Roof insulation with expanded clay

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Roof insulation with expanded clay
Roof insulation with expanded clay

The use of expanded clay for roof insulation, its features, advantages and disadvantages, technology of various types of roof insulation. Roof insulation with expanded clay is the oldest and most frequently used method of thermal protection at home. The comfort of living depends on the reliability of the roof, and this material helps to ensure this reliability for a long time. Today we will tell you how to use expanded clay for roofing.

Features of roof insulation with expanded clay

Expanded clay as insulation
Expanded clay as insulation

Expanded clay is a porous insulating material of dark brown color, obtained by firing clay for 30-45 minutes at a temperature of +1200 degrees. The raw material is crushed and loaded into a special oven that can rotate at a given speed. Moving in it, the clay sticks together into lumps, the rotation of the kiln gives them a rounded shape. The size of the granules and their quality are regulated by the rotation speed of the apparatus and the temperature of the hot air in it.

The result of the production process is an environmentally friendly, fireproof, frost-resistant bulk insulation with excellent thermal insulation and soundproof properties. It is of three types:

  • Expanded clay gravel … Its particles have a smooth oval shape and a size of 5 to 40 mm. The material is used for insulation of foundations and enclosing structures with the required thickness of the insulating backfill of more than 50 mm.
  • Expanded clay crushed stone … It has a rectangular shape with sharp corners, is obtained by crushing pieces of sintered clay, and is used as a heater.
  • Expanded clay sand … The size of its grains is in the range of 14-50 mm. This makes it possible to carry out insulating backfill with a thickness of less than 50-60 mm. Expanded clay sand can be used as a filler for mortars.

Due to the fact that sand weighs a lot, and crushed stone has inconvenient torn edges, expanded clay gravel is more suitable for thermal insulation of the roof. They can fill any cavities, creating a reliable insulating layer. To insulate roofs, you can use expanded clay of several fractions at the same time, and also add foam crumbs to it to heighten the effect.

In terms of thermal insulation properties, a layer of expanded clay 10 cm thick is comparable to a 250 mm wooden beam or a meter-long brickwork. The maximum effect of insulation can be achieved with a layer of expanded clay 15 cm thick. In addition, this method of saving heat is three times more economical compared to using wood, and using bricks - 10 times. It does not require special skills from the performer; expanded clay can be used to insulate the roof inexpensively, quickly and efficiently.

Expanded clay insulation for the roof is used only in the form of a dry bulk layer of a given thickness. Adding granules to concrete or cement mortar does not have a particular effect. Due to the fact that expanded clay is loose, its use is most optimal on flat roofs or with a slope of up to 5%.

The quality of the roof insulation made by expanded clay depends on the choice of good materials, including waterproofing, roof slope and calculation of its structure under load.

Advantages and disadvantages of roof insulation with expanded clay

Thermal insulation of the roof with expanded clay
Thermal insulation of the roof with expanded clay

Since expanded clay is based on a natural basis, it in many ways successfully competes with synthetic insulation. The structure of expanded clay can not be disturbed by temperature drops, moisture, or decay.

In addition, roof insulation with this material has a number of other advantages:

  1. Bulk insulation does not require joining elements and mounting fasteners.
  2. The roof insulated with expanded clay does not emit vapors harmful to health into the space.
  3. It is extremely not edible for living beings.
  4. Expanded clay, being a refractory material, cannot become a source of fire on the roof.
  5. Bulk insulation increases the heat and sound insulation characteristics of the upper floor of the house. Warming with high-quality expanded clay with a thermal conductivity of 0, 07-0, 16 W / m reduces heat losses by 70-80%.

The disadvantage of expanded clay insulation can be called a significant load of the material on the roof, despite the low weight of its porous granules. After all, the mass of the backfill layer with a thickness of 100-400 mm is very significant. Another disadvantage of insulation is its excessive absorption of moisture. Soaked material loses its quality. Therefore, when insulating the roof with expanded clay, a protective waterproof film should be laid on it.

Roof insulation technology with expanded clay

Since all roof insulation works are carried out outside, there are some restrictions regarding weather conditions. For example, it is unacceptable to conduct the technological process in atmospheric precipitation in order to avoid wetting of expanded clay. Therefore, before starting work, it is necessary to keep roll waterproofing ready. In addition to her, in the future you will need: buckets and a shovel, a vapor barrier membrane and a sharp knife, a rule for leveling the backfill and a rammer to compact it.

