How to insulate the roof of the house with your own hands

Well-calculated and well-assembled truss system, strong, reliable, non-leaking roofing - all this is wonderful. But we must not forget about one more thing - the effective thermal insulation of their homes from the upper direction, that is, from the side of the roof and attic floor. Inadequate or improperly executed insulation of these building elements becomes not only the cause of little comfortable living conditions in the house, but, crucially, it dramatically reduces the normal life of many building materials and structures constructed from them.

How to insulate the roof of the house with their own hands

Usually the questions of thermal insulation of the roof are thought out even at the design stages of the rafter system or attic floors, and the insulation system itself is installed parallel to the construction. But if suddenly, due to some circumstances, it turns out that the roof in the purchased house, for example, is not insulated at all, or the effectiveness of thermal insulation is clearly insufficient, the owners will have to deal with this issue themselves. That's when the information comes in handy how to insulate the roof of the house with your own hands, given in this publication.

Why is it necessary to insulate the roof? Why is it necessary to insulate the roof?

2 General principles of roof insulation

3 Roof insulation materials

• 3.1 Roof insulation
• 3.2 Films and membranes

4 Which layer of insulation is required?

5 Carrying out roof insulation

• 5.1 Workflow variants
• 5.2 Important nuances of roof ventilation
• 5.3 Avoid the most common mistakes!

6 Video: roof insulation from within with the materials of "Ursa"

First of all, it is necessary to accurately represent - how important is the necessity of warming the roof.

• Climatic conditions in most regions of Russia can not be called "soft" - even in the southern regions, very harsh winters often fall out. Heating costs during the cold period of the year usually become prevalent, and "eat up" a large part of the family budget. But with poor-quality heat insulation, energy consumption is converted into "money for air".

Look at the approximate scheme of the heat loss of an insulated or not insulated private house:

A roof with a roof that does not have an effective thermal insulation simply "steals" almost a third of the energy spent on heating the house. Of course, there can not even be any profitability. But even with such a completely unjustified expenditure of funds, it will be practically impossible to create a really comfortable microclimate in the house.

• With the advent of summer heat, the lack of thermal insulation also turns into a serious problem. The large roof area works as a kind of "solar collector", warming up in the sun and then transferring this flow of thermal energy down to the premises of the house. As a result - in the summers there is nothing to breathe, or the climate technology works with increased intensity, which, again, leads to absolutely unjustified costs.
• Absence of thermal insulation in the most negative way affects the condition of building structures. The normal life activity of a person is always accompanied by the release of large volumes of water vapor, which at the boundary of heat and cold, in the so-called "dew point" condenses, turning into water. The over-saturation of wooden parts of the roof structure with moisture leads to activation of rotting processes, to destructuring of wood due to cycles of freezing and thawing with the appearance of deep cracks, to the appearance and development of colonies of pathogenic microflora-mold and fungus, to the appearance of nests of insects.

The absence of thermal insulation can significantly shorten the life of the entire roof structure

Installation of thermal insulation allows you to shift the dew point to the outside, in the upper layers of the insulation, so that condensed moisture does not fall almost on the main structural elements of the roof structure, but freely evaporated into the atmosphere.

• Finally, the thermal insulation of the roof opens the possibility of the most rational use of existing areas. The insulated attic can very well become a very convenient utility room, and with sufficient height and connection to the heating system - a full-fledged living room.

Even a small loft can be turned into a cozy living room.

Extra room will never interfere. And if there is a deficit in the area - especially, since it will be easier and cheaper to equip an attic under a dwelling in any case than to erect a capital outbuild from scratch.

General principles of roof insulation

First of all, the owners of the house should determine in advance how the roof structure will be insulated. Here several options are possible.

Various options for thermal insulation of the roof of the house

• Flat roofing, which does not involve any loft space at all. In the private construction of residential buildings, this approach is used extremely rarely, therefore this topic will not be considered in the framework of this article.
• The second option - the attic space is not considered by the owners as a useful additional space. In this case, the main emphasis is on the quality thermal insulation of the attic floor, and to create a good ventilation of the under-roof space, in order to avoid the accumulation of dampness in it. This version of warming is also "put out of brackets" - it is dedicated to a separate publication.

