Attic insulation from the inside if the roof is already covered

How to properly insulate structural laying schemes

Attic roof insulation is an issue that requires the most careful consideration, since insulating a sloping roof is one of the most difficult procedures, since it requires simultaneous insulation of several planes. In addition to the internal living space, remote balconies and windows can be provided on its lower slopes, which, in turn, further complicates the thermal insulation procedure. Thus, before insulating the attic, it is necessary to evaluate the design features and the actual state of the attic space.

Let's look at several options for attic insulation.

Budget option: interrafter insulation

Mineral wool is an elastic heat-insulating material, and it is precisely due to this that it is held between the rafters.
The insulation is pre-cut into slabs 4-5 cm shorter than the height of the rafters. Its thickness is chosen based on the climate of the construction area and the material of the inner lining.
In the space between the rafters with attic sheathing, it is separated by a layer of vapor barrier. And on top of the roofing "pie" a hydrovapor barrier film is stretched (along the rafters). which is pressed with bars.
Obtained between these layers: thermal insulation - film and film - roofing, two ventilation gaps must be left open at the ridge and eaves assembly to allow free movement of air. To do this, in particular, the film near the ridge cannot be overlapped onto another slope, on the contrary, it does not reach 5-10 cm to the ridge.

The waterproofing film can break from temperature changes at the attachment points, so it is fixed to the rafters with a sag - about 2 cm.
The airflow should be at least 2 cm higher than the sagging film and insulation. However, this insulation technology has a significant drawback - the likelihood of “cold bridges” forming along the rafters.

Full attic insulation

Work begins with the first option, with the only difference being that the inter-rafter space is completely filled with mineral wool, to the very top. Next, wooden bars are sewn across the rafters. Their height should reach the estimated height of the mineral wool.
A second layer of heat-insulating material is inserted into the resulting frame, and it should cover both the rafters and the joints of the mineral wool of the first layer. That is, in this way all possible "cold bridges" will be removed.

The insulation must completely fill all the space provided for it. It should not leave depressions and cavities - loopholes for the passage of air.

After laying the insulating layer, a superdiffusion 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 be at least 5 cm. After that, the crate and roof are mounted along the bars of the counter-lattice.

The super-diffusion membrane is laid over the entire plane of the roof and, unlike the waterproofing membrane, overlaps through the ridge and without any gaps for ventilation. This method assumes the presence of a single vent, which is located above the superdiffusion membrane.
The second layer of insulation is laid from the inside of the room using the same technology as on top of the rafters. Across the rafters, bars of counter-lattices are sewn and mineral wool is laid between them. Next is the vapor barrier: depending on its type, they either shoot it with brackets to the rafters, or press it with wooden bars.

If a foil vapor barrier is used, then it must be installed with foil inside the room.The reflective layer will only work if there is a gap of 2 cm, otherwise the thermal infrared rays will not be reflected from the foil.

Attic sheathing, of course, depending on the type, is attached either directly to the transverse or to additional bars that hold the vapor barrier.

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Mansard roof installation tools and equipment

Roofing cannot be installed with bare hands. This will require the use of not only tools, but also special equipment. Depending on the type of roofing material, the appropriate inventory is selected.

When installing elements of the truss system, you can not do without:

Electric saws.
Electric planer.
Axe.
Hammer.
A set of chisels.
Screwdriver.
Electric drills.

When installing bitumen-based roll materials, you will need a gas burner. With the help of this device, the material is heated to the desired temperature, the joints are glued and fixed on the roof.

The gas burner reliably glues the bituminous base and roofing material

The use of a roofing crane will greatly facilitate the work. This equipment will save time and effort during the construction of the mansard roof.

A roofing crane, being a small-sized representative of lifting mechanisms, will greatly facilitate the process of building an attic

It should be noted that the equipment used in the construction of the attic must comply with the requirements of GOST 12.2.003–74. This standard establishes general safety requirements for the construction of industrial equipment:

special equipment used for melting bituminous materials must be equipped with thermal sensors and an exhaust pipe;
equipment designed to dry the base for rolled welded materials must be equipped with a special protective screen;
the process of refueling the fuel tanks of the equipment used must be mechanized.