Preparation for work

Flat roof repair
Flat roof repair

Before insulation, the roof, if it is old, needs to be repaired. From a flat concrete surface, it is enough to remove the peeled insulation, remove debris, seal the potholes and cracks revealed during inspection with a cement mixture, and, if necessary, fill in a new screed. With a wooden pitched roof, the situation is more complicated. In addition to revising and replacing its supporting elements, you should pay attention to the strength of the roof structure, since the weight of the insulation can make it impossible to use. In any case, calculation is required here.

If the pitched roof is not strong enough, it can be strengthened using beams or bars of a larger section, additional stops and crossbars. In addition, it is necessary to provide support for the elements of the inner roof sheathing on additional bars connected to the rafter beams with bolted fasteners. After making sure of the strength of all the main structural units of the roof, you can proceed to its insulation.

Thermal insulation of flat roof expanded clay

Thermal insulation of flat roofs with expanded clay
Thermal insulation of flat roofs with expanded clay

The horizontal plane of the upper floor allows you to realize all the advantages of bulk insulation without unnecessary problems. The planned roofing cake with expanded clay should consist of several layers, which are stacked alternately.

The first is a vapor barrier material that can be laid on the prepared surface in two layers for strength. It will protect the insulation from moisture emanating from the room located under the roof. This material can be a membrane or polyethylene film, the sheets of which should be stretched during installation and overlapped by 10-15 cm. The joints of the sheets should be glued with double-sided tape. If the base is concrete, no vapor barrier is required.

After installing the substrate, you can backfill the insulation. It will be correct if the calculation of its thickness is performed in advance for the climatic conditions of a particular region. It is simple and is determined by the formula: P = R * k, where k = 0.16 W / m (coefficient of thermal conductivity of expanded clay), and R is the thermal resistance of the structure, which can be found in SNiP.

But usually the thickness of the backfill is determined approximately in the range from 25 to 40 cm. If it is not enough, then after winter it will be possible to perform additional insulation of the ceiling from the inside with mineral wool or foam sheets. When backfilling the roof with expanded clay, one should not forget about the permissible load that the structure can withstand. The choice of the "golden mean" in this case is very important.

Expanded clay laid on the roof must be leveled using a rule, and then tamped to reduce voids between the granules of the material. It is convenient to compact the backfill using an electric platform vibrator or manually rolling the surface with a log.

Then, to move on the roof for maintenance purposes, the insulation must be protected with a cement-sand coating. Performing a screed on the roof covered with expanded clay, it must be reinforced with a metal mesh.

The final stage of work is the device of roll waterproofing in 1-2 layers. To do this, roofing material or other similar material must be glued to the dried screed, using a gas burner for work. Installation of such insulation is carried out gradually as the rolls are rolled out. In order for the roof to have an aesthetic appearance, it is recommended to decorate it with a topcoat. It can be a painted profiled sheet, shingles and even lawn grass, which can be sown on a prepared layer of black soil.

Pitched roof thermal insulation

Expanded clay for roof insulation
Expanded clay for roof insulation

It is more difficult to insulate a pitched roof with expanded clay. The main thing here is to achieve an even distribution of the insulation layer in the cavity between the rafters. If the slope of the roof is more than 5 °, then the filling of this space must be carried out according to the technology of internal backfilling of frame walls - in small portions with stage-by-stage stitching of the structure.

In order for the expanded clay granules not to roll down the slope, the cavities between the support bars of the roof must be separated by jumpers. Then the cells filled alternately with insulation should be closed with boards from the outside.

After filling all the free space between the rafters on the crate, you need to fix the waterproofing film and install the roof covering. From the inside of the attic space, a vapor barrier material should be fixed on the inner lining of the roof slopes. All insulating materials must be fastened with an overlap of panels with sealing of the joints with tape.

How to insulate the ceiling with expanded clay - watch the video:

Summing up, it should be said that although expanded clay in work is not entirely convenient, it is quite versatile. The uncomplicated technology of its laying makes it possible to insulate flat roofs and pitched roofs with expanded clay equally successfully.