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?
Current Market State building materials 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 is “related” to polystyrene foam chemical composition, but 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.
The roof is the most important structure of a building after the foundations. The quality of its installation determines the temperature and humidity conditions in the house, the safety of load-bearing structures and the comfort of living. It is important not only to choose the right roofing material, but also to insulate the roof from the inside with your own hands or with the help of professionals.
Why is insulation necessary?
Measures to protect against cold are necessary both during the construction of a wooden and stone building. Most often in private low-rise construction choose pitched roofs. The supporting structures of such a roof are in most cases made of wood, but it is possible to use metal trusses.
Schematic diagram of roof insulation
When choosing a wooden material, insulation is especially important, since it not only ensures a comfortable stay, but also protects structures from condensation. Damage caused to structures by moisture can be as follows:
- the appearance of mold and mildew on the surface of the wooden frame;
- the appearance of corrosion when using metal;
- increasing humidity in the house.
Roof insulation options
Depending on the type of roof, insulation is carried out using different technologies. Options constructive solution There are two roofs:
- pitched;
- flat.
In the first case, the roof is insulated from the inside. The insulation is fixed between the rafters, and the roof covering can be made of:
- corrugated sheets;
- metal tiles;
- ceramic tiles;
- flexible tiles;
- roofing steel sheets.
In the second case, insulation can be carried out both from above and from below. With this design option, it is not entirely correct to carry out work from the inside from the point of view of heating engineering. Most often, reinforced concrete slabs or a monolith are used as load-bearing structures, and insulation is laid on top of them. Fused materials are used for coating.
For an individual house, it is better to use pitched roofs; they will allow you to equip an attic and will not create problems with drainage.
Insulation materials
Scheme of thermal insulation of the roof from the inside with foam plastic For roofing made of corrugated sheets and other materials listed above, it is best to use the following types of insulation:
- mineral wool;
- Styrofoam;
- extruded polystyrene foam;
- polyurethane foam.
For wooden house it is necessary to take into account the resistance of the material to fire, so it is better to use non-flammable mineral wool or extruded polystyrene foam. More information about mineral wool insulation can be found in the article “Insulating a roof from the inside with mineral wool.”
The advantages of polystyrene foam include:
- low cost;
- good thermal insulation;
- light weight.
When used under a roof made of corrugated sheets or other materials, it is important to remember that polystyrene foam has low strength and is not resistant to simultaneous exposure to water and low temperatures. When choosing this material, it is important to properly protect the material from exposure to steam and moisture.
Scheme of thermal insulation of the roof from the inside with polyurethane foam Extruded polystyrene foam (penoplex) does not have the disadvantages of polystyrene foam. When used in the home, it provides reliable protection from the cold, is not afraid of moisture, and has fairly high strength. Insulating a roof from the inside with such insulation does not require special skills.. The disadvantage of penoplex is often its relatively high cost.
The fourth option for insulating the roof of a house is not as popular as the previous ones, but has a lot of advantages.
- polyurethane foam is sold in cylinders, which greatly simplifies its use;
- excellent grip on the surface;
- filling all cracks and irregularities;
- good thermal insulation.
Technology
The quality of thermal insulation of a house depends not only on the competent choice of insulation, but also on its correct installation. When insulating a roof made of corrugated sheets or other materials, the following order of layers is observed from bottom to top:
- covering the ceiling, for example, with plasterboard;
- lathing along the bottom of the rafters;
- vapor barrier;
- rafter legs;
- insulation between rafters;
- waterproofing and wind protection;
- counter-lattice to ensure sufficient ventilation gap (if necessary);
- sheathing under the roof made of corrugated sheets or metal tiles (moisture-resistant plywood is additionally laid under the roof made of flexible tiles);
- roof covering made of corrugated sheets or other materials.
When insulating the roof of a house, it is important to consider the following recommendations:
- mineral wool requires a mandatory ventilated layer 5 cm thick;
- The pitch of the rafters is selected depending on the width of the insulation to facilitate the installation process;
- when working with mineral wool or polyurethane foam, special clothing and personal protective equipment are required;
- vapor barrier is always located on the warm air side, and waterproofing on the cold air side;
- the height of the rafter leg should be equal to or greater than the thickness of the insulation.
Installation rafter system– one of the steps for proper roof insulation To properly insulate a house, work is carried out in the following order:
- installation of the rafter system;
- fixing waterproofing;
- installation of the top sheathing;
- insulation;
- vapor barrier;
- bottom sheathing.
- The mineral wool is held between the rafters by friction. In this case, the width of the insulation is taken to be 2 cm larger than the pitch of the rafters.
