Expanded clay and its fractions

 Expanded clay and its fractions

Expanded clay - this insulating material is an environmentally friendly product. This is a light and porous material, it is produced by firing low-melting clay. It is made in the form of sand, in appearance it looks like oval granules.

Bulk density - from 250 to 600 kg per m2 or maybe even higher, it all depends on the method of firing clay. Distinguish between small and large clay, depending on the fraction. The fact that it is, will be described in detail below.

 Expanded clay for insulation


The main purpose of expanded clay is thermal insulation, but this is not the only reason for which it is used.

It has the property of sound insulation, and can serve as a very good "underlying" material.

It can be used as a floor screed, for this you need to use small clay 0.1 - 0.2 cm, or smaller fractions.

It is not always possible to bring construction material to the place where it is required (construction, repair work, etc.) in bulk on large automotive vehicles. But this problem is easily solved by bagging the expanded clay into bags. Due to the relatively small weight of the bag, you can easily bring the material to the right place without involving a dump truck.

 Fine clay fine for floor screed


Since this is an environmentally friendly and highly demanded material, it has unique properties that it transmits with all its derivatives:

  1. It has both sound and thermal insulation.
  2. Great strength is not a small mass.
  3. Resistance to frost, moisture and fire.
  4. Long service life.
  5. Resistant to negative chemical effects.
  6. Resistant to the appearance of fungi and processes of decay.

And also it is natural and environmentally safe.

 Expanded clay

Types depending on the size of fractions

Externally, this material is similar to gravel. The composition has small and large granules of oval or spherical shape.

The granules of the composition look like a glassy mass, covered by a shell.

All granules vary in size, which varies from 0.05 to 0.4 cm. The material can be divided into 3 types of fractions. The scope of application depends on their size. The division into types is carried out by measuring the size of the granules:

  • 0-5 mm- expanded clay fines - used for leveling the floor and in the manufacture lightweight aggregate blocks.
  • 10-22 mm - used for insulation of floors and ceilings in homes;
  • 20-40 mm - it is used for warming roofs, basements, the floor in the garage and for thermal insulation of heating mains.

The use of the last two fractions in the screed make it thicker.

Expanded clay sand is considered to be the expanded clay of the smallest fractions, granules with a size less than the set, that is, less than 0.05 centimeters.

 Expanded clay 0-5 mm
Expanded clay fraction up to 5 mm is claydite sand
 Expanded clay fraction of 5 to 10 mm
Expanded clay fraction of 5 to 10 mm is used in the manufacture of expanded clay concrete blocks
 Expanded clay fraction of 10 to 20 mm
Expanded clay fraction of 10 to 20 mm is used for insulation of floors and floors in homes
 Claydite concrete fraction from 20 to 40 mm
Expanded clay fraction of 20 to 40 mm is used for insulation of the roof, basements



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

  • Clay rock, which melts easily, is constantly rotated and exposed to heat in pyrogenic furnaces.
  • Next comes the firing of the rock.
  • As a result, after these actions, sufficiently large granules are obtained, approximately 0.2 - 0.4 cm.

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

This material makes very good gravel and it has the following characteristics:

  • fire resistance;
  • resistance to frost;
  • water resistant

In the composition there are no impurities that could damage the cement - this is important, since this material is often used as a filler for the manufacture of lightweight concrete - claydite.

 Expanded clay from the gravel of expanded clay


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

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

Sand (fine fraction)

In order to get sand, large fractions are crushed or fines from clay are burned. After the above action is obtained clay pellets of small fractions of size less than 0.05 cm. The purpose of this particular sand is to knead it in a variety of mortars, as well as light concrete is also filled with it.

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

 Clay sand



House of expanded clay blocks easy enough to build. At the same time such construction is quite economical, and the house will have a number of remarkable properties.


Expanded clay found application in the construction of various baths. It can also be used as thermal insulation for the walls of the bath due to its properties: the required temperature is quickly set in the room and stored for a long time.For this purpose, it makes no difference what material to use: small fractional or large fractional.

 Expanded clay for thermal insulation

Laying communications

For the construction of water pipes or, for example, heating networks, you need to purchase such material as expanded clay. Then you will be calm about the fact that the heat reaches the house. Another advantage of this material is that in case of a leakage, it is not necessary to dig out solid ground. And after eliminating the accident to fall asleep all the same material again.

Other uses

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

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

Currently, many professional builders are no longer using the cement-sand screed as an outdated technology. When screed flooring covered with expanded clay, which greatly improves the quality.Such a coupler can even an inexperienced amateur builder.

 Expanded clay in the country

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

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

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

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

 Expanded clay


There are ten brands of this product on the building materials market. They vary in bulk density, which varies in the range from 250 to 800. It is calculated depending on the fraction in suitable measuring tanks.

Usually, the larger the fraction, the lower the bulk density.

Information provided for reference purposes. For construction issues, always consult a specialist.

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