The insulation of country houses and dachas worries a very large percentage of the country's population. Therefore, every possible insulation option is considered from all sides and tried on. With the advent of the Internet and forums on it, it has become more clear how people feel about this or that material. How he uses in practice, and not in words, new products offered by manufacturers or. Or, on the contrary, he clings tightly to old, well-proven methods. For example, floor insulation with expanded clay is, as they say, a time-tested technology. Considering the simplicity of the technology, even a beginner can handle expanded clay insulation.

Properties of expanded clay

Expanded clay is a thermal insulation material that is made from clay in high-temperature ovens. After such hardening, expanded clay is not afraid of fire and does not change its properties under the influence of temperatures, both low and high. This material has been known on the market for a long time and is successfully used in construction. Expanded clay is an absolutely safe material for health. No synthetic additives are used for its production. Some people are fundamentally against using it in their homes; expanded clay is an excellent substitute for foam and mineral insulation. I don’t want to talk about the shortcomings of other insulation, because if you think carefully, you will understand that there is no ideal insulation that suits everyone.

Expanded clay granules

Factions

Expanded clay is available in three types - sand, crushed stone, gravel. All structures are free-flowing. Therefore, it simply gets into all hard-to-reach places, completely covering the surface and leaving no room for cold.

Compliance with technology

If it is used in the manufacture of concrete, then due to its crushed stone structure it will adhere very firmly to the cement, and its weight will significantly reduce the weight of the concrete. When using expanded clay as insulation, it is necessary to strictly follow the technology proposed by the developers for this material. Firstly, the thermal insulation properties of expanded clay are fully manifested only if the backfill layer is more than 15 centimeters. Secondly, expanded clay is a fragile material and it is advisable not to break the granules. Broken granules retain heat less well.

It is possible to insulate both ground floors and concrete and wooden floors located both on the ground floor and on the floor.

Insulation on the ground

Floor insulation, when the insulation is laid out on top, on the ground, occurs as follows. The ground is level. Leveling the soil is carried out using a building level. The soil is covered with expanded clay.

The thickness of the expanded clay pillow is 30 centimeters. If it is already insulated with expanded clay, then the expanded clay pillow is 20 centimeters. But the cushion cannot be spread over the ground less than 10 centimeters. In this case, expanded clay, as an insulation material, completely loses its properties. Of course, you need to pour expanded clay evenly, with the same thickness along all edges. Beacons are used for this.

A beacon is a metal profile that is laid on the ground and divides the room into several parts. The distance between the beacons should be small, no more than 70 centimeters, so that it is convenient to monitor the correctness of the backfill. Expanded clay chips will be placed between these guides. Beacons are made strictly horizontally. To do this, wooden gaskets are placed under them. The goal is to pour expanded clay evenly over the ground, without distortions in one plane.

We scatter expanded clay using metal profiles

Waterproofing

The next layer will be waterproofing. Usually this is a plastic film, slightly larger than the floor area. The edges of the film are folded upward, and a concrete screed is placed on it. For a concrete floor screed, the ratio of sand and cement is 3:2, and 2 parts of water are added. Everything is quickly mixed and poured on top of the expanded clay. The mixture is carefully leveled. The concrete hardens. Excess film is cut off. If the height of the expanded clay pillow is less than 20 centimeters, it is easier to insulate the floor; the expanded clay does not even spill out of the bags. Holes are made in the bags, and additional expanded clay is added on top. The height of the bags laid flat is about 18 centimeters.

Expanded clay screed

Another waterproofing option is expanded clay screed. The prepared insulation cushion is filled with liquid cement-sand mortar, which is called “cement laitance”. This solution is designed to prevent moisture from penetrating into the granules. After all, expanded clay is capable of absorbing moisture. The consistency of the solution should be such that it does not accumulate on the surface of the crumbs and does not pass through it without a trace. This solution should evenly envelop the insulation. There are no exact proportions; the cement-sand mortar is made according to how it feels, not liquid and not thick. After this procedure, the expanded clay covered with “cement laitance” is allowed to dry for a day. Only then do I start screeding the floor. The ratio of sand and cement is 3:1. River sand is not used. For better mixing of the solution, use a construction mixer.

Other screed technology

You can make such a floor screed using a different technology. Water is poured into the container and expanded clay is added. Then sand and cement are poured. Everything is quickly mixed, laid out on the surface and leveled according to the beacons.

If you add less water, the mixture will be drier. You don’t have to pour it, but lay it out and compact it. This mixture will harden faster. Therefore, you will get to the finishing stage faster.

The screed takes approximately 25 days to dry. You can walk on it in 10 days. You can check whether the screed has dried or not using an ordinary glass jar. Place the jar on the screed and if it fogs up, it means the moisture has not yet evaporated. The screed has not dried yet.

When insulating the floor of the initial floor of a house, different consistencies of expanded clay (crumbs and crushed stone) are mixed or foam chips are mixed into the mixture.

How the floor is insulated with expanded clay, what is the installation sequence, what technology, see the video:

Clay expanded clay does not emit any harmful substances. Of course, the thermal insulation properties are two times worse than, for example, those of. But you can use more material and make the pillow thicker.

Thus, insulation with expanded clay is low cost, simple installation, good thermal insulation, and excellent environmental tests.

Expanded clay is granules, the fraction of which has different sizes. The porous material made from clay goes through several stages of preparation and firing. Under the influence of high-temperature conditions, the clay is sintered, forming into granules of a natural porous material that does not pose a danger to humans and is used in repairs and construction for backfilling the insulating layer.

Advantages and disadvantages

The technology for preparing the material gives it the following positive properties:

• Noise absorption;
• Thermal energy retention. For example, the most popular brand 500 has a coefficient of 0.12-0.15 W/mK;
• Light weight. Compared to concrete, the material is 10 times lighter;
• Immune to low temperature conditions;
• Resistance to chemical materials and mechanical shocks;
• Strength under the influence of moisture, drops, water;
• Long service life;
• Environmental friendliness;
• Affordable price.

In addition, floor insulation with expanded clay can extend the life of a wooden covering up to 50 years.

But there are also disadvantages. Achieving high performance characteristics is impossible if the layer thickness is less than 50 cm. Only in this case does expanded clay retain its heat and sound insulation qualities. Despite the resistance to moisture, constant dampness in the room where the expanded clay screed is laid will lead to a loss of effective insulation values. It is necessary either to increase the waterproofing layer, or to abandon expanded clay, giving preference to a base such as mineral wool.

