When building buildings, the problem of choosing high-quality thermal insulation arises. The material must have a long service life, low thermal conductivity and low cost. All criteria are met by perlite. Due to its flowability, bulk insulation of natural origin fits tightly and reduces energy losses by 30-50%.
Insulation specifications
The rock is formed in a lava flow during a volcanic eruption. It is formed as a result of the impact of groundwater on volcanic glass. The mineral has a specific structure and easily disintegrates into separate rounded parts - pearls. Another distinctive feature of the porous rock is the water content of about 1% of the total volume.
Expanded perlite insulation is used in construction, heat-treated in ovens at a temperature of 1100 ° C. When heated, moisture evaporates, imparting a porous structure to the mineral and increasing its size several times. The material becomes lightweight, acquires heat-insulating properties. It is manufactured in various sizes from fine sand to crushed stone. Dimensions of construction perlite - 0.16-1.25 mm, agroperlite - 1-5 mm. Perlite sand is characterized by a large spread in density - 40-200 kg / m3.
Specifications:
- thermal conductivity - 0.043-0.052 W / m * K;
- moisture by weight - no more than 2%;
- uneven grain sizes - up to 15% by volume of the product;
- moisture absorption - up to 400% of its own weight.
The insulation is chemically neutral, not afraid of the effects of alkalis and weak acids. It does not rot under the influence of moisture, microorganisms and rodents do not live in it. The heat insulator is used in a wide temperature range from -200 ° C to + 900 ° C. The material is environmentally friendly for people, does not contain toxic impurities and heavy metals.
Pros and cons of perlite
When choosing a bulk insulation, consumers have to compare several materials: expanded clay, expanded polystyrene granules, vermiculite or perlite. Each variety has features that are taken into account when making a decision. Volcanic glass bulk insulation is highly effective. The material does not shrink, like granular polystyrene foam, and does not get wet, like expanded clay. The main advantages of the insulation are:
- Low thermal conductivity of pearlite, which is provided by many voids of the porous structure of the mineral. Also, the structure of the mineral contributes to effective noise absorption.
- Low weight, allowing to reduce the total weight of the structure by up to 40%. Lightweight load-bearing walls do not require a massive foundation.
- The ability to operate in a different temperature range does not limit the use of the material.
- Fire resistance guarantees the fire safety of the insulation. He is able to stop the spread of fire. When heated, it does not emit smoke and toxic substances.
- The natural mineral is ecologically safe, there are no harmful impurities in its composition.
- Loose insulation fills the space evenly, fits tightly, leaving no cold bridges. The material does not cause difficulties when filling as foam granules.
Brittleness is the main disadvantage of pearlite.The mineral is easily destroyed, turning into dust. The material loses mass when transported in an open way, creates inconvenience during filling. Working with it requires the use of protective equipment: respirators, goggles, gloves. To make the sand less dusty, it is moistened with water before use.
Perlite's ability to absorb moisture is not always a negative characteristic. It is able to easily release water in the form of steam. The material prevents condensation on the walls. For normal operation of the insulation, it is necessary to ensure the removal of excess moisture to the outside.
Comparison with vermiculite
Among bulk insulation materials, the choice is usually made from two minerals - agroperlite or vermiculite. An unambiguous conclusion can be made by comparing their characteristics. Vermiculite is a layered dense material. In construction, it is used in expanded form. The mineral is heated to a temperature above 1000 ° C, during processing it increases in volume up to 20 times.
A significant advantage of vermiculite is its elasticity. Unlike perlite, it does not deform or crumble under its own weight. The insulation is heat-resistant and environmentally friendly. The high hygroscopicity of the backfill requires a high-quality ventilation device on the roof.
The physical and technical properties of materials are similar to each other. Loose substances differ in appearance: light perlite, brown vermiculite. The thermal insulation properties of perlite insulation are slightly higher than that of vermiculite. But the main factor in favor of volcanic glass insulation is its cheapness. The material costs 2-3 times less vermiculite, therefore it is more popular in construction.
