Insulation of the cornice, how to properly close the contour of the roof and wall. Everything you wanted to know about roof insulation

A self-built and equipped house is the real pride of any owner. An integral part of the arrangement of any residential building is the internal insulation of the roof. And if in most cases there are no problems with the thermal insulation of the walls, then the insulation of the roof structure can lead an unprepared master into bewilderment. Therefore, before proceeding to the practical part, study all the theoretical recommendations proposed below.

After installing the insulation and all related elements, the roofing system will look like a puff "pie". At the heart of the design is a system of rafters. All other elements are laid and fixed on it.

Modern roofing "pie"

In the classic version, the layers of the cake, starting from the finish roofing, are placed as follows:

roofing;
crate for mounting the finishing material. May be continuous or sparse;
bars of the counter-lattice. Needed to create a ventilation gap under the roofing material;
waterproofing film;
heat-insulating material;
vapor barrier material;
crate for mounting insulating materials and inner lining;
interior lining material.

A properly equipped roofing pie will significantly reduce heat loss in cold weather and prevent overheating of the space under the roof in the heat. Waterproofing will protect the insulation from atmospheric moisture, and the vapor barrier material will prevent the formation of condensate and the appearance of all the problems that accompany it.

What to insulate?

On the modern market there is a huge range of materials that can be successfully used for internal roof insulation. Try to avoid excessive savings - the materials must be of high quality.

Insulation parameters

When choosing a suitable insulation, you need to pay attention to a number of basic characteristics of the material, namely:

the weight. The heavier the insulation, the more significant the load it will exert on the roof. This imposes a number of additional requirements for rafters and lathing - their configuration and strength must correspond to the characteristics of thermal insulation;
thermal conductivity. It is better that this parameter be as low as possible, if possible no more than 0.04 W / m * S;
resistance to adverse external influences.

Preferred heaters

Not so many materials meet the above requirements. Among all the existing options for heaters, professionals recommend giving preference to mineral wool heat insulators and foam panels. Ceteris paribus, mineral wool is more preferable.

Additional insulation materials

In combination with a heater, the roof will need to be additionally insulated using vapor and moisture insulating materials. For roof waterproofing, polyethylene and roofing felt are usually used. These materials perfectly resist moisture.

The vapor barrier layer is best equipped with the use of special membranes, glassine or modern foil materials.

Regardless of the chosen insulation (installation is still carried out in the same sequence), in the process of performing work, you must adhere to a number of basic recommendations, without which you can not count on high-quality internal roof insulation.

All rules can be combined into one brief summary of tips, namely:

Thus, even before the start of thermal insulation work, the master needs to study a fairly large amount of information and remember a number of important requirements. The work must be done with the highest quality. Properly equipped insulation will make living in the house as comfortable as possible and will significantly reduce the cost of space heating.

Use the recommendations received and remember: you need to insulate with the obligatory installation of vapor barrier and moisture barrier layers. Only such a complex will make it possible to obtain a reliable, durable and resistant to any adverse external influences roofing system. It is better to do everything right at once and live quietly in a safe house than to patch holes in the roofing cake after every heavy rain.

Preparation for roof insulation

The order of insulation remains almost the same, regardless of the type of roof, the materials used and other points. Having dealt with the main points of thermal insulation work, you can successfully apply them in practice.

First of all, carefully prepare the roof for the upcoming internal insulation.

First step. Examine the truss system. If rotten and damaged elements are found, replace them with new parts.

Second step. Treat all wooden elements with an antiseptic.

Third step. Check the condition of pipelines and electrical wiring, if these communications are laid under the roof.

Roof Insulation Guide

Proceed to work on the internal insulation of the roof. The event is held in several stages. Go through each of them sequentially, not forgetting the recommendations received earlier.

It is assumed that the rafters, lathing and other necessary elements have already been installed and you just have to mount the insulating materials, and then lay the finish roofing.

First step - vapor barrier

Lay the film with a 10 cm overlap. To attach the vapor barrier to the bars, it is convenient to use a construction stapler with staples. Tape all seams twice. Be especially careful and thorough when sealing various difficult areas, such as the joints of the film with pipes, walls and other structural elements.

The second step is warming

ECOTEPLIN - roof insulation

Lay the selected insulation in the cells of the crate. Usually, the crate is assembled with the expectation that the step between its bars is a couple of centimeters less than the width of the insulation, so you can place the heat-insulating plates as tightly as possible. Directly, the bars of the crate should be nailed to the rafters perpendicular to them.