- Polyurethane foam adheres to the surface by penetrating into the smallest irregularities and crevices. Before starting work, it is recommended to moisten the surface with water from a spray bottle to improve adhesion.
- During operation, polystyrene foam and extruded polystyrene foam are kept on the roof of the house due to the bottom sheathing, and during the installation process you can use anchors, umbrella nails, tile mastic or liquid nails.
Proper insulation of the rafter system will ensure compliance with the temperature and humidity conditions in the attic or attic, protect structures from damage and reduce the financial costs of heating the entire building.
Heated air always rises to the top, and most heat losses occur through the roof or attic floor. That is why it is important to pay increased attention to insulation during roofing work.
For a long time in Rus', there were no problems with roof insulation at all: straw was knitted or reeds were dried, and that’s all - the roof of the house was reliably protected from both rain and cold. But modern coatings do not have any heat-insulating properties at all, and with all the development of progress, up to 30% of all heat leaks through such a roof.
Therefore, if you do not want to warm the atmosphere, study in detail the insulation of the roof from the inside - in this article we will cover all the points!
Conventionally, roof insulation in the construction world is divided into attic, when the roof slopes are insulated, and attic, when the ceiling is thermally insulated.
Like this? We can say that attics also have their own attic - this is a ventilation gap between the internal insulation and the laid roofing. The fact is that heat, according to all the laws of physics, always rises and seeks its release into the atmosphere. It passes through both the insulation and the vapor barrier, and together with water vapor. And here the external air is pulled in at the eaves plumb, which passes to the ridge and along the way picks up both vapors and excess heat. Through aerators or the same ridge, all this is safely removed and does not cause any problems.
Those. in an ordinary, unused roof, the attic occupies the entire space from the ridge to the attic floor, and in the attic, the attic is just a small space under the slopes between the insulation and the roofing. And in insulating both, the type of roof has its own approach, which we will now study.
Cold roof insulation technology
If your roof is cold, then the heat-insulating layer should not be on the slopes, but on the floor of the attic. This is where it stops the heat flow coming from below and prevents the cold from the roof from descending into the living space below. As a result, the temperature in the attic is kept within +1-2 degrees, the roofing material is not heated. In fact, such an attic serves as the necessary air gap between the living rooms of the house and the thin roof covering.
All roll, slab and bulk insulation materials are suitable for attic floors. Because the ceiling does not have a slope, it does not have any special requirements for the heat-insulating material used: nothing will crumble or be exposed.
Please ensure that, after insulating the roof, there remains properly organized ventilation: there should be dormer windows located opposite each other, ventilation ridges and aerators, and in the eaves there should be round-the-clock access to suck in outside air. As a result, the temperature in a non-residential attic should be as close as possible to the street temperature, and the living space below is already separated from it by proper thermal insulation of the floor.
Now let's take a closer look at insulating a cold roof.
Insulation with mineral wool
When insulating the attic floor with mineral wool, first of all pay attention to the distance between the slats or joists - it should be slightly less than the roll or mat of insulation.
Typically, thermal insulation of the internal space of the roof is complicated by the uneven surface of the attic floor, differences in its height, a large number of slats and bars, not to mention ventilation pipes and electrical wiring:
Ecowool insulation
If you want the house to breathe and steam to escape easily, then insulate the attic floor with modern eco-wool:
Insulation with blown-in cotton wool
Recently, blowing - roof insulation with blown-in cotton wool has become increasingly popular. The Japanese “insulation” Esbro-Vul II is used here, which does not emit dust and therefore does not create problems. And the blowing method itself is actually quite simple:
- Step 1. Place a vertical ruler on the floor and mark the required height of mineral wool spraying.
- Step 2. Apply insulation in an even layer to the desired level.
- Step 3. We lay the insulation so tightly that it weighs 25 kg per cubic meter.
Note that this type of insulation is the most popular in Japan, and has already found many supporters in Russia.
Glass wool insulation
And finally, glass wool - if you will not use the attic at all. The fact is that even glass wool closed under the sheathing sometimes causes irritation to the ENT organs. This is why you have to wear a respirator and goggles when working with it:
Insulation with sawdust
When insulating a roof with sawdust, follow these instructions:
- Step 1. First of all, you need to protect the wooden structure. To do this, we first apply an antiseptic composition, then fire-bioprotective mixtures, and on top - water-repellent agents.
- Step 2. The next step is to place a backing (cardboard is possible) and close the seams and cracks, if any, with foam (large) or sealant (small). When finished, we trim off the foam that has come out and level it with the beams.
