Expanded clay as insulation

In the realm of building and remodeling, expanded clay is becoming more and more popular as an insulating material. The process of heating natural clay to high temperatures causes it to expand and form small, porous granules, which is how this lightweight, environmentally friendly material is made. These granules are a desirable option for both new construction and renovation projects because they are not only very good at retaining heat but also have a number of additional advantages.

The outstanding thermal insulation qualities of expanded clay are among its main benefits. Each granule contains microscopic air pockets that function as heat-transfer barriers, keeping houses cool in the summer and warm in the winter. Because less heating and cooling is needed to maintain a comfortable interior temperature, this can result in significant energy savings.

Apart from its thermal properties, expanded clay exhibits exceptional durability and resistance against moisture, rot, and vermin. It ensures long-term performance because, in contrast to certain other insulation materials, it does not deteriorate with time. Because of its moisture resistance, it’s especially good for use in damp places like crawl spaces and basements.

Expanded clay also has the advantage of being versatile. It can be applied in many different ways, such as filling roof spaces and wall cavities, or as underfloor insulation. Because of its lightweight design, it is also simple to handle and install, which cuts down on labor expenses and construction time.

All things considered, expanded clay makes an eco-friendly and sensible insulation option. It is a great choice for improving the energy efficiency and comfort of any building because of its blend of thermal efficiency, robustness, and adaptability. Expanded clay provides a dependable and efficient insulation solution, regardless of whether you’re renovating an old building or starting a new one.

Property Details
Material Expanded clay is made from clay heated to high temperatures until it forms small, lightweight balls.
Insulation It provides excellent thermal insulation, keeping buildings warm in winter and cool in summer.
Durability Highly durable and resistant to moisture, rot, and pests.
Environment Eco-friendly and sustainable as it is made from natural materials.
Usage Commonly used in walls, floors, and roofs for insulation.

Characteristics

A loose insulating material made of ceramic pellets that have been fired at a high temperature is called expanded clay. Shale or fusible clays are the raw materials. After sorting, producers receive three fractions at the output: sand, crushed stone, and gravel (expanded clay, not to be confused with sedimentary rock).

Gravel

Round or oval-shaped ceramic granules are found in gravel. They are divided into three categories based on the diameter:

  • fine-grained – 5-10 mm. Mostly suitable for “warm floors”. In addition, they are mixed with other fractions, after which they insulate the walls or add them to the cement mortar to fill the screed;
  • mid-fraction – 10-20 mm. Main type of insulation. Used to create a thermal insulation layer on the floor, walls, ceiling, roof;
  • coarse – 20-40 mm. Used only where a thick layer of insulation is required, for example, backfilling on the ground for pouring a concrete screed.

Sand

Ceramic pellets that are tiny—up to 5 mm in diameter—are referred to as sand. It can be made by crushing sizable pieces of sintered expanded clay, or by sorting gravel and letting the fines fall off. "Warm" masonry mortar for bricks and blocks is made with sand that contains particles as small as three millimeters. The expanded clay cement floor screed’s primary filler is the 3-5 mm fraction.

Crushed stone

Granules of crushed stone range in diameter from 0.5 to 1.0 cm and have an uneven shape. obtained by pulverizing big sintered clay fragments. utilized to create lightweight concrete. There are ten density categories for expanded clay, ranging from 250 to 800 kg/m3, and thirteen compressive strength grades. The table provides the primary technical and physical indicators.

Table 1.

Advantages and disadvantages

Given the wide variety of contemporary insulation options available, expanded clay’s high consumer popularity can be attributed to its advantages:

  • low price – one of the most powerful arguments when choosing the type of thermal insulation material;
  • good thermal insulation properties;
  • durability – subject to operating conditions, the material does not lose its original characteristics for 40-60 years;
  • fire resistance – belongs to the class of non-combustible materials (NG);
  • resistance to temperature changes – at the household level it is impossible to create conditions under which insulation granules begin to collapse, i.e.e. tolerate any frost and fire;
  • high frost resistance – withstands up to 300 freezing/thawing cycles;
  • light weight – does not create mechanical loads on floor slabs;
  • the ability to be used in cement mortars, which, firstly, lightens the weight of the screed or blocks, and secondly, improves the thermal protection of the room;
  • high level of sound insulation;
  • strength;
  • environmental safety – the product contains no allergens, no harmful substances are released when heated;
  • biological resistance – does not serve as a basis for the proliferation of fungus and mold, mice and rats avoid settling near the material – can be sprinkled;
  • simple, yet convenient installation – no experience in performing thermal insulation work is required; thanks to its flowability, any difficult area can be filled.

