Insulation of the attic with mineral wool

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Insulation of the attic with mineral wool
Insulation of the attic with mineral wool

Thermal insulation of the attic with mineral wool, the features of such insulation, its advantages and disadvantages, preparation for work and the technology for its implementation. Insulation of the attic with mineral wool is one of the ways to keep warm in the house. Starting the thermal insulation of premises at the stage of installation of walls and floors, many do not pay due attention to the insulation of the roof and the upper floor of the building. But in vain, because 20% of the heat energy goes through the attic space. You will learn how to properly insulate its enclosing structures by reading this material.

Features of thermal insulation of the attic with mineral wool

Insulation of the attic with mineral wool
Insulation of the attic with mineral wool

To insulate the attic with mineral wool, three types of it can be used - stone wool, glass and slag. Insulation of the latter type, due to its rather modest characteristics, is used very rarely. As for glass wool, this material causes great discomfort when working with it. Its small and sharp fibers, penetrating through clothing, cause itching and irritation of the skin. Therefore, it is possible to work with glass wool only in protective equipment, which include thick overalls, a respirator, goggles and gloves. The best indicators by absolutely all criteria are possessed by stone mineral wool, which we recommend for use.

Cotton wool of any type is produced in the form of slabs or roll insulation. The material grade in the form of a two-digit number printed on its packaging indicates the density of the product. The higher its value, the more constructive value the insulation has.

For roof slopes up to 45 °, wool with a density of 30 kg / m is suitable for insulation3, this is its average value. The thickness of the insulating layer and the rafters is usually the same and is about 200 mm. Mineral wool is placed in the space between the rafters, that is, the insulation must hold on its own without the help of sheets of filing. If the material falls out of its own weight, then its density is insufficient. Usually roofs with a slope of more than 45 ° are insulated with insulation with a density of more than 35-43 kg / m3.

The thermal insulation properties of mineral wool, when properly laid, allow you to keep the house warm in winter and cool in summer. The insulated attic can be used as a room, additional utility room or workshop. However, regardless of such an application, the insulation of its floor should be mandatory, since this structure will serve as the main obstacle for warm air tending upward from the room, according to the laws of physics.

Pros and cons of attic insulation with mineral wool

Mineral wool in mats
Mineral wool in mats

As thermal insulation, mineral wool is very popular among developers due to the benefits that can be obtained from using this material.

Advantages of mineral wool:

  • In terms of their thermal conductivity, 50 mm thick mineral wool slabs are equivalent to a meter-long brickwork.
  • Mineral insulation is quite resistant to moisture: when wet, it absorbs less than 0.5% of its own volume of liquid.
  • The structure of the insulation with a chaotic arrangement of its fibers makes mineral wool capable of absorbing sounds - this property is indispensable for residential and office premises.
  • Thermal insulation with mineral wool prevents the spread of fire in a fire due to the fact that this insulation does not burn from exposure to an open flame.
  • The composition of raw materials for the production of mineral wool provides thermal insulation with durability, calculated with a minimum service life of the finished coating of 50 years.
  • Due to the minimal shrinkage of the insulation and resistance to mechanical stress, it can be used in multi-layer insulating structures.
  • The biological resistance of mineral wool ensures the absence of mold and small rodents in the thermal insulation made of this material.
  • The property of the material to pass steam contributes to the absence of moisture accumulation in the room and its free ventilation.
  • Mineral wool is easy to work with, lift to the attic and transport due to its low weight.

The disadvantage of thermal insulation with mineral wool in the attic can be called a property inherent in any insulation - an increase in thermal conductivity when wet. In order to eliminate it, manufacturers process such products with hydrophobic compounds that are absolutely safe for health. In addition, to prevent the insulation from getting wet, it is recommended to use steam and waterproofing during its installation.

Preparatory work

Preparing the attic space
Preparing the attic space

When insulating the attic space, careful preparation for this process is necessary. This is especially true for an old house. First of all, you need to carefully inspect the attic for the safety of the floor, the presence or absence of cracks on the gables and roof rafters. It is possible that some of the beams will need to be replaced.

First you need to remove the old floor covering, usually chipboard or plywood. If it sticks to nails, you can use a special crowbar to remove them, if on screws - a screwdriver.

It is recommended to carefully dismantle sheets that are still in good condition. In the future, the whole material will come in handy for finishing. After completing this work, you need to clean the sub-floor of debris, which can be quite a lot.

After cleaning, the floor beams will be accessible. It is necessary to assess their condition. If cracks or decay are present, the beams should be replaced as they bear the bulk of the floor load. When installing new beams, it is recommended to take a step between them taking into account the width of the insulation sheet. This will greatly facilitate its installation in the future.

The timber floor must not have gaps in the subfloor. If there is such a defect, it can be eliminated with polyurethane foam. After filling all the holes, the surplus of solidified material should be carefully cut off with a knife.

When the repair of the floor is completed, all its wooden elements should be treated with an antiseptic, a primer, and then an inexpensive varnish to create a protective layer on the structures.

Before insulating the attic, all roofing work must be completed. The gables and slopes of the roof must be insulated after the floor is insulated.

Important! It is recommended to insulate the attic of a new wooden house no earlier than six months from the date of completion of construction. This is due to the shrinkage of the log house, which can last for quite a long time, up to a year or even more. This process can be accompanied by natural deformation of structures associated with the properties of wood. Upon its completion, the identified defects must be eliminated before insulation.

