We learn how to insulate the roof of a house from the inside. How to insulate a roof in a private house Do-it-yourself roof insulation

How to insulate a roof with your own hands? First of all, let's talk about the roof parameters that are responsible for its thermal insulation qualities. One of the main ones is the presence of an insulating “pie” - a multi-layer structure that does not allow heat to leave the structure.

What to look for when choosing materials?

How to insulate the roof of a private house? What characteristics and dimensions of roof insulation should be?

Thermal insulation materials are characterized by:

• thermal conductivity coefficient;
• density;
• ability to absorb water;
• flammability;
• environmental safety.

These parameters should be taken into account when choosing thermal insulation materials. Let's talk about them in a little more detail.

The coefficient of thermal conductivity (thermal conductivity) in the case of insulating materials should have the lowest possible value - it is this that determines the insulating qualities of the materials. A low value of this parameter indicates the material’s ability to better retain heat.

The density of the insulating material, that is, its mass in a volume of 1 m 3 (remember, who forgot, the school physics course) determines the weight load on the rafter support system of the roof, walls and, accordingly, on the foundation of the building.

The moisture absorption coefficient in roof insulation should also be minimally low. Since most heat-insulating materials, when moisture gets into them, lose their heat-insulating qualities, negating the effectiveness of all roof insulation work. Therefore, waterproofing and vapor barrier of insulating material must be approached with all responsibility and seriousness. And the insulation material must have high moisture resistance - in other words, low moisture absorption capacity.

Flammability - determines the tendency of a material to ignite easily and maintain the combustion process. Naturally, it is necessary to use materials with low flammability in order to avoid the possibility of “one-time heating” from the roof of the building.

Today it is fashionable to talk about the environmental safety of the material. This also applies to roof insulation. After all, even minor emissions of substances harmful to human health, “multiplied” by a significant time spent in a building, can significantly reduce the time that person remains in full health.

Let's sum up the interim results! So, which roof insulation is best? We answer: the material must have low thermal conductivity with high moisture resistance, have sufficient mechanical strength, do not support combustion and be safe for human health! Like this! Do we all know? Let's go to the construction supermarket!

Which insulation to choose for a roof in a store?

The current state of the building materials market allows even a specialist to get lost in it. The “counter” of insulating materials for the roof is more “narrow”, but still, to navigate it you need to know at least the main types of insulation. This will help you communicate more easily, both with the sales consultant and with the craftsmen, if you decide to resort to their services for organizing roofing work.

As part of roof insulation, we will focus on:

• mineral wool (mineral wool);
• glass wool;
• polystyrene foam (expanded polystyrene);
• We’ll also talk about extruded polystyrene foam.

Mineral wool

Mineral wool (mineral wool) is a fibrous material obtained by melting and spraying mineral substances of mountain origin. Due to its fibrous structure, such mineral wool is an excellent thermal insulation material.

This material is supplied to the work site either in the form of rolls or in the form of slabs. This material has a fairly high density, which in some samples reaches 200 kg/m3.

From the financial side, mineral wool can be called “budget insulation” - both the material itself and the prices for its installation are quite “democratic”.

Glass wool

From the point of view of operational functionality, glass wool is similar to mineral wool. The raw material for its production is glass production waste. When choosing it, you should study the indicators discussed above and choose the best option.

Attention! Be careful! Work with glass wool must be carried out in a protective suit and in compliance with safety rules when working with glass wool, which can cause harm to health when working with it.

But in general, the use of glass wool can effectively and permanently solve the issue of roof insulation.

Styrofoam

The use of polystyrene foam as insulation is determined by its cellular structure. This is a material formed by foamed polymer material frozen in this state. The density of polystyrene foam is quite low, which, combined with its high thermal insulation qualities, determines the popularity of using this material. Polystyrene foam also has good sound insulation parameters. Polystyrene foam is produced only in the form of slabs of varying thicknesses and densities. The price of this material is the lowest of all the listed materials.

Extruded (extruded) polystyrene foam

Extruded polystyrene foam has a “related” chemical composition to polystyrene foam, but has incomparably higher performance characteristics in the field of thermal insulation.

This is due to the fundamentally different technological processes of their production. If the production of polystyrene foam consists of repeated “steaming” of polystyrene granules placed in a block mold with water vapor. The granules increase in volume many times over until they occupy the entire shape, as a result of which they “sinter” with each other. But as the granules increase, the micropores on their surface also increase.

This leads to a weakening of the bonds between the foam granules over time, and especially under environmental influences. As a result, the material can crumble into granules under the influence of the slightest mechanical force. Weak connections between granules also explain the “fragility” of the material during fracture deformation.

