What is mineral wool and how it is produced, what are the varieties of this insulation, its technical characteristics, features of the choice of material, pros and cons, installation technology. Mineral wool is an effective inorganic fiber insulation that comes in several varieties. Based on the composition of the fibers, mineral wool is divided into groups: glass wool, stone and slag. To retain heat, it "uses" air as a heat insulator.
Description and features of the production of mineral wool
Mineral wool is the general name for a group of inorganic insulation materials that have a fibrous structure and are made from certain rocks, glass and slag. Heat insulators "fix" the air layer and, with its help, qualitatively isolate the room from the cold. An insulating board or mat is made up of millions of fibers intertwined in a specific order.
Regardless of the type of mineral wool, the principle of production of all types is the same. In this case, exclusively non-flammable substances are used. The feedstock is melted in a cupola or smelter at a very high temperature up to 1500 degrees above zero. After a fiery liquid mixture is obtained, fibers of different thicknesses are drawn from it.
This process can take place using different technologies: blowing, centrifugal-roller, centrifugal-blowing, centrifugal-spinning-blowing, as well as other modified methods. In the manufacturing process, ultrafine fibers are obtained, which are deposited in special chambers, from where they are sent to lamellae or corrugating devices. They form the required initial volume of mineral wool.
Next, a binder mixture (most often, phenol-formaldehyde resin) is applied to the carpet in special equipment, which must firmly hold the fibers. After that, the cotton wool is placed in a chamber, where it polymerizes and gets its final shape. At the end of the production process, mineral wool slabs are heat-treated. It gives the material extra strength. Finished products are packed in a shrinkable polyethylene film, which protects the material from contact with moisture. However, even if the mineral wool is in the rain for a short time, it will not harm it, since during the production process it is processed with hydrophobic compounds. They protect the heat insulator from the negative effects of water during installation.
There are several forms of insulation release:
- Rolls … Mineral wool mats are used to insulate roofs, interfloor ceilings, walls, and other structures that do not experience heavy loads. The density characteristics of such cotton wool are not very high.
- Slabs … The material can be placed under a concrete screed, in places that will be exposed to significant mechanical pressure. Such insulation has a maximum density of up to 220 kilograms per cubic meter.
- Cylinders … Used for pipeline thermal insulation. They have an average density.
The main varieties of mineral wool
There are not many minerals that can make long, thin fibers. After a certain treatment, fibrous substances are formed from some rocks, glass, and various slags. Based on this, mineral wool is divided into three main types: stone (basalt), slag and glass wool.
Glass wool
This is one of the most common and budgetary thermal insulation materials. It has a fibrous structure and a yellowish tinge. The raw materials used are cullet, borax, sand, soda, limestone, dolomite. Glass wool has low thermal conductivity, it copes well with vibration loads. When squeezed, it is able to reduce its volume by 6 times. Thus, the cost of transporting the material is reduced. This insulation is the softest among all other types of mineral wool. It is recommended to use it where strong mechanical stress will not be applied to it. Recently, semi-rigid glass wool slabs have appeared on the market, they can be used to insulate ventilated facades. Insulation in the form of cylinders is intended for thermal insulation of pipelines. It is worth noting that this type of cotton wool is the most prickly. Therefore, when working with it, it is necessary to protect the skin, mucous membranes and respiratory organs with personal protective equipment.
Stone wool
The main advantage of stone (basalt) wool over other types of mineral fiber insulation is the ability to obtain material of different density, shape and resistance to mechanical stress. Stone wool is produced from various gabbro-basalt rocks. These are diabase, basalt, gabbro, to which dolomite and limestone (carbonate rocks) are added. This insulation has lower thermal conductivity values than glass wool. Also, stone wool has improved a number of other indicators, for example, resistance to mechanical and vibration loads. The material does not burn and does not absorb water well. Stone wool is available in low and high density. In the first case, it turns out to be flexible. In the second, it is solid. This heat insulator is considered the most versatile among other types of mineral wool, since basalt fiber can be used to produce materials with different strength indicators, make them of any shape and supplement with various coatings. Flexible and soft stone wool is used where large mechanical loads are not expected, in low-rise buildings, for thermal insulation of wells. A denser material is used to insulate multi-storey buildings. It provides not only heat, but also sound insulation. Curly varieties of basalt wool insulate pipes and pipelines. If a mechanical effect is exerted on the insulation, then tough varieties are used. Stone wool can be produced with fiberglass or foil backing. To give it greater strength, it is stitched with glass threads or wire.
Slag
This type of mineral fiber insulation is made from blast furnace slag. The latter is a stony or vitreous mass, which is a waste product when smelting pig iron in blast furnaces at metallurgical plants. The values of thermal conductivity are slag - rather high. In addition, it has other disadvantages. For example, it absorbs moisture quickly and easily, so it cannot be used in humid places. It is not suitable for insulating facades, because when interacting with water, chemical reactions begin to occur in the material, which lead to the formation of acids. They destroy the metal parts surrounding the slag. In addition, this type of mineral wool has poor resistance to vibration loads. Due to the presence of such a large number of minuses, slag wool is currently practically not used in construction.
