Wet floor screed technology with expanded clay. Floor screed with expanded clay: Pros and cons Pouring floors on expanded clay thickness and exposure

To obtain a smooth and high-quality floor covering, it is necessary to properly prepare the base for it. To do this, work is carried out for insulation, alignment, and wiring is laid, if so intended in the project. Very often, expanded clay is used to level the base. It has good performance properties, besides it is safe for humans and the environment. But at the same time, it is important to trace which fraction of expanded clay is used for floor screed, you need to use only those intended for this type of work.

Characteristics

Expanded clay is a natural material with pores. It is obtained by firing clay at a temperature of 1000 - 1200 degrees. Bulk density is considered the main characteristic of a substance, on the values of which heat-insulating and sound-proofing qualities depend.

When clay is heated, granules of different sizes are formed, due to this expanded clay has several fractions:

Crushed stone (granules have parameters of 5-40 mm, obtained by crushing large expanded clay, very often used for the preparation of concrete).
Gravel (divided into three types of granule sizes, 5-10, 10-20, 20-40, ideal for flooring).
Sand (particle size less than 5 mm, used for thin screed).

To determine which fraction is needed for a floor screed with expanded clay, it is necessary first of all to assess the condition of the base. Most often, small particle sizes are used so that there is no large load on the floor.

Advantages of expanded clay

Before using expanded clay to level the floor, you need to look at its positive aspects:

Provides a small load on the floor;
Thanks to the material, additional thermal insulation on the ground is provided;
Evens out large differences in height on the surface;
Relatively inexpensive material.

Very often the question arises, which expanded clay to use for floor screed.

Experts advise using small particles for an apartment, and for public spaces it is allowed to set fractions up to 40 mm.

What are the types of screed

Before deciding which expanded clay is needed for floor screed, it is important to understand its types. There are 3 ways:

Wet
The device is carried out in 2 layers. The first layer is prepared from cement, sand and expanded clay, after pouring it is leveled with the help of special beacons. For this, the upper boundary of the layer is determined by the level, beacons are placed. Pull the tape around the perimeter, fasten it with reinforcement. The field of this mixture is leveled along the beacons, allowed to harden for 2 days. After that, a second layer is applied using self-leveling compounds. What size of expanded clay is needed for this type of floor screed? A fraction of 5-20 mm is used.
semi-dry
First, expanded clay is poured, which is aligned with the beacons. After that, fittings and a tape around the perimeter are installed, the poured expanded clay is compacted. The final stage is pouring the second layer, which is prepared from cement and sand.
Dry
Considered the easiest way. First, the base is covered with a waterproofing material, on which expanded clay is poured. GVL sheets are installed on it in 2 layers, fastened with self-tapping screws. All joints are puttied, after which the surface is treated with a primer. It is very important to know which expanded clay for dry floor screed is needed to avoid a negative result. This method of laying the screed requires the use of a fraction of up to 10 mm.

How to make a calculation

What layer of expanded clay is needed for floor screed? To answer the question, you need to do a calculation.

In order to find out the size of the layer, it is necessary to divide the area of \u200b\u200bthe room by the total amount of material. For a wet screed, a layer of at least 7-8 cm is used. For a dry method, a layer of at least 10 cm is used. If a dry screed is laid on a warm floor, then 3 cm is enough.

Which expanded clay is better for floor screed? Experts advise using particles up to 10 mm for an apartment, in some cases it is allowed to use fractions up to 20 mm, it is done so that the floor does not sag.

In the harsh conditions of our country with traditionally frosty winters, many people think about insulating their houses and apartments: they thicken and compact walls, floors, ceilings. Technologies are improving year after year. The range is constantly replenished with various mixtures, dry fills and heaters. One of the solutions for floor insulation is the use of expanded clay screed.

Peculiarities

The floor screed is the first layer above the base. They choose it based on the type of room, the purpose of its use, the condition of the house and the intended decorative flooring. Expanded clay has been known for a long time, but does not lose its relevance and popularity as an additive in modern screeds. Mixtures sold in stores do not lose their properties when using it. This material is made from clay, purifying it of unnecessary impurities. Porous granules are formed from a solution of a liquid consistency under the influence of high temperatures.