Extruded polystyrene foam has no such disadvantages. During the manufacturing process in an extruder, the entire volume of raw materials is first heated to the melting temperature, a homogeneous mass is formed, which undergoes further transformation. The result of the process is a strong microporous structure of closed cells filled with gas, interconnected by molecular bonds. The “closedness” of the cells determines the water resistance and vapor permeability of such polystyrene foam at high thermal insulation parameters.

Thermal insulation materials - let's compare a little...

What is the best way to insulate the roof of a house? You decide…

Cotton materials, unlike polystyrene foam and expanded polystyrene, are also good sound insulators.

But, at the same time, mineral wool is highly susceptible to moisture. If the insulation absorbs moisture up to 2% percent of its mass, it will lose up to 50% of its effectiveness. Therefore, such thermal insulation material requires increased attention in terms of organizing waterproofing and vapor barrier.

Attention! When purchasing, pay attention to the integrity of the packaging - you can buy already “moistened” mineral wool.

It should also be understood that the cotton wool fibers themselves are hydrophobic (they repel cotton wool), but being “in the body” of the cotton material, they form microvoids between themselves, into which moisture is “absorbed” very well. Pay attention not to the hydrophobicity of cotton wool, but to such a parameter as moisture resistance.

The flammability of the material must also be taken into account. It is advisable to use materials with flammability class G1. Materials of this group will extinguish themselves when the source of ignition is eliminated.

Which insulation to choose for the roof? Suitable for your budget, installation capabilities and desired effect.

Roof insulation with mineral wool

Before insulating the roof with mineral wool, it is necessary to calculate the roof insulation and decide on the method of its installation: from above (in the absence of a roof covering) or from the inside.

The first method, in our opinion, is preferable, as it provides more convenient access to the roof truss structure.

Mineral wool insulation is a fairly elastic material, which makes it easy to install a spacer by cutting the width 2-3 cm more than the distance between the rafters.

The design of the roofing “pie” is as follows:

Depending on the material used for waterproofing, there are two options for its installation:

Let's consider the option of external installation of thermal insulation for the roof during its construction. The diffusion waterproofing membrane Fakro Eurotop N35 with a vapor permeability value of 1300 g/m2 per day was used as a waterproofing agent. This material can be safely placed on the surface of the insulation, which makes it easier to install insulation boards.

Mineral wool produced by TechnoNIKOL was used as a thermal insulation material.

The sequence of work or how to properly insulate the roof of a house with mineral wool:

Attention! This article discusses high-rise roof insulation work as an example. When doing it yourself, we recommend following safety precautions and using safety equipment!

1. We lay one row of waterproofing membrane on the roof overhang, securing it with a stapler.

2. On top of the laid film along the rafters we punch counter battens (25x40 mm) 66 cm long. This length of counter battens will allow you to conveniently fasten the first rows of the sheathing while on the roof itself.

3. Focusing on the edges of the rafters, screw in the first lathing strip with self-tapping screws, which should be 10-15 mm thicker than all the others (30x30 mm, 30x50 mm or 30x100 mm).

This is dictated by the fact that the edge of the metal tile sheet will not lie on the crest of the wave, but will lie on a plane. To compensate for the discrepancy in heights, the first rail is taken thicker.

4. Each subsequent sheathing beam must be 350 mm apart from the previous one (the wavelength of the metal tile).

5. Now that there are 3-4 rows of sheathing, and they can be used to move along the roof, we move on to the “internal” work. From the inside, we use a stapler to punch through a membrane-type waterproofing film, and on top of it we screw the internal sheathing with self-tapping screws, which will serve as a support for the heat-insulating material.

6. We lay layers of mineral wool on the outside of the roof. In this case, two layers of insulation were used, so when laying it it is necessary to use offset joints.

Today, insulating the roof of a house is a mandatory process. Small financial investments and simple construction operations will provide an opportunity to save a lot on heating. After all, as practice shows, heat loss through the roof is up to 20%. Therefore, in this article we will tell you what insulation materials are used for this, what technologies are used.

Insulating the roof will protect the entire house from the effects of cold Source pinterest.com

Types of thermal insulation material used

Thermal insulation of the roof includes insulation of the slopes of the structure, or more precisely the space between the rafters. We are not talking about thermal insulation of the attic floor, where bulk materials can be used. Therefore, expanded clay, sawdust, perlite, vermiculite, etc. are not used in this case.

The main types of insulation materials used in the thermal insulation process are mineral wool, polystyrene foam boards and polyurethane foam. The first two are mats and slabs, the second is a colloidal mass in the form of foam, which polymerizes in air into a durable coating with the best thermal characteristics. But it should be noted that polyurethane foam is not a cheap material.

House roof insulation technology

Roof insulation is carried out using two almost identical technologies.