What should I do if the attic is planned to be left "cold"?

In this case, the attic is to be insulated. How to properly insulate the ceiling under the "cold" attic - read the special publication of our portal.

• And, finally, the third option - the attic space is completely insulated. In this case, the thermal insulation system will be mounted directly under the roof slopes. This scheme can be considered optimal, both providing and normal degree of insulation of residential from the upper direction, and as giving, with proper installation, maximum protection of the roof system from external factors.

This is the kind of thermal insulation scheme that will be the subject of this publication.

First of all, it is necessary to understand the principle of thermal insulation of roof rajids. There is such a common term - "roofing pie".Such a name symbolizes the multi-layered thermal insulation system, and each of the layers is important in its own way, as it plays a certain important role. Consider the structure of the "roofing pie" in not the most complicated example.

The basic structure of the "roofing cake"

"The fundamental foundation" is always the rafter( position 1) - they serve as a bearing structure for both the roofing and the whole insulation system as a whole.

Between the rafter feet, the heat-insulating material( pos.2) is placed as tightly as possible without gaps.

The bottom layer of the insulation must be covered with a vapor barrier film( item 3), so that the material is not saturated with moisture, water vapor, and does not lose its qualities.

Bottom vapor barrier film holds the crate( item 4), which becomes the basis for fixing the interior of the attic( attic).

On top, on the side of the roof, the insulation is also closed with a special film coating( item 5), but it is of an entirely different property. This layer is designed to create waterproofing barter( in case of accidental leakage of the roof water will not get into the heater), to protect the thermal insulation from the erosive effects of the wind. But, at the same time, this coating should not become an obstacle to the free release of water vapor - condensate formed at the junction of heat and cold, in the "dew point" should have a free outlet into the atmosphere. This is ensured by the use of special membranes and the creation of ventilation gaps. This diagram shows a counter-board( item 6), which creates a gap between the heater and the membrane. There may be other solutions - this will be discussed below.

In any case, an air gap must always be created between the waterproofing windproof membrane and the roofing itself. For this, a counterbrus( pos.7) with a thickness of at least 50 mm is punched along the rafters.

Next, the crate( item 8) comes under a concrete roofing( item 9).The cladding can be sparse, that is, the boards or boards are mounted with a certain step. For some roofing coverings, a continuous crate is mandatory. Made, for example, from moisture-proof plywood or OSB.In any case, the ventilation gap will be provided.

As already mentioned - this is the basic scheme. In practice, there may be other variants that are more complex or, on the contrary, somewhat simplified( for example, without counter-plates, pos. 6), but the principle does not change.

Materials for roof insulation

The choice of materials for roof insulation is a special issue, since the type of roofing cake often depends on the type of thermal insulation. Let's start with insulation.

Heat insulation for roofing

• First of all, you need to immediately "push aside" bulk materials, such as vermiculite or expanded clay. No words, the materials are good, clean in terms of ecology, and are great for thermal insulation of many building structures. But using them for a sloping roof - this means significantly complicate your task. Ensure a uniform distribution of bulk material in the cavities of the roof structure, especially with a significant slope steepness, more than 20-25% - is not so simple.

Thermal insulation scheme with claydite

Undoubtedly, there is no impossible in this matter. However, it should be borne in mind that the coefficient of thermal conductivity of the same expanded clay is in no way comparable, for example, with mineral wool or styrofoam, that is, in order to achieve equal thermal insulation parameters a very considerable layer of backfilling will be required. And if we consider that the density of expanded clay is still significantly higher, then the construction of the insulated roof will turn out to be excessively thick and massive.

Bulk materials are good for walls, floors or ceilings. And for the roof there are still simpler and more effective solutions.

• For the insulation of the roof, polystyrene foam can be used. This material is characterized by high thermal resistance, it is light, easy to install, easy to process.