Areas of application

Due to its light weight and excellent performance, the raw material has a wide range of applications. In particular, expanded clay can and should be used in the following areas:

Floor construction

Expanded clay can be used to create an insulating layer for the floor surface. The material is an ideal solution, especially if you want to do the job well, but not invest huge amounts of money, which is especially important for insulating the base in the garage. Creating a substrate is possible in several ways, it all depends on the base or subfloor:

1. Reinforced concrete floors in an apartment or garage are filled with a vapor barrier base over the entire area; a regular film will do. Then the surface is filled with expanded clay concrete - the combination will significantly reduce heat conductivity and increase the efficiency of the material.
2. Wooden floors in a steam room, garage or house require a different approach. The technology is quite simple: protect the base from moisture with a film, pour a dry layer of expanded clay to the full height of the beams and you can lay the floorboards. Expanded clay, like mineral wool, is absolutely not a favorite habitat for rodents, so if the garage has an underground floor, the material is the right choice.
3. Foundation work. Here expanded clay is suitable for interior and exterior work. If insulation is carried out from the street side, the composition must be filled with the cavity under the blind area. Insulation inside requires filling voids to the height of the first floor. This works best in relation to difficult soil, as it allows you to reduce the level of foundation laying depth without the slightest damage to its thermal qualities.

Important! Regardless of the use of the material, the base for laying expanded clay must be protected from moisture. The video will show you how to do this. Reviews from professionals strongly recommend using this lightweight but functional material in places where additional means are being taken to strengthen the soil.

1. Arrangement of wall panels. Expanded clay insulation is carried out at the construction stage when using three-layer masonry. In this insulation pie, expanded clay concrete (blocks) is used as a load-bearing layer, then the base is expanded clay and cement laitance, and the last one is protection from panel slabs, brickwork, wood blocks and other things.
2. Roof, attic. Today it is possible to create a habitable space in the attic. Insulating walls and floors with expanded clay is a well-thought-out and proven solution. The light weight of the base will not overload the racks/foundation, and the dimensions of the structure are quite small. To create an insulation cake, it is necessary to use a waterproofing material that is used to cover the attic floor, then a layer of medium-fraction expanded clay is poured in and you can begin arranging the final floor covering. For the roof, it is necessary to carry out preparatory work, forming a void where the material will be poured. As a rule, this is the space between the inner and outer sheathing.

Advice! Arranging a steam room roof by filling the void with expanded clay requires a waterproofing layer for the internal sheathing. After watching the video, the user can easily calculate the volume of material, backfill technology and other nuances.

Finally

If you decide to use the material as insulation, you should look through reviews and read the advice of professionals:

1. The thicker the backfill, the better. The fine composition can be poured into any space, this will only improve the heat and sound insulation qualities of the room;
2. The technology for installing floor screed in an apartment or garage is simple: the expanded clay-cement mixture must be at least 10 cm thick;
3. The dry mixture is used only after a vapor barrier has been installed, especially in the garage or steam room. Mineral wool is ideal here, then a three-layer film of ordinary polyethylene. Overlaps on the edges are required, as is filling the entire area;
4. Floor insulation with expanded clay can be done with your own hands and on any floor of any building/structure. In a garage, country house or apartment with high ceilings, you just need to arrange a void for the base, isolate it from moisture and decorate it with the final flooring. Moreover, it is not difficult to calculate how much material is needed; it is enough to calculate the surface area and the height of the layer;
5. The diversity of factions is also taken into account. For example, when working on the ground, large sizes are more suitable, and for insulating the ceiling - a fine-grained substance, since it creates a compacted and effective backfill in small volumes;

Wooden construction is mainly country houses. Moreover, both new construction and those that were erected long ago as summer cottages. Today, these buildings are increasingly used for year-round living. Therefore, the issue of insulating all parts of the house becomes urgent.

The floor in wooden buildings is one of the coldest parts of the entire structure. According to various estimates, up to 20% of the internal heat in the premises is lost through the floors in wooden houses. It makes sense not only to design good insulation when building a new house, but also to take care of remodeling the floor in an already built one, but without floor insulation. Moreover, usually a residential wooden house is installed on a relatively high foundation. And this allows you to carry out insulation from below, without changing the level of the finished floor and without reducing the height of the room.

Floor insulation

When constructing ancillary wooden buildings, the floors can be located close to the ground or even laid directly on the ground. In this case, an insulating layer is still necessary, but it will have to be laid deep into the ground.

Any insulation of wooden floors must be carried out in compliance with the following rules:

• Mandatory installation of waterproofing in two layers. The bottom layer protects the insulation from moisture from the ground. The top layer protects against water penetration through the finished floor boards.
• Rough and finishing wooden floor elements are treated with special anti-rotting agents.
• For insulation, a material is selected that does not change its properties when in contact with wood.

Despite the recent emergence of modern insulating materials, expanded clay insulation of wooden floors still finds its application. And there are reasons for this.

Expanded clay: pros and cons

Insulating expanded clay - granules made by foaming and subsequent firing of clay.

Scheme for the production of expanded clay granules

It has a number of advantages when used as thermal insulation.

Advantages:

• Low thermal conductivity. The clay itself from which it is made is considered a good heat insulator. And the pores created inside, filled with air, further reduce thermal conductivity. As a heat insulator, it is several times more effective than clay bricks and twice as effective as wood.
• Light weight. Increasing the thickness of the expanded clay layer does not lead to a significant load on the floors.
• Cheapness. Despite the fact that it is inferior in thermal conductivity to many modern materials, its use allows you to save money, losing slightly in the quality of insulation.
• Fire safety. This material not only does not burn, but also does not emit any toxic substances when heated strongly.
• Resistance to temperature changes. Thermal insulating properties do not change in heat or cold.
• Resistant to household chemicals and humidity. Even when wet, mold does not form on it.
• Completely environmentally friendly. Made from natural material, it is not completely harmless.
• In addition to thermal insulation properties, it is also a good sound insulator.
• Convenient to use. To work with it, you do not need to have special skills, and no special tools and devices are required. The fact that expanded clay is a bulk material eliminates any requirements for maintaining exact dimensions when laying.
• Long term of use. It is believed that it retains its properties for decades.

Flaws

Expanded clay also has disadvantages. But their list is incomparable with their advantages:

• Large volume of heat-insulating layer. To create high-quality thermal insulation, the thickness of the expanded clay cushion must be at least 10 cm. But in practice, the expanded clay layer is usually 20–30 cm, rarely 40 cm. In some wooden floor designs, such insulation leads to a decrease in the space between the floor and the ceiling.
• Low moisture resistance. When a large amount of water hits it, it absorbs it. This leads to an increase in the weight of the thermal insulation. Over time, moisture will evaporate from expanded clay granules, but this is a long process.
• Laying expanded clay, despite its simplicity, is a tedious task. Spreading a thick layer, leveling with obligatory care so as not to destroy the shell of the granules - all this takes a lot of time.

Varieties of expanded clay

The quality of expanded clay as insulation also depends on the options for its production. Depending on the size, there are three main groups of expanded clay granules. And although for each group there are recommendations for its use, they usually use a mixture of granules of different sizes in one layer.

Expanded clay fractions

• Crushed stone – granules with a diameter of 20 to 40 mm. Recommended for backfilling the main layer of thermal insulation.
• Gravel - from 10 to 20 mm. Used to create thin layers.
• Sand is the smallest granules with a diameter of 5 – 10 mm. Suitable for insulating small voids in floor structures. When mixed with large fractions, it allows you to fill the gaps between granules. Used to create a “wet” concrete heat-insulating screed.