Above when the roofing material has not yet been installed.

From inside the attic when the roof covering is already installed and secured.

Methods for insulating a roof from the outside and inside Source kabel-house.ru

First option

It starts from the inside anyway, that is, from the side of the rafter system.

First along the rafters (across) vapor barrier membrane is installed. Laying is done in overlapping strips with an offset of 10-15 cm. The vapor barrier strips are attached to the rafters with metal staples using a stapler. The joints between them are closed with self-adhesive tape or construction tape.

Produced rafter system filing slab, slatted or sheet materials: plywood, chipboard, OSB, edged boards, lining, plasterboard, etc.

Now the whole process carried from above the rafters. Thermal insulation material is laid between them so that its edges are pressed tightly against the rafter legs. Minimum gaps should not be allowed, which during operation will become cold bridges, that is, they will allow cold air to pass through them.

On top of the rafters waterproofing membrane is installed in exactly the same way as the vapor barrier underneath. The waterproofing film must be installed from the roof eaves towards the ridge across the rafters. In this case, the edges of the upper stripes should cover the edges of the lower ones. The film should not be stretched too much; a slight sag will make it possible to compensate for changes in its dimensions at negative and positive temperatures.

All that remains is install the sheathing and roofing material.

Installation of sheathing for waterproofing Source interistroy.ru

On our website you can find contacts of construction companies that offer turnkey services. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.

Option two

Insulating a roof from the inside is, on the one hand, a simple process, but on the other hand, it requires knowledge of some nuances. Let's start with thermal insulation using polyurethane foam, as the simplest, but also the most expensive.

This foam insulation adheres to any building material, regardless of its adhesive properties. Therefore, polyurethane foam is applied without preliminary preparation of rafters and roofing material. It is supplied under pressure through a hose and a special nozzle.

Applying polyurethane foam to the roof from inside the attic Source svetvam.ru

It should be noted that polyurethane foam is a material that is afraid of sunlight. Under their negative influence, it dries out, turns brown, cracks and breaks. Therefore, if there are dormer windows in the attic through which the sun will penetrate into the attic space, then the insulation will have to be covered. If the sun's rays do not penetrate under the roof, then the thermal insulation layer does not need to be covered with anything.

Insulation with mineral wool slabs

Let us immediately note that mineral wool is a hygroscopic material, that is, it absorbs moisture well. Under its influence, it quickly loses its thermal properties. Therefore, it is important to properly waterproof the roof. From the inside it is done like this:

vapor barrier film is installed so that it fits the roof rafters and covers the space between them (this is clearly visible in the photo below);

Waterproofing the rafter system from inside the attic Source roomester.ru

between the rafters mineral wool mats are laid(the photo above also clearly shows how to do this), the main requirement is that the insulation does not protrude beyond the rafters, but is pressed tightly against them;

above vapor barrier film is stretched, which is laid in strips, like the top waterproofing, only it is stretched along the rafters;

Installation along the rafter system from inside the vapor barrier membrane Source beton-stroyka.ru

All that remains is to stuff it onto the rafter system from the inside sheet or slab material.

Insulation with polystyrene boards

Insulating the roof from the inside with polystyrene foam boards is almost no different from the previous option. It is simply necessary to indicate that polystyrene foam is a practically non-hygroscopic material. Particularly in this regard, slabs under the Penoplex brand have performed well. In all respects, it is better than mineral wool with one drawback - expanded polystyrene boards support combustion. But this does not prevent them from being used for insulating roof structures.

Let us add that the advantage of using polystyrene foam boards is the ability to refuse protective layers. That is, there is no need to use waterproofing films. Therefore, the slabs are simply laid between the rafter legs. The main requirement is a minimum number of gaps and cracks with minimum dimensions between the insulation boards and between them and the rafters. Therefore, the insulation is cut as accurately as possible in accordance with the installation pitch of the rafters.

If gaps cannot be avoided, then they are filled with a special adhesive composition, which is similar to polyurethane foam, only it does not expand in volume. The material will not only fill the cracks, but will also attach the insulation to the rafter legs.

Installation of foil-coated polystyrene foam boards between rafter legs Source ezlocal.com

Today, manufacturers offer Penoplex with a foil coating, which increases the thermal insulation characteristics of the slabs by reflecting thermal radiation emanating from inside the rooms of the house. That is, thermal energy is conserved.

Penofol insulation

This insulation is a layer of foamed polyethylene, covered either on one or both sides with foil. Flexible, thin and cheap, but with good thermal insulation properties, penofol has recently become more often used in thermal insulation processes. When insulating the roof of a wooden house from the inside (and not only in a wooden one), it is used as a roll covering.