Two types of expanded polystyrene can be used for insulation: non-pressed, more commonly known as polystyrene, and extrusion. Although extrusion foam polystyrene and higher in value, preference should still be given to him. This is due to the special structure of the material with closed pores - the panels are much stronger, have higher thermal insulation qualities, steam-waterproof, that is, for them, in fact, you can not even use waterproofing membranes.

Polyfoam is cheaper, applies generally to the most affordable insulation materials. But its mechanical strength is low, water absorption is already much larger. In addition, rodents and insects are very popular in the foam plastic.

Comparative characteristics of expanded polystyrene and extruded polystyrene at an average thickness of 50 mm

Description of material characteristics	Extruded polystyrene foam	Pressed foam
Illustration
Water absorption in% by volume for 30 days, no more	0.4	4
Water absorption in% by volume for 24 hours, not more	0.2	2
Water vapor permeability, mg / m × h × Pa	0.018	-
Thermal conductivity in dry condition at a temperature of( 25+ -5) C, W /( m × oC) not more than	0,028-0,035	0,036-0,050
Sound absorption coefficient, dB	23-27	42-53
Limit of strength at static bending, MPa	0,4-1,0	0,07-0,20
Compressive strength at 10% linear deformation, MPa, not less	0,25-0,50	0,05-0,20
Density, kg /m2, within	28-45	15-35
Operating temperature range, ° C	-50 to +75	-50 to +70
Flammability	From G1( moderate flammability) to G4( combustible)

Bothother material is almost impossible to perfect, without cracks or lumens to be inscribed in the "nests" intended for it between the rafters, that is, additional sealing of the insulation layer with the help of a mounting foam is required.

Heat insulation of roof slopes with extruded polystyrene foam in two layers. Clearly visible areas of adherence to the rafters

are filled with mounting foam. But the main disadvantage of foam polystyrene insulation is still high fire hazard, which is extremely important in the roofing system. None of the types of expanded polystyrene can be considered completely incombustible, and many types of foam plastic generally belong to class G4, that is, they burn well and, by melting, spread fire.

Styrofoam is not only able to burn, but also releases extremely dangerous toxic substances

Moreover, the burning of any polystyrene is always accompanied by the release of extremely toxic products that can cause severe poisoning and chemical burns of the respiratory system. People who inhale such smoke, the chances of being saved in a fire in people become minimal. It is worth thinking about this before deciding in favor of expanded polystyrene.

• The use of mineral wool heaters seems to be optimal in all respects. But here we need the right approach.

Slag as a roof insulator should not be considered

- Absolutely no use of slag - this material is short-lived, strongly absorbs moisture, quickly cracks, poorly holds the mold, and besides - has a very ambiguous chemical composition, depending on the quality of the feedstock - blast furnace slags. Very often such mineral wool is extremely acidic, which leads to activation of corrosion processes on building structures.

Quality glass wool - a good material, but still not without serious drawbacks

- A good insulation can be glass wool - it is relatively inexpensive, has good heat transfer resistance. All would be well, if not for its significant shortcomings. And to these can be attributed weak elasticity of glass fibers - they are brittle, crumbling, which creates many problems not only for installation. Even during operation, it is difficult to exclude the entry of microparticles into the atmosphere of living quarters - and this is the prerequisite for the appearance of allergic reactions, especially in people who have such a predisposition.

Another of its drawbacks is the strong absorption of water, which is not good for under-roof warming. In addition, glass wool is still prone to gradual caking, settling, and this, in turn, leads to a reduction in its thermal insulation characteristics.

- The optimal option can be considered the use as a heater blocks of basalt mineral wool. Basalt fibers are strong and resilient, so the material does not sag with time, it is easy to lay between guides, beams, rafters, etc. Almost allergic reactions such wadding does not give. Special hydrophobic impregnation of the material reduces water absorption to a minimum. At the same time, basalt wool perfectly passes water vapor, which is very important for a normal balance in the insulation structure.

The optimum option for roof insulation is the use of basalt wool blocks.

The material is easy to process, it perfectly keeps the shapes and sizes attached to it. Special elastic properties often allow the installation of basalt mineral wool blocks in general without additional anchorages - the vorspa between the rails of the battens or the rafters.

