Insulation of the attic from the inside, if the roof is already covered: the choice of material and the order of work

Attics are most often equipped to provide additional living space. At the same time, it is not necessary to live in the attic - all work on the insulation of the upper room is carried out with the expectation of high-quality thermal insulation of the house in order to save energy. In addition, being in a warm attic is much more comfortable than in a non-insulated room.

A residential attic is no longer a rare phenomenon in the construction of a private house with two floors. More and more attention is paid to the functional qualities of each centimeter of the attic area. Therefore, it is important to carry out repairs or make a project of the house in such a way that, if necessary, it would be possible to use separate premises, make them functional and more suitable for living. In order to feel warm and cozy under the roof at any time of the year, insulation work is carried out taking into account the peculiarities of the attic. For example, special insulation is important when the roof is already covered.

There are certain standards for carrying out such work from the inside in the attic under the finished roof. It is worth considering that the attic as such is not equivalent to the attic space. The attic always has a characteristic slope, and the highest point of height is usually at a level of 2.5 m. Different materials can be used for thermal insulation of such a room. The most common ones are mineral wool and foam. When carrying out work on the attic insulation, it is necessary to take into account what the room will look like in appearance, whether it will not lose "extra" meters.

For high-quality insulation of the attic from the inside, if the roof is already covered, the correct technology is important. So, when insulating walls and ceilings, one or another method of performing work is used. For example, a multi-layer structure is used to insulate the roof of an attic (for example, a 5-layer screed with foam glue).

All work on the interior decoration of the attic for the purpose of insulation is carried out in five stages.

• The roof is insulated, the rafter system is processed. Rafters made of wooden beams can be seen under the roofs of houses built according to old construction technologies. Usually the roof of such houses is covered with tiles or slate. The materials have a very high thermal conductivity. In such cases, they say that the roof is simply protected from wind and external weather influences.

• Waterproofing quality Is another important criterion for ensuring the reliability of the roofing structure as a whole. Waterproofing is a must in the attic. For this purpose, membrane films are usually used, which can pass steam, but do not pass moisture. In old houses, instead of a special film, you can often see a simple roofing material with similar properties. The main feature of insulating materials is optimal protection of the roof at the joints, preventing moisture from entering the heat-insulating material. Waterproofing coatings today are characterized by vapor permeability.
• Insulating materials. Of modern means, those are used that are characterized by low thermal conductivity. Insulation parameters between 0.03-0.04 Vi / mk in quality and durability are comparable to reinforced foam.Minvata or extruded polystyrene foam (penoplex, penoizol) are also actively used to insulate the attic from the inside. In terms of efficiency, penoplex is rated higher than others, but it costs more. The selected materials must meet the main requirements - to provide heat exchange in winter, to protect against overheating in summer.

• Vapor barrier materials. Usually we are talking about a membrane film that will help preserve the original properties of the insulation. The material should not provoke the formation of condensation, which is a disaster for thermal insulation materials.
• Decorative properties. The insulated attic must meet the design requirements of the room, correspond to the general concept of the design of the house. That is why so much attention is paid to the cladding. Plasterboard, OSB boards or other types of materials that can be laid on the ceiling, walls, and attic floor are often used as decorative finishes.

The reliability of the house is also determined by the roof structure. The roof can be gable, broken, differ in slope. Due to the design features of the attic, it is possible to obtain additional usable area. To do this, it is necessary to competently dispose of the attic space of the house, especially for low-rise buildings. An important role in this case is given to the characteristics of the roof. Traditionally, pentagonal gable structures with a slope of different sizes were suitable for organizing an attic room. A convex kink on such roofs was formed due to the difference in slopes.

Externally, you can evaluate the shape of the attic structure by several parameters.

By slope and roof configuration:

• a triangular roof with a multilevel slope of the lower and upper parts in the form of a gable structure without kinks;
• pentagonal variations on the theme of a roof with slopes on convex corners (two docked parts are clearly visible in the structure).

Attic roofs have a multi-tiered rafter system. In the lower tier there is a usable area with a height of 2-2.5 m (a diagram is being prepared in advance). Height parameters are indicated for ease of movement inside. The second tier is the shape of the top of the roof, which can have an arbitrary height. Although here you can experiment with the height to get the optimal comfortable roof shape. In this aspect, it is more advantageous to use a pentagonal attic, in which the corners seem to go along an imaginary circle. It is worth considering that the attic can be equipped not only with a gable roof. Using basic technologies, it is possible to arrange and insulate the attic in single-pitched or hipped roof structures.

The main technologies for the device of a pitched roof, known today.

• Inclined. The lower tier of the attic is being built, then the upper part is being equipped.
• Hanging. Depending on the technical features of the roof structure, the upper part is equipped. With a schematic section of the attic roof, you can see that at the bottom it looks like a trapezoid, and at the top it looks like a triangle.