It is simply placed from the inside of the attic on the rafter legs and secured to them with metal staples or small nails with a wide head. The main thing is to lay the joints joint-to-joint and seal the joint itself with self-adhesive film with a foil coating. Then slats are made along the rafters (this is sheathing), along which sheet or slab material will subsequently be installed.

Roof insulation with foam Source evroremont-kmv.ru

Which insulation is better

It all depends on such a characteristic as thermal conductivity. The smaller it is, the better the thermal properties of the material, the smaller the layer it can be laid.

Please note that the thermal conductivity of penofol is not the best on the list. But the thickness of this material is 4 mm. The thickness of mineral wool is 50 mm, polystyrene foam boards are 47 mm. In this regard, polyurethane foam still wins. It has better thermal characteristics than other insulation materials, and the applied layer does not exceed 50 cm. In addition, foam insulation is applied in a non-joint manner. The layer is solid and durable.

Video description

Step-by-step insulation of the roof from the inside is shown in the video:

Generalization on the topic

Insulating a roof in a wooden house (and not only) is a serious process that requires a special approach to construction work. The main task is to choose a thermal insulation material and strictly follow the technology of its installation.

In practice, roof insulation in private houses is carried out when it is planned to install a warm attic or residential attic. It is not customary to thermally insulate a cold roof; usually in this case, insulation is used to cover the ceiling between the attic and living space. Concrete flat roofs also need thermal insulation, since a huge amount of heat is lost through them. This article will tell you how to properly insulate wooden pitched roofs and concrete floors with your own hands.

Types of insulation for roofing

Nowadays, few people ask the question whether it is necessary to insulate the roof of a private house, since the answer is obvious. If you don’t want to overpay for heating, you’ll have to invest in thermal insulation. But how you can insulate the roof of your home, what material to choose for this purpose - this question interests many.

After all, the technology and sequence of work depends on the type of insulation chosen, which we will discuss further. So, at the moment, you can insulate a gable roof, including with your own hands, using the following materials:

• mineral wool in rolls based on fiberglass;
• mineral wool in slabs and rolls based on basalt fiber (stone wool);
• foamed polystyrene boards (foam plastic, extruded polystyrene foam, penoplex);
• sprayed polyurethane foam (PPU);
• foamed polyethylene with a layer of foil (penofol, isolon).

For reference. Not long ago, another new insulation material appeared on the modern market - ecowool, made from recycled waste paper and therefore characterized by a high degree of environmental friendliness. It’s just that using ecowool to insulate a roof, especially a pitched one, is very inconvenient, and it won’t be cheap.

The best insulation for the price is rolled mineral wool with fiberglass, offered by a well-known manufacturer - IZOVER. It protects the house quite well from the cold and can serve for a long time and successfully under one condition: the absence of moisture, its wool absorbs a lot and after that ceases to be a heat insulator. In addition, glass wool is not suitable if non-flammable insulation for the roof is required. The temperature limit of the material is 200 °C, upon reaching which it is destroyed.

The same brand IZOVER, and also URSA, produce non-flammable mineral wool from basalt fiber, suitable for insulating any pitched and soft roofs. She also likes to absorb moisture, but at the same time resists flame perfectly. It is very popular in the field of thermal insulation of roofs due to its affordable price; it is offered in rolls and slabs. The most famous manufacturer is the Polish brand ROCKWOOL.

Next come polymer insulation, whose properties are exactly the opposite - they repel water, but are flammable. Polystyrene foam is cheap, but still susceptible to slight vapor permeation, so during installation it is better to protect it with a vapor barrier. At the same time, expanded polystyrene and penoplex are practically impenetrable and do not require any protection, which simplifies the installation of roof insulation. And most importantly, all these materials have higher thermal insulation properties than any cotton wool.

Note. There is a lot of discussion about whether it is possible to insulate a roof with foam plastic and other flammable polymers. If we are talking about a private house, then no one will be fined for this, but you must understand that in this way you are increasing the fire danger for the building as a whole.

It will cost the most to insulate a roof with polyurethane foam, since it is impossible to do it yourself without specialized equipment. The technology of such thermal insulation consists of applying a layer of polyurethane foam to the surface, which grows in volume from 30 to 120 times. At the same time, polyurethane foam is the best insulation in all respects; it is not afraid of moisture and has the lowest thermal conductivity. It can also be called fireproof, because polyurethane does not immediately collapse when exposed to flame.

Materials made from foamed polyethylene have good thermal insulation properties, but due to their small thickness they can only be used together with other insulation materials. Thanks to the closed pores and the foil layer, the same penofol will serve instead of the inner layer of vapor barrier.