In addition to size, expanded clay insulation varies in density. Industrially produced expanded clay is divided into several categories with a density from 200 to 800 kg/cub.m.

Methods for creating heat-insulating layers from expanded clay

In general, the device of expanded clay insulation differs little from the use of other materials. Expanded clay is located under the finished floor using moisture-proof materials.

Insulation with expanded clay, general principle

Depending on the location of the insulated floor (on joists laid on the foundation, on the ground or on a concrete base), the technology by which expanded clay is laid under a wooden floor also differs.

Backfill between joists

This is the easiest way to lay an expanded clay pillow. In this case, wooden logs serve as the base for the floor. If they are on a foundation, then panels or subfloor boards are attached to them. They can be tacked to the joists from below or attached to bars nailed to the joists from the side. The use of lightweight expanded clay is an advantage - the load on the subfloor is small.

The next steps are:

• It is recommended to treat the logs and subfloor boards themselves with anti-rotting agents. This is especially necessary when creating new insulation in a long-built house.
• The space between the joists is lined with a waterproofing film. As a substitute, you can choose polyethylene or roofing felt. If transverse bars are installed between the joists, then each cell is covered separately.
• Expanded clay granules are poured into the prepared spaces between the joists. It is recommended to mix large and small fractions of expanded clay to completely fill the volume.
• After backfilling, the expanded clay layer is leveled along the upper edges of the logs. The logs act not only as a support, but also as an indicator of the level of insulation backfill.
• It is advisable to compact the leveled layer of expanded clay slightly. When tamping, you must not damage the granules, since they will absorb moisture through the cracks.

Expanded clay poured onto a wooden subfloor along the joists

Installation of the floor along the joists can also be carried out on a concrete base as a subfloor. The technology for filling expanded clay in this case is no different.

Filling expanded clay along joists on a concrete base

Backfilling expanded clay for a wooden floor on the ground

Such floors can be installed in utility rooms or garages. But the expanded clay pillow is not laid directly on the ground. The procedure is as follows:

• The top layer of soil is removed.
• A layer of gravel is poured. It will perform the function of waterproofing, protecting the expanded clay from moisture from the ground.
• The gravel is covered with sand, which must be compacted thoroughly.
• A protective film is laid over the sand.
• The insulating layer of expanded clay is poured onto a sand cushion, leveled and lightly compacted.
• Further installation of the floor depends on the wishes of the builder. You can lay the floor directly on top of the expanded clay, or you can fill the expanded clay layer with concrete, forming a “wet” screed. Or you can use a layer of expanded clay as a rough insulation layer, creating another insulating layer above it, on top of which you can lay the finished floor.

Expanded clay bedding as a subfloor on the ground

Concrete screed using expanded clay

If you plan to install a concrete base under the floorboards, then you can insulate such a floor by “building” expanded clay into the concrete screed:

• The base prepared for the screed is covered with waterproofing.
• The entire surface is covered with expanded clay. Small fractions are predominantly used.
• The expanded clay layer is leveled and compacted.
• For greater reliability, a reinforcing mesh is placed on top of the expanded clay.
• The last stage is pouring concrete.

Concrete screed on expanded clay cushion

Dry expanded clay screed

This method of flooring has become known recently. The preparatory part depends on the base on which it is planned to install the screed - on the ground, on a rough wooden floor or on a concrete slab.

The base is covered with a protective film, onto which expanded clay is poured. After leveling the expanded clay cushion, it is covered with sheets of plywood or gypsum fiber. Fastening the sheets with glue or self-tapping screws.

Scheme of dry screed with insulation

Final work

Any option for installing an expanded clay insulating layer means completing the rough stage of flooring. The insulating layer must be covered with a hydro- or vapor barrier material. And on top of this insulation made of plywood or other sheet material, a substrate corresponding to the selected floor covering is fixed.

With the flooring option on joists, the finished wooden floor can be installed directly on them, without creating a separate substrate.

Section of a wooden floor with expanded clay insulation

In the modern world, when energy prices rise literally every day, home owners pay a lot of attention to insulation.

Not only walls, but also floors are insulated.

In most cases, expanded clay is used for insulation.

Expanded clay is a bulk universal building material with a porous, light structure.

The shape of this insulation can be round or oval.

Expanded clay is obtained by firing light alloy clays in special drum-type kilns.

Firing temperature - 1000-1300 degrees.

Depending on the quality of the clay, the resulting material has different densities.

Its mass depends precisely on the density indicator: from 250 to 600 kg/cubic. meter.

Depending on the size of the expanded clay granules, three types of fractions are produced:

• expanded clay sand (up to 10 mm);
• expanded clay gravel (10-20 mm);
• expanded clay crushed stone (20-40 mm).

Expanded clay is able to solve two very important problems at the same time: leveling the surface and insulating it.

Expanded clay is especially effective for insulating the floor of the first floor.

Moreover, this material can be used as insulation not only on the floor.

It is also poured onto the ceiling of the top floor of the house, and expanded clay is also used when filling the walls of the house.

About the properties of expanded clay

In addition to its main property - retaining heat in a room, this material also has many good properties.

It is thanks to them that it is still a leader among insulation materials.

Here they are:

1. Thermal insulation level. It is enough to pour only 10 centimeters of expanded clay so that the thermal insulation is exactly the same as with 30 cm of natural wood! Or a whole meter of brick wall! Expanded clay has a thermal conductivity of only 0.12 W/mK.
2. Decent strength.
3. High degree of sound insulation.
4. Durability. Since expanded clay is made from clay, its service life is almost endless.
5. Fire resistance and heat resistance.
6. Light weight.
7. Easy to install.
8. Low price.

This wonderful material has only one drawback - poor moisture resistance.

If the granules of this insulation are saturated with moisture, then it remains in them for a long time.

Therefore, high demands are placed on operation.

Insulation process

This video will show you the technology of floor insulation with expanded clay under a screed:

Preliminary surface preparation

The process of filling the material is not particularly labor intensive.

However, if you want the expanded clay to “work” with maximum efficiency, then you should do some preparatory work.

Believe me, you shouldn’t be lazy, because the material can be damaged irrevocably.

So:

1. The first step is to calculate the load on the floor. The thickness of the coating is determined.
2. If there is damage to the old floor in the form of cracks or potholes, they must be repaired.
3. After sealing the cracks, it is necessary to lay a layer of waterproofing on the floor. Thick polyethylene film will do. It is important that when laying the film, its edges extend onto the walls. After filling and filling is completed, excess film is removed.

It will take little time to complete such preparatory work.

But there are a lot of benefits from them!

After everything is prepared, proceed directly to laying the floor.

It should be said that this does not require special knowledge and skills.

Floor on the ground on joists

Let's consider insulating the floor with expanded clay on the ground on joists.

If the logs are removed, the soil surface is completely cleared and compacted.

Then any material based on bitumen (glassine, roofing felt, etc.) should be laid on it as waterproofing.

Then the required layer of this insulation is poured on top of the waterproofing.

Expanded clay is covered with a layer of expanded clay or coarse river sand, reinforced and the screed is poured.