- Step 3. Now we fill in the sawdust in two layers: first the larger fraction, as well as shavings, and then the fine ones, so that dust does not form in the room.
- Step 4. To prevent rodents from growing on the attic floor, add dry lime and small broken glass to the sawdust.
Warm roof insulation technology
The mansard roof is a special design. There is also a cold attic here, only it is very small, because... the insulated attic ceiling is pulled almost flush against it using additional sheathing. In fact, there is only space for ventilation, and nothing more. And ventilation serves to ensure that the heat from the attic does not touch the roofing, on which the snow in winter should remain as a heat insulator and not melt.
Here is a striking example of the most standard situation of improper insulation of an attic: they install the cheapest rafters of 15 cm, put fluffy mineral wool in two layers of 5 cm and cover it all with a roofing covering. Ventilation - only 5 cm, without inflow and outlet, because... There was no specialist nearby to advise. As a result, in the summer there is unbearable heat, from which even air conditioners cannot help, and in the winter there is a generous amount of ice on the roof. And all because in this circuit it is the street air that heats up the most. In other words, that very small attic that we talked about must definitely be there, and far from 5 cm.
And in such a roof you need to think through the vapor barrier especially carefully:
And further. The material used to make rafters is always designed for a certain weight. Yes, the roof is under soft tiles It can also be built from drywall profiles, but it cannot be insulated with heavy basalt wool. The attic roof also needs a good forced ventilation so that the insulation does not rot or deteriorate. Therefore, carefully read all the points of the master classes we prepared:
Insulation with mineral wool
Follow these simple instructions:
- Step 1. Install hydro and wind protection. If possible, use modern membranes - they are stronger and more durable. In any case, fasten the material with an overlap, and seal all joints with construction tape.
- Step 2. Now measure the distance between adjacent rafters.
- Step 3. Using a regular or stationery knife, easily cut the insulation into the required pieces and insert it between the rafters.
- Step 4. We install additional lathing between the membrane and the inner lining.
Please note that you need to attach the vapor barrier membrane with the smooth side to the insulation, and the fleecy side - inside the room.
If the distance between the beams is no more than 60 centimeters, it will be more convenient for you to use square insulation mats:
- Step 1. It is advisable to add rough sheathing inside, under the rafters, so that the insulation has something to rest on. Make the distance between the bars about 20-30 cm. Ordinary uncut wood with medium-sized nails is also quite suitable for this purpose, it is only important that the bars are of the same thickness.
- Step 2. After installing the rough sheathing inside the structure, remove all dust and dirt using a construction vacuum cleaner.
- Step 3. Next, we treat all wood with a special agent against fungus, rot and mold. Just use for this purpose not a spray gun, which is less effective, but a regular paint brush. With its help, you can achieve deep penetration of the product into the wood, and this is important.
- Step 4. Allow the product to completely absorb and dry for two to three days.
As a result, all your sheets should lie tightly - a little tighter than you need at first glance. This is the only way to avoid the presence of cracks and subsequent freezing of the roof.
And one more point: ordinary mineral wool slabs are not particularly suitable for insulating roof slopes, because... They don’t stick well between the rafters, but they can be used to insulate gables.
Glass wool insulation
To insulate roof slopes with glass wool, purchase the best, from famous manufacturers. Such glass wool practically does not contain dangerous glass dust, which is what annoys workers the most. Also, even after installation it does not emit harmful substances, which is even confirmed by the Finnish Institute of Health. After all, it’s one thing to throw this “thorn” onto the ceiling of an unused attic, and another thing to cover it with clapboard in a billiard room or personal account on the attic floor.
Combined insulation
If desired and appropriate, you can insulate the roof from the inside using two different types insulation at the same time. But one important point must be taken into account - vapor permeability. The fact is that when selecting different insulation materials for an effective combination, we usually only summarize their heat-insulating properties. But their vapor permeability is completely different!
And, if, for example, you put mineral wool down first when insulating, and foam plastic on top, then the water vapor that gets into the wool will begin to tend to the colder part of the roof and bury itself in the absolutely non-breathable foam plastic. As a result, all the insulation will simply suffocate and “delight” with mold. But on the contrary, it is possible: first we put foam plastic on the bottom of the rafters, and then mineral wool on it. If some steam passes through the vapor barrier and the cracks between the foam boards, it will easily overcome the mineral wool and enter the ventilation duct. Therefore, there is such a rule: the top layer of insulation should always have high vapor permeability and thermal conductivity.
And finally, if the warm roof will be used as a sauna or an additional bathroom, insulation and roofing in it need to be thought out especially carefully.