The following tools are required for the installation of a mansard roof roofing pie:

Yardstick.
Hammer.
Axe.
Sharp knife.
Construction stapler with staples.
Hacksaw.
Plumb.
Graphite pencil.
Cord.
Metal scissors.
Wire cutters.
Drill with drills of different diameters.
Screwdriver.
Plane.
Calculator.

Mansard roof repair

In most cases, the basis for repairing a roof with an attic is leakage due to deformation of the covering flooring under the influence of atmospheric phenomena due to uneven shrinkage of the building or incorrectly selected lumber for the rafter block. It is possible that wind and snow loads were not taken into account during construction, poor-quality roofing materials were used, or gross violations were made during installation. The main thing is to identify the true cause in a timely manner in order to further eliminate the problem.

Replacing a damaged section of roofing material is the easiest type of repair work. But here it is necessary to take into account the type of covering flooring. For example, it is quite easy to replace a broken tile with a new fragment. But the repair of bituminous shingles will require a professional approach - it needs to be torn off, sealed and nailed a new strip. If the work is carried out in cold weather, then the shingles are first softened with a building hair dryer. This must be done very carefully so as not to solder together new and old fragments of tiles.

Damaged shingles of bituminous tiles must be torn off, and repaired or new coating elements should be nailed into place.

If the cause of the leaks is not in the roofing, then you will have to carry out a full repair according to the following algorithm:

A temporary wooden frame is erected over the roof, which is covered with plastic films to protect the living quarters from the weather.
The old roofing is dismantled and all layers of the roofing cake are dismantled.
Examine the truss system. An assessment of its condition should be given by experts. It may be enough to remove the mold, treat with an antiseptic, replace the elements eaten away by the fungus, correct the geometry and strengthen the roof structure. But it is possible that you will have to completely change the entire truss system.
After repair or maintenance of the carrier block, all layers of the roofing pie are laid anew, after analyzing their condition - whether they are suitable for further use or whether it makes sense to replace some materials with new ones.

Video: mansard roof repair - fixing mistakes

If the homeowner does not have the funds to repair the truss structure, then, as a temporary option, it is possible to replace the existing roof with two-layer bituminous shingles. This durable roofing will protect the roof from leaks for a certain time, will make it possible to solve financial problems and subsequently eliminate the real cause.

Building a mansard roof on your own is a complex, but very exciting process. The daily transformation of the house is inspiring, so you want to achieve the final result as quickly as possible.

Performing the work step by step, it is important to follow the instructions, take into account the recommendations and not neglect the little things. And then the mansard roof will delight for many years

The choice of thermal insulation

The design of the attic roof has the following features that you need to focus on when choosing a material for its insulation:

Lightweight materials should be used as roofing and insulation for a mansard roof, since its design is not designed for increased loads.
To insulate the mansard roof, the most effective materials should be used so that the thickness of the roofing cake layer is minimal - this will also help reduce the weight of the roof structure.
It is mandatory to install a ventilation system for the roof space, which provides humidity control in the room.

Mineral wool

Mineral wool is often used to insulate mansard roofs. Her virtues:

Light weight.
High thermal insulation qualities.
Good vapor permeability and sound insulation.
Environmental friendliness and fire safety.

The amount of insulation corresponds to the area of the roof slopes minus the area of the openings

Among the disadvantages of such thermal insulation of the attic roof are the relatively high price and the tendency to get wet. In addition, mineral wool can become caked over time and lose its properties.

Important: For roof insulation (inclined and vertical surfaces), it is better to use mineral wool in slabs rather than rolls - this will facilitate installation.

You can also use glass wool to insulate the attic roof, but it is less convenient to use and requires protective equipment: gloves, overalls and glasses.

In cold regions, the thickness of such thermal insulation should be 150-200 mm - this can be ensured by laying mineral wool slabs in two layers. With external insulation, work on the installation of the material should be carried out only in dry weather.