Now all that remains is to lay the vapor barrier, tile insulation and any flooring.

Subfloor in a wooden house. If you don't know how to make it, visit our website.

What kind of helicopter is used for grinding concrete floors? Find out about it in this article. We recommend!

The base is on logs, which are supported on brick supports

In private houses, especially wooden ones, this is the floor design that is used.

In this case, the insulation is poured only to the level of the joists placed on the posts.

Then the skull blocks are nailed and the flooring is made of wood slabs or boards.

Laying the floor over a concrete slab

Such insulation is installed only in those rooms where the flow height is very high.

Because after filling the expanded clay layer and installing the screed, the floor level will rise significantly.

Before starting work, remove the old flooring down to the bare slab.

Then repairs are carried out (if necessary), during which all irregularities and cracks are repaired.

A polyethylene film is laid, which plays the role of waterproofing, and a layer of expanded clay is poured onto the film.

Backfilling is carried out to the front door from the farthest corner.

In order for this insulation to lie flat, beacon slats are pre-installed according to the level.

Now the resulting “pie” should be moistened with “cement laitance” so that the expanded clay granules adhere to each other.

After 24 hours, when the expanded clay after distribution is fixed with cement laitance, a screed is made.

Expanded clay concrete base in a bathhouse or garage

The design of this floor is very simple.

Strips of waterproofing material are spread directly on the ground.

It can be either dense polyethylene or any bitumen-based material.

Laying of waterproofing is carried out by approaching the wall to the height of the planned pouring.

Then you need to set the beacons level so that the floor surface is horizontal.

The next step is mixing the solution.

The solution is where the main feature lies.

Solution composition:

• cement – ​​1 part;
• sand – 2 parts;
• water – 1 part;
• expanded clay - 3 parts.

Ideally, expanded clay gravel should be used.

Then the concrete will be more dense and durable.

After the mixture has been thoroughly prepared, it is poured over the surface, focusing on the beacons, carefully compacted, and after hardening, the surface is ferruginated with cement laitance.

Waterproofing

It probably caught your eye that the word “waterproofing” is mentioned by us very often.

Yes, it is true.

Because the insulation cannot be wetted with water.

Wet expanded clay is effective only as part of concrete.

And even then its efficiency will be an order of magnitude lower than that of dry material.

It is for this reason that before starting to fill the expanded clay, waterproofing is installed.

And there are a lot of options:

• bitumen-based mastic;
• various polymer mixtures;
• material impregnated with bitumen;
• polymer-cement mixture;
• rubber cover;
• high density polyethylene film.

The most economical and therefore the most common waterproofing option is polyethylene film.

However, the vapor permeability of polyethylene film is very poor.

The waterproofing properties of this combination are exceptional.

This composition is also distinguished by its durability.

To maximize the effect of expanded clay as a thermal insulator, it should be used as a dry backfill on top of waterproofing, and not as one of the components of concrete.

The thickness of the layer of this insulation should not depend on your desire, but on the permissible load on the floor.

To attach beacons, alabaster is used, which dries quickly and allows you to set the level quickly and efficiently.

In order for the structure to be intact and the expanded clay layer not to deform under load, it is reinforced with a metal mesh.

To ensure that expanded clay granules adhere better to each other, fractions of different sizes are used, that is, large and small granules are mixed.

The floor will reach its design strength only after 28 days.

Of course, in a few days it will be possible to walk on it, but this should not be done.

Let it gain strength.

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Material properties

For the manufacture of expanded clay, only natural materials are used. Clay is used as a base, which goes through the stages of processing - cleaning and drying. Upon completion, the crushed mass is placed in a special oven, where a porous structure is formed under the influence of high temperatures. The heat treatment area is constantly rotating and depending on the speed, different types of expanded clay are formed.

As a result of this process, three types of thermal insulation material are obtained:

1. Sand. It is used for the production of expanded clay concrete and other similar building materials. It is characterized by small fraction sizes - up to 5 mm. It is not used as insulation.
2. Gravel. To make it, clay blanks of a certain size are preliminarily formed. As a result of firing, they acquire sizes from 20 to 40 mm. Due to its good heat transfer resistance, it is used to form a thermal insulation layer.
3. Crushed stone. Almost completely similar to the group described above, excluding sizes - from 10 to 20 mm. However, it differs in shape - it has more open cells, which is not the best option for insulating the floor with expanded clay under a screed. There is a high probability of saturation of the layer with moisture.

Main characteristics and advantages

Distinguished by:

Today a type with reduced moisture absorption is also produced.

Thanks to the mode and technology of clay processing, the pores inside the granules are filled with air. This provides the material with such important characteristics as low volumetric weight, in other words, bulk density and high thermal insulation properties.

• sand –5–10;
• crushed stone – 10–20;
• gravel – 20–40.

The maximum error from the specified parameters can be only 5% for the entire batch.

Simplified and standard technologies

Insulation is carried out during the construction of a house, immediately before pouring the screed, or, in extreme cases, during major repairs.

The main rule when performing floor thermal insulation is the accurately calculated thickness of expanded clay. It should be enough to provide thermal protection for the house: for concrete, a layer of at least 10 cm is used, and for soil – up to 30 cm.

Standard - under screed

Simplified technology: cheaper, faster

The main difference of this method is the absence of a cement screed. In this case, the thermal insulation layer of expanded clay may be thinner. The whole process is cheaper than the standard one and requires significantly less time. The installation of waterproofing and flooring can be carried out immediately after the installation of the layer - it is carried out in the same way as the standard one.

This technology is called “dry” screed. Gypsum fiber sheets are laid on the resulting base, the grooves between them are coated with adhesive mastic or glue, and at the same time they are secured with self-tapping screws.

Insulation by joists

This is one of the popular ways to insulate a home. According to one option, the base is leveled by pouring a thin layer of cement screed. After which, after allowing it to dry, a vapor barrier material, say, glassine, is laid. Then the entire area is covered with an even layer of expanded clay. But this method creates some inconveniences, since it can be difficult to ensure a smooth surface and uniformity of the layer. More acceptable in this sense is another one - according to lags.

Wooden blocks soaked in antiseptic are laid along the room, strictly monitoring the horizontal plane of the exposed frame (you can adjust it using wooden pads). They are fastened in half-meter increments using self-tapping screws. Expanded clay is poured into the formed areas exactly up to the upper edge of the bars. This is an indicator of the evenness and uniformity of the laid material. Since there will be no load on the insulating layer, surface treatment with concrete mortar is not necessary. After which the entire structure is covered with waterproofing material, for example, polyethylene film.

On such a floor you can immediately lay boards, plywood, chipboard, OSB boards or fill it with screed. Then finishing material is installed on their surface. By the way, this technology is also used to insulate the loggia floor under the tiles.

The insulation of the floor of the first floor is carried out using the same technology. At the same time, the additional weight of the entire heat-insulating layer is significantly less than for a concrete screed. This method is also applicable for attic spaces.