Moreover, some manufacturers, in particular, Rockwool, produce extremely easy-to-install panels with a spring-loaded edge( "flexi" technology).Such units after installation are reliably fixed between the load-bearing elements of the frame.

Stacking of insulation boards equipped with a spring-loaded edge "flexi"

The most important advantage of mineral wool is fire resistance. The material is classified as non-combustible and does not emit hazardous substances for human health.

One of the best options is the ROCKWOOL LIGHT BATTS

insulation boards. As an example, the characteristics of the insulation boards from the Rockwool basalt wool, LITE BATTS, can be cited. It is a universal material suitable for various types of thermal insulation works. The best way they are suitable for the warming of the roof slopes.

• ExcellentThe results show technology atdusting of insulation materials on the internal surfaces of the roof rails. In particular, more and more often the owners of houses choose to use sprayed polyurethane foam

Spraying of polyurethane foam insulation on the internal surface of the roof slope

In the context of this publication, this option will not be considered, Roof insulation. And for this technology requires special equipment, equipment, raw materials. And without the work experience, it will not be easy to perform such thermal insulation.

Modern thermal insulation technologies - application of

foamed polyurethane For such a thermal insulation technology of building structures, there is a "train" of enthusiastic as well as very critical reviews. To understand the advantages and disadvantages of foaming with is the special publication of our portal.

Films and membranes

Creation of "roofing pie" involves the use of films and membranes for various purposes. In this issue, it is necessary to clearly understand what role a barrier is assigned to, since a violation of the installation procedure will not only lead to a reduction in the insulating qualities of the design being constructed, but also to its rapid deterioration.

• Let's start with a water vapor barrier film that is attached to the room. Its task is to prevent the penetration of water vapor into the layer of insulation, the concentration and overpressure of which in the premises where people live is usually much higher than in the open air.

For these purposes, conventional polyethylene films with a thickness of at least 200 μm can be used. Well retained steam foil materials, which, in addition, are able to reflect the heat flow to the side of the room. There are also special parabarrier films, which are a multi-layer structure made of polypropylene, woven polypropylene cloth and a special coating with a viscose component that does not allow condensate drops to roll down - they dry out on the surface with normal ventilation. By the way, such films, under certain conditions, can also be used to create an upper waterproof barrier - this will be discussed below.

One example of a vapor barrier film

In order to avoid "loopholes" when creating a vapor barrier layer, overlapping of the canvas, as well as their abutment to the surfaces, will need to be sealed with waterproof tape.

• Another thing - the membrane, which is stacked over the heater. Their function is to prevent direct atmospheric water from entering the insulation( for example, if the roof is damaged), to protect the material from wind blowing, but not to interfere with the free flow of steam, in order to avoid condensation. The venting gap above them will promote active evaporation of moisture into the atmosphere.

But the membranes are also different, and this is reflected in the overall "construction of the roofing pie".

- Superdiffusion membranes are usually a non-woven polymeric material of fine synthetic fibers, characterized by the highest vapor permeability, more than 1000 g / m2 per day. Such membranes, in turn, can be of one-sided type - it is necessary to make sure that the right side( usually with the manufacturer's logo) is facing upwards, or two-sided, the laying of which can be done arbitrarily, either side upwards.

- Diffusion membranes - as a rule, they are polymeric( polyethylene or polypropylene) films with fine perforation. Miniature holes let steam through, but water, due to its inherent surface tension, can not penetrate from above. Such membranes are much cheaper, however, and the steam-transmitting ability is already lower.

Examples of superdiffusion and diffusion membranes

The features of the application of these or other membranes, as well as how they affect the construction of the "roofing pie" will be covered below.

Which layer of insulation will be required?

Now, if the insulation material is selected, it's time to decide which layer of thermal insulation is necessary. It is possible to use exemplary recommendations, but it is better to make a simple calculation - it will accurately show the thickness of the required insulation. Insufficient layer will interfere with the creation of a comfortable microclimate. And redundancy - also not needed - this is unnecessary costs and weighting of the whole "roofing pie".