Styrofoam or Styrofoam

Insulation of mansard roofs with foam plastic is common due to its low cost. Among the advantages:

Little weight.
Low thermal conductivity.
Ease of processing and installation.
Good operational qualities.
Doesn't deform.
Not afraid of moisture.

How to insulate the roof of the attic with foam

Insulation of the mansard roof with foam plastic has a significant drawback - fire hazard. But you can use extruded polystyrenes, which do not burn, but only melt, but their cost is much higher.

Polyurethane foam (PPU)

New effective material for attic roof insulation.In fact, it is a modified polyurethane foam. PPU can only be used to insulate a mansard roof from the inside, a video with application technology at the end of the article, but at the same time:

The thickness of the insulation layer is minimal.
PPU has good adhesion, and when applied, it fills all the voids in the structures.
It is simultaneously heat, hydro and vapor barrier.

Insulation with PPU

Spraying polyurethane foam requires special skills and equipment, but there will be no seams at all, which will prevent freezing of structural elements.

When choosing the best way to insulate a mansard roof, you can also focus on such material as ecowool. This natural insulation (made from linen) will not only protect you from the cold, but also from overheating in the heat, is breathable and environmentally friendly. Ecowool provides a seamless coating and does not require a vapor barrier. Suitable, for example, for insulating sloping mansard roofs due to easy installation on inclined surfaces.

Roofing cake not insulated

Types of insulation for roofing pie.

This type of roofing cake design is created if the building has an insulated ceiling under the attic, and it is planned to be in the attic room only in summer. Here, the main task of the insulating structure will be to insulate the attic from condensate entering from the outside, so that moisture can go outside. So that the microcirculation of air is not disturbed, a gasket should be made of a waterproofing perforated film.

When arranging an uninsulated roofing pie, the sequence will be as follows:

truss system device;
laying a waterproofing layer;
fixing the counter-lattice;
fastening the crate;
laying roofing material.

The insulated design includes more layers. It is used for arranging residential attics and the task is not only waterproofing, but also ensuring the safety of heat. Under the roof, the thermal regime is much different from that on the ground floor of the building.

The roof itself in the summer can warm up to fairly high temperatures, and in winter there is often such a phenomenon as the freezing of the roof. In such housing, a comfortable atmosphere cannot be achieved. Roofing cake is arranged to perform the following tasks: keeping heat inside in winter, providing insulation for air that may come into contact with a frozen roof, and in hot weather, the cake does not let hot air inside.

Attic roof insulation from the inside between the rafters

The process of internal insulation of the mansard roof should begin at the stage of construction of the building. This is the only way to check the correctness of the layers of the roofing "pie". At the same time, it is advisable to draw up a detailed diagram of the attic room with your own hands and mark on it the places that are subject to insulation from the inside.

Very often, the attic structure has a cropped structure. Simply put, between the lower part of the roof slope and the interior decoration of the room there is free space that does not need to be insulated.

But in such a situation, it is important to insulate the ceiling along the very edge of the roof structure.

First, the insulation must be unpacked so that the mineral wool gains its original shape. The material is cut to the required size. Be sure to leave a margin of 25-35 mm for a snug fit to adjacent rafters.
The canvases are pushed into the space between the rafters. It is necessary to slightly press on the middle of the insulation so that it straightens. In this case, it must be borne in mind that the thickness of the beams must be at least 25 cm.
A vapor barrier layer is laid over the insulation with an overlap of 10 cm, and the joints are glued with adhesive tape. The insulation is attached with staples or crate.
For the crate, slats 2.5 cm thick are stuffed.
A decorative finishing material is fixed on top of the rails.

At this stage, all work on the insulation of the attic can be considered completed. But in order to fully understand the essence of the installation process, you can familiarize yourself with the video, warming the roof of the attic floor. If you plan to insulate the attic in an old building, and there is no desire to disassemble the roof structure, then there is a little trick. The waterproofing layer is rolled out directly from the inside of the attic, wrapping the rafters and leading the material into the space between them. But in such a situation, it will not be possible to protect wooden beams in the event of a leak of roofing material.