Thermal insulation in bags

It is not recommended to scatter expanded clay on the ground for the floor. This is due to shrinkage of the heat-insulating material. But you can first make a concrete or wooden base on which the heat insulator will be poured. An exception is the technology for insulating the foundation of a house, when a trench filled with expanded clay mixture is made around it.

Thermal insulation of the floor on the ground with expanded clay can be carried out directly in the package - just lay bags with granules of a fraction of 10-20 mm on a layer of compacted sand. About three bags are needed per square meter of pre-leveled and compacted surface. They must be filled so that the layer thickness is 15-20 cm. After laying, the bags are carefully cut or perforated. This must be done so that there is no air left inside, but the granules themselves do not spill. The free space between the bags is filled with loose filler of a finer or the same fraction. Work continues according to the already known scheme.

Despite more than average thermal insulation parameters, the use of expanded clay granules in some cases is the only possible option. This especially applies to fire-hazardous premises – bathhouses, boiler rooms. The only alternative to this type is basalt wool. But its cost is significantly higher, and its mechanical strength is lower.

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Types and distinctive properties of the material

Expanded clay is a high-quality bulk insulation in the form of small oval and round pebbles, made by firing clay with an admixture of shale rocks. Expanded clay is produced in high-temperature furnaces, inside of which there is constant intensive movement of fractions of the future insulating material.

Types of expanded clay and its bulk density

One of the distinctive features of expanded clay is the volumetric weight (density) of the insulating material, which per 1 m3, depending on the fractions, is only from 200 to 400 kg.

Thermal insulation fractions fired at high temperatures are divided into three main types according to their size.

Thermal conductivity of expanded clay

Although in this regard this bulk substance is still inferior to mineral wool insulation and polystyrene foam, a characteristic feature is the high thermal conductivity of expanded clay, which is much more effective than brick or wood.

In terms of thermal conductivity, the benefit of a 10- or 12-centimeter layer of expanded clay insulation can be compared with the effectiveness of a one-meter thick brick wall or about 25 cm of wood.

Advantages and disadvantages of expanded clay insulation

A characteristic feature of this natural bulk substance is a number of advantages inherent to expanded clay, which are reflected in the process of using this heat-insulating material. The substance is characterized by such positive properties as:

• ease;
• strength;
• high degree of heat and sound insulation;
• non-flammability;
• frost resistance of all types of fractions;
• indifference to an aggressive environment;
• environmental cleanliness;
• durability;
• low price and accessibility for consumers.

The disadvantage of expanded clay when insulating floors is its poor moisture resistance, and therefore there is a need for additional use of waterproofing substances. You also need a fairly voluminous layer of this material to achieve efficiency in the process of retaining heat in the room. Insulating the floor involves filling the space with expanded clay 15 to 30 cm thick, while for insulating walls with polystyrene foam, a sheet thickness of 5–10 cm is sufficient.

In terms of environmental properties, natural expanded clay insulation is significantly superior to synthetic materials, which, due to insufficient strength, are practically not used when working with floors.

Application for insulation of various types of floors

When using expanded clay as floor insulation, all properties and features of the material must be taken into account. Expanded clay is used for a wide variety of flooring types, in residential and commercial buildings of any type, where there are various categories of hard covering.

1. Concrete floors. They are used in residential apartment buildings and commercial buildings, garages, public buildings, and commercial establishments. To protect rooms from low temperatures, it is necessary to insulate the cold floor surface using expanded clay.
2. Wooden decks over concrete floors. Such options are used in multi-apartment and utility premises, as well as in private houses, on loggias and glazed balconies, in educational institutions, and public buildings. The heat-protective layer is poured under the surface of wooden floors onto the laid waterproofing material.
3. Wooden decking above the ground. It is used, as a rule, in private homes of owners and involves pouring expanded clay directly onto prepared soil with preliminary placement of an insulating layer on it.

Its strength has made this substance an almost indispensable material for effective insulation of indoor floors.

Methods of working using expanded clay

The process of insulating a floor with expanded clay involves three methods of laying insulation:

• dry method;
• wet;
• combined.

The use of the dry method involves pouring expanded clay, consisting of different fractions, onto a waterproofing material that protects against dampness between the joists or onto a previously insulated ground surface. The base of the floor is made of boards, thick plywood, chipboard or OSB boards. The dry backfill method does not provide for a high load on the floor insulated in this way.

The use of the wet method is used in areas of high loads on the coating and involves mixing solid insulation elements with cement mortar, which is laid out ready-made on the surface, after which a screed is made. The effectiveness of thermal protection when using the wet method of floor insulation is noticeably reduced compared to the dry method, but the protection of the room from the penetration of cold from the ground remains significant.

The combined method involves pouring cement mortar only on the top layer of expanded clay backfill, as well as the process of screeding after the mortar has completely dried. The combined method is close to the dry method in terms of efficiency and quality of heat transfer and is used where there is a high load on the base.

Step-by-step instructions for insulating wooden floors with expanded clay

When working with a plank base, in most cases, expanded clay acts as insulation - as an environmentally friendly material for residential premises.

The procedure includes the following steps.

1. Dismantling the floor. The wooden surface of the flooring is removed, allowing access to the joists that hold the base.
2. Checking and replacing lags. Before proceeding to the next stage of work, all joists are subject to mandatory inspection for integrity, absence of rot and fungal formations. Damaged joists must be replaced. The level and rigid stability of the lag are checked.
3. Preparing the surface of a concrete or soil base. The concrete base on which expanded clay fractions are supposed to be filled is cleared of debris, leveled with mortar or foam, and chips, potholes and cracks are repaired. The soil is compacted and compacted with sand.
4. Laying waterproofing. Polyethylene or other waterproofing materials are laid on the base so that the film covers the walls of the room along the entire perimeter by 7–10 cm. The insulating material is attached to the lags that are under the film using a regular stapler and evenly distributed in the recesses between the lags.
5. Backfilling of insulation. To achieve a denser compaction and ensure the absence of free space, expanded clay of different fractions is mixed. Expanded clay is poured between the logs with a thickness of 15 to 25 centimeters and carefully compacted in the corners to prevent the formation of empty space. The top of the backfill is covered with waterproofing material.

Finally, the rough wooden floor is attached to the joists protruding from the backfill, the rising ends of the film are cut off, the front covering is laid and secured with baseboards around the entire perimeter of the room.

Step-by-step instructions for insulating a concrete floor with expanded clay

Work on a concrete surface, just like on wooden flooring, requires a certain step-by-step procedure.

1. Dismantling the old concrete base, if it is laid on the ground and is not a floor slab on the floors of the building. During the work, in addition to dismantling, the surface is cleaned and leveled.
2. Laying waterproofing. The waterproofing material for concrete floors can be a hardening liquid or film and must be wrapped on the walls.
3. Attaching damper or mounting tape. It is carried out around the perimeter of the room at the level of the future screed.
4. Installation of metal beacons. To determine the uniform level of insulation backfill over the entire surface of the prepared base, at a certain distance from each other, install beacons that are equal in height to the level of the tape. To do this, use cords stretched between the walls and determining the height. Beacons can serve as ordinary self-tapping screws rigidly fixed in the floor, guiding metal strips or corners along the floor.
5. Expanded clay backfill. The insulation is evenly laid between the beacons, aligned with the level of the guide beacons and lightly compacted.
6. Laying reinforced mesh. To achieve the greatest strength, a metal mesh is placed on a leveled expanded clay surface with a deviation of 5 cm from the walls.
7. Screed. Cement and sand are mixed in a 1:3 ratio with water to a certain thickness and poured onto the expanded clay, starting from the corner along the guide beacons. The screed is leveled, removing excess mortar.

