How to cut stone wool insulation

Knife with stainless steel blade

A long-blade insulation cutting knife made of durable stainless steel is suitable for working with mineral wool of any thickness. To cut the insulation of different stiffness, larger and smaller teeth are located on each side. Such a blade easily enters the thickness of the slab, allowing even curly cuts to be made thanks to the sharp tip.

Operational features of basalt wool

Mineral wool has the following advantages:

  • a wide range of products. Mineral wool is produced in the form of plates, rolls or mats. Due to this, it is possible to choose the option that is best suited for the thermal insulation of a certain section of the building. Also, the types of mineral wool differ in density: the material in the form of slabs has a high density, and the roll insulation is lighter;
  • has high thermal insulation characteristics. Mineral wool has a porous structure. This material is made up of small layers. Due to this, it retains heat well, and also provides excellent sound insulation;
  • fire safety of the material. Minvata does not burn and does not spread fire. For this reason, it is often used for thermal insulation of interfloor ceilings. Mineral wool manufacturers claim that this material can withstand temperatures above 900 degrees Celsius;
  • mineral wool does not deform, and this is a very important advantage. This material does not shrink, therefore, there is no formation of “cold bridges” that cause heat loss;
  • frost resistance. This property allows the use of mineral wool for thermal insulation of external elements of the building;
  • mineral wool is an environmentally friendly material. It is used for thermal insulation of health resorts and medical institutions, as well as children’s rooms.

This insulation is produced in various forms. plates, cylinders, mats; you can buy cotton wool covered with foil.

Mineral wool has features that cannot be called positive. These include:

  • low strength. This is due to the high porosity of mineral wool;
  • to ensure a high level of thermal insulation, this material should be used together with a waterproofing film and a vapor barrier membrane;
  • when using mineral wool with fiberglass, it becomes unsafe, since formaldehyde is added to it;
  • high hygroscopicity (therefore high waterproofing is done).

To fasten such insulation, planks are nailed to the inner side of the rafters (they make a lattice), to which cotton wool will be attached. From the outside, the cotton wool is laid in one layer (the layers depend on the thickness of the cotton wool).

After laying the insulation, waterproofing is applied. The important thing in this step is not to confuse the sides of the insulation. The upper layer is moisture-tight, and the lower layer is an obstacle to steam.

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The waterproofing is not stretched, there is an air space between it and the cotton wool. There should be some air space in front of the skate, which will create additional traction.

Basalt insulation scheme.

  • thermal insulation and hydrophobization. The first parameter ranges from 0.042 to 0.048 W / mK. Other well-known insulation materials (for example, expanded polystyrene, polyurethane foam) have approximately the same characteristics. Mineral wool is not able to accumulate moisture (hygroscopicity is less than 1%), which makes its weight unchanged. A distinctive feature can be called vapor permeability, which guarantees insulation and, at the same time, intensive moisture exchange between the external environment and the walls of the building;
  • density, strength. The insulation has a sufficient density (from 30 to 100 kg / m3), which guarantees high thermal insulation properties with optimal strength. The rigidity of the material is ensured by the direction of the fibers; they are located horizontally and vertically;
  • soundproofing. Good noise protection characteristics are achieved due to the porous structure of the cotton wool;
  • resistance to aggressive environment. Vata is “indifferent” to alkali, acids; does not rot, is not affected by the fungus. Rodents also bypass this insulation side;
  • fire resistance. Basalt wool is able to withstand heating up to 700 ° C. This protects the structure from complete destruction in the event of a fire and gives time for the evacuation of residents;
  • health safety. In the production, resins containing harmful substances (formaldehyde, phenol) are used. However, compliance with the technology involves their introduction into the composition of the insulation in a chemically bound state. Substances become completely neutral in relation to the environment and do not pose a danger to humans.

Material strength

Basalt fibers are randomly arranged inside the material, and some of them go in the vertical direction. Thanks to this, even not very dense stone wool is able to withstand considerable loads.

So, at 10% deformation, basalt wool has a compressive strength of 5 to 80 kilopascals. The specific value of this indicator depends on the density inherent in a given grade of material.