The structure of the insulated roofing pie

Roof pie made of corrugated board.

Rafter. All layers of the cake should be together about 35 cm. This must be taken into account when performing the rafter system. Decide on the material that you will lay as a heat insulator - this will help you find out if the height of the rafters will be sufficient.

It is the rafters that bear the main load of the gravity of the roof. Therefore, it is better to create them from coniferous trees, choosing such elements in which there are no flaws. The moisture content of wood should not exceed 22%. All wooden elements must be impregnated with an antiseptic. The pitch of the rafters and their thickness are chosen depending on what material is selected to cover the roof.

Vapor barrier. The actual installation of the roofing pie begins just from this layer. The last of the inner layers will be the finish.

Moisture must be present inside the housing. Most of all it is contained in the warm air, which, obeying the laws of physics, rushes up - into the attic. Ventilation is not able to ventilate to such an extent that all excess moisture is eliminated, they fall on the roof structure and settle in the form of condensate. The vapor barrier layer protects the insulation, arranged next, from moisture penetration. When saturated with moisture, thermal insulation loses its performance.

Among the materials used to create a vapor barrier layer, the following are most often used:

vapor barrier film. It is made multilayer, with the addition of a polymer reinforcing frame, which does not allow it to sag;
glassine - a vapor barrier with a democratic price, which has a significant disadvantage: over time, its ability to retain moisture disappears;
foil materials.

The latter are a film, one of the sides of which is pasted over with foil. There is also a material similar to chocolate wrappers, one side of which is foil, the other is paper. Both options perform not only a waterproofing function, but are also a good barrier to infrared radiation. It causes heat leakage from the room, and the foil layer helps to significantly reduce heat loss even without insulating materials.

Fastening the vapor barrier to the rafters is carried out as follows:

Rolled material is rolled along the rafter legs in the direction along the ridge. Laying should be carried out from below, with an overlap of 15 cm on the previous layer.
The film is attached to the surface with a construction stapler.
The joints of the material and the edge adjacent to the wall are sealed using a connecting tape or adhesive tape.

When laying the film, do not stretch it, it should sag slightly between the rafters.

The choice of insulation

At the stage of preparation for the installation of the roofing cake, you should decide on the choice of material for insulation. The number of layers and the thickness of the thermal insulation depend on the correctly selected type and technical characteristics. A wide range of materials for the insulation of roof structures is presented on the modern construction market. Among the most requested are :

polyurethane foam;
extruded polystyrene foam;
glass wool;
mineral wool.

Foamed glass can also be used, various types of natural insulation for installation from the inside (wood chips, seaweed, granulated paper, etc.).

There are four main criteria for choosing a thermal insulation material :

coefficient of thermal conductivity;
moisture resistance;
fire resistance;
environmental Safety.

Note! To insulate a mansard-type roof, it is recommended to use a material with a thermal conductivity coefficient of 0.05 W / m * K and below. The higher the moisture resistance of the insulation, the longer it will retain its functional qualities.

The fire resistance index is an important criterion for ensuring the safety of the home

It is also important to consider the environmental friendliness of the material and its safety for humans. But the last two parameters do not affect the durability and effectiveness of roof insulation.

The higher the moisture resistance of the insulation, the longer it will retain its functional qualities. The fire resistance index is an important criterion for ensuring the safety of the home

Mineral wool - a heater made from a melt of rocks. The material holds heat well, does not rot, is resistant to temperature extremes and aggressive environments, and practically does not absorb moisture. Mats of various thicknesses made of mineral wool are especially convenient to use for roof insulation, if the pitch of the rafters matches the width of the mat.

Glass wool is made from molten glass, in terms of 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 insulating characteristics. Glass wool is frost resistant. Moisture can accumulate between the glass wool fibers, so waterproofing must be done correctly.

Mineral wool and glass wool allow you to insulate the roof with minimal financial investment. The disadvantages include the need to create a thick layer of insulation and several layers of vapor and waterproofing.