If we consider old traditional insulation materials, such as expanded clay or sawdust with clay, then it is quite difficult to insulate inclined roof slopes with their help. They are usually used for thermal insulation of the floor of a cold roof. Expanded clay or clay is used to fill the recesses between the floor joists in the attic, having previously laid a film.

Insulation calculation

There is nothing difficult in calculating the amount of thermal insulation material, knowing the insulated surface area of ​​a pitched, flat or gable roof. In addition, the size of the insulation is most often tied to the standard interval between the roof rafters (600, 1000 mm). Another thing is to correctly determine its thickness, for which you will need to refer to the regulatory framework.

For each region, regulatory documents establish a minimum value for the heat transfer resistance (R) of roofing structures. That is, the thickness of the insulation should be such that it provides this value, no less. The table below shows the minimum thermal resistance indicators for some cities of the Russian Federation:

If we take Moscow and the region, then for this area the value of R should be no less than 4.67 m2 °C/W. Having adopted the most popular insulation - URSA mineral wool, we find out from publicly available sources its thermal conductivity coefficient λ, equal to 0.045 W/m2 °C. After this, we calculate the thickness of the thermal insulation layer:

In this formula:

• δ – desired thickness in meters;
• R – standard thermal resistance, equal to 4.67 m2 °C/W;
• λ – thermal conductivity coefficient of cotton wool, assumed to be 0.045 W/m2 °C.

Hence δ = 4.67 x 0.045 = 0.21 m = 210 mm. Since the correct solution is to take the thickness of the roof insulation with a margin, and not at the minimum, the final result of the calculation is 250 mm. For convenience, below is a diagram showing the thermal conductivity of various materials:

By the way, this calculation method does not take into account the resistance of the roofing due to its relatively small value. Any metal roof, such as metal tiles, does not retain heat at all. Slate, ceramic and bitumen tiles behave a little better, but compared to the required insulation layer, their resistance to heat loss is negligible.

Advice. When choosing a thermal insulation material, be sure to pay attention to its density; the degree of thermal conductivity depends on it. The greater the density of the insulation, the stronger the material, but also the higher its ability to transmit heat. This will ultimately affect the calculated insulation thickness.

Roof insulation technology

It should be noted here that it is most convenient to properly insulate a pitched roof from the inside during construction. But it is better to insulate a concrete slab from the outside by laying a layer of insulation under a soft roof, rather than then hemming the ceiling from the inside. The thermal insulation “pie” diagram for this option looks like this:

First, a waterproofing membrane is laid on the concrete base, and on top of it is slab insulation of sufficient density (for polystyrene foam this is 35 kg/m3, mineral wool - at least 125 kg/m3). Then a cement-sand screed 50 mm thick (minimum 30 mm) is placed on top. The last stage is laying the roofing material, usually roofing felt. The technology is described in more detail in the video:

The composition of the insulation pie for gable roofs of regular and broken construction depends on the material used. But 2 rules remain the same for all options:

• A diffusion membrane must be laid under the roofing. It does not allow water to pass through, but allows steam to escape;
• between any roofing covering and the membrane there must be a ventilation layer through which air circulates from the overhang to the ridge, as shown in the diagram:

Important. If there is no diffusion membrane on an old, cold roof, then to insulate it you will have to remove the metal tile or slate covering and lay waterproofing on the outside. It is not allowed to stretch the membrane along the rafters from the inside, since it will not be able to drain water to the street.

Insulation with mineral wool

So, before installing metal tiles or slate, a diffusion membrane should be laid, ensuring a tight fastening using counter-lattice bars. The canvases must be laid horizontally, starting from the bottom, to allow for the flow of water over them, with an overlap of at least 10 cm, as in the photo:

The next step is internal insulation, for which you need to cut mineral wool and insert it between the rafters. It is necessary that the size of the insulation in width be a couple of centimeters larger than the interval between the rafters. This will allow you to insert it tightly, the cotton wool will not fall out.

If the width of the rafters allows you to insert cotton wool of the calculated thickness, then next comes a layer of film for vapor barrier, which is nailed to the rafters with lathing strips for installing the interior finishing. The width of the strip is 4-5 cm, due to which an air gap will appear between the finish and the vapor barrier. The diagram of the entire “pie” for roof insulation is shown in the figure:

When the width of the rafter board is not enough, the whole assembly becomes somewhat more complicated. You will have to lay the wool in a second layer, for which you need to horizontally nail bars of the required width to the rafters. Insulation is laid between them in the same way, and then according to the previous algorithm.

Note. To insulate a pitched roof with mineral wool, the composition of the “pie” remains the same, only the work will have to be done while standing on a scaffold, as when insulating the ceiling.

