum fiber boards.

This is a great solution if you need to insulate the facade using the innovative Capsimet technology. The execution algorithm is as follows:

• take the right amount of expanded clay sand;
• prepare a slurry;
• mix both materials 1: 1;
• pour into the space between the cladding and the wall.

A medium-sized product stands out with a small bulk area, for this reason it is often used for insulating attic rooms, basements, foundations, if it is necessary to equip a high-quality layer of thermal insulation. It is an indispensable material for drainage when planting small trees and shrubs.

The larger fraction is used as a heater:

• for arranging the roof, if you plan to equip a residential attic room, especially if you plan to install a pitched roof:
• thermal insulation of floors in wooden houses;
• wall insulation, if they are constructed using well masonry;
• and when installing street water supply and drainage systems, it is simply irreplaceable;
• when laying heating mains - the backfill has a low thermal conductivity.In addition, if an accident occurs, then labor-intensive work on excavation will not have to be carried out - expanded clay is light, loose and does not cake.
• insulation and arrangement of slopes on flat roofs and lawns on terraces
• helps to reduce the depth when pouring the foundation;
• as a covering material for soil;
• as drainage when filling dirt roads laid in places with high soil moisture.

The advantage of using expanded clay gravel is the fact that it can be reused - it does not lose its strength characteristics, even after contact with water.

In addition to its thermal insulation characteristics, it has excellent sound insulation performance, it is often used as part of an underlay for various structures.

Another plus is the budget cost, which makes it affordable for a wide range of consumers and private developers.

The use of expanded clay in various areas of construction is quite justified, due to its unique characteristics. For example, the use of material as a filler when pouring concrete structures, not only improves the performance of noise and thermal conductivity, but also reduces the specific gravity of the building, which saves money on the construction of the foundation.

Fill methods

In total, there are three methods of screed using expanded clay. You should disassemble the method of use and the advantages of each of them in more detail.

Semi-dry screed with expanded clay

This method is used in cases where it is necessary to both raise and insulate the floors in the room. To achieve thermal insulation, the expanded clay layer must be at least 10 cm

Here it is important to take a large fraction of the backfill - at least 20 mm. If it is important for you only to raise the floor to the required level, you can also use smaller particles.

In this case, waterproofing is necessary in order to protect the expanded clay layer from moisture. Beacons are set to the required height, and expanded clay is backfilled. Follow it with a rule to tamp and level the layer.

After that, you should proceed to pouring a concrete screed. A cement-sand mortar or a special mixture can be used. For the convenience of work, it is better to pre-shed the expanded clay layer with a concrete mixture, highly diluted with water - cement milk. This will prevent the expanded clay grains from floating and facilitate pouring with the basic solution. Also for these purposes, laying a layer of granules with a film may be suitable. Only in this case, the laying should be done very carefully so that the film does not break.

Expanded clay concrete

This is the so-called wet screed. In this case, it is necessary to carefully measure all the unevenness of the base and determine how thick the screed layer will be. This method is advantageous to use if you have to raise the floor level to a considerable height, as well as to save concrete mix. Expanded clay is combined with sand concrete, the resulting composition is carefully stirred and distributed over the floor. It is better to first soak the expanded clay granules with water, so that later the consistency of the mixture does not turn out to be too dry. Mixing is best done with a construction mixer, because no spatulas and sticks can achieve a uniform consistency without clots and lumps.

To strengthen the expanded clay concrete screed, you can use a reinforcing mesh, and as beacons - any slats that are easiest to get. The mesh should not reach the required height by a couple of centimeters. Next, distribute the solution evenly over the grid, leveling it with a rule. After finishing laying the mixture, do not wait for it to dry. Prepare the mortar for the top leveling layer. It can be a cement-sand screed, and a self-leveling floor. It is applied already to the zero mark, leveled with a rule and left to dry.