Advantages and disadvantages

To use a screed with expanded clay, you need to understand what the advantages of this method are, why you need to do this at all.

This screed allows you to significantly increase the height of the floor. In cases where it is necessary to raise the level to a considerable height due to distortions of the base or simply to reduce the distance between the floor and the ceiling, it is not advisable to pour a thick layer of concrete.
In old houses and structures with wooden floors, even with a small layer of pouring, the base may not withstand the load of concrete mortar. Filled floors in this case minimize the risk of damage to the floors.

Even strong drops, pits and cracks can be filled with expanded clay and get a flat surface.
In cold climates, an important plus is the frost resistance of expanded clay.

The safety of use is determined, among other things, by resistance to heat.
The material is very durable - it does not corrode, does not burn or rot.

For the environmental qualities of the coating, excellent vapor and air permeability is required.
Despite the natural basis, expanded clay screed is not affected by microorganisms, fungi, mold and rodents.

Due to its light weight, the material can be transported without any problems even in large volumes.
Laying technology allows an unprepared person to cope with the work. Handling the composition is quite simple.

Expanded clay additives are very budgetary. The product is easy to find in stores. Often, those whose choice falls on the purchase of expanded clay do not want to isolate the coating, but save on the screed, because concrete mixes are quite expensive.
The material is moisture resistant. Its water absorption reaches 20%. This means that when flooded, it does not deform for a long time.
If you need good sound insulation, then the choice should definitely fall on expanded clay. At the same time, unlike expanded polystyrene and foam plastic, it has greater strength and lower thermal conductivity. The best sound insulation is achieved by adding expanded clay to concrete.

Expanded clay screed has not so many disadvantages:

If you are making a dry screed, you need to protect the base from water penetration. It will not be absorbed, creating dampness and mold in the room. Waterproofing is always given great attention when finishing with expanded clay.
Avoid single granule size when dry-filled. Heterogeneity will give greater density and uniformity to the coating.
To retain heat, small granules will be useless, like a narrow layer of screed. It is necessary to raise the floor level by at least 10 cm.

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, the subfloor should be prepared. If you are making repairs in an old apartment or house, carefully remove the old screed with a crowbar or puncher. Next, you need to get rid of debris, dust and pollution. Estimate the opened base. It should not have chips, cracks, greasy spots. If you find gaps more than 1 mm wide, they must be sealed.

cement-sand mixture;
putty or sealant.

Deep penetration priming is necessary for the mixture to properly bond to the substrate surface. Grease stains should be removed or cleaned. Next, treat the entire surface of the floor, using the composition for the primer.

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 are creating will be located. This can be done using laser or water levels. As a rule, it is set no higher than 15 cm from the base. The flooring device involves laying a waterproofing layer. It may seem to many that in the living rooms in the apartment this stage is optional, but it is not.

Waterproofing can be done in several ways:

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

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

The thickness of the layer is indicated in the recommendations on the packages. Next, you need to let the coating dry. This will take more time than the previous methods. Then the laying of the expanded clay concrete layer is carried out. When the coating is completely dry (drying time varies depending on the composition of the concrete mixture), you can proceed to the fine finishing of the floor covering.

Backfill types

An important indicator in relation to expanded clay is its density. It depends on the size of the applied fraction. In construction, GOST 32496-2013 is used, which regulates the technical features of expanded clay granules, but due to optional certification, manufacturers can produce various options according to their specifications.

The most common division into:

Expanded clay gravel. The size of the granules is large - 20 - 40 mm. The lightest backfill is obtained from granules of this size.
The gravel is smaller. Its particles have sizes from 10 to 20 mm. They are usually obtained by crushing gravel.
Expanded clay sand less than 10 mm in size. All expanded clay remains fall into this category.

If we talk about the thermal insulation properties of expanded clay, then it is advisable to use gravel and crushed stone, and use waste to obtain a more porous coating.

Filling methods

In total, there are three ways of screed using expanded clay. It is necessary to analyze 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 only important for you to raise the floor to the required level, you can 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. Walk on it with a rule to tamp and level the layer.

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

These two methods are also necessary so that the moisture from the concrete layer goes less into the porous expanded clay granules. Then the coating will be more reliable and durable. For pouring concrete mortar, you can use a reinforcing mesh. This will make it easier to gradually, in sections, fill the layer and level it to obtain a smooth surface.