Foam insulation

When thermally insulating a roof with foam plastic slabs, it is recommended to follow the same sequence of actions as when insulating with basalt wool. One clarification: the slabs need to be cut not by 2 cm more than the interval, but by a couple of millimeters, since the material is quite dense and durable. It also doesn’t hurt to protect the foam from the inside with a vapor barrier, since this insulation is destroyed by prolonged exposure to moisture.

Advice. Instead of a vapor barrier, a layer of foil foam can be laid on top of the foam. The sheets are laid end-to-end and glued with aluminum tape.

Another thing is extruded polystyrene foam or penoplex, which repel water vapor. It is not necessary to cover them with film, and the dense structure allows you to fasten the plates with self-tapping screws. When the width of the rafters is not enough, the second layer of penoplex is attached to them exactly as shown in detail in the video:

Conclusion

The complexity and duration of the roof insulation process largely depends on the thermal insulation and physical properties of the insulation. The eternal rule applies: cheap material must be laid in 2 layers and protected from vapors, which means more labor will have to be invested. Expensive insulation materials are attached much more conveniently and quickly. The least of your worries will come from insulation with polyurethane foam, which is very important for a broken roof structure, but it will also require a lot of money.

Insulating the roof of a house is an important stage in the construction or major repair of a roof. The choice of technology for installing a heat-insulating layer depends on the configuration of the roof, the type of insulation and the requirements for the room located directly under the roof.

The need for roof insulation

How to insulate a roof to significantly reduce heat loss at home? First of all, you need to choose the right materials for insulation and strictly adhere to the installation technology. A high-quality insulated roof increases the thermal efficiency of the house by 15%, allowing you to turn the attic into a room suitable for year-round use.

The highest demands are placed on insulating the roof of a residential attic of houses located in areas with cold winters. The roofing pie of summer attics or exploited attics may include a thinner layer of thermal insulation. The roof, under which an unused attic is located, is usually not insulated - thermal insulation is mounted on the attic floor or the ceiling of the living premises. An uninsulated non-residential attic is well ventilated, which prevents rotting of the wooden elements of the roof frame.

When installing pitched and flat roofs, different methods of roof insulation are used.

Thermal insulation of flat roofs

How to make an insulated roof when installing a flat roof? It should be noted that a flat roof can be insulated both from the outside and from the inside.

It is recommended to first carry out external insulation, and based on the results of the winter season, determine the need for internal insulation.

The composition of the flat roof pie includes:

• vapor barrier;
• heat insulator;
• waterproofing layer made of rolled material;
• bulk layer (drainage + cement-sand mixture).

External insulation is most conveniently performed using mineral basalt wool. You can also use polystyrene foam and other rigid insulation materials. It should be taken into account that polymer insulation cannot be used when installing roofing coverings with high fire safety requirements.

Insulation of a pitched roof

The roofing pie of a pitched roof is made with insulation along the rafters. It is important to understand how to properly insulate the roof of a house in order to avoid mistakes that will ultimately lead to damage to wooden structures.

The most popular insulation in private housing construction is mineral wool. This is an easy-to-install, non-flammable material that can be purchased at a low price. But the structure of the wool itself promotes the accumulation of moisture, which causes a significant decrease in the thermal insulation properties of the material, and also, over time, provokes rotting of the elements of the rafter system. Thus, when creating insulation, it is important to provide for proper ventilation and vapor and waterproofing of the roofing pie.

Installation of a pitched roof heat insulator is carried out from the attic side during the construction or repair of the roof. If repair work is being carried out, before laying the insulation, it is necessary to check the condition of the rafters - rotting elements must be replaced with new ones. It is also worth treating all wooden structures with a fire-retardant compound.

The pitched roof pie includes:

• finishing roofing covering;
• hydrobarrier (layer of waterproofing material);
• heat insulator;
• vapor barrier;
• interior decoration (optional).

Proper roof insulation requires high-quality air exchange, for which it is necessary to create air gaps between:

• under-roof waterproofing and roofing;
• insulation and water barrier;
• vapor barrier and internal lining (if provided).

Air circulation (free inflow and removal) is ensured by special vents, one of which should be located in the roof overhang, and the second under the ridge.

Materials for thermal insulation of pitched roofs

Roof insulation technology involves the use of various materials. The most popular heat insulators include mineral wool and glass wool (in slabs or rolls), slab polymer materials - polyurethane foam, polystyrene foam. The principles of their installation are similar, but it is worth noting that installing slab material is much simpler and more convenient.

As waterproofing, roofing material or a waterproofing membrane is usually used, which is impermeable to water, but capable of removing moisture from the insulation. The vapor barrier layer can be made of:

• roofing felt;
• polyethylene film;
• glassine;
• foil materials laid with foil towards the attic.