With a strong desire, you can do without the crate - you stuff nails along the edges of the rafter legs and pull the wire between them. She will hold the insulation plates. However, it is better not to abandon the crate - it is more reliable with it.

The insulation itself is usually laid in 2 layers. In this case, the top layer must be laid with a certain offset relative to the bottom one - it is impossible for the joints of the insulation plates of both layers to coincide.

The third step is waterproofing

Place the waterproofing film so that it completely covers the insulation, crate and rafters. To fix the film, it is most convenient to use a construction stapler with staples.

Bring waterproofing under the roof overhang - this will create the conditions necessary for the effective removal of water in the future.

In the end, you just have to lay the selected roofing material on the roof.

Thus, independent internal insulation of the roof, although it is a very important and responsible event, there is nothing super complicated in its implementation. Do everything in accordance with the instructions, and very soon your house will become really cozy and warm, and heating costs in the cold season will decrease significantly.

Successful work!

Video - Do-it-yourself roof insulation from the inside

Not at all a simple knot, as a rule, we often ignore it, both by roofers and façades. They often do it poorly, because it is closed with hemmed material, if you can’t see why try. Let's figure it out.

Just imagine, the last crown of the box at home, the ends of the rafter legs fall outside the perimeter of the well of the house, pockets are formed between them, to plug these pockets they push in a sawn board on the knee, and that’s it, the fit at the board is bad, they put it in order to be, but in the case of insulation along the rafters, this node is the completion of the wall and the insulation contour along the rafters. Meanwhile, in this place of the wall and roof, processes of increased danger always occur, for example, from the outside in winter, warm air flies there from ajar windows, and from the inside, this node is a leak of warm air from the room with a poor-quality vapor barrier, which ultimately eventually leads to the formation of icicles on the eaves. And for a number of other reasons.

Poor thermal insulation of ceilings. Poor attic ventilation. On a warm roof, a roofing cake is incorrectly made. Natural factors during thaws. Improper use of the attic space.

What I am talking about in this article is just one of the stages so that this does not happen to your roofs.

In fact, there is nothing particularly difficult, you just don’t need to rush and do everything carefully, carefully. Of decisive importance is the material with which you work and accessories, as a rule, all connections are glued and sealed, and it is best to use materials and accessories from one manufacturer, this will guarantee the long-term operation of these units.

No wonder people have said since ancient times that the main thing is a reliable roof over your head. Professional roofers also confirm that only a reliable, durable roof ensures comfortable living in the house. Moreover, the reliability and durability of this complex structure, sometimes depends on seemingly very insignificant elements.

For example, the roof eaves, despite their small size and percentage of the surface area of the slopes, this element performs important functions that affect the service life, insulating ability and strength of the roof. In this article we will talk about the device of the roofing cornice of the house, how to form it and the optimal size.

Roof eaves - an important element of roof structures, this term refers to the lower parts of the roof slopes, which are their continuation. Installation of cornices is carried out during the arrangement of the truss system by increasing the length of the rafters or by installing fillies. From above, the cornice, like the entire area of \u200b\u200bthe slope, is covered with roofing material, and from below it is sewn up with the help of lumber, spotlights, and siding. In the construction of the roof of the house, it performs the following functions:

Protects the walls of the house from moisture. The cornice overhang of the roof protects the upper part of the outer walls from the ingress of atmospheric moisture and dirt, while maintaining their attractive appearance and integrity.
Prevents the runoff of melt and rain water on the foundation blind area. The device of the roof eaves is such that it carries out streams of water and blocks of snow sliding off the slope, further from the foundation of the house, preventing erosion and destruction of the blind area.
Gives the roof a finished, neat look. Roof overhangs, being a continuation of the slope, give the structure a more proportional look, harmoniously completing the architectural design of the house.

Note! Installation of cornices is an obligatory stage of roofing work, which is required by the technology of roof construction, regardless of its type, shape and type of waterproofing coating. Even flat roofs have a small extension protruding beyond the outer walls of the building.

Kinds

Many homeowners are interested in whether it is possible to decorate a roof cornice with their own hands, since its visual device seems extremely simple. Experienced craftsmen believe that this is a job even for a non-professional. The main thing is to understand the purpose and types of cornices. In the design of pitched roofs, the following 2 types of overhangs are distinguished:

Fronton. The gable overhang is the part of the roof slope that protrudes beyond the outer walls of the house from the side of the gable. As a rule, this type of cornice has a short length and is formed by a crate and a frontal bar that gives it a shape.
Cornice. A cornice overhang or cornice is called the lower part of the slope, starting from the intersection of the roof plane with the outer load-bearing walls. These cornices are usually much larger than gable cornices as they prevent splashes of water flowing down the slope from hitting the wall finishes.