Insulation of various types of floors with expanded clay brings effective results if the necessary conditions are met at all stages of the work, and the degree of a certain load on the floor covering is also taken into account.

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Properties of expanded clay

Expanded clay is a thermal insulation material that is made from clay in high-temperature ovens. After such hardening, expanded clay is not afraid of fire and does not change its properties under the influence of temperatures, both low and high. This material has been known on the market for a long time and is successfully used in construction. Expanded clay is an absolutely safe material for health. No synthetic additives are used for its production. Some people are fundamentally against the use of synthetic materials in their homes; expanded clay will perfectly replace foam and mineral insulation. I don’t want to talk about the shortcomings of other insulation, because if you think carefully, you will understand that there is no ideal insulation that suits everyone.

Expanded clay granules

Factions

Expanded clay is available in three types - sand, crushed stone, gravel. All structures are free-flowing. Therefore, it simply gets into all hard-to-reach places, completely covering the surface and leaving no room for cold.

Compliance with technology

If it is used in the manufacture of concrete, then due to its crushed stone structure it will adhere very firmly to the cement, and its weight will significantly reduce the weight of the concrete. When using expanded clay as insulation, it is necessary to strictly follow the technology proposed by the developers for this material. Firstly, the thermal insulation properties of expanded clay are fully manifested only if the backfill layer is more than 15 centimeters. Secondly, expanded clay is a fragile material and it is advisable not to break the granules. Broken granules retain heat less well.

It is possible to insulate both ground floors and concrete and wooden floors located both on the first and on the next floors.

Insulation on the ground

Floor insulation, when the insulation is laid out on top, on the ground, occurs as follows. The ground is level. Leveling the soil is carried out using a building level. The soil is covered with expanded clay.

The thickness of the expanded clay pillow is 30 centimeters. If a concrete floor is already insulated with expanded clay, then the expanded clay cushion is 20 centimeters. But the cushion cannot be spread over the ground less than 10 centimeters. In this case, expanded clay, as an insulation material, completely loses its properties. Of course, you need to pour expanded clay evenly, with the same thickness along all edges. Beacons are used for this.

A beacon is a metal profile that is laid on the ground and divides the room into several parts. The distance between the beacons should be small, no more than 70 centimeters, so that it is convenient to monitor the correctness of the backfill. Expanded clay chips will be placed between these guides. Beacons are made strictly horizontally. To do this, wooden gaskets are placed under them. The goal is to pour expanded clay evenly over the ground, without distortions in one plane.

We scatter expanded clay using metal profiles

Waterproofing

The next layer will be waterproofing. Usually this is a plastic film, slightly larger than the floor area. The edges of the film are folded upward, and a concrete screed is placed on it. For a concrete floor screed, the ratio of sand and cement is 3:2, and 2 parts of water are added. Everything is quickly mixed and poured on top of the expanded clay. The mixture is carefully leveled. The concrete hardens. Excess film is cut off. If the height of the expanded clay pillow is less than 20 centimeters, it is easier to insulate the floor; the expanded clay does not even spill out of the bags. Holes are made in the bags, and additional expanded clay is added on top. The height of the bags laid flat is about 18 centimeters.

Expanded clay screed

Another waterproofing option is expanded clay screed. The prepared insulation cushion is filled with liquid cement-sand mortar, which is called “cement laitance”. This solution is designed to prevent moisture from penetrating into the granules. After all, expanded clay is capable of absorbing moisture. The consistency of the solution should be such that it does not accumulate on the surface of the crumbs and does not pass through it without a trace. This solution should evenly envelop the insulation. There are no exact proportions; the cement-sand mortar is made according to how it feels, not liquid and not thick. After this procedure, the expanded clay covered with “cement laitance” is allowed to dry for a day. Only then do I start screeding the floor. The ratio of sand and cement is 3:1. River sand is not used. For better mixing of the solution, use a construction mixer.

Other screed technology

You can make such a floor screed using a different technology. Water is poured into the container and expanded clay is added. Then sand and cement are poured. Everything is quickly mixed, laid out on the surface and leveled according to the beacons.

If you add less water, the mixture will be drier. You don’t have to pour it, but lay it out and compact it. This mixture will harden faster. Therefore, you will get to the finishing stage faster.

The screed takes approximately 25 days to dry. You can walk on it in 10 days. You can check whether the screed has dried or not using an ordinary glass jar. Place the jar on the screed and if it fogs up, it means the moisture has not yet evaporated. The screed has not dried yet.

When insulating the floor of the initial floor of a house, different consistencies of expanded clay (crumbs and crushed stone) are mixed or foam chips are mixed into the mixture.

How the floor is insulated with expanded clay, what is the installation sequence, what technology, see the video:

Clay expanded clay does not emit any harmful substances. Of course, the thermal insulation properties are two times worse than, for example, mineral wool. But you can use more material and make the pillow thicker.

Thus, insulation with expanded clay is low cost, simple installation, good thermal insulation, and excellent environmental tests.

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When to choose expanded clay

The range of heat-insulating materials on the modern market is so large that it can be difficult to settle on just one. However, it is worth learning the full range of properties of this unique material in order to understand that there is no better option than to insulate the floor with expanded clay.

A list of properties that make this simple material a leader among its competitors:

• Low thermal conductivity - the porous material contains air bubbles, which provide high-quality thermal insulation. A 10 cm layer of expanded clay exceeds the thermal conductivity parameters of a similar wooden surface by 3 times, and brickwork by 10 times.
• Sound insulation is a property in demand in apartments of multi-storey buildings; the expanded clay floor will serve as a reliable barrier to the penetration of noise from neighbors below, while simultaneously preventing the spread of sounds in the opposite direction.
• The strength of the material allows it to be used in the bottom layer of the floor pie without additional supporting structures (expanded clay is available in different grades of strength from 250 to 600).
• Resistance to rot and fungi, mold (unlike wood-based materials) increases the service life of the floor and its durability.
• Chemical inertness - expanded clay is a natural material, does not release any substances into the environment, and is also resistant to chemicals.
• Heat resistance - quality is relevant in terms of fire safety.
• Frost resistance - expanded clay does not lose its properties at extremely low temperatures.
• Light weight - allows you to insulate the floor with expanded clay under a screed in houses where a large load on the floors is undesirable (read: “Insulating the floor under a screed - practical tips”).
• The granular fraction of the material makes it easy to work with - one person who does not have construction skills can handle the backfill.
• Low cost is an additional bonus for a material that has a range of excellent qualities.

