Insulation of the attic with expanded clay

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Insulation of the attic with expanded clay
Insulation of the attic with expanded clay

Advantages and disadvantages of warming an attic with expanded clay, options for creating heat-insulating coatings, determining the quality of a bulk mass, rules for forming a protective layer. Warming an attic with expanded clay is a traditional way of insulating a technical floor. To form the coating, the fragments are poured in a thick layer onto the floor in pre-prepared cells. It is allowed to use the material in conjunction with other products. We will talk about the rules for creating a protective shell using a free-flowing mass in this article.

Features of thermal insulation of the attic with expanded clay

Thermal insulation of the attic with expanded clay
Thermal insulation of the attic with expanded clay

High humidity in the room, mold on the ceiling and on the walls, cold - this is what awaits the careless owner if the ceiling is left without thermal insulation. All the heat from the room will go through the roof, heating the surrounding space. The problem can be solved with the help of expanded clay - a free-flowing mass that is produced from clay rocks. In the attic, you can use granules of the following fractions: sand - particle size 5-10 mm; gravel - 10-20 mm; crushed stone - 20-40 mm. Before insulating the attic with expanded clay, fragments of different sizes are mixed, which allows you to fill all the voids.

The product is poured only on the floor. Loose mass is considered a universal remedy and is able to insulate all types of floors. The load-bearing capacity of the structure can serve as a limitation. The material is quite light, but with a large layer thickness, a large load will act on the logs and walls. The roof of the upper floor is covered from the inside with other means.

The work is easiest to carry out during the construction phase of the house. In this case, you can easily waterproof the ceilings of the rooms under the attic and mount a ventilation system. Thus, expanded clay is protected from humid air from living quarters, and the ceiling is protected from the appearance of mold and mildew.

If the insulation is carried out in a residential building, the floor of the attic must be covered with a vapor barrier film to prevent the bulk mass from getting wet.

It is not recommended to pour expanded clay directly for another reason. When working with it, a lot of dust is emitted. In addition, it is formed during operation. An additional layer between the ceiling and the granules will protect the lower rooms from the penetration of crushed fragments.

When determining the thickness of the layer, one can focus on such comparisons: 10 cm of a substance retains heat, like 25 cm of wood or 60 cm of brickwork 1 m thick.

Advantages and disadvantages of warming the attic with expanded clay

Expanded clay as insulation
Expanded clay as insulation

The heat insulator has properties that allow you to block the heat leakage from the dwelling through the roof.

The main advantages of this material include the following qualities:

  • Absolute inertness to various aggressive environments, decay, mold. The material does not burn, does not crack when freezing.
  • Rodents do not take root in the loose mass.
  • It is convenient to work with.
  • The insulation contains no components that react negatively to cement.
  • The product does not allow condensation to form.
  • After installation, the house becomes quieter.
  • To create an insulating layer, no changes to the floor structure are required.

Users should be aware of the problems that arise when insulating an attic with expanded clay:

  • To achieve the desired result, the layer of granules is poured thick enough.
  • The dimensions of the coating exceed the thickness of modern synthetic products.
  • The loose mass must be protected from moisture.

Attic insulation technology with expanded clay

The sequence of works when insulating all types of attic floors is the same and consists of three main points: waterproofing the floor, filling the area with a loose mass, protecting the coating from roof leaks from above. More details about each operation are below.

The choice of expanded clay

Expanded clay for attic insulation
Expanded clay for attic insulation

Only high-quality material has good thermal insulation characteristics. It is impossible to check the compliance of the declared parameters with the actual ones without the proper equipment, but you should not make a purchase without a minimum check of the goods. Pay attention to the following points:

  1. Expanded clay properties must comply with GOST 9757-90.
  2. When purchasing prepackaged goods, first check the condition of the packaging. The bag must be whole, clean, factory-made. Brown or brown spots on its surface indicate the presence of dust that forms after the destruction of the fragments.
  3. Examine the pellets. They must have the correct shape with a smooth change in geometry, which ensures the permissible density and thermal conductivity of the insulation layer. Asymmetrical elements are formed due to a violation of production technology.
  4. Choose expanded clay with fragments of approximately the same size.
  5. The particles are fragile, so fragments are allowed in the bag. Their number should not exceed 5% of the volume of the bag. A lot of waste comes from improper transportation and storage.
  6. The presence of moldy elements indicates the presence of low-quality components in the insulation.
  7. Bulk mass sold in bulk must be stored in a dry warehouse. Do not buy an insulator that is outdoors. Wet granules cannot prevent heat leakage.
  8. Buy expanded clay produced by reputable companies. If you are offered a product from unknown companies, look for reviews on the Internet about them.

For information! Foreign companies sell their products 4 times more expensive than domestic ones.

Preparatory work

Attic vapor barrier
Attic vapor barrier

The process of thermal insulation of the attic begins with the preparation of the base. To do this, follow these steps:

  • Clear debris from the floor.
  • On the area to be insulated, assemble a fence, which must be filled with a free-flowing mass. It is made from wooden boards, boards, etc.
  • Treat lumber with products against rotting, burning and insect damage.

The height of the walls should be 1-2 cm higher than the calculated thickness of the insulating layer. You can determine the size of the coating yourself according to SNiP "Construction Heat Engineering". When using the reference material, take into account the thermal conductivity of expanded clay, which for medium fractions is 0.07-0.1 W / m. After obtaining the result, determine the weight of the coating and check the bearing capacity of the structure.