Expanded clay concrete

This is the so-called wet screed. In this case, it is necessary to carefully measure all the irregularities 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, carefully stir the resulting composition and distribute it over the floor. It is better to soak the expanded clay granules with water first, 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 reinforce 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 level 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 until it dries. Prepare a solution 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.

After about a day, it is necessary to remove the beacons. Be sure to treat the openings from them with a primer and fill with cement. The advantage of the expanded clay-cement screed is that it can be poured without problems with your own hands, all proportions are made by eye until the necessary viscous consistency is obtained. Such a screed can be part of a multi-level system and be used as a draft under the self-leveling floor. It may also be sufficient for laying a fine finish that does not require an even subfloor (such as a tile floor).

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 pouring with any solutions. The base is prepared as usual, but any possibility of moisture entering the waterproofing layer must be excluded. Lighthouses are exposed to a necessary mark. The minimum thickness of the expanded clay layer with this technique is 5 cm. The granules need to be selected in small or medium sizes, 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 they will require a huge amount, but they will not create the desired thermal insulation effect.

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

This type of screed has a lot of advantages:

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

Thermal insulation is top notch. There is no need for underfloor heating on expanded clay cushion.
The work can be completed very quickly, and immediately after completion, proceed to the next stages of repair.
Dry screed provides excellent sound insulation.
The cover does not warp.

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

Layer thickness

The thickness of the coating will depend on many aspects: the size of the granules, the level of floor elevation required, and the functionality of the screed. It is better to take a minimum layer of screed using expanded clay at least 3 cm. Depending on the method of coating, the layers can vary greatly. For pouring with expanded clay concrete in order to raise the height and level, a thickness of 3-5 cm will be enough. If you want to get a heat-insulating effect, the layer should be at least 10 cm.

A light screed with a thin layer fits better with the use of small granules. This saves money and reduces workload. In the case of dry backfill, fine fractions of 3-6 mm can be used to level the floor, but for thermal insulation it will be necessary to lay a layer of special materials. If you are primarily interested in heat-saving properties and anti-noise effect, then you need to fill up 10-15 cm from the base, and take large fractions.

How long does it dry?

This question concerns the wet and combined type of screed. Sand concrete takes a long time to dry. With a mixed type of screed, you must wait at least 14 days for the top layer to dry in order to continue finishing work. Full strength and ability to perceive the maximum load will gain the coating after 28 days. However, these recommendations vary depending on the thickness of the layer. If you used the wet method, and the thickness of the screed is more than 5-6 cm, then you need to increase the period to 6 weeks. In any case, if you are in doubt about the drying time of the coating, cover the floor area with a film and press it in several places with wooden slats.

If condensation appears after 1-2 days, the screed must be dried further, because if all the accumulated moisture does not have time to evaporate, then the strength and integrity of the coating will be at risk. Such a floor will no longer be reliable and durable. If you prepare a mixture with the addition of modern components or special plasticizers, then this increases the chances of obtaining a high-quality surface and, of course, reduces the drying time, sometimes even by half. Information is usually indicated on bags with ready-made formulations. This method is more expensive, but more guarantees are given. It is only necessary to choose high-quality mixtures of trusted manufacturers.

How to calculate the expense?

Expanded clay consumption for different rooms will depend on the strength of the base and its maximum load, layer thickness, your preferences for heat and sound insulation. The more expanded clay you add, the more heat the coating can retain, but the strength will suffer. For a wet solution, it is better to take expanded clay backfill and concrete in proportions of 1: 1. The amount of granular material is measured in liters, not kilograms. Usually, a layer 1 cm thick is taken for calculations. It is necessary to determine how many liters of expanded clay are needed to cover 1 square meter. m area. This value will be equal to 10 liters.

To find out the consumption of expanded clay for the standard area of \u200b\u200bthe apartment (usually 20 sq. M is taken), you need to multiply 10 liters by 20 sq. m. It turns out 200 liters. The layer height is chosen based on the purpose of the room. On the ground floor and in cold rooms, a height of 10 cm is selected, in other types of housing a layer is taken from 3-4 cm. Thus, in a new building in a one-room apartment with an area of 40 meters, a layer of 5 cm can be applied. m will account for 50 liters of expanded clay. Therefore, the entire area of the apartment will require 40 * 50 \u003d 2000 liters - 40 bags of 50 liters.