To create a roofing pie with high functional characteristics, it is recommended to use a special vapor barrier membrane to create a vapor barrier: it removes condensation outside from the insulation and does not allow steam and moisture to pass into the roofing pie.

Stages of work on insulating a pitched roof

The roof insulation scheme is quite simple. First of all, you need to measure the distance between the rafters. The slabs of cotton wool insulation should be cut according to the results obtained, adding 1 centimeter. This will allow you to fasten the heat insulator between the rafters. This stage of work is greatly simplified if the roofing system is initially designed and installed based on the use of slab insulation boards of a certain width.

If there is no waterproofing between the rafters and the already installed roofing, you should first secure a water barrier. The membrane should envelop the rafters; it is most convenient to fasten it with a construction stapler to the rafters themselves and to the roof sheathing in the openings between them. The waterproofing must be installed under the eaves at the bottom of the roof to ensure moisture drainage. It should be taken into account that with this method of fastening the hydrobarrier, the insulation must be installed without the necessary air gap. For this reason, it is recommended to use a superdiffusion membrane as a waterproofing material.

If there is a waterproofing layer under the roofing, nails are placed on the rafters in increments of about 10 cm. The nails should be located at a distance of 3-5 cm from the waterproofing layer. It is necessary to stretch a polyethylene thread or cord between the nails, tamping them to the end. This will help create an air gap between the hydrobarrier and the insulation. If the heat insulator is planned to be fixed with a cord, and not with lathing for internal cladding, nails must also be driven along the outer edge of the rafters.

If, when deciding how to insulate the roof of a house, you chose cotton slab insulation, then the prepared elements must be slightly compressed and inserted between the rafters. When using stiffer foam boards and similar materials, it is important to accurately size them so that the boards fit snugly into the opening. It is recommended to carry out insulation in two layers. If you have to mount not solid sheets into the opening, but narrower fragments, joining them along the length or width, you need to make sure that the joints of the second layer do not coincide with the joints of the first. The heat insulator should not protrude beyond the plane of the rafter legs. If the rafters are not wide enough to install two layers of insulation, additional timber is nailed to them.

The roof is the first line of defense of a house, taking on all the blows of the elements, be it rain, hail, snow, wind or scorching sun. The effectiveness of its protective functions largely depends on the quality of insulation. We are talking about both direct heat loss, which accounts for up to 25% of all heat loss in the house, and about protecting roof structures from external factors. Therefore, during construction or renovation, it is very important to properly perform insulation and remember that there are no secondary elements in the design of the roofing pie.

Cold and warm roofing: design features

First of all, it is necessary to distinguish between these two types of roofs. Cold means with a cold attic and insulation of the house along the attic floor. Warm - with a residential attic and insulation between the rafters. Why is it important? The fact is that, regardless of the type of roofing, cold and warm roofs have different designs.

Inexpensive but durable waterproofing films are most often used as part of a cold roof. Their main task is to ensure effective removal of condensate and prevent it from entering the attic, including the insulated ceiling.

The procedure for insulating a cold roof

1. When installing a cold roof, the waterproofing film is laid perpendicular to the rafters. The membrane rolls are rolled out with an overlap of 100-150 mm and the joints are glued with construction tape.
2. Then the film is secured to the rafters with counter-lattice bars. After this, a sheathing is mounted across the rafters, onto which the roofing covering is attached.
3. For flexible tiles, a so-called “solid” sheathing is made, i.e. lay solid sheets of OSB or other similar material on the counter beams.
4. The ventilation gap between the film and the roofing can be minimal, especially since the attic itself is a ventilated room.
5. When the roof is ready, insulate the attic floor, not forgetting to install a vapor barrier under the insulation layer.

Construction and installation of a warm roof

Work on arranging a warm roof, as in the case of a cold one, also begins with laying waterproofing. At the same time, it is important to remember that a simple film can no longer be used, since the insulation will be located directly under it, which must “breathe”, releasing excess moisture into the atmosphere. Otherwise, the thermal insulation may become damp and will not perform its function well.

In order for the insulation to evaporate excess moisture, the waterproofing layer must be vapor permeable. Therefore, instead of films, hydro-windproof membranes are used, for example, ISOVER Vetranet (AM). Without allowing water to flow down and wet the insulation and rafters, it allows water vapor to pass from the bottom up. Another advantage of Vetranet (AM) is that it can act as a temporary shelter, protecting the structure from rain and allowing the installation of the roof covering to be postponed for up to two months.

Some homeowners are trying to save money and, instead of membranes, use cheap micro-perforated films, which, according to their manufacturers, also combine waterproofing properties with vapor permeability. However, not everyone knows that this is only validly observed as long as the film is still hanging. As soon as it comes into contact with any base from below, a leak immediately appears in this place. And in a warm roof, the waterproofing lies on a layer of insulation.