Dry floor screed with expanded clay

If the semi-dry method is a combined screed, then backfilling with expanded clay granules does not require subsequent filling with any solutions. The base is prepared as usual, but it is necessary to exclude any possibility of moisture getting on the waterproofing layer. Lighthouses are set up to the required mark. The minimum thickness of the expanded clay layer with this technique is 5 cm. Granules must be selected of small or medium size, it is advisable to combine different sizes to distribute the layer more evenly with fewer voids. It makes no sense to use small waste, because a huge amount of them will be required, but they will not create the desired thermal insulation effect.

It is better to divide the surface into strips using wooden slats - this will make it easier to level the granular layer and lay the following materials. Do not tamp the expanded clay, but carefully roll it out. Next, lay a layer of moisture-resistant drywall. If the sheets are thin, it is better to lay them in two layers, gluing together, and the seams must be coated with putty. You can also use waterproofing mixtures. After completing the installation of drywall, you must cut off any protruding pieces of tape or film.

This kind of screed has a lot of advantages:

• The smooth surface is suitable for applying any kind of finishing coat.
• The layer can withstand high loads.
• The floor covering turns out to be quite light, so it can be used on old dilapidated floors without any risk.

• Thermal insulation at a height. There is no need for underfloor heating on expanded clay cushion.
• The work can be done very quickly, and immediately after completion, proceed to the next stages of repair.
• The dry screed provides excellent sound insulation.
• The coating is not deformed.

Sometimes builders suggest using expanded clay for filling in a rough screed directly on the ground instead of sand or gravel. This can be done only if the groundwater level is low, otherwise the high humidity will lead to negative consequences for the entire climate in the house, and good heat conservation will no longer play its role here.

Technology

First of all, you need to prepare all the tools and calculate the required amount of materials.

You may need:

• bucket;
• mixer, construction mixer or just a stick;
• brush or needle roller;
• spatulas;
• rule;
• construction beacons;
• building level (water or laser);
• ruler and special marker;
• brushes and rollers.

At the initial stage, you should prepare the base of the floor. If you are renovating an old apartment or house, carefully remove the old screed with a crowbar or hammer drill. Next, you need to get rid of debris, dust and dirt. Evaluate the opened base. There should be no chips, cracks, or greasy spots on it. If you find gaps more than 1 mm wide, they must be repaired.

In this case, it is recommended to pre-treat them with a primer, and then apply one of the composition options:

• cement-sand mixture;
• putty or sealant.

The next item will be the choice of the zero mark. This is the definition of the height at which the top layer of the flooring we create will be located. This can be done using laser or water levels. As a rule, it is exposed no higher than 15 cm from the base. The device of the floor covering involves the laying of a waterproofing layer. It may seem to many that this stage is optional in living rooms in an apartment, but this is not so.

Waterproofing can be done in several ways:

If you live in a private house, it is better to apply the long-known roofing felt. Overlap the layers, leading to a certain height on the walls. The base is pre-coated with bitumen mastic for gluing the roll material to it. Seams also need to be treated with mastic.

• In apartments, it is enough to apply insulation with foil.Choose dense materials for layer strength. The film is also secured with an overlap and overlapping the walls. Glue it with construction tape. To minimize the effect of the coating layers, the perimeter of the room is pasted over with damper tape.
• You can also use a waterproofing coating made from special water-diluted mixtures. They process the entire surface of the floor and the bottom of the walls.

General characteristics and properties

The parameters for expanded clay are determined by GOST, which regulates the quality of building materials with a porous structure. Let's take a closer look at the main properties:

• fractional composition. Three fractions have been identified, varying in the ranges of 5 - 10, 10 - 20, 20 - 40 mm. Fractions that are rarely used in construction are highlighted in a separate category. They include crushed stone and expanded clay granules with fractions from 2.5 to 10 mm, a wide mixed fraction of 5 - 20 mm. Heat-insulating interlayers used as bulk material are represented by a mixture of all expanded clay samples, the fractions of which are 5 - 40 mm. This is explained by the need to fill the void areas in order to increase the stiffness of the structure and eliminate the convection of air flows;
• density grade. Seven values ​​have been established, the data of which are given in the table:

M 700 and M 800 are not produced for general consumption; this requires prior agreement with the customer. The indicator of true density exceeds the bulk value by one and a half to two times. This parameter characterizes the density of expanded clay, without taking into account the intermediate areas between individual granules or fragments;

• material strength. Expanded clay gravel has thirteen grades with different strength values ​​after being squeezed in a cylinder. For crushed stone, eleven values ​​are normalized with the same abbreviation as for gravel marks. At the same time, crushed stone and gravel of the same grade have differences in strength. It should be noted that as the density of the material increases, its strength increases. There is also a mutual relationship between the brands, regulated by standards, which completely excludes the preparation of low-quality expanded clay with a high density indicator, but immediately collapsing from small loads;
• compaction factor. This value is agreed with the customer and does not exceed the value 1.15. It is used to take into account the compaction of the mass of material obtained from transportation or storage, which often happens with fine expanded clay. The need to apply such a coefficient is caused by frequent shipments of materials by the bulk method, which is very convenient for the sale of large volumes;
• thermal conductivity. An important parameter characterizing the level of thermal insulation of the material. For expanded clay, this coefficient is 0.10 - 0.18. The range is rather narrow, which once again confirms the high thermal insulation qualities of the raw materials. This coefficient increases with increasing density, which is explained by a decrease in the number and size of porous areas that contain air;
• moisture absorption. Another important indicator that determines the behavior of expanded clay when exposed to a humid environment. The material is considered a sustainable raw material, the water absorption value is 8 - 20 percent;
• soundproofing. Like many other heat-insulating materials, expanded clay is characterized by increased sound insulation. The best results are achieved by laying a layer on a wooden floor, using expanded clay as an interlayer separating the outer surface of the floor and floor pits;
• resistance to low temperature conditions. Since the basis of expanded clay is clay, and the level of water absorption of the material is low, the raw material has a high index of frost resistance. In terms of numbers, the standards are not standardized because expanded clay resists low temperatures by default.

Preparation of the foundation and carrying out calculations

In order to correctly make a floor screed with expanded clay, you will need to carry out a set of preparatory actions, which will include the following - dismantling old structures, cleaning and cleaning the surface, calculating the thickness of the layer and the total number of guides.

For minor damage in the form of potholes, chips and cracks, use the usual cement-sand mixture, which is applied to the base after its priming. In case of strong chips and deep cracks, jointing of damage, priming in several layers and filling with mortars are performed.

Before laying the plastic film for gluing the tape, the surface is cleaned of dirt, and the damage is rubbed with a cement mortar

Calculation and marking of the thickness of the leveling layer begins with the definition of its main functions. For insulation and sound insulation of the floor, it is recommended to use at least 15 cm of the leveling layer. With a simple leveling and surface adjustment, 5-10 cm will be enough.

Marking is done using a pencil, tape measure and level. To do this, 1 m retreat upward from the surface of the base and put a mark on the plane of the wall. According to the mark, in compliance with the level, draw a line parallel to the floor surface.

After, from the drawn line, the distance to the base plane is measured. Find the minimum value, lay 5-7 cm up from it and beat off the line across the entire area of ​​the room.

Scheme for calculating and marking the height of the leveling layer

The bottom line is the "zero level" or the height of the future layer. In the process of measurements, it should be borne in mind that the minimum thickness in the thinnest place should not be less than 5 cm.

To determine the number of required guides, you can use simple formulas:

• DK - ((DP - 15) * 2) = P1, where DK is the length of the room, DP is the length of the rule, P1 is the distance between the extreme guides;
• P1 / DP = KN, where P1 is the distance between the extreme guides, DP is the length of the rule, KN is the number of guides excluding the extreme ones;
• (DK - P2 * 2) = P3, where DK is the length of the room, P2 is the distance from the wall to the first guide, P3 is the distance between the guides.

In the process of calculations, it should be understood that the length of the rule (DP) is reduced by 15-20 cm, since when aligning it should overlap the adjacent row. The distance between the wall and the extreme guide (P2) should be 30-40 cm. In the course of calculations using these formulas, we get the number of guides not including the extreme ones.