It is possible to insulate the roof structure from the inside with the help of polymeric materials - expanded polystyrene or polyurethane foam. The advantages of polyurethane foam (gas-filled plastic) include a high ability to retain heat, lightness, and durability. Polyurethane foam does not pass steam and is not affected by moisture. Extruded polystyrene foam allows you to effectively insulate the roof - its thermal conductivity coefficient is 0.05 W / m * K. The material has hydrophobicity, does not pass steam. Flammability class from G1 to G4, depends on the brand of material. The disadvantages of polymer insulation 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 friendliness, various types of natural insulation have their drawbacks. Foamed glass is highly brittle. Granular paper, as well as mats made from reeds, straw, seaweed and similar materials, are highly flammable and require special skills during installation.

How to insulate mansard roofs criteria for choosing material for insulation

The choice of high-quality heat-insulating materials for warming the attic from the inside is a very responsible process. The thickness and layering of the roofing cake will depend on the type of insulation and its main characteristics.

Due to the fact that the attic is a room of a specific design, then the choice of insulation should be based on the requirements for it:

The minimum level of thermal conductivity. It is advisable to purchase materials with thermal conductivity indicators that do not exceed 0.05 W per square meter.

Low degree of moisture permeability. Due to the fact that condensation can form under the roof, and often the roof can simply leak, the heat-insulating material should not absorb moisture, which adversely affects its main parameters

If it is impossible to adhere to such rules, it is important to equip high-quality waterproofing.

Material for internal insulation of the attic should have a minimum weight. This parameter is very important, since the roof structure cannot be overloaded.

Weight parameters directly depend on the density of the material. Mineral or basalt wool is well suited for the roof. Heavier options are not advisable to use.

High rates of fire safety. It is important that the insulation does not support the combustion process in the event of an open source of fire.

The ability of the insulation to retain its original shape. Due to the fact that the insulation is laid on a non-standard surface at an angle, rolled soft materials can slide down after a certain time, forming large voids in the upper part. Therefore, the insulation for internal insulation of the attic should not lose its shape and size.

High frost resistance. which is due to sudden temperature changes in the under-roof space.

Long operational resource.

It is very important to correctly calculate the thickness of the insulation, which should be based on the characteristics of the construction region, the thickness of the walls of the house, the presence or absence of insulation, and the thickness of the roofing cake. All these parameters are of high importance, and only on the basis of them, you can choose the right thickness of the heat-insulating material.

If you skip the calculation stage, then it is better to opt for mineral wool 25 cm thick.

How to properly insulate the roof of the attic from the inside with your own hands

Many homeowners succumb to the temptation to equip the house with a comfortable residential attic. Such a desire is natural, this is a great opportunity to increase the area and living space of your home. In addition, this gives the building a special charm, brings a certain amount of romanticism to its appearance.

Special roof windows enhance the impression. Today, most new private housing is already being built with an attic. But often, wanting to increase households, and in not new houses, the owners equip and insulate old non-residential attics.

Attics are located almost under the roof

What are the usual requirements for them? It is important that it is cool enough in summer and dry and warm in winter. In order for the room to meet the indicated requirements, it is important to know what processes take place in it, to understand the essence of competent insulation

It is not difficult to do all the necessary work with your own hands, their technology is quite simple. The main thing for this is a conscientious partner and the availability of the necessary tools. If everything is done technologically correctly, the wooden rafters will not get wet and rot, and the heat-insulating material will serve for a long time and reliably.

In what cases may you need attic insulation

The attic floor is a room of a special design, in which the walls practically merge into a single whole with the roof surface and the ventilation gap does not exceed 100–150 mm. It is for this reason that the room cools down quickly in winter and heats up in the summer. The entire surface of the roof structure, as it were, is a heat accumulator in the summer heat and through it the heat goes outside with the onset of cold weather. First of all, this is due to the level of thermal conductivity of the materials used for the construction of the roof.

In winter, heat flows from batteries rise upward according to the laws of physics, being distributed under the roof vault and volatilizing freely into the street, since the materials from which a standard roof is made easily conduct heat.