So, in order to ensure the necessary microclimate in the residential building even in the harshest winters, the resistance to the heat transfer of building structures( walls, floors, coatings, floors, etc.) must meet the normative design values. These parameters are set by SNiP for each region, depending on its climatic conditions. To bring the table does not make sense - it would take up too much space. It is better to place a map - a map of the territory of Russia, according to which it will be easy to find the required table parameter.

Map-scheme of the territory of the Russian Federation with the values ​​of the standardized resistance to heat transfer

In our case, once the roof is insulated, and it is planned to use the attic as a useful area, a red meaning is taken for coatings.

So, the value is known. It should be composed of the sum of the values ​​of the thermal resistance of all layers of the "roof cake", which are involved in thermal insulation.

Rtab = R1 + R2 +. .. + Rn

R1 and further, up to Rn is the resistance of each of the layers of the structure. But in our case, there are not so many of them. Seriously you can only consider the heater itself, and the interior finish of the attic.(wood, lining, plasterboard, etc.), but the roof covering itself, whatever it is, does not take any part in this, as it is separated by a ventilating gap with free circulation of the outside air.

The roof covering is not taken into account when calculating the thermal resistance, as it is separated by a ventilation gap.

The resistance value Rn( m² × ° C / W) is expressed by the formula - the ratio of the thickness of the layer to the coefficient of thermal conductivity of the material of its manufacture.

Rn = δn / λn

δn - layer thickness in meters.

λn is the thermal conductivity of the material.

Since in our case we take into account only two layers - the insulation and the internal covering of the walls( if it is solid), then the formula for calculating the required thermal insulation thickness is obtained as follows:

δut =( Rtab - 0,16 - δob / λob) × ll

0,16 is the approximate level of thermal resistance of air from both sides of the "roof pie".

δут and λут - thickness and coefficient of thermal conductivity of the heater;

δob and λob - the same parameters, but for the inner skin of insulated rays.

Now, having the necessary tabular data, having measured the thickness of the interior trim layer and taking into account the coefficient of thermal conductivity of the chosen insulation, it is easy to find the required thickness of the thermal insulation layer. This dependence is embedded in the calculation calculator below; this will be easier for the reader.

Calculator for calculating the required thickness of the roof slopes

The obtained value is rounded up and leads to the standard produced thicknesses of the selected insulation material. Very often we have to use two-layer insulation - this will be discussed below.

Carrying out the roof insulation

Usually, the calculations of the future roof insulation system are carried out preliminary, even at the design stage of the roofing structure itself. The fact is that it is much more convenient to provide in advance the dimensions of the thermal insulation material and, in accordance with this, set the step of installing the rafter legs. For example, the use of basalt wool blocks with a width of 600 mm is planned. The rafters are installed with the same pitch, and due to the thickness of the beam, the clearance between them is about 550 mm - an excellent parameter so that the vospors can tighten the insulation as tightly as possible.

The height of the beam of the rafter's leg also plays a role. It should be enough for laying the heater and leaving, if necessary, an additional ventilation gap. There are situations when the beam has to be increased upwards, nailing additional racks to it( one of these options was shown on the "roofing pie" scheme).

All wooden components of the roofing structure must be pre-treated with appropriate special formulations to increase the resistance of the wood to biodegradation and to fire.

Processing of the roofing system with antiseptic and fire-retardant impregnation

Workflow variants

In what direction is the work to create the "roofing pie"?On this account, there is no unity of opinion. It seems that the bottom-up sequence is begging, in which the roofing becomes the final "chord".However, for such an approach it is necessary to guess a fairly long fair period, since it is unlikely that it will be possible to fully mount the insulation, cover it with a membrane, perform the necessary crate( and sometimes even a grating) and cover the roof for one to two days. But even one sudden storm cloud is capable of completely ruining all the work - to soak through the insulation, leading to its uselessness. In addition, with this approach, the main work on the insulation of the roof will have to be carried out at altitude, which is far from always convenient and safe.

Different approaches to work: first insulation, then waterproofing( left), or vice versa( right).