How to correctly calculate the amount of expanded clay per square meter?

This natural material will be simply irreplaceable for insulating a garage roof. In terms of efficiency, only mineral wool can be compared with it, the use of which is also widespread and it is impossible to say unequivocally which of the heaters will be better. The main thing is the correct installation and selection according to technical characteristics, based on specific requirements and conditions. The heat insulator must provide not only a low level of heat loss, but also protection from fire, noise, have a low weight and comply with sanitary environmental standards. Moreover, its price must be acceptable.

Expanded clay, in the best possible way, meets all of the above requirements. It is a light and porous ball of quartz clay, which swells at temperatures above 1000 degrees Celsius. By fractions, this unique material is divided as follows (count from the end of one fraction to another): up to 5 mm (sand), up to 10 mm, up to 20 mm and up to 40 mm.

Depending on the fraction, its density and layer thickness, the answer will depend to the question - how to correctly calculate the amount of expanded clay per square meter? The smaller the granule size, the higher the density (in tons):

How much a cubic meter weighs, the fraction we need, we already know. Now it is necessary to calculate how many cubic meters the expanded clay used to insulate the garage roof will take.To do this, multiply the surface area on which the material is laid by the thickness of the required layer. We get the required number of cubic meters and multiply by the density of the fraction. We get the total weight of the consumed expanded clay, if we divide it by the area of ​​the covered surface, we will get the amount of expanded clay per square meter.

Preparatory work

The screed laying technology requires careful preparation of the base, its hydro and sound insulation, the installation of beacons and the fastening of a damper tape around the entire perimeter of the wall.

Subfloor preparation

The initial, but most important stage in the construction of the floor is the preparation of its foundation.

Concrete floors are cleaned of old screed and debris, cracks are repaired.

Rotten and walking boards change in the wooden subfloor, cracks and fallen out knots are sealed with parquet putty.

The subgrade is leveled. A layer of expanded clay and sand is backfilled on it to create a cushion under the screed. The process of preparing the base for the screed is discussed in detail in the material "Preparing the base for the screed", which can be viewed here.

Waterproofing

The use of expanded clay in the floor screed requires mandatory work on the waterproofing of the screed. This is due to the hydrophobic properties of expanded clay, as a result of which the expanded clay floor screed is destroyed by moisture.

Insulating layers can be laid under the screed, on the screed, and also, which is gaining popularity recently, on both sides at the same time.

Polyethylene film is widely used as insulating material.

Other waterproofing materials: roofing material, bitumen, liquid rubber, special primers, etc. are also used, but much less frequently, due to their higher cost and high labor costs.

The features of waterproofing are described in detail in the work "Waterproofing under a screed" (see here).

Thermal insulation

The problem of home insulation is very relevant for individual developers. In private houses, the ground floor is either on the ground or above the basement. In both cases, it is necessary to carry out thermal insulation work.

Warming the floor with expanded clay under the screed allows you to keep the heat in the house better than modern materials - polystyrene and expanded polystyrene. In addition, it is easier to implement and much cheaper.

Soundproofing

Sound insulation of the floor, when using expanded clay as one of the components of the screed, is not performed. The function of noise absorption is performed by porous expanded clay granules.

Installation of beacons

It is impossible to get a flat screed surface without the use of beacons when pouring the solution. Their installation involves two stages of work:

1. determining the screed line and applying it to the wall, as well as calculating the number of rows of lighthouses and determining their location based on the floor (a description of the procedure for performing the work is given here);
2. installation of beacons.

The type of lighthouses is dictated by two factors: the method of waterproofing and the type of screed. So, the use of film and roll materials to protect against moisture excludes the device of beacons on self-tapping screws.

The dry screed provides for the extraction of the beacon guides, which can only be done when using U-shaped profiles (the technology of the beacon device is discussed in the material "How to set the beacons for the floor screed?").