The developers with whom I once worked were always concerned with questions such as whether it is necessary to insulate the roof from the inside and, if so, whether it can be done without the help of a specialist, i.e. with your own hands?
Here the answer is the purpose of the building itself; if it is residential and there is an attic floor equipped as a room, then it is definitely worth insulating.
Therefore, I will tell you in more detail about how to insulate the roof of a house from the inside with your own hands in this article.
What will keep the heat inside the attic?
In any area of construction, you should not give preference to cheap materials. This stingy trait of a person's character often leads to consequences when he pays many times the amount.
You can save on roofing if, for example, you give preference not to tiles, but to metal tiles. But if you are looking for the cheapest material from the same types, then know that you will be in trouble.
I’m not scaring you, but I advise you to warn yourself against possible problems.
High-quality insulation material along with the right technology installation allows you to protect your building from the cold as much as possible and will even extend its service life.
- According to some sources and household practice, 15% of the heat is lost through the roofing layers. Therefore, if the house is already in use, and you feel that there is somehow not enough heat, then look into the attic space. Most likely you will need additional insulation of the roof from the inside, but don’t worry because you can do it yourself without calling a specialist, just look at a couple of photos on the Internet
- If your attic floor does not yet have a living room, and you need additional meters of space, then insulating the roof will allow you to occupy this room, while in the process of working with your own hands you will understand exactly how your roof structure and at the same time perform a preventive examination of her
By the way, on the Internet there are quite a large number of sites and forums with the heading “we insulate the roof with our own hands,” which contain a large number of video materials.
When all the construction processes are completed, or rather, when the pie is already hidden under roofing material, suddenly it turns out that these insulation boards will not be enough, then there are two ways of development of events.
- The first thing is to disassemble the entire roof and get required amount insulation boards. Moreover, you will need to call the construction team again, who may have been to blame for this anyway.
- The second is to insulate the roof from the inside with your own hands.
I think if you are a reasonable person, you will act according to the second scenario.
If there are no errors in the building design, this does not mean that over time you will not become cooler or you will not improve your attic. Perhaps, by reading this article, you already need this. Therefore, I will tell you below technological process how to insulate the roof of a private house with your own hands.
Requirements for the pie and analysis of its components
In construction, the roofing cake is considered to be the vapor barrier, thermal insulation and waterproofing layers, which together is what it is. The cake is placed on the elements of the rafter system. If you make a cross section of the entire pitched roof, you can see the following layers:
- Roof covering
- Lathing (possibly a continuous covering in the form of boards)
- Counter-lattice. It is organized to create gaps through which the wind will blow. This is called natural ventilation
- Waterproofing material
- Thermal insulation boards
- Vapor barrier film
- Internal lathing
- Sheathing
If your roof consists of such layers, then we can say that it was done correctly. In winter, heat loss in its attic space will be minimal, but still, if they bother you, and you decide to equip the top floor, then order a team of builders, and they will insulate the attic roof from the inside in the shortest possible time, but if you do not have the funds, then You can always do it yourself, just watch a couple of videos in the article.
What role does the vapor barrier and waterproofing layer play in the construction pie?
If you insulate the roof of a private house with your own hands, then you should remember about a reliable waterproofing device. After all, she must:
- Limit the access of moisture to thermal insulation boards
- Remove water vapor coming from inside the room
Not all materials can cope with such tasks. They use special membranes and films. Waterproofing in the form of a film - most often micro-perforated material, usually has three layers. It is a polypropylene mesh laminated on both sides to polyethylene.
The membrane has a non-woven structure.
The layer located in the middle has a high hydro-vapor barrier, and with the help of outer layers it is provided with the necessary strength. This vapor barrier layer is often called superdiffusion.
They have one important distinguishing feature when compared with films. They can be laid without a gap on the insulation itself, when the use of films provides for some distance from it. This is due to the fact that the membrane is vapor permeable, but the film is not.
When using films, the gap in the cake is created by laying small slats on the insulating boards themselves. This technique allows the wind to move freely inside the cake and dry it.
If this is not done, then condensed moisture will form, which, when it gets into the heat-insulating boards, will sharply reduce it beneficial features. Even a small amount of moisture reduces the usefulness of the slabs by 50%. 
What parameters should you look at when purchasing thermal insulation boards?
There are often cases when it is necessary to insulate the roof eaves from the inside, but do not think that some difficulties may arise here; all the work can also be done with your own hands, and if you need it, then you should choose the right material.
But what indicators should you look for when choosing it in a hardware store?