Important! Unlike a cold roof, in a warm roof the ventilation gap between the roofing covering and the waterproofing must be sufficient for all excess moisture to effectively evaporate, carried away by air currents ascending from the eaves to the ridge.

Calculation of counter beam for ventilation gap

• With a standard slope slope (25-40º), the height of the counter beam should be at least 50 mm, for steep slopes (more than 45º) - at least 40 mm. The flatter the slope, the worse the traction under the roof, so for slopes of 5-25º you need a counterbeam with a height of at least 60 mm, and for a slope of less than 5º - 100 mm.
• The length of the slope also matters. All given values ​​are valid for slopes up to 10 m long. If it is longer, then you need to increase the height of the ventilation gap by 10% or additionally install aeration pipes. More details on the calculation methodology can be found in SP 17.13330.2011 “Roofs”.

The ventilation gap should not be interrupted so that the air flows ascending from the eaves to the ridge do not encounter obstacles, and the water rolling down the membrane does not accumulate anywhere. Therefore, no crossbars should be placed across the beams of the counter-lattice.

Do-it-yourself roof insulation (step by step)

1. The insulation is installed after installing the hydro-windproof membrane. It is mounted from below, from the attic side, between the rafters and from the bottom up. With multi-layer insulation, all layers of thermal insulation material are laid with the seams staggered. If the thickness of the required layer of thermal insulation exceeds the height of the rafters, then they are built up with bars of the required thickness, which are stuffed perpendicularly.
2. A vapor barrier film is mounted on the bottom of the rafters. It is attached to the rafters with overlapping horizontal stripes, with the blades overlapping by 100-150 mm, using a construction stapler or nails with a wide head. The joints and places where the film is attached are sealed using vapor barrier tape or reinforced construction tape.

The disadvantage of using conventional film as a vapor barrier is the numerous tears and punctures during its installation. Even an experienced builder will not notice everything; as a result, the insulation may get wet in places. Therefore, for high-quality vapor barrier, we recommend using specialized membranes, for example, ISOVER Paranet (B).

This is a durable two-layer vapor barrier, which is installed with the smooth side facing the insulation and reliably protects the roofing cake from fumes. The rough inner surface allows you to retain drops of condensation that form in heated rooms in winter.

Choice of insulation

This is a responsible task. Thermal insulation should be lightweight, easy to install and at the same time effective. Of the modern varieties of mineral wool, quartz wool best meets these conditions. The thermal conductivity of its light grades is 0.037-0.041 W/(m*°C), which practically corresponds to the performance of polyurethane foam. At the same time, quartz wool is 1.5-2 times lighter in weight than stone wool with similar characteristics.

Thanks to thin (3.5-5 microns) and long (25-30 cm) fibers, it is characterized by high strength and elasticity, therefore it fills the entire space between the rafters without gaps or cracks, preventing the formation of cold bridges.

To insulate the roof and attic floors, it is advisable to use cotton wool in rolls, since it is more convenient to install it in solid pieces along the entire length of the rafters and a compressed roll holds 1.5-2 times more material than in a package with compressible slabs. As a result, the cost of transporting insulation is reduced by 1.5-2 times.

As a rule, insulating the roof of a house with your own hands for permanent residence involves laying mineral wool in two layers, since one layer (maximum 150 mm) is not enough for the harsh Russian winters. In this case, for the first (outer) layer you can use ordinary quartz wool (for example, ISOVER Warm Roof with increased sound insulation and moisture resistance), and for the second - ISOVER Pitched Roof Comfort with a craft vapor barrier coating. The insulation is installed between the rafters with the backing down, after which it is glued to them with ISOVER Paranet adhesive tape.

Mineral wool does not rot or decompose from exposure to moisture

Is it possible to insulate a cold roof?

You won’t be able to simply “add up the insulation” of a cold roof in an old house: the covering will have to be completely removed. This is due to two reasons: the need to organize a ventilation gap of sufficient height and to replace the waterproofing film with a vapor-permeable membrane. There is no way to do this from the attic side. True, if the house has “history,” then the roofing usually still needs to be replaced.

If it was built relatively recently, then completely covering the roof means incurring serious costs. Therefore, it is better to make a decision in advance about what will be located above the top floor. It’s even better to play it safe: even if you decide to make a cold roof, you can use a hydro-windproof membrane instead of a film and choose a thicker counterbeam. It is possible to equip the attic even after a few years, the main thing is that it is possible in principle.

So, all decisions have been made, materials have been selected, which means you can start working. The main thing to remember: there are no trifles in the roofing business! A properly installed roof will reliably protect the house from cold, heat and bad weather and will serve faithfully for many years.