Kitchens in "Khrushchev", having a small area, require a layer of 3 cm or more. For such a room, you will need from 150 liters of expanded clay. It must be remembered that surfaces may have irregularities and deviations, so the calculation formula is only approximate. It is better to take expanded clay with some margin. For pouring a layer of concrete, the approximate consumption per 1 cu. m of expanded clay will require 300 kg of cement "M500" and the same amount of sand.

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 features of expanded clay make it possible to get the best result in a relatively short period of time.

Expanded clay itself is a 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 exposure to high temperature.

For you, it will be needed first of all in order to raise the floor level to the desired height, insulate it and significantly strengthen it. Floor screed 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 right 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 even out even strong irregularities that other mixtures cannot cope with;
ease of screeding even without additional skills.

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

There are frequent cases when no alternative other than expanded clay simply fits:

It is necessary to process an area exceeding 15 centimeters in height. Cement mortar in this case will cost much more, and its strength will be an order of magnitude lower.
When it is impossible for the screed to greatly add weight to the building due to a weak foundation.
The presence of wooden floors (together with expanded clay, it is also recommended to use foam plastic as a heat insulator with low weight).
If you do not have a large budget for repairs and want to spend less on the materials used.

How does a do-it-yourself floor screed with expanded clay. Preparatory stage and miscalculation of materials

Instruments:

level;
construction mixer;
ruler;
rope;
rails 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 state - remove construction debris, clean it of foreign objects.

dismantle the old floor;
vacuum or sweep small debris;
clean and cement small 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 rails must be set exactly on the 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). If it is not there, you can replace it with ordinary water. But in this case, you will need to use a rope to mark the level with all the accuracy.

Set the 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. To fix the beacons, you can use gypsum or cement mortar. But the second implies the need to work quickly, until the solution has frozen and begun to harden.

It is not difficult to calculate the desired ratio of expanded clay to a 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 greatly deteriorate. 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 between 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 vary due to different density, so when buying, be guided by volume).

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

As a standard, let's take a room with dimensions of 9 square meters and an average layer thickness of 60-65 mm. We make the calculation: 9 x 0.06 \u003d 0.54 cubic meters. m., which is exactly 540 liters. screed solution.

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

Screed option No. 1

After you take measurements and mark the level of the screed, you need to fill in fine expanded clay over 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 point of the future screed. Using a level, make the expanded clay layer completely even and spread 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 during pouring will decrease. For the formation and hardening of such a film, it will take a day. Finished at this stage. Now you just need to wait.

At the end of the day, you can proceed directly to the finishing screed. Pour 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 the rule and leave to dry for 2-3 days.
When the screed is dry, remove the beacons, and seal the resulting holes with cement.

Screed option No. 2

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

Prepare a screed solution. To make it suitable for use, you must first fill the expanded clay in a large container, pour water and mix with a construction mixer. Next, add cement and sand in the right amount to the container and also mix everything. There is no exact proportion in this case.
Gradually add sand and cement to the solution until it becomes a homogeneous viscous mass without lumps.
Pour the finished composition to a height of up to 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 align 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 adhesive tape or electrical tape.
Under expanded clay, it is best to put a layer of waterproofing. For this purpose, mastic, plastic film or hydrosol can be used.
Profiles and rails are the best options for beacons.
It will take at least a month for the screed to dry completely at standard room temperature and humidity.
In the process of drying, you need to regularly water the surface with a small amount of water to avoid the appearance of cracks.
If a plasticizer is added to the solution, then the likelihood of cracks 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 denser 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, higher strength and thermal insulation can be achieved.
During the screed, work the building rule on yourself over the entire surface area.
Reinforcing the surface of the screed 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. Without expensive tools and materials.

The main purpose of the floor screed is to create a rough surface that hides protruding structural and communication elements. Such flooring is necessary not only for arranging the floor covering, but also to protect the room from extraneous sounds and condensation. In addition, the concrete base has heat-insulating properties. One of the most effective technologies for creating basic floor insulation is an expanded clay concrete screed, the pouring of which is associated with certain features, which we will consider in more detail.