Such strength characteristics of basalt wool guarantee that the heat insulator will serve for a long time without changing its shape and size for the entire period of use.

Basalt wool fibers.

Stone wool is chemically passive. this is its undoubted advantage. If it is laid close to a metal surface, then you can be one hundred percent sure that rust will not appear on the metal. And basalt insulation treats aggressive biological media quite calmly.

It is not characterized by decay or damage by mold and other harmful microorganisms. It steadfastly withstands the invasion of the house by rats and mice. after all, these rodents cannot handle cotton wool from a stone.

High resistance to aggressive substances allows the use of this insulation for the insulation of many technical structures that operate in difficult conditions.

Indeed, it cannot stand out from basalt wool, since it is completely neutralized even during the production of the material. However, at the stage of manufacturing this mineral insulation, phenolic fumes are extremely small. much less than the permissible limit of 0.05 milligrams per m2 / hour.

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Unlike glass wool fibers, basalt fibers do not irritate the skin, do not prick and do not cause allergies.

Today on the construction market there are a large number of grades of stone wool of various densities, the technical characteristics of which are somewhat different from each other.

But all types of basalt insulation are distinguished by their strength and long service life.

This insulation can be used in almost all building structures. They can insulate both the roof of any shape and walls, partitions, ceilings.

Mineral wool is one of the best, simplest and most common materials for insulation and sound insulation of walls and ceilings today, and is also known in several other fields of application. In addition, it is easy to mount, that is, you can independently insulate the premises.

Many people do not know how to cut mineral wool correctly without violating its structure, in this material we will consider all the ways to properly cut mineral wool, as well as advise the tools that are best suited for this.

Mineral wool is usually classified according to the principle of the material from which it is made. Hence it follows that the mineral wool made from different raw materials also differs in structure. fibers, and, accordingly, in the type of cutting. So there are the following types of mineral wool:

  • Glass mineral wool. Consists of glass melts.
  • Stone mineral wool. It is most often made from various rock melts.
  • Slag mineral wool. Raw material. blast furnace slag.

In fact, you should pay attention to the fact that sometimes mineral wool is harmful. This is due to the fact that it contains dust and phenol-formaldehyde resins. Therefore, it is necessary to treat this material selectively, although mineral wool cannot be classified as carcinogens for humans.

Cutting of mineral wool can be carried out both independently at home and using various equipment. The equipment for cutting mineral wool boards can be different. The question is scale. The rock wool cutting machine is suitable for large and large scale enterprises, manufacturers, etc. But a knife for cutting mineral wool will become an indispensable assistant in cutting insulating materials at home.

It is important that the cutting of mineral wool does not damage the fibers, so equipment must be selected carefully. The cut must be straight.

It is important that the work is done properly. Circular cutting of mineral wool can be convenient. The rock wool cutting machine can handle this task with ease.

If you do not know how to cut mineral wool at home, we can advise you on excellent tools that are best suited for cutting mineral wool.

So, for cutting mineral wool, a good, sharp stationery knife or a hacksaw for metal is best suited, carefully trim the mineral wool in the right directions, for greater accuracy you can draw a mowing line with a pencil or cut straight along a ruler. The process of cutting mineral wool is somewhat similar to cutting paralon, only you need to apply a little more effort, pressing a little harder on the tool for cutting mineral wool.

Cross cut material

For cross-cutting, the rock wool roll is unpacked. Make markings on both sides. Then a flat bar is applied: a ruler, a piece of profile or a bar.

A knife or hacksaw is carried out along the bar. If it did not work to cut off the insulation in one motion, the cut is repeated several times. The material is cut to the end so that it does not have to be torn off, in this case the geometry will be violated. We’ll have to equalize the insulation.

Important. When the insulation is cut, they put a board so that the knife does not blunt.

Features of installation of mineral wool insulation

Before installing mineral wool, you must do the following:

  • check the rafter structure. If rotten elements are present, then they must be replaced;
  • treat the roof with antiseptics;
  • check communication systems: water supply and electricity;
  • the pitched roof is best insulated with material in the form of slabs or rolls, since they fit well on the crate.