Mineral wool specifications
The popularity and wide scope of use of mineral wool is due to its technical characteristics. Let's consider them by their main properties:
- Thermal conductivity of mineral wool … This indicator indicates how much heat energy will be transferred through a material of unit density at a certain temperature difference. Data are indicated in W / (m * K) or W / (m * C). The thermal conductivity of mineral wool is always indicated on the packaging. According to GOSTs, this indicator should fluctuate between 0, 041-0, 045. It depends on the density and thickness of the insulation fibers. Sometimes some manufacturers indicate a rather low coefficient - up to 0, 032 W / (m * C). This should give rise to doubts and serve as a reason for checking the quality certificates of such products.
- Density of mineral wool … Shows the amount of fiber contained in one cubic meter of product. This value is measured in kilograms per cubic meter. Average parameters of mineral wool - 20-220 kg / m3.
- Noise isolation … The chaotic structure of the fibers allows the use of mineral wool for sound suppression as well. Many manufacturers have product lines that are designed to isolate sound and vibration. This indicator is usually indicated on the package - Aw. If it is 0, then the material is capable of reflecting sound waves. If the value is 1, then it absorbs them.
- Vapor permeability … Mineral wool is characterized by a high vapor permeability index - 0.48 g / (m * h * hPa). Steam seeps through the fibrous structure of the material, but is not absorbed. At the same time, it is important to ensure that the steam can escape outside, and not accumulate in the slabs or mat.
- Dimensions of mineral wool … This indicator may fluctuate depending on the scope of the material. For example, slabs, as a rule, have dimensions of 60x100 centimeters with a thickness of 5-20 centimeters. Such dimensions make the products easy to transport and install. In addition, 60 centimeters is the most common step when arranging a rafter system. For mineral wool in rolls, sizes are characteristic that allow covering a large area: 60-120 centimeters - width, 50-150 centimeters - thickness, about 9 meters - length. The cylindrical insulation has a diameter of 2-27 centimeters and a length of up to 1 meter. The thickness of mineral wool ranges from two to ten centimeters.
- Flammability of mineral wool … This indicator is one of the main advantages of the insulation as a whole. Mineral wool is a non-combustible type of thermal insulation. It is suitable for insulating surfaces with temperatures up to 650 degrees above zero. When heated, it does not emit toxic substances. Information regarding the flammability of the material is indicated on the product packaging. A1 is the highest fire safety class. An important parameter is the smoke-generating ability of the heat insulator. Mineral fibers practically do not emit smoke when burning. This quality corresponds to the indicator S1. In addition, the insulation does not crack under the influence of fire. This is indicated by the d0 icon.
Advantages of mineral wool
The advantages of mineral wool have determined its high popularity and demand in the market for thermal insulation materials. The following positive characteristics of mineral wool should be highlighted:
- High performance of thermal insulation … Mineral wool has one of the lowest thermal conductivity, which allows it to be used almost everywhere, regardless of climatic conditions. The material does not need additional insulation.
- Water tightness … High-quality glass wool and basalt wool perfectly let steam through and do not absorb water. Thanks to this, the building is reliably protected from the formation of moisture.
- Resistance to chemicals … High-quality mineral wool is not subject to destruction when it comes into contact with various alkalis and acids.
- Good air exchange … The insulation provides air circulation, the structure "breathes", which guarantees the formation of an optimal microclimate inside the room. At the same time, there is no need for additional ventilation devices. The risk of condensation is quite low.
- Good sound insulation … The special elastic structure of the mineral wool endowed it with acoustic properties. In a room insulated with this material, you will not hear sounds from the street.
- Fire resistance … In the event of a fire, rock wool will not support combustion and will not spread fire. In addition, the heat insulator does not emit smoke when in contact with fire.
- Long service life … The insulation is practical and durable. The average term of use is 25-50 years. Rodents do not damage the mineral wool, and microorganisms do not multiply in this material.
- Environmental friendliness of the material … For its manufacture, 100 times less energy resources are spent than they are saved during the period of operation. In addition, mineral wool from reliable manufacturers does not emit harmful compounds into the air, even when heated.
Also note that some varieties of mineral wool have good fiber strength and can withstand a strong static load. They are not subject to shrinkage and deformation. To a greater extent, these qualities relate to stone wool.
Disadvantages of mineral wool
As for the disadvantages of mineral wool, they are rather ambiguous. Modern manufacturers of high-quality insulation have practically brought to naught all the disadvantages that were originally inherent in the material.
In general, it is worth noting such shortcomings that companies for the production of mineral wool insulation are actively fighting:
- Loss of qualities when wet … By absorbing water, mineral wool largely loses its thermal insulation properties. When moistened by only 2%, the thermal conductivity of the material increases by 10%. To avoid this, manufacturers produce products that have been treated with special hydrophobic compounds. It is also recommended to use steam and waterproofing when installing insulation.