Preparing a mixture for expanded clay concrete screed

When making a screed mortar, first of all, you need to pay attention to the brand of cement used. If you are repairing interior living rooms, then the M 150 and M 200 brands are suitable for the screed, and the M 300 is best used for industrial premises.

Advice! The number after the “M” marking indicates the volume of cement in the concrete mix. Accordingly, the higher the brand, the better its technical characteristics, first of all, this concerns strength.

In order to prepare a screed mortar, it is necessary to choose the “right” aggregate.

Expanded clay is small particles of fired clay. Depending on the type of processing, the following types of this material are distinguished:

Gravel. Rounded granules are best suited for wet screeds. In this case, particles with diameters of 5-20 mm have the best performance characteristics.
Rubble. Raw aggregate consisting of irregularly shaped granules. It has lower characteristics than gravel, but its cost is lower.
Expanded clay sand. Brownish material with large grains of sand. Ideal option to prepare expanded clay concrete for screed, the thickness of which does not exceed 3 cm.

The proportions of the components for the mixture must also be calculated based on the type of screed that you decide to make.

Methods for creating a screed from expanded clay concrete

There are two methods for pouring concrete screed using expanded clay concrete.

Wet screed

For a wet screed in a residential area, it is necessary to mix the components in the following proportions:

1 share of PC;
3 shares of sand;
4 shares of aggregate (expanded clay).

Based on this, we obtain approximately 30 kg of sand cement per 25 kg of expanded clay.

If the screed is made for industrial or public use, then for 1 m2 of area you will need:

50 kg of expanded clay;
60 kg of sand concrete;
45 kg of sand;
15 kg of cement.

Thus, you will get a reliable and durable screed 5 cm thick.

Follow these steps to prepare the solution:

Pour expanded clay into a container (it is better to use a concrete mixer).
Add water and wait until the aggregate granules are saturated with it.
While constantly mixing the mortar, slowly begin to pour in the cement and sand.
Continue stirring until the aggregate granules turn gray and the mixture itself is homogeneous.

The finished solution is poured only on the waterproofing layer of the screed (for example, a vapor barrier film or durable polyethylene). After preparing this layer, you must:

Perform surface marking.
Install beacons and guide profiles.
Pour expanded clay concrete into a small area (strip) between the beacons.
Pour the finishing screed and level it.
Pour the next strip in the same way, and then the entire surface.

One day after the final pouring, the guide profiles must be removed and the resulting voids filled with cement mortar.

Healthy! So that the “fresh” screed does not crack during the hardening process, it must be covered with polyethylene and moistened daily with water.

Such a floor dries completely in 4 weeks, but it is possible to lay a laminate or other floor covering already 2 weeks after pouring a wet screed.

Semi-dry screed

If you decide to make a semi-dry expanded clay screed, then you will need:

Thoroughly clean the concrete base and repair all cracks and irregularities in it with concrete mortar without expanded clay.
Lay a waterproofing material on the concrete surface and glue a damper tape around the perimeter of the room so that it extends at least 15 cm onto the walls.
Set the beacons at a distance of 50 cm from each other.
Fill up with expanded clay, starting from the far corner of the room (you need to fill it up in such a way that the expanded clay layer is 2 cm below the level of the lighthouses).
Spill the granules with cement milk (a mixture of water and concrete, in a ratio of 2: 1).
Tamp down a layer of expanded clay.

Advice! Already at this stage it is extremely important to form an even layer of granules. To level expanded clay, you can use the rule - a special tool that looks like a meter-wide spatula.

After a day, you can start preparing and laying the cement-sand mixture for the final leveling of the surface. It is poured gradually, sequentially filling the areas separated by beacons and carefully leveling the surface of the screed. After another 24 hours, beacons can be removed, the holes from which are sealed with concrete and sprayed with water. The final leveling is done using grout and small portions of the cement mixture. Completely such a screed will dry in 2-3 weeks.

In custody

Regardless of the type of screed you choose, if you make it yourself, you can save an impressive amount and get a light base for flooring that retains heat and does not let moisture through. The main thing is to choose high-quality expanded clay and mix the cement-sand mortar in the correct ratio.