There must be a ventilation space between the mineral wool layer and the roofing material. When insulating a pitched roof in a private house, not only thermal insulation is provided, but also noise insulation.

Inexperienced specialists often make the following mistakes:

  • do not use a heat insulator whose width is less than the distance between the rafter legs. In this case, heat loss will occur through the slots;
  • do not insulate the roof with material with a high level of moisture. This will cause rotting of the wooden elements of the rafter frame;
  • if you do not install a hydro and vapor barrier, then the thermal insulation system will not work properly, moreover, its service life will be significantly reduced.

For example: MORA knife for cutting mineral wool

stone, wool, insulation

The Swedish company MORA produces tools for cutting mineral insulation. A knife with a stainless steel blade is used for cutting stone and glass mineral wool. The blade is made of special cold rolled stainless steel and has a serrated edge. The ergonomic and comfortable plastic handle is suitable for use with gloves. Its characteristics:

  • total length. 500 mm;
  • blade length. 335 mm;
  • blade thickness. 1 mm;
  • weight. 0.238 kg.

A knife with a blade made of carbon steel is used for cutting various types of mineral insulation. Has a smooth, made of high quality carbon steel blade with a length of 350 mm. Plastic handle provides a good grip when wearing work gloves.

Recommendations on how to work with insulation

Insulation of the attic space is an effective way to reduce body losses as a result, the house needs to be heated less, which means that you can save on electricity. Mineral wool insulation is a versatile high performance option for thermal and acoustic performance as well as fire resistance.

Insulation consists of fibers. When working with material, a large number of harmful particles are emitted into the air. Fine dust is harmful to human breathing and skin. Therefore, when working with it, take precautions.

What rules need to be followed:

  • work in a well-ventilated area.
  • use personal protective equipment for work: mask, goggles, respirator.
  • work in overalls: well-buttoned overalls, headwear, construction gloves.
  • after work, hands and face are thoroughly washed under cold water. Overalls are shaken out of dust.

Which cotton is better?

There is no unequivocal answer to this question, since in different conditions the material of different types will be the best option.

Basalt soft wool. It is used where high loads are not expected. This material can be used to insulate walls made using frame technology, as well as for thermal insulation of floors and roofs. The fact that cotton wool is soft does not mean at all that its performance is poor. They simply make it from thin fibers, which ensures the presence of many cavities in the insulation, in which air is retained, which prevents heat loss.

Mineral wool of medium hardness (density). It is used mainly for warming ventilated facades, where high-speed air flows are created in the air cavities. It is also used for fire-prevention measures, sound and heat insulation of ventilation channels. Medium density mineral wool can be installed without problems instead of soft basalt wool, but the cost of thermal insulation will be more expensive.

Rigid basalt wool. This insulation is used in places where high loads are possible on it. For example, where it is planned to insulate walls with reinforcement and plastering (wet method) or when creating certain types of floors.

Cylindrical pipe heaters. Usually they are produced with a diameter of more than 50 mm. They are slotted parts that can be expanded and slid onto the pipe, or two-part models that are connected on the pipe.

Foil basalt wool. This insulating material is characterized not only by low heat transfer, but also reflects heat, directing it inside the premises. Mineral wool can be covered with foil on one or both sides. When laying, the heat insulator is installed with the foil side to the heat source. The scope of this insulation is quite extensive, it is considered a universal material suitable for all methods and types of thermal insulation.

Sewing cotton wool. It is a very strong mats, one side of which is sheathed / reinforced with steel mesh (galvanized, stainless, fire-resistant, acid-resistant). The canvases can be of various thicknesses and can be used to perform various types of thermal insulation. Stitched cotton wool is usually non-combustible, therefore it can be used to insulate surfaces with elevated temperatures (up to plus 660-700 degrees).

An important technical characteristic of mineral wool is its specific density. Insulation, the density of which is up to 75 kg per cubic meter, is ideal for thermal insulation of planes where the impact of heavy loads is not expected, for example, for laying in ceilings in attics and roofs. Basalt wool of low density is often used for wrapping pipes of heating plants, boilers and similar nodes / communications.