Important! In fact, the cornice is an extension of the rafter legs. Since the overhang is at the bottom of the slope, the minimum snow load falls on it. However, the installation of a gutter or snow retainers changes the distribution of loads, so it can be subjected to significant pressure.

Formation methods

Before you make a cornice for the roof, you need to understand the structure of this element of the roof structure, as well as how to form it. The installation method of the overhang depends on the design and type of roof, on the length of the slopes. The most common technologies with which you can form a roof cornice are:

Extension of rafter legs. The easiest way to form a roof overhang is to use rafter legs that are longer than the pitch. The more you want to get an overhang, the longer the bars from which the rafters are made should be. The disadvantage of this method is to increase the weight of the frame, and, consequently, the load on the foundation.
Building rafters with filly. To form a roof cornice, you can build up the ends of the rafter legs with the help of fillies - lighter and cheaper elements from a thinner edged board. Thanks to fillies, the frame has less weight, despite the large cornice.

Professional craftsmen consider it appropriate to use fillies to form an overhang if the length of the slope exceeds the standard size of lumber. Usually the length of the boards from which the roof frame is made is 6 meters. If the roof slope is 6 meters or more, the installation of the cornice is carried out using fillies.

Optimal size

It is often difficult for non-professional craftsmen to determine what size a cornice should be made. This is indeed a very important design decision, because if it is too small, then melt or rain water from the slope will fall on the cladding of the outer walls, on the blind area of the foundation, leading to destruction, as well as damage to the appearance of the structure. When choosing the length of the cornice, the following factors are taken into account:

Climatic conditions. The optimal size of the roofing cornice depends on the amount of precipitation in winter and summer. In snowier regions, roofs with a wide eaves are traditionally used to protect walls and foundations from snow. For example, alpine chalets located in the mountains usually have cornice overhangs at least 1 meter wide.
Roof pitch. The greater the angle of inclination of the roof slopes, the smaller the eaves can be made. This is due to the fact that with a flat roof, the trajectory of falling snow and water goes far from the outer walls of the house. If the slopes are steep enough, then it is better to make the eaves wider to protect the structure from splashes of water that can reach the wall during heavy snowmelt or heavy rains.
proportions of the house. A wide eaves with a sloping roof make the building visually lower, squat, distorting the optimal proportions. A narrow overhang with a high, steep roof, on the contrary, stretches the silhouette of the house.

Important! The minimum allowable width of cornices is 45-50 cm, but this is clearly not enough for regions with high snow load. If necessary, the size of this structural element is increased to 1 m.

Hemming material

Installation of overhangs is carried out at the final stage of work on the assembly of the truss frame. As soon as the crate is ready, the rafter legs are trimmed in level, and then the frontal (wind) bar is fixed at their ends. To protect the lower surface from the penetration of moisture or the settlement of birds overhang, the eaves are filed. This task can be accomplished using various materials:

Remember that the ventilation of the under-roof space is an important factor affecting the life of the truss frame. Therefore, experienced craftsmen for filing overhangs recommend using spotlights. It is better to use models with central perforations that provide an average level of ventilation.

Hemming methods

In order for the eaves overhang not only to perform its functions qualitatively, but also to look aesthetically pleasing, neat, it is necessary to hem it correctly. To do this, it is not enough to choose high-quality material, you also need to decide on the method of filing, which depends on the slope and length of the ramp. There are two methods:

Diagonal lining. This method consists in filing the cornices with soffits so that they are parallel to the slopes. Thus, roofs with a large slope, but a small slope length, are hemmed. The diagonal method is considered more time consuming.
Direct hemming. This option differs in that the roof cornice is closed with spotlights using a box located at a right angle to the outer wall of the structure. Direct filing takes less time, but it is more expensive in terms of building materials.

Video instruction

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Large country - large volumes of housing construction. Not only multi-storey, but also private. And every developer needs and needs knowledge on general issues of construction, on norms and rules, including about roofing processes.

Competently executed roof structures are the key not only to a warm home and a comfortable atmosphere, but also to the durability of other elements of the structure.

The device of a roof is an important stage of construction of buildings.