The arrangement of a flat floor surface always causes a lot of difficulties, especially if it is required to carry out its restoration and further laying of heat-insulating materials. Floor screed with expanded clay is a comprehensive solution that has a number of positive aspects and allows you to solve several problems at once.

Features and benefits of this method

Expanded clay screed is a relatively simple method for leveling various types of floors and subfloors. The addition of a filler with a different fraction size will allow not only to adjust the level and plane of the floor, but also significantly improve the soundproofing qualities of the leveling layer.

Expanded clay, in addition to sound-absorbing characteristics, has high thermal insulation qualities. a fifteen-centimeter layer laid under a concrete mortar allows you to get the effect, as in the case of a meter-long brickwork.

The use of expanded clay allows you to significantly reduce the cost of paying utility bills in the winter, reduce the operating period of noisy air conditioners and fans in the summer.

The main methods of leveling the floor with the use of fillers and concrete mortar

For the repair and restoration of old floors using expanded clay, three methods of arrangement are mainly used:

Leveling by pouring concrete or cement-sand mixture with the addition of filler.
Self-leveling floor with expanded clay aggregate or use of expanded clay concrete.
Dry screed with expanded clay.

All three technologies have their own sequence and nuances in the performance of work. But due to the use of almost identical components, the preparatory and design work is based on similar principles.

The arrangement of the screed with the addition of expanded clay is most rational in the following cases:

if necessary, reduce the weight exerted by the leveling layer on concrete or wooden floors;
if necessary, improve the soundproofing and noise-absorbing qualities of the base;
it is necessary to reduce the consumption of concrete mix and related components;
if the height difference on the surface is more than 10-15 cm;
the use of electric floor space heating systems is expected;
to protect hidden communications running and partially in contact with the floor slab.

The main advantage of this filler is the combination of two indicators important for the screed - layer strength and low weight. Due to the use of material with different fraction sizes, the load on the floor slab is reduced, which is especially important for old buildings and buildings that have undergone major repairs.

Selection of material and size of used fractions

The main types of material used for arranging and leveling the floor

Expanded clay is an environmentally friendly building material made from natural clay by exposure to high temperatures. As a result, a filler is obtained, which has a predominantly oval shape and a different fraction size.

Due to the peculiarities of production, the material has a porous structure, which gives it high insulating characteristics, low thermal conductivity and weight, sufficient strength and moisture resistance.

For construction work, including when arranging a dry, semi-dry and wet floor screed with expanded clay, such types of material are used as:

sand is a filler with the smallest particle size - up to 5 mm. Particles are small crumbs or crushed residues from larger species. It is mainly used for producing lightweight concrete and arranging a thin-layer screed;
crushed stone - a material having an average fraction size of up to 40 mm. It is used for the production of lightweight types of concrete, as a filler and insulation for concrete mortar. Recommended for use in private and suburban construction;
gravel is a filler with a grain size of 5-40 mm. It has a good combination of strength characteristics and low weight. Along with crushed stone, it is used for arranging screeds, leveling and insulating the floor in private homes.

The optimal fraction of expanded clay should not exceed the allowable range of 5-40 mm. That is, to obtain an ideal dry filler, it is recommended to pre-mix the material with fine and larger particles.

As a result, a fractional mixture will be obtained, without the formation of large voids and having a high density, relative to a certain volume. If it is necessary to facilitate the design, larger fractions are used, thereby achieving the desired density indicators, relative to the specific gravity.

If it is required to carry out work with a minimum shrinkage value, on the contrary, only fine filler with a grain size of up to 5 mm is used.

Calculation and proportions of the material

Calculation of materials for floor screed with expanded clay is based on nominal data. That is, to carry out calculations, you will need to know - the area of \u200b\u200bthe room, the thickness of the leveling layer, the grade of expanded clay by bulk density.

The calculation of the required filler volume is carried out according to the following formula - room area * layer thickness = filler volume.

For example, for a room with an area of 20 m2 with a layer thickness of 15 cm, we get - 20 m * 0.15 m = 3 m3. The standard bulk density of expanded clay for leveling the floor corresponds to the M400 grade, which indicates a content of 400 kg per m3.

Two types of bags of 25 kg and 50 kg are available for purchase in hardware stores.