Stone wool, the density of which is up to 125 kg per cubic meter, keeps its shape well and is great for insulating ceilings, walls inside buildings, and various vertical structures. It is used for thermal insulation of brick walls, as well as foam block or aerated concrete surfaces. Mineral wool of this specific density allows not only to insulate the building, but also to ensure its reliable sound insulation.

Basalt wool of high density. from 175 to 200 kg per cubic meter, is characterized, in addition, by increased rigidity, hence the abbreviation in its name (PPZh). Such insulation is used for thermal insulation of initially too cold planes. reinforced concrete, sheet metal. The PPZh-200 brand is also excellent for arranging additional protection of residential buildings from fire. Only high density mineral wool can be installed using the technology of facade insulation with a wet method.

Is it true that mineral wool needs to be protected from moisture and wind?

During the operation of insulated buildings, their walls, roof and other structures should be protected from high atmospheric humidity and from being blown by strong winds. Therefore, after installation, the mineral wool insulation from the outside is covered with canvases made of a vapor-permeable moisture and windproof membrane. This allows you to prevent the penetration of cold wind and oblique rain drops into the thickness of the wall. At the same time, water vapor from the inner space, through diffusion passing through the walls, will be able to escape outside without obstacles.

The undoubted advantage of mineral wool is its vapor permeability, and this property should be used to the maximum. When installing mineral wool heat-insulating materials between the bearing wall and the insulation, it is not necessary to lay a vapor barrier, since such sealing will negatively affect the climate inside the building. The lack of artificial ventilation in this case will lead to an increase in humidity and the formation of condensation, which, in turn, will cause the formation of mold and mildew.

A vapor barrier film must be used when installing thermal insulation indoors. in this case, it is installed on the warm side of the mineral wool. This allows you to protect the insulation from water vapor from the premises. Reinforced polyethylene can be used as a vapor barrier, which is placed between the insulation and the cladding.

If the design allows, it is imperative to provide a ventilated air gap between the insulation and the external finish. This will help keep the rockwool dry without compromising the vapor permeability of the building.

What to do if you need to use cotton wool with a layer of 15 or 20 cm, and the insulation is supplied with a thickness of 5 or 10 cm?

There is nothing complicated here. You need to calculate the required thickness using the formulas or using an online calculator (we talked about this in the last article), and then you can easily type an insulating barrier from several layers. In addition, this method allows you to easily eliminate the problem of the formation of cold bridges and blowing out joints. To do this, when installing insulation, the sheets of the outer and inner layers should be shifted relative to each other by 20-30 mm in order to reliably overlap the seams.

It is important to create a safe working environment

This is really important. As in any business, adherence to simple safety procedures will help maintain health, carry out work at the optimal time and at a high quality level. What you need to pay attention to:

  • it is better to cut the insulation in cold weather, since for work it is necessary to wear a protective suit made of dense fabric, which will prevent skin contact with mineral wool fibers and its irritation;
  • to protect hands, wear special gloves. with silicone or rubber dusting on the palms;
  • you will need special glasses to protect your eyes;
  • respiratory organs will be protected by a respirator.

Such measures must be observed, since when the insulation is cut from under the knives, material particles rise into the air. May come in contact with the eyes, respiratory tract, and cause skin irritation.

In addition, it is important to remember:

  • when working with this type of insulation, you need to periodically take a break, during which you need to ventilate the room;
  • the cut pieces must be shifted carefully, without throwing, in order to reduce the amount of fibrous suspension in the air;
  • there should be no children on the construction site at this time, even in protective equipment.

As you can see from the above, there is nothing super complicated in cutting mineral wool. Subject to the indicated rules, it will not be difficult to perform work efficiently and safely.