The only disadvantage of expanded clay is its ability to retain moisture for a long time. This drawback can be easily mitigated by following the technology of installing a floor with expanded clay and carefully gluing the waterproofing layer.

Preparation is an important step

Preparing the base for filling with expanded clay begins with cleaning the surface. A clean base is assessed for curvature and differences in plane. This is done in order to see what layer of expanded clay is needed to insulate the floor, level the surface and calculate the required amount of material.

The optimal layer thickness is 80 - 100 mm; to determine the required number of granules, make a mark on the wall to a height of 8 cm at the highest point of the room, from which then, using a level, mark a horizontal line around the perimeter of the room.

The average backfill height is obtained by measuring the distance to the horizontal line in several places, which is then divided by the number of measurements. So, if three measurements are made with values ​​of 10, 15, 8 cm, then the average height of the backfill will be (10 + 15 + 8): 3 = 11 cm. Then the area of ​​the room (width x length) is multiplied by the height (average value) obtained the number indicates how much expanded clay is needed to insulate the floor of this room.

Preparation itself comes down to the following steps:

1. Sealing cracks and potholes with mortar (for concrete floors).
2. Waterproofing the base. To do this, use any available technologies and materials: special mastic, preparation of a waterproofing solution from polymer dry mixtures. If the floor is insulated with expanded clay on the ground, then the optimal solution would be polyethylene film (not thinner than 100 microns) or rolled material (roofing material). Read also: “How to make a heated floor on the ground - a step-by-step guide.”
3. Installation of beacons - metal profiles are leveled and secured with mortar.

Note: beacons are not needed (clause 3) if the floor is dry insulated with expanded clay along the joists of the old floor, which are not planned to be dismantled, but are going to be used for laying a new wooden covering

Methods for insulating floors with expanded clay

There are several ways to insulate and level a floor with expanded clay. The choice is made based on the features:

• Surfaces;
• Permissible load on the base;
• Room assignments.

Thus, a dry expanded clay cushion is lighter than an expanded clay screed of the same thickness. The thermal insulation properties of dry expanded clay are also higher, but the surface strength and ability to withstand loads are better for expanded clay concrete floors constructed using the “wet” method of preparing the solution.

Dry backfill for wooden floors

Wooden floors are laid on logs - horizontally located bars. If, during the process of dismantling the old wooden floor, it turns out that the joists are well preserved and do not require replacement, then you should not remove them, adding more work to yourself. In this case, it is easier to insulate the floor with expanded clay along the joists.

To do this, waterproofing is laid in the spaces between the joists. Then a layer of expanded clay is poured, on which a foil vapor barrier is laid. For additional warmth, you can put another layer of other insulation on top (foam plastic, expanded polystyrene) flush with the top edge of the log. Then a wooden floor is laid, the slats of which are nailed to the joists. Read also: “Insulating the floor in a wooden house from below - how to do it and what to use.”

If it is planned to completely dismantle the wooden floor and install a concrete screed, for subsequent finishing with a decorative coating (tiles, laminate), care should be taken about the beacons. Without correctly aligned guides, you will not be able to obtain the level surface needed for flooring. A layer of dry expanded clay is poured with cement laitance to fix the granules. After the milk has hardened, the surface is leveled along the beacons with a cement-sand mortar.

Since it is not always possible to sufficiently insulate the floor with expanded clay (in cold regions when laying on the ground), an additional layer of foam insulation is included in the floor cake. Sheets of foam plastic are glued to an expanded clay cushion and covered with a screed (read: “Insulating the floor with foam plastic under a screed - installation instructions”).

A similar technology is used for insulation and soundproofing of floors in apartments with concrete foundations. A necessary condition is high ceilings. If the house has low ceilings, then a layer of expanded clay with a screed will make them even lower, which will affect the comfort of living. In this case, it is better to consider options with other materials, which will most likely cost more, but will not steal space.

Dry and fast method - clean job

The ease of laying such a floor allows you to do it yourself and quickly. Ideal for an apartment in a multi-storey building, since the weight of the structure is light and no mixing of screed mortar is required.

Operating procedure:

• Free the floor from debris and dust.
• Lay a waterproofing layer. If the waterproofing is of a liquid, flowing consistency (mastic, cement-polymer mortar), then cracks and crevices are first covered to prevent liquid from flowing into the floors.
• Beacons are installed.
• Expanded clay is poured in, and it is carefully compacted along the way.
• Lay sheets of plywood (chipboard, OSB) in two layers. The first layer is fastened together with glue, the second is screwed to the lower panels with self-tapping screws.

The dry base of such a floor is suitable for finishing with any decorative coatings: from linoleum to laminate.

Expanded clay is available in several strength classes and 4 types of granule sizes, so inexperienced home craftsmen often ask: “which expanded clay is best for floor insulation?” in order to provide the floor with the best protection from the cold.

You should know that despite the fact that the heat-saving qualities of expanded clay of a large fraction are higher, a dry screed must be installed from a mixture of materials with different sizes. This will allow you to get a solid base in which small granules will fill the space between large ones and provide a dense and durable coating. For apartments, medium (1 - 2 cm) and fine gravel (0.5 - 1 cm) are usually used.

Floor installation with expanded clay concrete screed

Expanded clay as a floor insulation material in a wooden house has no competitors due to its versatility. It can be used as an additive to cement-sand screed for constructing a concrete floor in outbuildings: garage, bathhouse. Unlike a dry base, expanded clay concrete screed has increased strength, wear resistance while maintaining good thermal insulation qualities.

The construction of the floor using the “wet method” consists of laying an aqueous solution made from sand, cement, expanded clay (ratio 2:1:3) onto a surface prepared in the usual way. As the screed is laid out, it is “slammed down” with a heavy floor polisher or a special tamper. This will allow you to get a smooth surface without roughness formed by protruding expanded clay granules.

Nuances you need to know when insulating a floor with expanded clay with your own hands:

• If the heat-saving effect is a priority, then dry expanded clay is used. A dry pillow retains heat better.
• The technology of the dry method depends on which layer of expanded clay for floor insulation is sufficient in specific conditions. If the thickness of the pillow is large (more than 10 cm), then it is worth pouring two layers, separating them with gypsum board sheets. plywood, etc. This design will ensure the stability of the coating.
• To secure the beacons, you can add gypsum or alabaster to the solution - this will speed up the setting and allow you to begin work on filling the expanded clay immediately after setting the guides.
• The use of granules of different sizes provides better adhesion and, accordingly, greater strength.
• Reinforcing the expanded clay layer with a metal mesh increases the reliability and strength of the structure.
• The expanded clay-concrete screed reaches its final strength after 4 weeks, so you should not subject it to excessive loads right away, despite the fact that it hardens literally on the second day.

Insulating a wooden floor with expanded clay or leveling the concrete base in an apartment with your own hands will save money. They can be used on an expensive decorative coating, which will become an interior decoration and a magnificent background for home photos and videos.

Which waterproofing to choose

The price range of materials in this category is as wide as their variety:

• Bitumen mastics;
• Polymer mixtures;
• Rubber hydraulic barriers;
• Polyethylene film;
• Roll materials of various compositions.