Physical processes of heat transfer

In a heated house, temperature changes are inevitable, the presence of moisture in the air in the form of steam, condensate. Steam is produced by the vital activity of a person or animals, penetrates building structures, cools and moistens them. The vast majority of building materials allow air to pass through to one degree or another. Therefore, any residential building, individual or multi-apartment, is an air volume in which warm air rises through all structures.

In high-rise buildings, a traction effect appears. Warm air rises to the upper floors, this is especially noticeable in the entrances, and penetrates outside through windows and attics. On the lower floors, on the contrary, there is an influx of outside cold air. This process also occurs in a one-story heated house, only with less dynamics.

On the other hand, warm air vapor condenses into water in the structures, which not only moistens them, but also has the ability to flow down, filling the cavities in the structures. The main function of the condensation of water vapor is assumed by the uppermost part of the building - the roof. In winter, this process is intensive and constant, and in summer it is predominantly at cool night time.

The most modern and effective way to prevent or significantly reduce moisture condensation in the roof is to make it ventilated naturally or forced. Natural cold ventilation does not require energy costs, so its design is preferable. However, there are roofs of complex architecture that lack the power of natural ventilation, then forced ventilation comes to the rescue.

Ventilation removes warm moist air into the surrounding space, thereby leaving the load-bearing structures, insulation dry, prolonging the service life and providing thermal insulation. We need to manage this process, which is carried out with the help of the so-called roofing pie.

The concept appeared relatively recently and denotes a multilayer roof structure, in which the leading place is given to the creation of ventilation ducts. There are two types of roofing cake: for heated and insulated rooms and for cold roofs. Each layer is interconnected functionally with other layers, and the absence of any reduces the protective properties of the entire pie.

If the attic is a cold, uninsulated part of the building, it is carried out in several successive layers. The following tools are required for work.

a hammer;
drill with drills 4-12 mm;
wood saw;
stapler (stapler) electric or mechanical with staples 14x8 mm;
level, meter ruler, square;
scissors;
screwdrivers of different sizes;
flute brush for antiseptic cutting of wooden parts;
construction sealant.

On the upper side of the rafters, a waterproofing film is laid (not to be confused with a vapor barrier). The sag of the film should be 20-40 mm to drain condensate. It is fixed along the rafters with a counter-lattice 30-50 mm thick and as wide as the thickness of the rafters themselves. It is better to glue the film at the attachment point with double-sided tape.

To reduce waste, the film can be laid in horizontal rows from the bottom up and with an overlap of 100-150 mm. The joints of the strips are glued, creating a continuous web. The water formed from the condensate will flow down the film to the roof eaves.

After the installation of a waterproofing layer, a crate for roofing is sewn across the rafters on the counter-lattice. The width of the board, the gap between them is selected depending on the roofing material.

For ceramic and soft tiles on the crate, use an inch board 100 mm wide. It is laid with a gap of 50-100 mm, after which it is completely sewn up from above with a building board or waterproof plywood with a thickness of at least 9 mm. An underlying layer is still laid under the soft tiles.
The crate from the board 30x100 and with a step of 300-400 mm is performed under a metal tile or corrugated board;
For a metal seam roof, a crate is used from an inch board 150-250 mm wide, sewn onto a counter-batten with a minimum gap of 20-50 mm.

At the end, roofing material is laid directly on the crate or building slab. It is fastened with special nails, screws or clamps to the crate. The roof attachment points are protected with sealants, and the crate is pre-treated with an antiseptic. Additionally, you can perform a rough filing along the rafters from the side of the attic.

Between the roof and a ventilation gap appeared in the total thickness of the battens and counter-battens. This is 55-80 mm of the height of the under-roof space along the slope of the rafters. In winter, the warmer attic air, partially penetrating through the waterproofing, will rise to the roof ridge and be discharged into the atmosphere without having time to condense moisture. And in summer, the air heated by the roof is also removed from under the roof.

Attic ventilation is important for the under-roof space. It is carried out through the dormer windows, arranged on the gables from different sides. Ventilation of the living space, attic and roof space are interconnected, and one of their goals is to reduce steam and condensation in the roofing pie.

Ventilated insulated roof construction

Often the attic is used as an attic, insulated from the side of the roof. In this case, several more layers are added to the roofing cake. Now there is no attic air gap between the living space and the roof. Warm and humid attic air immediately penetrates into the under-roof space. And if you do not take additional measures to remove it, there will be much more condensate and the structures will start to get wet. Thermal insulation materials will no longer perform their functions and the air in the room will be cold. We'll have to increase the heating.

