Thermal insulation

The consequences of insufficient thermal insulation are structural damage, and uncomfortable and unhealthy housing and work. Heating up insufficiently insulated spaces requires a greater amount of thermal energy, which leads to an increase in the cost of using and maintaining the space, but also to greater environmental pollution.
Better thermal insulation is achieved by the installation of materials with low thermal conductivity, ie high thermal resistance. The thermal resistance of the material increases with respect to the thickness of the material.
Insulating materials typically contain many air-filled cavities, combining low air conductivity and at the same time preventing the movement of air and thus the convection of heat (heat transfer is in substances that can flow).
The types of thermal insulation materials are diverse and can be divided into inorganic and organic materials. Of the inorganic materials, stone and mineral wool are the most widely used, while expanded organic polystyrene is the most popular among organic materials. Other materials with thermal insulation properties are clay, perlite, vermiculite, coconut, cotton, linen, wood wool, cellulose, cork, straw and so-called. transparent and vacuum thermal insulation. Transparent insulation allows solar energy to be received and transferred to the building, while at the same time it prevents heat loss from the building as well as ordinary thermal insulation. Vacuum insulation is done in modular panels, and because of its exceptional insulating properties, considerably less thickness is required than conventional thermal insulation for the same thermal properties. This insulation is still very expensive and is used mostly for the rehabilitation of buildings where it is not possible to install larger thicknesses of insulation due to eg the monumental value of the building.

Aerogels are artificially formed with the lowest density of any known porous solid. It is derived from a gel in which the liquid constituent of the gel is replaced by gas. The result is a solid with several outstanding properties, the most important being the thermal insulator and extremely low density. It is also called frozen smoke, solid smoke or blue smoke because of its translucent nature and the way light is diffused into the formation. The first aerogels were made of silicon gel. Kistler’s later work included aluminum, chromium and tin oxide based aerogels. Aerogels are good thermal insulators because they consist almost entirely of gas, and gases are very weak heat conductors. Although seemingly fragile, many aerogels have very good mechanical properties. However, they are very brittle and resistant to bending and cutting.
Expanded polystyrene or styrofoam has good insulation, today it is one of the most popular insulation materials. It is mainly used as a thermal protection in all exterior structures and as a floating floor in floor floors. It has significantly lower fire performance than stone wool and is not resistant to temperatures higher than 80 ° C. It is often used for thermal protection of basement walls – extruded polystyrene. In the first month after production, the expansion agent (pentane gas) is still excreted, later the material is completely stabilized. When the expansion agent evaporates, the products stabilize in dimension, so it is a matter of aging or aging. Polystyrene boards should last 60 days or more to be able to be installed in facades and flat roofs. The vapor permeability of expanded polystyrene depends on the volume weight of expanded polystyrene.

Mineral is one of the best thermal insulators. It is a mineral insulating material for thermal, sound and fire insulation in construction, industry and shipbuilding. Stone wool has high fire resistance, is vapor permeable and partially waterproof. It is resistant to aging and decay, and to microorganisms and insects. It is used in all external structures for thermal protection and in partition walls for sound protection. The only place where it is not recommended is to insulate basement walls underground. It is obtained either by blowing steam (air) through an incandescent blast furnace slag or by pouring a mass of diabases over rapidly rotating, chamotte discs. The resulting fine glass filaments fit into “wool”. Mineral wool also includes glass wool and stone wool.