If you do not need to do anything with the shape of the attic, then you can proceed directly to work on the insulation of the room from the inside, choosing a suitable high-quality material.

When choosing the best insulating material for the attic, one should take into account the main characteristics of the material, its valuable properties, the pros and cons for a particular structure.

As the main criteria for the selection of insulation, the following should be highlighted:

• good thermal insulation (for example, foil-clad material, insulation with mineral wool, expanded polystyrene, basalt material);
• economical use (rational insulation);

• strength and durability;
• moisture-repellent properties;
• soundproofing;
• ease of styling.

The best qualities are those of the insulation, which has a lower thermal conductivity coefficient. For example, less than 0.04 W / mS. This is taking into account the thickness of the material and climatic conditions. The question still remains about the possibility of using the same heat-insulating material for cladding walls and floors. More universal qualities of the material will just allow you to work on any coating (walls, floors, ceilings). Usually walls, gables and floors are "wrapped" with such material. This allows you to achieve the same amount of insulation around the entire perimeter of the room.

When choosing insulation materials, one should not forget about the sound-absorbing properties of the material. To understand this issue, it is worthwhile to imagine noise on a steel roof even from a light rain, especially when it comes to a residential attic. Calmness and comfort are the most important criteria for home improvement. Also, when choosing a heater, it is necessary to check the supporting structure, from what materials it is made (metal, wood, reinforced concrete). Combustible materials (rafters) will not allow the use of some types of insulation. But, in general, safe and environmentally friendly facing materials are used today. Among them there are both traditional (glass wool) and more technological (ecowool, foil plate). Let's take a look at some of them.

For internal insulation of the attic in the presence of a roof, such fireproof and moisture-repellent materials are used as mineral wool, glass wool, ecowool, penofol, polystyrene, a pie made of slabs with sawdust, extruded polystyrene foam. Insulation material in the form of slabs and mats is suitable for single or multi-pitched roofs. The lathing is done in a similar way. Plates are convenient for transportation and installation.

Many people find it more convenient to use materials in rolls. You can easily cut a piece to the desired length. Roll insulation made from traditional materials is suitable for roofs with rafters at a standard distance from each other. If necessary, the material can be filled in the remaining free space.

The so-called sprayable materials for lining the attic do not leave joints and areas for the penetration of cold. For example, a polyurethane foam spraying method can be used. For such insulation, no preliminary preparation of the attic is required. The material is simply poured to a certain thickness (usually the thickness of the rafters). These materials are distinguished by the fact that they are resistant to the development of mold and mildew. Spraying is convenient to carry out both on the walls and on the ceiling.

The quality and durability of the material depends on the manufacturer, operating conditions and on the characteristics of the material. The insulation should be as resistant to mechanical stress as possible, so you should always choose the one that is better for specific indicators. The construction market today is replete with modern heaters of different brands, differing in weight, color, installation features.

It is important to decide on the parameters here:

• the material may be lightweight;
• the material must be sufficiently rigid;
• it is necessary to choose a heater that is resistant to any deformation for the entire period of operation.

A small mass of insulation allows it to be used between the rafters of the attic structure. With a stronger frame, it is possible to use heavier material (slabs).They are mounted on a crate or on a rafter structure. Depending on the frequent load on the roof (snow), you can decide on a soft or hard insulation. Too soft will have to be repaired. Excessively hard can lose in thermal insulation properties, for example, when the ceiling is insulated. And, of course, the insulating material for the attic should not crack, deform or change over time. It is not always possible to immediately decide on the choice of material for insulating the attic from the inside, even when it is not necessary to cover the roof.

All thermal insulation materials have their own advantages and disadvantages. Having unique characteristics, such materials are evaluated according to universal criteria.

• Even a budget option for insulation (for example, polystyrene) should keep the house warm. Therefore, you need to use a material with a thickness of at least 10 cm. Plates made of the same foam are practically weightless, no special installation is required, they are suitable for any type of attic. However, Styrofoam is highly flammable. Therefore, when choosing a heater, one should not always give preference to cheap analogs.
• Extruded polystyrene foam can be used as insulation both indoors and outdoors. It should not be confused with foam, the latter has a different structure. Expanded polystyrene does not react to chemical reagents, has low thermal conductivity, does not absorb moisture. Slabs of material can have different densities, but they can be highly deformed.

• Penofol is used as a more modern means as a heater, but also as a more expensive one. Insulation in the form of a roll material can easily replace mineral wool. It is not affected by moisture. It is believed that this material has properties that can protect against radioactive waves.
• Spraying with liquid polyurethane foam will allow you to achieve the desired resistance to drafts. Rather, they will not be, since the insulation can close the joints and gaps on any surface. When using the material, there is no need for additional laying of heat-insulating material.