Mineral wool has the following advantages:

  • a wide range of products. Mineral wool is produced in the form of plates, rolls or mats. Due to this, it is possible to choose the option that is best suited for the thermal insulation of a certain section of the building. Also, the types of mineral wool differ in density: the material in the form of slabs has a high density, and the roll insulation is lighter;
  • has high thermal insulation characteristics. Mineral wool has a porous structure. This material is made up of small layers. Due to this, it retains heat well, and also provides excellent sound insulation;
  • fire safety of the material. Minvata does not burn and does not spread fire. For this reason, it is often used for thermal insulation of interfloor ceilings. Mineral wool manufacturers claim that this material can withstand temperatures above 900 degrees Celsius;
  • mineral wool does not deform, and this is a very important advantage. This material does not shrink, therefore, there is no formation of “cold bridges” that cause heat loss;
  • frost resistance. This property allows the use of mineral wool for thermal insulation of external elements of the building;
  • mineral wool is an environmentally friendly material. It is used for thermal insulation of health resorts and medical institutions, as well as children’s rooms.

This insulation is produced in various forms. plates, cylinders, mats; you can buy cotton wool covered with foil.

Mineral wool has features that cannot be called positive. These include:

  • low strength. This is due to the high porosity of mineral wool;
  • to ensure a high level of thermal insulation, this material should be used together with a waterproofing film and a vapor barrier membrane;
  • when using mineral wool with fiberglass, it becomes unsafe, since formaldehyde is added to it;
  • high hygroscopicity (therefore high waterproofing is done).

Working with Mineral Wool

To fasten such insulation, planks are nailed to the inner side of the rafters (they make a lattice), to which cotton wool will be attached. From the outside, the cotton wool is laid in one layer (the layers depend on the thickness of the cotton wool).

After laying the insulation, waterproofing is applied. The important thing in this step is not to confuse the sides of the insulation. The upper layer is moisture-tight, and the lower layer is an obstacle to steam.

The waterproofing is not stretched, there is an air space between it and the cotton wool. There should be some air space in front of the skate, which will create additional traction.

Basalt insulation scheme.

  • thermal insulation and hydrophobization. The first parameter ranges from 0.042 to 0.048 W / mK. Other well-known insulation materials (for example, expanded polystyrene, polyurethane foam) have approximately the same characteristics. Mineral wool is not able to accumulate moisture (hygroscopicity is less than 1%), which makes its weight unchanged. A distinctive feature can be called vapor permeability, which guarantees insulation and, at the same time, intensive moisture exchange between the external environment and the walls of the building;
  • density, strength. The insulation has a sufficient density (from 30 to 100 kg / m3), which guarantees high thermal insulation properties with optimal strength. The rigidity of the material is ensured by the direction of the fibers; they are located horizontally and vertically;
  • soundproofing. Good noise protection characteristics are achieved due to the porous structure of the cotton wool;
  • resistance to aggressive environment. Vata is “indifferent” to alkali, acids; does not rot, is not affected by the fungus. Rodents also bypass this insulation side;
  • fire resistance. Basalt wool is able to withstand heating up to 700 ° C. This protects the structure from complete destruction in the event of a fire and gives time for the evacuation of residents;
  • health safety. In the production, resins containing harmful substances (formaldehyde, phenol) are used. However, compliance with the technology involves their introduction into the composition of the insulation in a chemically bound state. Substances become completely neutral in relation to the environment and do not pose a danger to humans.

Do I have to use protective equipment? What kind?

Mineral wool is considered a safe heat-insulating material, both during operation and during installation. However, with long-term work with this insulation, it is better to protect yourself using personal protective equipment.

Stone wool, in comparison with glass wool, is much more convenient and safer to work with, but you should still be careful when installing it. It is best to work on cold days in an overalls made of dense fabric that covers the whole body from contact with mineral wool. It is not recommended to touch this material with bare hands; to protect them, you can use “glazier’s gloves”. fabric with rubber or silicone dusting in the palm area. It is also imperative to protect the eyes and scalp. Wear a respirator to protect the respiratory system.

During the installation of stone wool, you should take a break to ventilate the room. Open packs of material must be shifted carefully, not allowing them to fall, so that microparticles do not stand out from them. There should be no children on the construction site during the installation of thermal insulation, as well as those who do not use personal protective equipment.