The difference between them is in the raw material from which they are obtained, the technological process and the ultimate properties of the material. The main raw material from which glass wool is obtained is quartz sand with the addition of recycled glass. Stone wool is obtained from stone minerals, dolomite, basalt and diabase with the addition of coke.
Polyurethane foam or PU foam is also used a lot, especially for roof repairs. It has even better thermal insulation properties. It has good moisture properties and temperature changes.
Perlite is an eruptive aluminum-silicate stone that is mechanically ground and briefly heated to 1000 ° C. In this, the water contained in the rock is converted into water vapor and inflates the material and increases its volume by 15 to 20 times. The resulting product is a white granulate up to 6 mm in grain size. The individual grains are composed of cells, which are responsible for the thermal insulation properties. Perlite insulation materials are mainly used as backfill insulation, rarely in the form of sheets. Expanded perlite is not flammable but is sensitive to moisture. Therefore, when used as hydrophobic core insulation using silicones in dispersions, without solvent content or with artificial resins. Perlite insulation panels consist of expanded perlite, which is treated with organic and / or inorganic fibers and binders. The fibers are prepared and molded together with the expanded perlite wet process into insulating panels. Finished panels are sensitive to moisture and should only be installed where normally flammable materials are permitted under construction and building regulations.
Porofen is a hard foam of phenolformaldehyde resin. For thermal insulation, especially for flat roofs. The harmfulness of formaldehyde and phenol as a volatile substance should be noted.
Cork is a very good thermal insulator, obtained from the bark of the oak oak. Cork boards are produced by grinding the bark and expanding the cork particles in autoclaves and then cutting the blocks of expanded cork into panels of various lengths. Another way of producing panels is to press cork particles bonded with bitumen or other adhesive. Except in panels, cork is also delivered in particulate or expanded granules in loose state or glued to a strip (usually bituminous). Due to their beautiful appearance, the panels can also be used to cover walls and even floors (heavily pressed boards) in triple function: as a thermal and sound insulator and as a decorative surface.
Wood fiber boards (wooden wool) are produced by joining the fibers with cement. The panels are light because they contain cavities. Their density ranges from 200 to 500 kg / m3 (but also up to 1000 kg / m3, for hard boards). Nowadays, they are often used in combination with even better thermal insulation than thin, hard bark (combi panels). For thermal insulation, mixtures of wood particles (sawdust) and some binder may also be used, either in the form of pressed boards or cast at the installation site.
Sheep wool has thermal insulation properties similar to mineral wool. Low thermal coefficient of thermal conductivity. The collected natural wool is washed several times to remove lanolin and then mixed with polyester to help retain its shape. The wool wrap generally contains 85% wool mixed with 15% polyester. Sheep wool is a natural fiber derived from a fully renewable resource. Cleaning, exposure to air and thermal treatment of binding during the production consumes minimal energy. It uses only 14% of the energy that was otherwise used to produce mineral wool insulation. Sheep’s wool is hygroscopic and will therefore absorb and release water vapor without impairing its thermal performance. In cold weather, sheep’s wool absorbs heat from moisture in the air, allowing it to reduce heat loss from the building. In warm weather, the release of moisture has a cooling effect on the fibers which reduces the heat flow in the building. Wool has a higher fire resistance than cellulose and cellular plastic insulators. It melts when it comes into contact with the source of the flame, but should itself extinguish itself. It has been treated with a non-hazardous fire retardant to improve its fire resistance, flammability and flame spreading surface.
Baled straw has two to three times lower thermal conductivity than modern building materials and much lower than current building regulations. Straw is a renewable material that can be produced (grown) every year. The energy needed to produce this material comes from the Sun – a renewable energy source. When an object ceases to function, straw can be composted or used in mulching for many years. No waste issues. The straw is burning. Yes, but plastered thatched walls are less prone to fire than traditional wooden houses. Because the straw in the bales is very thickly squeezed, there is not enough oxygen in it to ignite. Straw is an extremely healthy alternative to modern building materials. Straw is a natural material and has no harmful effects. It does not cause allergies because it is not hay, so it does not contain pollen (straw is made from cereals and hay is mowed meadow, so it contains pollen of field flowers). The air quality in houses made of straw is much better because it does not release any evaporation, such as formaldehyde, which is often emitted by modern materials. In addition, unlike concrete, thatched walls breathe, resulting in substantially fresher air on the premises.