Damper tape

When dry screed, the damper tape is attached against the floor covering so that it does not creak during operation. In other cases - for the entire thickness of the screed layer, to compensate for its expansion under the influence of temperature and humidity.

The tape is attached to the wall with a stapler or double-sided tape.

Preparatory activities

The same preparation is carried out both for the usual execution of the screed and for the semi-dry one. That is, there is no difference in whether the floor screed is dry or semi-dry will be necessary for flooring.

It is very important here to level the foundations where the work will be carried out.All existing cracks and pits, if possible, are eliminated with a cement mortar

Bulges can be knocked down. We must not forget about the waterproofing layer, which can become a regular plastic film. The better the material is chosen, the better qualities it can show during operation.

After that, sand is poured, acting as a pillow for expanded clay. Usually its layer is 20-30 mm. The pillow should also be leveled and leveled using a rule of thumb. As for tamping sand, it will be sufficient to just walk over the entire plane. In this case, the weight of a person will be enough.

The choice of expanded clay is carried out depending on the fraction (small, medium and large fraction). It falls asleep throughout the room, starting from the far corner. After filling the required layer, it should be leveled. On the top of the expanded clay, beacons are installed, which serve as the main one for the sub-floor level.

Profiles are used as beacons, which are mounted on the base using a cement-sand mortar. Subsequently, the screed is poured, somewhat stepping on the lighthouses, and they simply "hide" into the base of the subfloor.

Expanded clay screed: what is it and when to use

Expanded clay concrete is the so-called lightweight concrete, in which expanded clay is used as an aggregate. It is usually used where the screed layer is large. This means that the load on the floor will be significant. Expanded clay is a lightweight aggregate and concrete with such aggregate has a lower mass. But it is worth considering that a claydite-concrete screed makes sense with a thickness of 6 cm. Then the difference in weight will be about 40-60 kg per square meter. The greater the thickness, the greater the gain in weight.
Cons of expanded clay concrete:

• The price of expanded clay concrete in comparison with a cement-sand screed (CPS) is about 30% higher.
• It is more difficult to manufacture.
• More problematic when styling.

And that is not all. You will not get a perfectly flat surface. It will be fine under the tiles, but under the linoleum, laminate and other coatings, a leveling screed will be needed on top. This is additional time, and it must also be taken into account when calculating the thickness of the expanded clay concrete layer.

On top of expanded clay concrete, under many floor coverings, it will be necessary to pour a leveling layer

What is expanded clay and its types

Expanded clay is a specially fired mixture of clay and shale. There are two types of this material - expanded clay gravel and crushed stone. The gravel has a rounded and oval shape, crushed stone with sharp edges. Both materials are graded by density. It can be from 150 to 800 kg / m³, and sometimes even higher. Grades M250 (density 200-250 kg / m³) or M300 (from 250 to 300 kg / m³) are used as aggregates for concrete.

A screed made of expanded clay concrete is used if it is necessary to increase the height

There are also different fractions (grains of different sizes):

• less than 5 mm - expanded clay sand;
• 5 - 10 mm - small;
• 10 - 20 mm - medium;
• 20 - 40/50 mm - large.

Expanded clay is added to the screed mainly of the middle fraction. It is possible and small, but it is much more expensive, and there is no strong need for fine aggregate. Large is used in a semi-dry screed.

Types of expanded clay screed and their features

There are four technologies for making a screed from expanded clay concrete:

Dry screed based on expanded clay sand and gypsum plasterboard

We will not talk in detail about a dry screed - this is a separate topic. We are talking about expanded clay concrete and screed from it. All three options can be used both in the house and in the apartment. The first two are heavier in weight. They are also more reliable. In the sense that, subject to the technology, there are no load restrictions. The third option - with a layer of mortar over bulk expanded clay - is more problematic. It will still not work to ram the expanded clay, and situations may arise when a cavity forms under the screed layer. The top layer will, of course, sag. This can only be eliminated by redoing everything. So ... the problem.However, if the floor needs to be raised to a great height, this can be done.