From this point of view, it seems more profitable and reliable first to provide reliable waterproofing of the roof structure - fastening the membrane, installing the lathing and, probably, immediately and covering the roofing. After that, there is an opportunity, completely without fear of the vagaries of the weather, without much haste, to deal with the issues of warming, working from below, in safe and convenient conditions, on the attic floor.

However, often there are situations when any method becomes the only possible. A typical example - two-layer insulation with the removal of the second layer on the outside of the rafters. And such a case is by no means a rarity - such a scheme makes it possible to minimize the number of cold bridges to a minimum, and, in addition, to save usable space in a cramped mansard room. A typical example is shown in the diagram below:

Two-layer roof insulation scheme with second layer removal to the outside of the

rafter system. With this approach, the work will be carried out in the following order:

The first step on the rafters( item 3) from the attic side is fastening the vapor barrier film. 1).It is usually covered with horizontal stripes, moving gradually from top to bottom, with mandatory overlapping of the webs of at least 100 ÷ 150 mm, and sealing these overlaps with waterproof construction tape. It is necessary to seal all the places of abutment of the film coating to other surfaces - walls, floor, pipes, etc.

Often, at the same stage, the inner lining( item 2) of the attic space( attic) is performed. In the presented scheme there is a small inaccuracy - it is not recommended to press the skin directly to the vapor barrier, as this can cause the accumulation of dampness in this narrow, unventilated slot. It would be more reasonable to fill rafts with a thickness of at least 10 ÷ 20 mm or to mount a control bar of the same thickness, in increments depending on the selected finishing material. After this, it will be possible to bravely coat the inner room.

All further work will already be performed from the top.

Between the rafters, on the insulated vapor barrier, the slabs of insulation material( item 4) are laid, as tightly as possible, without leaving any gaps. On a plan, their thickness should be equal to the height of the rafter beam. For example, 150 mm thick mineral wool plates are laid, and calculations show that a 200 mm layer is required for reliable thermal insulation. So, we will add one more layer in 50 mm from above.

For this, perforation bars perpendicular to them are filled with bars of the crate( item 5) of the required height( in our case - 50 mm).The step between the bars should ensure a tight installation of the heating plates( item 6) - this has already been mentioned above. In addition, try to spread out the slabs in such a way that the joints of the first row heater are overlapped - so the cold bridges are minimized.

waterproofing diffusion membrane flooring The next step is laying the waterproofing vapor permeable membrane( item 7).It is attached with staples to wooden parts. Plank it with horizontal stripes, moving from the cornice overhang to the ridge. Thus, each upper web will be found on the bottom, providing, if necessary, a drain of moisture down. The lapping should be at least 100 ÷ 150 mm( often a liner overlapping line is applied on the membrane).Be sure to pay attention to the "working" side of the membrane - this can not be mistaken. As the membrane is plastered, it is additionally fixed by counter-brushes( item 8), which, in fact, create the same ventilation gap between the membrane and the roof. Its height should be at least 50 mm.

A crate( item 9) is mounted above the counterbars, with parameters depending on the selected roofing. And the last step will be, actually, the roofing.

By the way, qualitative membranes are quite capable of becoming a temporary protection of the heating system, that is, deteriorating weather becomes not so fatal.

And here is the completely opposite situation when the second layer of insulation is fixed from the inside:

Warming is also a two-layer, but the second layer is attached from the attic space

With this approach, it will probably be more profitable to start with fixing the waterproofing and the roofing, perhaps - and immediately mount androofing. And then move to the attic and continue working there, in sequence: the insulation - the main layer, the lath under the second layer, the installation of the second layer of thermal insulation, the plating of the vapor barrier, the counter rails or the lath under the hull and, finally, the skinning of the ramps from the inside with the selected material.

With single-layer insulation, both versions of the sequence of performance of insulation, waterproofing and roofing work are possible.

Important nuances of roof ventilation

As already mentioned, in order for moisture to evaporate freely into the atmosphere, a gap of at least 50 mm should remain between the vapor permeable membrane and the roofing coating in any case. However, in a number of cases this is not enough. There are three possible options:

• When using a quality superdiffusion membrane with a vapor permeability of over 1200 g / m²( some can even go up to 4-5 thousand grams), there is no gap between it and the insulation layer - moisture can find a free outlet.
• If diffusion membranes are used with the quality "senile", with a vapor permeability of less than 1000 g / m², then another ventilation gap is required between them and a heater, at least 20 ÷ 40 mm. This can be ensured by increasing the height of the rafter beam or by increasing its height with the bar.