- Density of the purchased material. Low density implies the presence of a larger number of pores in the body of the product, which will certainly be a positive quality for thermal insulation. For example, if you take polystyrene foam, it has high thermal conductivity, and this quality is the main one for thermal insulation
- Thermal conductivity. A low value indicates how well the material can insulate heat. In addition to porosity, such material can be affected by air temperature and humidity. The higher their performance, the greater their thermal conductivity
- Water absorption. This figure should be as small as possible if you do not want to do roof repairs every year
- Resistance to negative temperatures
- Flammability
- Chemical resistance
- Environmental friendliness
The last point is the most important in light of recent events, when the whole world is striving to use air pollutants in as small quantities as possible.
Yes, I think you yourself will not be too comfortable living in a house and knowing that the roof of your building is stuffed with harmful building materials.
What materials are most often used as insulation boards?
Today, the three most commonly used insulation materials are known.
- Mineral wool or glass wool. Both products are produced by manufacturers in the form of rolls or slabs. Glass wool is slightly worse in its characteristics than mineral wool, judging by heat resistance
- Polystyrene foam (or scientifically polystyrene foam). You've probably met him often in your life. It is produced in slabs and already in extruded products. Its only drawback can be considered high flammability. In order to protect your roof from such protection, it itself must be equipped with decent fire protection. By the way, when burned, this material releases a large amount of toxic substances.
- Polyurethane foam. Manufacturers of such material supply it to the store in liquid form or in slabs. Using the first type of this material, you are unlikely to be able to insulate the roof from the inside with your own hands because this is a rather difficult process that requires certain tools. If you don’t believe me, then find a video on this topic online and look at it with your own eyes.
The technological process of insulating the attic space, regardless of the roof structure
In modern construction, more and more unique projects are being created. And the higher the uniqueness of the building, the more likely it is that its roof is complex. Therefore, some people in the past came up with special techniques for producing insulation on various roofing structures.
For example, on a sloped roof they use methods that are completely unsuitable for a flat type.
According to technology, during such work as insulation pitched roof from the inside, with your own hands, a certain order in actions must be observed, safety precautions must be followed.
IMPORTANT: All work must be performed with maximum quality. No cracks, depressions or voids are allowed. If there are some damages on the insulated surface, they should be eliminated before starting the main work.
Remember that waterproofing on the elements of the rafter system must always be present. This does not depend on whether the roof will be insulated in the future. The waterproofing layer will provide reliable protection against condensed moisture, which quickly forms if there is no gap between the wooden elements and the back side of the roofing.
If your roof is similar to that described above, then you should first organize decent protection from moisture, because, as already mentioned, the penetration of water vapor into the insulation boards reduces its useful properties by half, or even more. At the same time, do not forget to leave a gap in the necessary places. For this, as a rule, 2cm is enough.
For waterproofing, I advise you to purchase a superdiffusion membrane. It will allow you to avoid creating additional gaps between the layers of waterproofing and insulation.
So, when the words are said, you can move on to the process. We insulate the roof with our own hands and do the following:
- The installation site is being prepared. At this stage, various protruding nails or screws are removed, problem areas on the wood are rubbed, so as not to tear the thin components of the pie
- We lay thermal insulation boards. Its installation is carried out between the rafters in several layers. Their minimum number is 2. This will remove end-to-end joints between the mats. The total thickness of the laid material must be at least 20cm. There are cases when rafter legs interfere with the laying of the second or subsequent layers. Then you should simply fasten the slabs directly on top of these elements. This will give you a more durable layer.
- Lathing device. It acts as a kind of holder and is usually attached to the rafters through a layer of insulation, while capturing the vapor barrier
Insulating a pitched roof from the inside with your own hands is a simple matter, but what can be said about a flat one? If you watch some videos on this topic, you can clearly say that working with the second type is somewhat more complicated, but overall it also looks simple.
The process of insulating a flat roof:
- Preparing the base. Everything is clear here, the process is identical to a pitched roof. We clean elements that can damage the roofing pie
- Installation of insulation boards. The catch here is that the installation is done on a purely horizontal surface. Therefore, the installation of supports is required. To do this, special bars are attached to the ceiling at the very beginning of the work. Their pitch should be slightly less than the entire width of the roll or slabs. In this case, their height should be equal to the width of all layers. It is worth noting that installation should be done as tightly as possible, and as an additional fastener, the plane of the material is often coated with glue or mastic
- Installation of vapor barrier and sheathing
Insulation of the roof is a necessary task when arranging the attic floor. And it, in turn, is a good opportunity to increase living space, which often finds its use when guests arrive.
Choose the right choice of materials and you will always be enveloped in the warmth of your home.