In addition to those layers that have already been made in the cold roof, a thick layer of insulation is added, which is laid between the rafters from the inside. If ordinary rafters are 150 mm wide, then the thickness of the insulation between the rafters can be no more than 100 mm. The reason is the need to leave a minimum gap (do not touch) until the waterproofing sags, which reaches 40 mm. If there is a touch, the water flowing down the insulation will enter the insulation. To increase the thickness of the layer, a timber of the required thickness is sewn onto the rafters and a heater is added.

Then it is covered with a vapor barrier film. The goal is to minimize the ingress of steam from the room into the insulation so that it does not get wet. Wet insulation is no good, it does not hold heat and, in addition, moisturizes the surrounding structures. First, a rough, and then a finishing lining is sewn onto the vapor barrier.

Now the path of wet steam to the roof is blocked, and although a small part of it still penetrates, it is carried out into the atmosphere by the under-roof ventilation air flow without harming the roof structures. And if the warm room itself is not ventilated, where will the steam go? Through all sorts of microscopic pores and crevices, it will still go up to the roof. This will be facilitated by the excess pressure formed in the warm room of the attic.

To relieve excessive pressure, reduce the moisture content in the living room and thereby help under-roof ventilation to remove moist air into the atmosphere will allow the ventilation of the room itself.

Ventilated cornice device

The longitudinal ventilation ducts of the roofing pie will not work effectively if, on the one hand, in the lower part, at the very cornice, the flow of atmospheric air is not provided. On the other hand, it is necessary to let humidified air out from the very top of the roof - from the ridge.

The waterproofing film is the most durable of all types of films used in building a house, so it does not allow water or moisture to pass through even under high pressure.

The waterproofing film is removed and glued with a sealant to a metal cornice strip installed in the plane of the crate. The roof is fixed on top. Air flow is carried out in 3 ways. Firstly, through the gaps of the roofing material profile, secondly, through the gable overhangs and, thirdly, through the micropores of the waterproofing film, drawing steam out of the insulation.

When sheathing the cornice, ventilation holes or gaps are provided in its lower part, depending on the many options for the design of the cornice. One of the modern methods is a continuous filing of the cornice with perforated plastic panels for roof ventilation.

Creating a ridge hood

Depending on the design of the roof covering, the air flow from under the roof is collected in the ridge and discharged into the atmosphere either through structural gaps along the length of the ridge or through gable openings. For example, a set of ceramic and metal tiles includes special ridge elements with ventilation gaps. Additionally, there are additional elements for a non-standard ridge shape.

This is the outer part of the roof. The internal device is performed in a certain sequence.

the counter-lattice along the rafters is not brought to the geometric height at the same distance of 20-40 mm. Bars of oncoming slopes do not join;
a crate in 2 solid boards from both slopes on the ridge is also performed with a longitudinal gap of 40-80 mm;
the waterproofing film along the ridge is cut with a margin of 200 mm from both slopes;
between the ends of the counter-lattice and the batten along the ridge, a 40x100 mm ridge beam is vertically installed;
a waterproofing sheet is fixed to it and glued with a sealant;
from above, this structure is closed with a ridge according to the instructions and technology;
end elements of the ridge are installed from the side of the gables, in which ventilation holes or gaps are provided.

Some features of a ventilated roof

Roof ventilation is not an independent process. On the contrary, ventilation or its absence in the premises directly affects the air exchange in the roof. In order to effectively remove destructive moisture from residential premises through the roof, it is necessary to consider the ventilation of all elements of the building as a single process.

If the shape of the roof is complex, has many transitions, valleys, the ventilation processes must be divided into sections and air flows in the roof should be formed separately. As a result of effective ventilation, the air in the under-roof space should be replaced approximately 2 times within an hour.

The effectiveness of a ventilated roof depends on the slope of the slopes. The steeper they are, the stronger the ventilation process occurs. And, conversely, in roofs with a slope of less than 20%, under-roof ventilation is unstable, effective only under wind pressure.

It is always useful to install additional exhaust elements (aerators) on the roof to help enhance the natural ventilation of the roof. They should be placed on roofs of complex shape, when conventional means are no longer enough. Aerators are installed near the ridge.

The thermal insulation properties of the insulation and the durability of roof structures directly depend on the presence of moisture in them. Therefore, a ventilated roof and the design of ventilation of the premises is economically beneficial even in the case when it is necessary to install forced air exchange.