The aforementioned benefits of expanded clay call for explanation and commentary.

  • The list of advantages is compiled based on the opinions of experts and consumers.
  • The experience of the StroyGuru website employees in the construction industry makes it possible to question some of the experts’ statements.

Let’s get things easy first.

1. Is expanded clay a substance used for insulation? Expanded clay granules have a thermal conductivity coefficient that ranges from 0.1 to 0.18 W/(m×°K). The pellets’ size and bulk density determine the precise value. Since a blend of fractions is utilized for insulation, the true thermal conductivity falls between 0.14-0.15 W/(m×°K). Accordingly, a 5-centimeter layer of SPB-25 foam insulation is equivalent to a 15-centimeter-thick layer of expanded clay and a 12-centimeter-thick layer of mineral wool. In summary, expanded clay has low efficiency and can be categorized as insulation.

2. The cost of the budget. Here, experts and customers compare the cost of materials in cubic meters. Ceramic pellets are actually superior in this situation. For some reason, though, no one considers the fact that expanded clay granules require three to five times the amount of insulation as other forms. All calculations are then done in reverse. For instance, the cost of expanding clay flooring insulation is 1.3–3.1 times higher than that of polystyrene foam. Although it seems unbelievable, it is real. We advise skeptical readers to perform the computations on their own.

3. Effective sound absorption. Like many other insulating materials, expanded clay is not a very good sound-isolating material. With a dynamic elasticity modulus of 15 mPa, it is highly elastic. In contrast, this figure is only 0.3–0.6 mPa for basalt wool, which is used in recording studios to insulate against sound.

4. Low weight. The weight of the ceramic pellets as stated in the statement is accurate; it is unrelated to the amount of expanded clay that is applied to the floor’s base. And that weighs a few tons. It will not damage the floor slab; however, the rough wooden floor needs to be constructed from boards that are at least 25 mm thick. Thinner boards run the risk of breaking under mechanical load.

5. Power. What kind of strength we are discussing here is unclear. Strength cannot be discussed when discussing static or dynamic loads because the material is brittle. Simply tread on a few granules on the floor slab to verify. Not everything is clear here, though; you can walk on a layer of several centimeters without worrying about breaking anything, even though some of the pellets won’t be crushed. In conclusion, you must walk on the layer that has already been poured during the insulation process because the material is brittle.

Regarding shortcomings,

  • very high level of water absorption – 15-25% of weight. The problem is aggravated by the fact that, due to the porous structure, the pellets dry for a very long time, not for days, but for months. When wet, heat conductivity increases several times. Another problem with wet expanded clay is frost. A few degrees of negative temperature is enough for water to destroy ceramics from the inside;
  • the large thickness of the thermal insulation layer steals the volume of the room, which is very important for low ceilings;
  • tendency of pellets to form dust.

Application area

Thermal insulation is achieved by using expanded clay as insulation:

  • floor – can be used as a dry screed, expanded clay concrete screed, combined screed (cement mortar is poured on top of the dry screed);
  • walls – filled between the load-bearing wall and decorative brickwork. Another option for wall insulation is expanded clay concrete blocks;

  • ceiling – insulation is poured onto the ceiling from the attic side;
  • roofs.

Manufacturers and prices

All of the CIS countries have expanded clay production facilities. Although product quality varies, raw material quality (clay quality) is the main determinant. There is a small amount of the human element as well.

Similar businesses can be found in practically every region of Russia. Among the TOP 10 are:

  • "Expanded clay" (g. Ryazan);
  • Expanded clay plant ZhBI-3 (g. Belgorod);
  • "Klinstroydetal" – brick factory in. Wedge;
  • "Expanded clay plant" (g. Serpukhov);
  • "PSK Shchurovsky Plant" (g. Kolomna);
  • "KSK Rzhevsky" (g. Rzhev, Tver region);
  • "Meliz" (Kursk region);
  • "Experiment" (g. Kostroma);
  • "Expanded clay plant Aleksinsky" (g. Aleksin, Tula region);
  • "Belkeramzit" (g. Builder, Belgorod region).