- High dust level … This disadvantage is especially noticeable when working with glass and slag. The fibers of these heaters are brittle, and their fragments are sharp and thin. Penetrating under clothing, they cause severe itching and skin damage. It is also extremely dangerous to breathe air that contains fiberglass particles. It is necessary to carry out installation work using these materials only in overalls, a respirator and goggles.
- Evaporation of phenol-formaldehyde resin vapors … Some builders and environmental organizations argue that mineral wool is hazardous to health, since the fumes used in the production of phenol-formaldehyde resin are carcinogenic. However, numerous studies of insulation show that the content of these toxic substances in the material is negligible, and therefore they cannot harm health. To date, this issue continues to be controversial.
Selection criteria for mineral wool
An excellent indicator of product quality is its compliance with GOST. Mineral wool slabs are manufactured in accordance with GOST 9573-96.
When choosing mineral wool, you must follow these recommendations:
- Check with your retailer or find the appropriate information on the packaging for which direction the fibers are going. If it is vertical, then the heat insulator will store heat better. If it is chaotic, the insulation is more durable, it is able to withstand heavy loads.
- Consider the scope of application of the mineral wool. If you plan to insulate the floor or roof, then you should not purchase mineral wool for facades. Otherwise, the material will quickly lose its thermal insulation qualities.
- Pay attention to the future loads to which the surface insulated with mineral wool will be exposed. If the mechanical pressure is high, then buy the plates with the highest density. In this way, you avoid compaction of the material and, consequently, a decrease in thermal insulation qualities.
- To insulate the roof from the inside, choose foil mineral wool. It will help reduce the loss of radiant heat. It is recommended to buy the same material for the insulation of chimneys.
- Check the thermal conductivity readings on the packaging. Some manufacturers provide incomplete information, underestimating the data. They do not indicate the temperature at which these values are valid. Remember, at different marks on the thermometer, the value of thermal conductivity will change. This applies to all types of insulation.
Price and manufacturers of mineral wool
The relatively low cost of this insulation also contributed to the growth of its popularity. Today there are several companies whose products have proven themselves in the construction market:
- Ursa … Produces specialized mineral wool - for roofs, facades, floating floors, as well as universal insulation. The density of the product is relatively low. The material can be found in slabs and rolls. The price of mineral wool from this brand ranges from 1 to 1, 2 thousand rubles per cubic meter.
- Isover … Another manufacturer that produces specialized products for different purposes. There are lines of universal insulation, facade, roofing, floor, suitable for plastering. Plates cost from 1, 4 thousand rubles. Rolled mineral wool - from 1 thousand rubles, cylinders - from 500 rubles per cubic meter.
- Knauf … The company specializes primarily in the production of materials for roof and wall insulation. At the same time, the density of the insulation is low. The line does not include mineral wool for facades with the possibility of subsequent plastering. The price is relatively high. A cubic meter of rolled material costs from 1, 3 thousand rubles. In plates - from 1, 4 thousand rubles.
- Rockwool … This mineral wool manufacturer offers absolutely the entire range of insulation - from universal to specialized. The cost of production is quite high. Plates cost from 1, 6 thousand rubles, rolls - 2, 8 thousand rubles, cylinders - 380 rubles per cubic meter.
Brief instructions for the installation of mineral wool
The installation technology of this insulation consists of three main stages: surface preparation, material installation and finishing work.
Let's briefly consider how to insulate the surface with mineral wool using the example of facades:
- We remove all extraneous elements from the surface: surveillance cameras, drain systems, non-functional parts, lighting devices.
- We remove old coatings - paint, plaster. If there are manifestations of mold or mildew, then we eliminate them.
- We prime the surface.
- For the installation of mineral wool, we use special glue, as well as dowels. If you do not use fasteners, then over time, the structure may simply collapse, since it is quite heavy.
- We fix the guide profiles with dowels, which will have to hold the thermal insulation layer.
- Apply a layer of glue to the seamy side of the mineral wool.
- We attach the material to the surface and fix it with dowels.
- Fastening of mineral wool is carried out by the type of brickwork. After creating the first row, align it in all directions until the glue hardens. Next, we begin to lay the second row.
- When the entire surface is covered with mineral wool, we carry out reinforcement. To do this, cover a layer of insulation with glue, put a reinforcing mesh on it and press it tightly.
- Cover the mesh with another layer of glue on top.
The final stage is finishing. It should be carried out only after all layers of glue have completely dried. Mineral wool can be painted, plastered, covered with siding. The main thing is that the finishing material does not contain acrylic. It allows air to pass through, and this contributes to the accumulation of moisture inside the mineral wool. This significantly reduces the life of the material.
Watch a video review of mineral wool insulation:
Mineral wool is a fibrous thermal insulation material that can be made from various inorganic substances. The insulation has a number of undeniable advantages, which, combined with its low cost, have made it very popular. Installation of mineral wool is quite simple and even a beginner can do it.