Attic insulation technology with mineral wool

Thermal insulation of the attic includes insulation of the upper floor, roof and gables. These works should be carried out in stages in the order indicated. Before insulating the attic of a house with mineral wool, you need to prepare: plywood or edged boards, waterproofing and vapor barrier film, insulation, overalls, goggles, gloves, knife, spatula, tape measure, tape and a construction stapler. After that, you can proceed to the main stage of work.

Thermal insulation of the ceiling with mineral wool

Thermal insulation of floors with mineral wool
Thermal insulation of floors with mineral wool

It provides for the use of two technologies - insulation of the floor from the side of the living quarters and from the side of the attic. Ideally, it is best to apply them at the same time. This will help to achieve the highest quality result.

Thermal insulation of the floor from the inside of the room is performed at the stage of the false ceiling installation. In this case, the insulation is laid in its structure. Exterior trim made of plasterboard or other sheet material perfectly masks mineral wool, but at the same time part of the height of the ceiling is lost due to the thickness of its "pie". With this type of insulation, it is recommended to use reflective mineral wool insulation and lay it between the elements of the ceiling lathing with a foil layer down. Despite its small thickness, it can retain up to 70% of the heat in the house. In addition, the outer layer of the suspended ceiling itself serves as a kind of barrier in the path of the heated air leaving upward.

For thermal insulation of the ceiling from the side of the attic, the range of possibilities is much wider. In addition to foil insulation, here you can use any materials that can retain heat: expanded clay, polystyrene and many others. However, for the full use of the attic and the installation of the floor on it, the best option would be to lay mineral wool under the flooring as a heater that does not interfere with the exchange of moisture between the structures of the house.

The method of installing mineral insulation depends on the type of floor. The difference between installing thermal insulation on a reinforced concrete or timber floor is that in the latter case, the mineral wool must be placed between the load-bearing beams. The isolation device process is as follows.

First, for the convenience of moving along the floor, you need to lay wooden boards or thick plywood on its beams. The next stage is the installation of the vapor barrier material on the subfloor. This film is single acting. It must be laid so that air flows freely through the insulation layer from the living quarters to the attic. The sheets of the film should be laid with an overlap, and their edges should be placed on the walls. The joints of the canvases must be sealed with tape along their entire length.

After installing the vapor barrier film, you can proceed directly to the insulation of the floor. Roll out a roll of mineral wool should be started from the outermost side of the floor. The insulation is easily cut with a knife, but for this it is advisable to put a wooden board under the material.

After laying the first strip of insulation, the second should be placed side by side, and roll out the roll from the end of the first strip and ending with the far point of overlap. When joining the sheets of insulation, the gaps between them are not allowed.

If there are any obstacles such as a chimney, the insulation strip should be cut off, and in its continuation, cut a hole along the contour of the part protruding from the floor and put in its place. All cavities and cracks, which are often formed in this case, can be sealed with scraps of insulation.

The outlets of the electrical wiring of the lamps from the lower room to the ceiling should be protected with insulation before installing the insulation. This is especially true for wooden floors, which, unlike mineral wool, burn.

After installing the insulation on the floor of the attic, it must be covered with plastic wrap to protect it from moisture that can penetrate into the material from the roof of the house. The film should also be overlapped and sealed at the joints.

When the waterproofing is ready, the insulation can be covered with plywood or plank flooring, which should be screwed to the wooden floor joists. A ventilation gap of 30-50 mm should be left between the insulation and the inside of the finished floor.

Roof insulation with mineral wool

Roof insulation with mineral wool
Roof insulation with mineral wool

When performing thermal insulation of the attic under the roof, it is necessary to use the basic rule: the insulation should be protected from moisture only from the inside, air is needed outside, that is, the ventilation gap. It helps to remove moisture from mineral wool, thus maintaining its insulating properties.

However, from the side of the street, the insulation must be closed from precipitation, wind and at the same time organize an outlet for water vapor in its direction. For this purpose, a special diffusion membrane is used, which must be placed between the roof rafters and the roof covering before thermal insulation. It will protect the insulation from direct moisture penetration, while simultaneously letting water vapor into the air, from which moving air will carry them away. The ventilation gap must be arranged under the roof covering throughout its entire area.

The sheets of diffusion film must be placed horizontally on the top of the rafters. You should start working from their bottom. When laying, the edges of the membranes should overlap each other by 100 mm. Their joints must be sealed with tape. Fastening the film to the side of the rafters should be done using a construction stapler.

After completing this procedure, you can start working with mineral wool. Insulation must be laid between the rafter boards. To do this, first it needs to be cut into strips, the width of each of which will be 2 cm more than the laying gap. Such installation does not require additional fixing of the insulation. It should be noted that, adapting to the standard pitch of wooden rafters, mineral wool manufacturers produce slabs with a width of 0.6 m, and rolls - 1.2 m.

After completing the thermal insulation, the insulation should be covered with a vapor barrier film and the internal finishing of the roof slopes should be done.

Warming with mineral wool gables

Mineral wool Isover
Mineral wool Isover

The insulation scheme of the gables may vary depending on the material from which they are made. So, for example, it is more expedient to insulate brick gables from the outside, given the location of the "dew point".

In general, the gables are insulated using the same technology as the walls of the building from the inside. That is, first it is necessary to make a frame on the pediment from a galvanized profile or a wooden bar. After that, mineral wool should be placed in its cells and protected with a vapor barrier film.

You need to complete the work by covering the frame with a suitable sheet material. If you use double cladding, for example, from OSB and moisture-resistant plasterboard sheets, the attic can be completely deprived of drafts, make it warm enough for living or economic activity.

How to insulate an attic with mineral wool - watch the video:

To qualitatively insulate the attic with mineral wool means not only to save on heating the house, but also to give the room under the roof a new purpose. Good luck!

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