The cost is determined by the kind of ceramic pellets (crushed stone, sand, or gravel), the fraction’s size, and the expanded clay and packaging brands. Thus, for 2040 rubles, a large bag with a volume of 2.8 m 3 and a fraction size of 10–20 mm can be purchased. (728 rubles/meter three).

The price of small packaging is much higher, ranging from 1800 to 3640 rubles. for 1 m 3 (a bag of the M200-250 brand with a volume of 0.05 m 3 costs 99 rubles).

Insulation technology

Diverse technologies are used to insulate different types of buildings.

Stan

Expanded clay walls are insulated using a complicated three-part structure. The first layer is a load-bearing element, and the second is a backfill of expanded clay pellets that has been compacted and sprayed with impregnation, such as "cement laitance" (a 3:1 water-cement mortar that is diluted with 1 Portland cement and 3 water), and the third is a decorative material lining or a layer that is used to attach the finish.

This wall construction option is not appropriate for all wall materials due to its complexity and additional labor requirements.

Concrete with air. A building is constructed first, and then an extra wall is built (laid out). In order to prevent it from settling over time, expanded clay is poured into the well, compacted, and impregnated with binding compounds. Installing ventilation gaps is necessary to get rid of condensation moisture.

Encase walls. Expanded clay is not the best insulation choice in a building design like this because it can cause problems during compacting and damage the frame. Even after impregnation, ceramic granules cake and settle if you don’t artificially compact them.

Wooden home. Ceramic granules are not used as wall insulation because the wall might not be able to support such a load.

Ceiling

Ceiling Expanded clay is covered with a layer of 5–10 cm for a warm roof and 30–40 cm for a cold one (poured onto the ceiling from the back side) to insulate the ceiling space only in private buildings.

Roofs

It is rare to insulate a pitched roof with expanded clay, but the technique is straightforward:

  • boards are packed along the bottom of the rafters, forming a plane on which the insulation will be poured;
  • a vapor barrier film made of polyethylene is laid overlapping. It has several functions: vapor and waterproofing, preventing small fractions of pellets from spilling through the cracks between the boards;

  • Ceramic granules are poured over the film in an even layer;
  • the thermal insulation layer is covered with a vapor barrier membrane;
  • a counter-lattice is filled to create a ventilation gap;
  • boards are attached on top of the counter-lattice to secure the roofing material;
  • roof is being installed.

Floor

There are three ways to insulate the floor:

  • perform a dry screed (for a wooden floor – dry insulation);
  • carry out thermal insulation using the “wet method”;
  • pour a layer of ceramic pellets under the cement screed.

All work methods are covered in detail in the following articles on our portal:

  • “Dry floor screed with expanded clay”;

  • “Technology of wet floor screed with expanded clay”;

  • “How to make a floor screed with expanded clay?».

Note: additional technologies are used to insulate expanded clay coverings in bathhouses; these will be covered in a different article.

Expanded clay provides a flexible and efficient insulation option for a range of building requirements. Because of its excellent thermal insulation and lightweight, porous structure, buildings can stay cool in the summer and warm in the winter. As a result, there may be large energy savings and an improvement in occupant comfort.

Known for its longevity and durability, expanded clay also has insulating qualities. It is a dependable material for both new construction and renovation projects because of its resistance to fire, moisture, and pests. Because of the material’s natural composition, it is also environmentally friendly, which supports sustainable building techniques.

Expanded clay is also simple to work with and has a wide range of uses, including roofing, landscaping, and insulation for walls and floors. Because of its versatility, it’s a well-liked option for builders and homeowners searching for an affordable, high-performance insulation material.

To sum up, expanded clay is an excellent option for insulation because of its versatility, durability, and thermal efficiency. Expanded clay can offer long-term advantages and peace of mind as an insulation material, whether you are building a new home or remodeling an old one.

Expanded clay’s lightweight, strong, and environmentally friendly qualities make it a great material for insulation. Constructed from heated and expanded natural clay, it offers efficient thermal and acoustic insulation for a range of construction uses. Because of its porous structure, which traps air, heat transfer and energy costs are greatly reduced. Expanded clay is also fire, moisture, and pest resistant, which makes it a dependable and durable material for both new construction and renovations. Because of its adaptability and sustainability, it is a top choice for people looking for effective and sustainable insulation solutions.

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Timur Kiselev

Professional builder with 15 years of experience. I know everything about the construction of houses, cottages, bathhouses and other buildings. I will be happy to share my knowledge and experience with you.

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