In this case, the snow melts, which, turning into ice, destroys the roof. In turn, in the summer heat, the air in the attic room heats up so much that it becomes hard to breathe. At the same time, even a very powerful air conditioner will not work to cool such a room.

How to be in such a situation? There is only one answer - to insulate the attic room with high quality, choosing the right heat-insulating material, the parameters of its thickness and the place of installation in the under-roof space, in compliance with the technological process.

For example, if the insulation is made with insufficiently thick material, selected by eye, then the problem will be solved only partially and the room will still be cool and uncomfortable. Only the right insulation in terms of thickness and thermal conductivity will allow you to qualitatively isolate the attic from the roof structure, and with the construction of proper ventilation, all excess moisture will be quickly and freely removed to the outside.

Arrangement of a residential attic space

When building a private house, some owners even try to use the attic area for living quarters.

Mansard roof structure.

On the attic floors, in some cases, “summer”, that is, unheated, rooms are planned. But it is still preferable to have rooms in which full insulation is made and you can live comfortably not only in the warm, but also in the cold season.

Insulating material in attic spaces is usually installed on the floor: this helps to keep the heat that comes out from the floor below it. At the same time, an empty attic serves as a layer that does not allow cold to pass into the room from the roof.

When insulating an attic room, everything happens a little differently. All heat-insulating material from the floor is, as it were, transferred to the roof structure. Therefore, a roofing pie in buildings with attics will be an indispensable structural element.

Warm roof

The mansard roof must be warm. Recall that pitched roofs can be warm and cold. The difference between them is the composition of the roofing cake. A warm roof involves the insulation of roof slopes, as well as equipment for hydro and vapor barriers.

For roof insulation, you can use any type of insulation: expanded clay, polyurethane foam, expanded polystyrene, foam concrete, foam glass, cellulose and basalt fiber insulation. Basalt mats are the most popular.

The insulation is placed in the space between the rafter legs. To enhance the effect, you can put in two layers. In this case, the second layer is spread so as to close the joints between the mats of the first. A reinforced waterproofing layer is required. The lack of cotton wool - when moisture gets in, they can not only lose their heat-saving qualities, but also increase the load on the truss system.

Do not allow the heater to get wet. To prevent the condensation of indoor vapors on the inner layers of the roof, a vapor barrier membrane is placed over the mats. To protect the insulation from condensate, the formation of which is possible on some types of roofing materials, for example, steel, waterproofing is laid between the roofing and the insulation.

As a waterproofing, a film or membrane is used. The use of the latter is preferable. The material has excellent diffusion properties. It is impervious to water, but perfectly passes steam. Thanks to this, water evaporating, pass through the layers of the roof, without settling anywhere. In addition, membranes are more practical in terms of space saving. Unlike films, they do not need to leave a gap between layers.It fits directly on the insulation.

First of all, the valley is processed. From top to bottom, the membrane is laid along the entire length. The joints are glued with a special tape, preferably of the same brand as the waterproofing. Rolls of waterproofing membrane are rolled out horizontally from the eaves towards the ridge. Individual canvases are laid with an overlap of 15 cm. Joints are made on the rafters. The material should be well stretched, without sagging.

Styrofoam boards can be used to insulate roof slopes. Compared to mineral wool, they do not absorb moisture in the event of a leak in the waterproofing system.

Foam boards are laid between the rafter legs on the crate. The width of the rafter pitch can reach 2 m. It is laid without a gap. The minimum layer thickness is 100 mm. The maximum is not strictly defined. The thickness of the insulation layer is calculated for each specific case, taking into account the climatic features of the area where the house is located.

Plates are attached with glue or dowels. If gaps have formed between them and the rafters, they are filled with sealant or mounting foam. You can't leave it open. Cold bridges form in them, which leads to the formation of condensate. The result is the appearance of mold and rotting of the rafters. A vapor barrier is laid on top of the foam boards and sewn up with clapboard, wood board or drywall. Depends on the functional purpose of the roof space.