• Ecowool for the attic has been used relatively recently. This material consists of 80 percent cellulose. The rest is antiseptic additives. When using ecowool, the shrinkage of the material during operation is taken into account. Modern material is resistant to fire, does not get wet, does not collect bacteria.
• Almost all mansard structures of country houses are covered with mineral wool. This material is very popular due to the qualities of heat and sound insulation. It can be laid on a crate or on a frame. Mineral wool is not subject to decay, but it must be remembered that the material is able to absorb moisture and thereby increase in size. And this gives additional weight to the structure.

Material with universal parameters - modern insulation, allows you to create the most comfortable conditions and the desired microclimate in the upper part of the house, protecting against heat loss. Insulation installation depends on its technical characteristics. Consumption is determined by its thickness. There are different installation options, since almost everything is used in the construction business today - from mineral wool to foam. You can calculate the required thickness of the insulating material according to a certain scheme and based on the main parameters of SNiP. When calculating thickness, craftsmen are guided by regulatory requirements. The characteristics of both the heat insulator itself and the attic structure are taken into account.

Rules for calculations.

• When choosing a heater for an attic room, the operational density of the material is taken into account. The heat insulator is selected in such a way as to ensure the overall thermal conductivity of the wall materials.

• The indicator of the load on the structure must be taken into account when installing the insulation. Thermal insulation materials differ in weight - it is larger with a higher density of the insulator.So, if the structure is stone or made of bricks, this will allow the use of any material for cladding. For a wooden frame, insulation of a lower density is suitable.
• Determination of the dew point. According to this parameter, when calculating the choice of a heat insulator, the quality of the wall decoration, both inside and outside, is taken into account. The presence of dense plaster, for example, allows you to "save" on insulation. An incorrectly selected insulation thickness will lead to the accumulation of condensate, which will negatively affect the performance of the entire structure.

You can calculate the thickness of the heat-insulating material using the formula: R = P / K, where

• P is an indicator of the thickness of the material;
• K is the value of the thermal conductivity coefficient.

When choosing heat-insulating materials, the parameters of their thermal conductivity are compared. So, the coefficient of thermal conductivity of expanded polystyrene (which is the most popular) is 0.042 with a thickness of 124 mm. Usually thinner material up to 100 mm is used. Minvata (the next most popular) has a thermal conductivity coefficient of 0.046, where the thickness of the material is 135 mm. The heat insulator is used in the form of plates or rolls.

Work on the attic insulation at the same time affects the thermal insulation qualities of the roof. The mansard roof is also the roof of the house, representing an inclined part of the rafters, on which the waterproofing and insulation are installed. All waterproofing runs along the rafters. Thermal insulation is more "economical", the insulation is placed between the ceiling beams of the attic, the material is hemmed from below.

The work is being carried out in stages.

• Insulation of attic floors. Attic insulation technology allows you to start with the floors. The process resembles the installation of thermal insulation cladding on wooden floors. In this case, mineral wool mats or polystyrene foam boards are used.

• We insulate the walls of the attic. If the house is insulated from top to bottom, then additional insulation of the attic walls is not required. But in general, it is a good idea to use a thin heat insulator to enhance the effect of adjoining the wall. To do this, wooden slats are nailed on the back sides of the racks (supports) (with a distance of 30-40 cm, similarly the slats are stuffed on the ceiling), heat insulators are installed on the slats. This can be, for example, pre-cut sheets that are placed between the supports. A vapor barrier is provided on top.

• Insulated attic ceiling. For this part of the work, such insulating materials as basalt insulation, polyurethane foam, mineral wool or foam are used. Modern roofing insulation is a heat-saving layer. Here it is important to ensure that there are no gaps and gaps between the plates during the installation process. You can use a more convenient material - roll insulation. Waterproofing and vapor barrier are mandatory.
• Finishing of the attic. At this stage, it implies the implementation of a number of works to give a finished look to the attic. Usually, drywall sheets are used for this purpose. They are mounted on a frame with a crate. The ceiling and walls of the room are often sheathed with clapboard. It all depends on personal preference.

It is better to insulate the attic in spring or autumn. In the process of work between the roof and the heat-insulating material, there must be enough space for ventilation - an air gap. This will help protect surfaces from mold, rot, and mildew. The thickness of such a layer depends on the thickness of the material itself, its shape.To improve the tightness of the structure, the vapor barrier is overlapped, and then all joints are closed with tape.

When decorating a plasterboard ceiling in an attic room (subject to a finished roof), profiles are used. It is possible to perform thermal insulation of the pediment after the attic space of the house is insulated (work is carried out outside). Before insulating floors, you need to make sure that they do not need to be additionally reinforced.

Even if all work is done correctly, there is a risk of small condensation formation. Therefore, it is better to provide the structure with a double air cushion (for insulation). This will help maintain continuous air circulation and moisture removal.

The attic, warm from all sides, is perfect for winter living!

In the video below, see tips for clearing the attic.