In a heated room, the greatest heat loss occurs through the roof, since, in accordance with the laws of physics, warm air rises. Heat penetrates through the roofing pie and is transferred to the topcoat, which in winter is covered with a layer of snow. Snow has a porous structure, and due to internal air pockets it acts as an external heat insulator at air temperatures below -2 degrees.
If the heat loss of the house through the roof is high, the roofing material is heated, which causes the snow to melt. When the air temperature drops, the melted snow forms an ice crust. This is dangerous for roofing, as when freezing water has a negative effect on the outer surface of the roof. Ice, unlike snow, is not a heat insulator, in addition, it is denser in structure – an ice crust on the roof significantly increases the load on structures. If the insulation from the inside is done correctly, in the winter on the roof the snow does not melt.
In the hot summer period, excess heat is transferred from the roof inside the room. The air can overheat so much that even the air conditioners will be difficult to maintain a normal microclimate on the attic floor. Installation from the inside of the roof of a reliable insulation layer will avoid such problems. Of course, the air in the attic will be heated more than in the rooms of the first floor, but the difference will not become uncomfortable.
Features roof ventilation attic type
Insulation of the mansard roof requires a special approach. This is due to its design features. If we compare the structure of an ordinary roof and a mansard, it is obvious that the main difference is the size of the ventilation space between the living quarters and the roof. Ventilation conventional roof is provided by the presence of an attic with dormers. The ventilation space of the mansard roof is very limited – it is only about 10-15 centimeters.
Proper ventilation is extremely important when arranging the roofing pie of the roof roof. The ventilation gap between waterproofing and insulation contributes to the removal of excess moisture from under the roof, ensuring protection of the entire structure and extending its operational life. In winter, ventilation prevents overheating of the roof and the formation of ice on it. In hot weather, part of the heat is removed due to ventilation from under the roof, thus avoiding overheating of the air in the attic and structural elements of the roof.
The choice of insulation
At the stage of preparation for the installation of the roofing pie, you should decide on the choice of material for insulation. The number of layers and the thickness of the heat insulation depend on the type and technical characteristics chosen correctly. A wide range of materials for warming roof structures is presented on the modern construction market. Among the most sought after are:
- polyurethane foam;
- extruded polystyrene foam;
- glass wool;
- mineral wool.
Foamed glass, various types of natural insulation for installation from the inside (wood chips, algae, granulated paper, etc.) can also be used.
There are four main criteria for choosing a thermal insulation material:
- coefficient of thermal conductivity;
- moisture resistance;
- fire resistance;
- environmental Safety.
Note! For warming the roof of the attic type, it is recommended to use a material whose thermal conductivity coefficient is from 0.05 W / m * K and lower.
The higher the moisture resistance of the insulation – the longer it will retain its functional qualities. An indicator of resistance to burning is an important criterion for home security. It is also important to take into account the ecological purity of the material and its safety for humans. But the last two parameters do not affect the durability and efficiency of roof insulation.
Mineral wool – insulation made from rock melt. The material keeps heat well, does not rot, is resistant to temperature extremes and exposure to aggressive media, practically does not absorb moisture. Mats of different thickness, made of mineral wool, are especially convenient to use for warming the roof, if the step of rafters corresponds to the width of the mat.
Glass wool is made of glass melt, with its properties, this type of insulation is close to mineral wool, but has a lower thermal threshold of -450 ° C. It has good heat and sound insulation characteristics. Glass wool is resistant to freezing. Moisture can accumulate between the fibers of the glass wool, so waterproofing must be carried out correctly.
Minvat and glass wool allow to insulate the roof with minimal financial investments. The disadvantages include the need to create a thick layer of insulation and several layers of steam and waterproofing.
It is possible to warm the roof structure from the inside with the help of polymeric materials – polystyrene foam or polyurethane foam. The advantages of polyurethane foam (gas-filled plastic) is a high ability to retain heat, lightness, durability. Polyurethane foam does not allow steam and is not exposed to moisture. Extrusion of polystyrene allows you to effectively warm the roof – its coefficient of thermal conductivity is 0.05 W / m * K. The material is hydrophobic, does not allow steam. Flammability class from G1 to G4, depends on the brand of material. The disadvantages of polymeric insulants include their artificial origin and relatively high cost.
If there is a goal to build a house exclusively from environmentally friendly materials, you can insulate the roof with natural heat insulators. Despite good thermal conductivity and environmental cleanliness, various types of natural insulation have their drawbacks. Foam glass is highly brittle. Granulated paper, as well as mats of reeds, straw, algae and similar materials are characterized by high flammability and require special skills when performing installation.
Insulation installation technology
To understand how best to perform the installation of insulation during the arrangement of the roofing pie, you need to familiarize yourself with the step-by-step instructions for the work. In general, the insulation of the roof of the house comes down to the following actions:
- preparation of space for the installation of insulation;
- laying insulation layer;
- fixing material.
At the stage of preparation of the truss construction project, the step with which the rafters will be installed should be determined. It should be borne in mind that the roof system must be reliable, that is, the step must not exceed the recommended values. If the type of insulation is chosen in advance, it is recommended to install the rafters so that the mats or plates of the insulation come in tightly between them from the inside. This simplifies the technology of insulation and minimizes the waste of thermal insulation material.
Above the insulation, between the crate and the rafters, waterproofing is laid. The material is overlapped, laying starts from the bottom edge of the slope. Then the wooden countermounts are mounted – their thickness creates the required ventilation gap of the roof. Reiki can be fastened to the rafters with nails, but it is better to use screws. To the prepared construction from within between the rafters the insulation is laid and fixed.
Truss foot, made of metal or wood, is a cold bridge, as its coefficient of thermal conductivity is much worse than that of a heat insulator.