For our example, it turns out that for a given room of 20 m2 for a dry screed of 15 cm, 1200 kg or 24 bags of expanded clay, weighing 50 kg, will be required. In practice, this value may differ upwards, since the surface has drops, potholes and depressions.

When mixing the concrete mixture, the proportions for the mortar are as follows - 1/3/8, where 1 part is cement M400 or M500, 3 parts is fine-grained sand, 8 parts is a mixture of filler with particles of 5-40 mm moistened with water.

In the process of preparing the solution, it is allowed to adjust the proportions based on the consistency. When using a dry mix with different grain sizes, the proportions may differ, as the filler will have a higher density.

Foundation preparation and calculations

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

It is necessary to analyze the old structure of the floor and flooring, remove all unnecessary elements and related construction debris. Next, make a visual assessment of the technical condition of the surface, find out the presence and degree of damage to the base, and perform work to eliminate them.

For minor damage in the form of potholes, chips and cracks, use the usual cement-sand mixture, which is applied to the base after it is primed. In case of severe chips and deep cracks, the damage is patched, primed in several layers and sealed with building mixtures.

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

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

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

After, from the drawn line, measure the distances to the base plane. They find the minimum value, lay 5-7 cm up from it and beat off the line over the entire area of \u200b\u200bthe 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. During the measurement process, it should be taken into account that the minimum thickness at the thinnest point should not be less than 5 cm.

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

DK - ((DP - 15) * 2) \u003d 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 \u003d 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) \u003d P3, where DK is the length of the room, P2 is the distance from the wall to the first rail, P3 is the distance between the rails.

In the process of calculations, it should be understood that the length of the rule (RP) is reduced by 15-20 cm, since when aligned 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 according to these formulas, we get the number of guides, not including the extreme ones.

Expanded clay screed technology

Preparatory work - gluing the edge tape and arranging waterproofing

A floor screed with expanded clay provides for laying a waterproofing layer and gluing an expansion joint. For waterproofing, roll materials, liquid waterproofing based on bituminous mastic or polyethylene film can be used.

For living rooms, bedrooms and rooms with a slight degree of exposure to moisture, laying a polyethylene film with a density of 150-200 microns will suffice. The film is laid with an overlap on the walls, the joints are glued with construction tape.

In the lower part of the wall, to a height of 20-25 cm along the perimeter of the room, a damper tape is glued. This approach will eliminate the absorption of moisture into the base of the floor, prevent possible damage to the screed during drying and reduce the penetration of external noise through the walls and adjacent ceilings.

The sequence of actions for floor screed with expanded clay when doing it yourself will consist of the following steps:

A metal mesh is laid on top of the waterproofing layer to reinforce the surface. The recommended mesh size should be at least 10 cm.
Runs and parallel guides. To do this, you can use a U-shaped profile measuring 60 × 30 mm or profile pipes of the required section.
To fix the beacons, a mixture of concrete mortar with alabaster is used, which is placed under the profile or pipe. During installation, the height of the beacons is adjusted according to the level. At the final stage, the guide is embedded in the solution and left to dry.
Proceed to the preparation of the composition of the concrete mixture and filler. To do this, add ready-made concrete mix and expanded clay moistened with water to a container with water. When mixing with your own hands, first mix the cement with sand in the right proportion, and only then add it to the water.
The resulting mixture is poured from the far wall in the room. The solution is fed in portions, after which it is evenly distributed over the surface and leveled using a metal rule.
After filling and leveling, the screed is covered and left for a day. After 24 hours, the U-shaped profile is dismantled, and the joints are filled with a similar composition. Complete drying will occur in 21-27 days.

There is a second way to arrange a wet screed with expanded clay. To do this, the filler is poured onto the waterproofing layer, spread over the surface and lightly tamped. A reinforcing mesh with cells of at least 10 × 10 cm and a section thickness of 4 mm is laid on the surface of the filler.

Spilling with cement milk in this particular case is not carried out, as this will require prolonged drying, worsen the soundproofing qualities of the layer and significantly increase the load on the floor slab.

After laying the mesh, the concrete mixture is prepared and fed, distributed and leveled in the same way. In conclusion, before performing finishing work, it is recommended to watch a video - do-it-yourself screeding.

Categories

Popular