When choosing waterproofing that suits your financial capabilities, it is worth remembering that:

1. Liquid mixtures and mastics require a clean and solid base, and sometimes priming. After all, they must form reliable adhesion to the surface.
2. Rolled materials are laid freely, so they are indispensable for waterproofing expanded clay laid on the ground. It is necessary to ensure that the strips overlap by at least 10 cm; for some types of waterproofing of this group, manufacturers recommend gluing the overlapped edges of the strips. Read also: “How to make expanded clay floors with your own hands.”

Silica gel granules are another waterproofing option. It is scattered in a thin layer (1 cm) under expanded clay or mixed with dry backfill at the rate of 1 to 10. An excellent absorbent is not popular because of its flammability, chemical composition, and explosiveness. However, under certain conditions (a thick floor cake with a reliable barrier to silica gel vapors), the method has a right to exist.

Expanded clay has excellent heat-insulating properties. It is actively used in the process of constructing foundations, constructing floors between floors, and even for constructing attics. Just 10 cm of expanded clay crushed stone layer is warmer than 30 cm of wood and 100 cm of brick wall. Expanded clay is also ideal for installing heated floors. It is only important to use this unique material in a screed technologically correctly - and there are three such options.

To get started, here are a couple of introductory videos:

Advantages and disadvantages of expanded clay

Expanded clay is produced using a special technology: special types of clay are fired at high temperatures. The result is small granules with a porous structure, which have a number of important advantages:

• Environmental friendliness
• Durability
• Thermal insulation
• Soundproofing
• Strength

And at the same time, expanded clay is quite affordable for everyone. Its only drawback is that it is not resistant to moisture, and this already implies some limitations in use.

Types of expanded clay backfill for screed

The density of expanded clay, which the market offers today, ranges today from 250 to 600 kg/m3, according to which it is distinguished into the following types:

1. Expanded clay crushed stone. This material is 10-14 mm in size and is most often used for preparing concrete.
2. Expanded clay gravel. This one is used for installing durable and lightweight floors, and has three categories: 5-10 mm, 10-20 mm and 20-40 mm.
3. Expanded clay sand. Used for thin ties, the size does not exceed 5 mm.

The choice of the type of fraction depends on the specific room in which you will be screeding with expanded clay, and using what technology.

We use expanded clay in the screed: 3 options

Thus, the standard recipe for a living room is a package of 50 kg per 60 kg of cement-sand mixture. But for industrial premises, where the load on the floor is more significant, different proportions are needed. Let's just say that expanded clay will not withstand high pressure, and therefore is not suitable for warehouses with equipment.

Semi-dry screed with expanded clay: insulate and raise the floor

A semi-dry screed with expanded clay is the only option in which there is no need for thorough preparation of the base. You just need to sweep and remove construction debris from the cracks. And so that there is no moisture, of course.

If there are wires under the floor, we hide them in corrugation and press them well to the base. After cleaning, we cover everything with solid PVC film or a special vapor barrier, for example, glassine for a wooden floor. Its task is to protect expanded clay from exposure to moisture from below, which often forms on the interfloor ceiling. The film must be laid overlapping, secured with tape.

Now we mark the level of the new screed. It is better to do this using a professional laser level. We mark the lines on the wall and repeat them with a regular pencil or marker. If there is no laser, use a regular rack level.

We now leave a 10 cm gap along the walls, where we insert the heat-insulating material. Additionally, it will provide good sound insulation. As a last resort, use a standard edge tape one centimeter thick and ten centimeters wide. Now we pour out the expanded clay from the bags and distribute it over the entire surface of the floor using the usual rule.

In the first case, you need to pour the expanded clay with milk of cement in advance. Expanded clay granules are hygroscopic and, due to their porosity, absorb moisture quickly. Therefore, if you do not make such preparation, the dry granules will be pulled out of the screed by this water, and it will shrink unevenly. But even with preliminary wetting, it cannot be guaranteed that water from the screed will not flow at least a little towards the backfill.

A semi-dry floor screed is used to level the base and serves as a foundation slab for the finishing coating. You will learn more about the design of such a floor and the secrets of the correct technology from the material:.

In the second case, this no longer threatens, because even ordinary plastic film will easily prevent moisture from reaching the bedding. But then you need to be very careful so that the film does not tear anywhere.

Concrete screed with expanded clay, or expanded clay concrete

Before installing a concrete screed with expanded clay, i.e. expanded clay concrete, give the base a “diagnosis”. Simply determine how uneven the floor is:

• Step 1. To do this, pick up a regular two-meter level, place points in the corners of the room, and find the centers of the lines connecting the walls and floor.
• Step 2. After this, divide the space into segments and check each section separately.

Based on the detected curvature of the floor, calculate how thick the new screed will be. Now it is important to make the solution correctly: pour the granules into a large metal bath and pour enough water so that it is exactly half a palm above the level of the expanded clay. Some of the water will be absorbed because The granules have a porous structure. Simply mix the expanded clay with water until the mixture changes color. After this, add sand and cement.

Expanded clay concrete should also be distributed between the lighthouses. We level it well and let it dry for two days. Next, you can make another such layer or begin finishing the floor.

For serious unevenness, ready-made solutions from the Vetonit company are also suitable - these are mixtures where expanded clay crushed stone is held on a cement-containing binder. Such a leveler is capable of well leveling any unevenness, even those that reach 30 cm. By the way, such a screed also dries faster than ordinary concrete.

Dry screed with expanded clay: modern technologies

Here are the main advantages of dry screed with expanded clay:

1. A strong and absolutely flat floor base that can withstand a load of 500 kg per square meter.
2. Hypoallergenic and free of any harmful volatile substances in the air.
3. No cracks, no breaks, no chips, like with a regular screed.
4. Ready for use immediately upon completion of installation.
5. Good sound insulation.
6. The floor is so warm that it does not need any additional systems.
7. The shortest turnaround time: even a fairly spacious room can be laid by one work team in just 3 hours.

Absolutely any covering can be installed on the finished surface: parquet, porcelain tiles, laminate or even tiles. You can’t just have a water heated floor - only an electric one, and preferably a film one. Such a dry screed with expanded clay is especially valuable because it creates virtually no additional load on the floor slab.

But ordering such a screed based on an advertisement is quite risky - violations of the technology will lead to the floor “boiling” when walking, and certainly not being even. So, you should be wary if the workers you hire:

• Expanded clay is used not in large fractions, but crushed.
• Instead of GVLV sheets, use those that are not intended for such work. For example, gypsum boards.
• The gap between the wall and the sheets is too large.
• The folds at the edges of the connection to the wall were not cut.
• The sheets are fastened together not with glue, but with polyurethane foam.

This is how it happens that fairly high-quality materials are used unprofessionally, and such a screed subsequently bends even under a person. This is where the myths come from that only “wet” or semi-dry screeds are the only normal method for making a smooth and durable floor.

But you must admit that any success depends on how you approach the matter, and this is especially important in the construction industry.