For this reason, warming the attic, you should not limit the installation of a heat insulator between the rafters – on top of the already laid mats and rafters it is better to perform a continuous heat-insulating layer. For a continuous layer, it is better to use a thinner insulation. This method improves the quality of insulation. The disadvantages include the fact that while the rafters are hidden, and they are more difficult to use in the future for fastening other structural elements. To facilitate further work, the location of the rafters should be correctly noted.
A vapor-permeable film should be laid over the insulation. Its use allows you to divert excess moisture. Then the prepared structure is fastened with crate. At the final stage of the work, the ceiling is covered. Properly executed roof insulation allows year-round use of the attic floor as a dwelling in which a favorable microclimate is maintained. For a detailed answer to the question of how to insulate the attic roof, it is recommended to pay attention to the thematic video with detailed instructions.
Attic roof insulation schemes: inter-cropped space
Attic roof insulation technology is in general similar to the conventional roof insulation method. However, the requirements for it impose more stringent. This is due to the design features of the attic roof. The walls of the attic of the attic are either integral with the roof, or are attracted close to it, so in winter they cool faster, and on hot, hot days they heat up considerably.
Mansards are used year-round and in them, unlike cold attics, they warm the side walls, the slopes of the roof and part of the ceiling. Schematically, the attic roof insulation is a multi-layered roofing “pie” made of layers:
- vapor barrier – if it is not present, condensate that accumulates in the room can go through the insulation into the roofing space and cause significant damage to the supporting structure;
- thermal insulation – it is very important than to warm the roof. The range of thermal insulation materials is quite wide: mineral wool or glass wool, slab or roll. and the effectiveness of heat insulation largely depends on its correct choice;
- ventilation gap – does not allow stagnation of moisture in the under-roof space;
- waterproofing – protects the insulation from getting wet. One solution is to use an anti-condensate film, which is also absolutely vapor-permeable;
Attic insulation video instruction
All of them are required, with each layer, as you can see, has its own specific function. But before insulating the roof of the attic, it doesn’t bother to know that two of them – the insulation layer and ventilation determine up to 80% of success in achieving comfort in the attic rooms.
Therefore, the answer to the question of how to properly warm the attic roof, partly lies in the other – the better to warm.
How to insulate correctly: design schemes of laying ↑
Insulating the attic roof is a matter that requires the most careful consideration, since insulating a sloping roof is one of the most complex procedures, since it requires the simultaneous isolation of several planes. In addition to the internal living space, external balconies and windows can be provided on its lower slopes, which, in turn, further complicates the insulation procedure. Thus, before warming the attic, it is necessary to evaluate the design features and the real state of the attic space.
How to insulate with mineral wool ↑
Let us examine several options for attic warming.
Budget option: intergrow warming
- Mineral wool is an elastic insulating material, and it is due to this that it is held between the rafters.
- Insulation is pre-cut into plates 4–5 cm shorter, than the height of the rafter. Its thickness is chosen based on the climate characteristics of the construction area and the material of the inner lining.
- In the intergroup space with attic lining, it is separated by a vapor barrier. And on top of the roofing “pie” stretches (along the rafters) hydro and vapor barrier film. which is pressed into bars.
- Obtained between these layers: insulation – film and film – roofing, two ventilation gaps must remain open at the ridge and the eaves of the node, to ensure the free movement of air. For this, in particular, the film near the skate cannot be overlapped on another ramp, on the contrary, it does not reach 5–10 cm to the ridge.
- The waterproofing film from temperature fluctuations in the places of attachment can break, therefore, it is fixed to the rafters with a sag – approximately 2 cm.
- Air production should be at least 2 cm higher than the sagging film and insulation. However, this insulation technology has a significant drawback – the probability of the formation of “cold bridges” along the rafters.
Full attic insulation
- Work begins with the first option with the only difference that mineral wool completely fills interspaces, to the very top. Further across the rafters stitch wooden bars. Their height must reach the estimated height of the mineral wool.
- In the resulting frame is inserted into the second layer of insulating material, and it should cover both the rafters and the joints of mineral wool of the first layer. That is, in this way all possible “cold bridges” will be deleted.
Insulation must completely fill all the space provided for it. It should not remain hollows and cavities – loopholes for the passage of air.
- After laying the insulation layer, a super-diffusion membrane is laid directly on top of it, which is pressed with wooden bars. The height of the bars should correspond to the height of the ventilation gap, which should not be less than 5 cm. After that, the crate and the roof are mounted on the counter-grill bars.
- The super-diffusion membrane is laid over the entire plane of the roof and, in contrast to a hydro-vapor barrier carpet, with an overlap over the ridge and without any gaps for ventilation. This method assumes the presence of a single ventilation vent, which is located above the superdiffusion membrane.
- The second layer of insulation is placed inside the premises using the same technology as on the rafters. Across the rafters stitched bars of the counterbrattice and placed between them mineral wool. Following – vapor barrier: depending on its type, or shoot staples to the rafters, or pressed with wooden bars.
If foil vapor barrier is used, it must be installed with foil inside the room. The reflex layer will work only if there is a gap of 2 cm, otherwise thermal infrared rays will not be reflected from the foil.
- The lining of the attic, of course, depending on the type, is attached either directly to the transverse, or to the additional bars that hold the vapor barrier.
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Sources: http://kotel.guru/uteplenie/mansarda/uteplenie-mansardnyh-krysh-iznutri-instrukciya-i-video.html, http://vseokrovle.com/mansardnaja/65-uteplenie-mansardnoj-kryshi.html, http://stylekrov.ru/sxemy-utepleniya-kryshi-mansardy.html