An insulating layer for a medium-sized room is usually in the range of 12-16 cm. For severe winters, it increases to 50 cm. The thickness also increases with an increase in the size of the insulated area.

To protect expanded clay from moisture saturation, the ceiling is covered with a vapor barrier. The material can be different. From modern means can be distinguished "Izospan" brand "C" or "B". It is allowed to use roofing material. To save money, you can use plastic wrap. Waterproofing is done in this way:

  1. Cut the canvas into pieces that are 20-30 cm larger than the area to be covered.
  2. Cover the area with cuts with an overlap of 10-15 cm on the walls and adjacent areas. Glue the joints with reinforced metal tape. Attach the film to the wall with tape.
  3. After laying the roofing material, treat the joints with mastic.
  4. On a wooden partition, wrap all wooden structures with a vapor barrier film.

The adhesive tape used for sealing joints and attaching to walls must have the following properties:

  • The product is reinforced metallized, covered with an adhesive composition with a layer of more than 20 microns.
  • Has heat insulating and sealing properties.
  • Withstands high mechanical stress.
  • It retains its properties at very low and very high temperatures.

Installation instructions for expanded clay

Attic insulation scheme with expanded clay
Attic insulation scheme with expanded clay

To insulate a cold attic with expanded clay, it is necessary to correctly form a protective "pie" on the attic floor. Perform the following operations:

  1. Pour clay 10 cm thick on the vapor barrier film. Knead the soil well, distribute it evenly over the surface and compact it slightly. In combination with expanded clay, it improves the heat-insulating characteristics of the "pie" and also improves the quality of the granules' laying. Instead of clay, a layer of sand of the same thickness can be poured onto the floor. It must be leveled and compacted.
  2. Install the beacons on the base and set them in one horizontal plane using a building level. They are needed to control the thickness of the coating. The distance between the beacons determines the length of the ruler with which the surface will be aligned.
  3. Mix granules of several fractions, they will fill the space intended for insulation more densely.
  4. Fill the fenced area with a loose mass below the level of the upper edge of the shield by 1-2 cm. During operation, the material can be lightly tamped, which will improve thermal insulation.
  5. If the upper floor is not planned to be used, cover the granules with a vapor-permeable film to protect against possible roof leaks.
  6. Expanded clay in an exploited attic must be protected from damage. One option is to mount a wooden deck and secure it to the joists. During installation, provide a guaranteed gap between the insulation and the boards so as not to damage the fragments.

For free movement, expanded clay is poured from above with a liquid cement composition. The sequence of work is as follows:

  • Prepare a mortar of 3 parts sand to 1 part cement. The mixture should be liquid enough to fill the entire area on its own.
  • Fill with expanded clay with a layer of 3-5 cm. Apply the composition in such a way as not to make potholes in the bulk mass and not to damage the structure of the "pie". Any defect at this stage will later be very noticeable, and it will still have to be eliminated.
  • The cement laitance will seal the top ball and squeeze air out of the voids between the elements. A dense monolithic ball is formed, which does not allow water to pass through. The insulating properties of the coating will deteriorate slightly, but it will be possible to walk on it without fear of crumbling the granules.
  • Wait for the layer to dry completely. The cement screed will harden in a week, but the design strength is reached in a month.

The moisture content of the coating can be determined by placing a large piece of plastic wrap on the floor. Glue the edges with tape to the surface. If a wet spot appears under the canvas after a day, the cement is not completely dry.

Further work depends on what plans exist for the use of the technical floor. If the attic is necessary for storing items, place plywood or planks on the screed. In the case of creating a living space, fill it with a cement-sand mortar 10-15 cm thick, and then lay the floor covering. After creating the coating, assess its condition.

The insulating sheath before plastering must meet the following requirements:

  1. The loose mass, after filling the space intended for it, has a moisture content in accordance with SNiPs.
  2. The flatness of the surface formed by the granules is checked with a two-meter ruler. After placing the tool on the beacons, the dimensions between the ruler and expanded clay may differ by less than 5 mm.
  3. The actual thickness of the insulation may differ from the design by 10% upward and 5% downward.
  4. Excess of the volumetric weight of the material used over the calculated value of more than 5% is not allowed.

How to make a screed in an attic with expanded clay

Screed with expanded clay
Screed with expanded clay

This method of thermal insulation is used when there are large differences in floor height. After leveling the surface, no additional insulation layer is required, which saves money.

The work is done in this way:

  • Prepare the base as in the previous case. The presence of a vapor barrier film is required.
  • Install base surfaces to level the surface of expanded clay concrete.
  • To prepare the mixture, mix sand and cement in a 3: 1 ratio in a concrete mixer. Add water approximately 10-20% of the total dry mass.
  • Pour expanded clay into the solution at the rate of 2 parts of cement-sand mortar per 1 part of filler and mix the components again. Add water if necessary. It is impossible to indicate the exact amount of liquid, it all depends on the brand of cement and the properties of the granules.
  • The finished solution should resemble a thick dough in which all the fragments are coated with cement.
  • Pour the mixture onto the floor, smooth it roughly with a trowel and more precisely with a board that rests on the base surfaces.

After drying, the technical floor is ready for use.

How to insulate an attic with expanded clay - watch the video:

The attic has been covered with expanded clay for more than 100 years, despite the appearance of more modern heat insulators. Inexpensive material can replace high-tech products, provided that the installation technology is strictly observed. In order not to be disappointed in the results of the work, take the process of insulating the technical floor seriously.

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