When fastening the membrane to the rafters in this situation, do not pull it - it should hang slightly so that the material does not rupture when the temperature is lowered( shown in the illustration, the right fragment).

Provides a sagging membrane( left) and a simple conductor to limit the landing of the heating block.

And how to ensure that when laying insulation boards between the rafters from below provide the necessary clearance over them? It is solved by the device of a simple conductor( in the illustration - the right fragment).At a tedious height, small carnations are stuffed, between which stretches in the perpendicular and diagonal directions of the line. By the way, in the same way, you can solve the problem of temporary fixing the insulation blocks from below, when, for example, because of the small steepness of the slope or insufficiently tight fitting to the rafters, they strive to fall down.

• Finally, the third case, in view of the lack of the possibility of obtaining diffuse membranes, it is necessary to perform under-roof waterproofing from a film material that does not possess vapor-permeable properties.

In this case, two ventilation gaps are also provided, but their height should already be increased to 60 ÷ 80 mm. By the way, such a trip is often practiced in cases where for increasing the load-bearing capacity rafters are used from a beam of great height much greater than the thickness of the necessary insulation. The use of expensive diffusion membranes in this situation looks simply unprofitable.

In any scheme, there must be a way of free movement of air from the eaves to the roof ridge. On the cornice overhang there are slots for ventilating the under-roof space, which can then be closed, for example, by punching perforated spotlights. At the top, on the ridge, there should also be a free outlet for the air flow. This is provided either by the design of the ridge itself, or by the installation of special ventilation windows-hoods.

Provision should be made for free movement of air to ensure ventilation. Bottom eaves can be covered with perforated soffits

. If the circuit assumes two ventilation gaps, above and below the membrane, then for the bottom stream, you also need to think about the way out. If an expensive superdiffusion membrane is used, then this is not essential. In any other case, a ridge with a width of at least 20 mm should be made in the ridge part.

Try to avoid the most common mistakes!

It makes sense to list the most common mistakes made by newcomers when warming the roof slopes.

• Unjustified savings on insulation material. The calculation proposed above shows the minimum permissible thickness, which always has to be reduced to standard dimensions only in the BIG side. Insufficiency of thermal insulation is an inevitable energy loss.
• Insufficient attention to difficult areas of the roof, for example, to places of connection of rafters with mauerlate. In these areas there are often cavities not filled with a heater, which become not only "bridges", but the real "highways" of cold.
• When using rigid heaters( expanded polystyrene) - loose fit of the panels to wooden structures and to each other. All lumens should either be caulked with fragments of the material, or be filled with mounting foam, so that even small crevices do not remain. It is better to use both konopatku, and foam.
• Use for truss system and roofing of non-dried wood. The sawn timber must undergo the drying process, and the permissible moisture level in them is no more than 20%.It makes sense after purchasing the material to give him the opportunity to dry up further, providing the necessary conditions for this. At the same time, it is strictly forbidden to cover the stack with a polyethylene film.
• Insufficient thickness of ventilation gaps. Disturbance of normal ventilation always leads to the accumulation of dampness, extremely dangerous for the roofing structure.

Do not forget about the vent rupture of the membrane in the area of ​​the ridge!

• Ignoring the requirement to provide a rupture in the layer of waterproofing in the area of ​​the ridge. As a result of this omission, a "wet dome" is inevitably formed at the top point, which will lead to the rotting of the timber on such an important part of the rafter system.
• And, finally, one should never lose sight of the fact that an attic space, insulated by a similar technology, using an internal vapor barrier, turns into a sort of "thermos".In order not to turn it into a real "hotbed", an effective ventilation system, natural, or even forced, must be provided.

At the end of the article - a small video lesson on the heat insulation of pitched roof

Video: roof insulation from inside with materials of "Ursa"