Varieties of loose thermal insulation
Perlite insulation comes in various forms. It is recommended for the construction of residential buildings and industrial facilities, outbuildings. Depending on the type, the material is added to the composition of the plaster mortar, is backfilling the walls or is laid like ordinary slabs. A decorative coated material is used as a cladding.
Slabs
Pressed boards are the most convenient form of using mineral rock. They are used for thermal insulation and fire protection of buildings. It is easy to work with the plates, the appearance of dust, typical for sand, is excluded. In their manufacture, mineral raw materials are mixed with cement, liquid glass or bitumen. The resulting material has low thermal conductivity, it is heat-resistant and durable. Insulation is divided by density into several grades. The characteristics of the material depend on the additives used. Its advantages: light weight, soundproofing qualities, durability.
Sand
This type of insulation is used as filling voids in walls, ceilings, floors. The most popular in construction is perlite sand of the M-75, M-100, M-150 grades. The material is lightweight and does not create excessive pressure on the base. Insulation is purchased in bags, from which it is filled into voids. The main advantages of pearlite sand are fluidity, fire resistance, chemical and biological inertness. The thermal conductivity of the material increases with an increase in the density of the backfill.
Dry mixes
Dry construction mixtures based on expanded perlite are distinguished by increased thermal insulation properties. In addition to sand from volcanic rock, the composition includes cement or gypsum. To prepare the plaster solution, it is enough to add water in the amount specified by the manufacturer. The mixture is used for facade insulation, interior work, and decorative coating. The use of compounds in a masonry mortar when erecting walls from concrete blocks improves the thermophysical performance of the structure. Perlite-based building mixtures are durable, non-combustible, environmentally friendly.
Application area
In its natural form, the mineral is used in various economic areas:
- the food and medical industry uses the mineral as a cleaning filter;
- in agriculture, perlite loosening additives are popular.
Expanded perlite is usually used in the construction of buildings. It allows you to ensure optimal performance of sound and heat insulation of walls, floors, roofs. Insulation is effective in case of uniform filling and composition of insulating products. It is used to fill the masonry of external and internal walls, when installing a floor heating system, insulation of ceilings.
Wall insulation
Perlite is popular as a heater for walls of a frame house or a brick building, erected by the method of well masonry. The use of a mineral filler reduces the cost of the overall construction estimate. The thickness of the layer depends on the climatic conditions of the region. It is calculated at the stage of preparing a house construction project.
Thermal insulation with pearlite sand begins at the initial stage of wall construction. Its recommended bulk density is 60-100 kg / m3. When insulating the basement and basement, sand is added to the plaster mix. After finishing the laying, the structure is covered with floor slabs. They are carefully sealed with a solution so that moisture does not get into the cracks.
Roof insulation
Perlite thermal insulation is used to insulate flat roofs, attic and interfloor ceilings, floors. For roofs of complex shapes, a special material has been created - bitumen perlite. This is a composition of pearlite sand and heated bitumen. The slabs are given the desired shape. Among the advantages of the product are fire resistance and good thermal insulation characteristics. Perlite-bitumen materials can be used at low negative temperatures.
Insulation technology
The high hygroscopicity of the backfill requires the installation of a waterproofing layer. An important condition is the use of only dry perlite. The width of the hole into which the mineral is poured depends on the climatic conditions of the region. It is at least 15-20 cm. During the construction process, perlite is poured into the inter-wall space gradually, after the construction of 4-5 rows of bricks or concrete blocks. Tamping is done by tapping with a wooden mallet. The free flow of the material in this case is a useful property. It fits tightly, leaving no voids.
When insulating floors, a plasterboard or chipboard flooring is preliminarily laid on the base. The backfill layer is at least 1 cm thick. It is covered with kraft paper or cardboard. Cellulosic materials do not prevent moisture evaporation. Perlite-bitumen slabs are used for pitched roofs.