How to cut a mineral wool slab: an overview of knives and saws

Mineral wool is an artificial building material that is made for heat and sound insulation of residential buildings and industrial premises. The material is not afraid of fire, resistant to various weather conditions. For convenience, they are produced in rolls and mats. It is not enough to purchase insulation, it is also important to know how to work with it, this will be discussed below.

  • 1 Recommendations on how to work with insulation
  • 2 How to cut mineral wool in a roll
  • 3 How to cut insulation

The better to cut mineral wool?

Today, a method has been developed for obtaining a special type of insulation. stone wool made from basalt. Twenty years ago, this mineral wool was used exclusively for the needs of the defense industry, and today this insulation is widely used for thermal insulation of any buildings.

The composition of mineral wool does not contain such environmentally harmful components as acrylic and phenol-formaldehyde resins. It consists only of natural binders, therefore it is safe for humans. This heat-insulating material not only perfectly retains heat, but also allows you to create reliable sound insulation of premises. Basalt mineral wool is becoming more and more popular and has already been tested by time, but people still have a lot of questions regarding technological issues, which we will try to focus on in this article.

Correct material handling

Since the material is porous, brittle and hygroscopic, it must be handled appropriately.

When transporting and storing mineral wool, it is recommended to observe the following rules:

  • In the process of loading and unloading, do not throw packages, but stack them neatly, avoiding them falling and strong squeezing.
  • Transport bales in covered trucks, laying them horizontally on a flat bottom. Fix the insulation so that it does not hit the body walls.
  • Store products in dry, closed rooms. If this is not possible and it is stored outside, cover with a film or tarpaulin to protect it from precipitation.
  • Remove the slabs from the stack just before laying them. This will prevent moisture absorption and reduce the risk of accidental damage to the material.

The technology of insulation involves the installation of plates with spikes, with a compression of 1-2 cm on each side. Based on this, you need to cut the mineral wool with an error in size of no more than 0.5 cm.

Terms of use

Before starting work, it is imperative that you familiarize yourself with the manual for using the knife and ensure the safety of the installation in order to prevent both gross and minor mistakes and harm to your health. There are several basic rules.

Insulation should be cut at low ambient temperatures. in order to safely start cutting mineral wool, you will have to put on a special durable suit that will prevent skin contact with toxic material and its irritation.

Cover your hands with rubber or silicone coated gloves to protect your hands from cuts and abrasions during careless cutting.

The respiratory organs must be covered with a strong respirator, and the eyes must be protected with the help of special professional glasses, since glass particles of foam or mineral wool can get into the respiratory tract or into the mucous membrane of the eyes.

During the installation process, it is necessary to take short breaks and open windows to ventilate the room. If possible, it is best to work immediately in a well-ventilated room.

So that the heat-insulating material does not break off and particles fly off less from it, the cutting tool must necessarily be technically sound and well sharpened. To reduce the amount of dust in the air, the insulation should be cut along the location of the fibers.

In the process of cutting, you need to count on the remainder of a small layer about 2 cm long in order to ensure a tight overlap of the space to be insulated.

Mineral wool lends itself better to cutting before unfolding.

Mineral wool panels should be removed from the packaging box and cut one at a time so as not to accidentally damage its shape when transferring material from one place to another and when placing them on top of each other.

Already cut pieces of insulation cannot be simply thrown onto the floor or onto another piece, since a huge amount of foam fibers will immediately begin to rise into the air. The material should be handled with great care.

In addition, when carrying out installation work on your own, the best option would be to consult with specialists, since you may have to cut pieces of complex shape. Professional advice will help you avoid unnecessary waste of material. Manufacturers also advise you to start cutting the cotton wool before unrolling the roll, and to ensure even and accurate cuts, you must mark the material in advance with a ruler.

Residual insulation material does not have to be thrown away. They will remain suitable for insulating storerooms, garages, sheds or other utility rooms. Plus, they can be recycled and sold at low cost for later use.

At the end of the work, it is recommended to thoroughly wash your face and hands with soap and cool water.

For more information about knives for cutting insulation, see the video below.