How to properly insulate the roof with foam

The available thermal insulation material is polystyrene. It is widely used for arranging various surfaces. For roof insulation, it is important to choose the right heat insulator, determine the thickness of the layer and lay it correctly. In this case, it is necessary to take into account the type of roof, the structure of the roofing cake and a number of other features.

Characteristics and features of foam

Polystyrene granules are produced using thermal foaming technology. As a result, foam is created, which can be in the form of granules or slabs of small balls pressed together. The first option is presented in a crumbly form and is rarely used, while the second is more common and easy to install.

Polyfoam is very lightweight, easy to install

The foam structure of the material is 98% air. This makes the slabs effective as a heater, because air is the best heat insulator.

The thickness of the pressed elements can be from 20 to 1000 mm. The parameters are also varied: 1000x500 mm, 1000x1000 mm, 2000x1000 mm. Therefore, it is easy to choose the best option for a heat insulator, but you should also understand its characteristics.

The main characteristics of foam of any shape are expressed as follows:

  • the level of thermal conductivity is 0.038 W / (m * K);
  • self-burning period no more than 4 seconds;
  • water absorption in 24 hours no more than 2%;
  • density from 11 to 35 kg / m3;
  • possibility of application at temperatures from -50 to + 75 ° C;
  • third or fourth flammability classes (depending on the grade of material);
  • resistance to bacteria, decay.

Advantages of polystyrene: low price, the possibility of thermal insulation of different areas of the house, simple installation technology. Plates are easy to lay and fasten on different surfaces, so such insulation does not take much time.

Roof insulation with foam - a budget and quick option for thermal insulation

Disadvantages of polystyrene: unstable to the effects of some solvents (acetone, etc.), emits corrosive smoke during combustion. During installation, it is important to carefully protect the material from ultraviolet radiation, since the structure is destroyed by sunlight.

Density of material

When choosing this insulation for the roof of a residential building, you should pay attention to the density, since the durability, strength and thermal conductivity of the foam depend on it.

To determine this characteristic, you need to study the marking, where the density is indicated after the letter designations. For example, PSB-S-15 is non-pressed polystyrene, the symbol "C" means that the material is self-extinguishing, the density is indicated by the number 15 and is measured in kg / m3. Popular grades with a density of 25, 35 and 50 kg / m3.

High-density foam is excellent for insulating walls: even thin sheets are suitable for this

The choice of a particular option depends on the installation method and the type of roof. For the arrangement of pitched structures from the inside, you can use a material with a characteristic of 15 or 25 kg / m3. Here, a high density is not required, since with internal thermal insulation, there is no load on the foam that can damage the plates.

Loose structure is less durable than dense options

If a flat roof is insulated or outdoor installation on slopes is carried out, then the option with a density of 35 kg / m will be more practical.3... In this case, waterproofing is laid on top of the material and the finishing roofing is laid.

Slabs with low stiffness (that is, less dense) under snow load are easily damaged and need to be replaced. But a material with a high performance contains less air and retains heat indoors worse than slabs with a loose structure. Therefore, it is so important to take into account the density of the foam for each specific case.

Roof preparation for insulation

An obligatory step when laying any heat insulator is the preliminary preparation of the roof. This process creates an optimal basis for maintaining the properties of the material for many years and preventing leaks, drafts and freezing.

When insulating a pitched roof with foam, the structure of the roofing pie remains standard

The main requirement for any insulated surface is cleanliness, strength and dryness. These conditions will allow you to properly lay a heat insulator of any type. Before installing the foam, the following must be done:

  • remove protruding nails from the surface, correct irregularities and other defects;
  • clean the surface from dirt, mold, debris;
  • treat wooden elements with an antiseptic and fire retardant;

    Roof treatment with a special impregnating compound protects the wood from fire and protects against the appearance of mold during operation

  • if there are depressions or potholes on the concrete, then a cement-sand screed should be made on it;

    A cement-sand screed on a flat roof helps to level all surface imperfections

  • eliminate cracks and cracks with polyurethane foam or other suitable materials;
  • dry the surface after processing.

Before installing the foam boards, you need to prepare a waterproofing material. For the arrangement from the inside of the pitched roof, special tension membranes are used.

On the pitched roof, steam and waterproofing is first pulled, then it is covered with roofing material, and after that it is already insulated from the inside

If the work is carried out outside a flat roof, then a bitumen-polymer membrane based on fiberglass can serve as waterproofing. In any case, it is necessary to observe the sequence of layers, which will ensure the protection of the insulation and maintain comfort in the house.

Styrofoam laying technology

To work with polystyrene foam boards, you need a simple set of tools. The main ones are:

  • roulette;
  • pencil;
  • a sharp construction knife or hacksaw;
  • foam gun;
  • stapler and staples.

If the material will be fixed on a flat concrete surface, then special dowels with a wide thermal head are prepared.

Umbrella nails allow you to secure foam slabs to a flat roof

A vapor barrier film is a must for any roof. For cladding the slopes from the inside, you will need slats with a cross section of about 2x5 cm. A vapor barrier and wall decoration will be attached to them if the roof is attic.

The device of the roofing pie of a pitched roof is clearly shown in the diagram: a layer of waterproofing is laid on top of the insulation, and a vapor barrier membrane is laid below

Pitched roof mounting

To protect the pitched roof from heat loss, the internal foam method is often used. The technology of operation is simple and includes the following stages:

  1. A crate is mounted above the rafters and a waterproofing film is attached, then the roof covering is laid.
  2. The foam slabs are cut to fit the width of the gaps between the rafter legs.
  3. The insulation is laid between the rafters with tight pressure to each other, but with a gap between the waterproofing layer. The slots are filled with polyurethane foam.

    Styrofoam can be easily laid between the rafters and fixed from the inside with wooden sheathing

  4. The crate is attached for the ventilation gap: the slats with a pitch of about 50 cm are nailed to the rafters.
  5. The vapor barrier is fixed - there should be a gap of about 3-5 cm between the film and the foam.
  6. The walls of the attic are lined with wood.

The technique of such insulation is easy to carry out on your own. But it should be borne in mind that for high-quality roof protection, a foam layer thickness of 5 to 20 cm is required. Additionally, you can use mineral wool slabs, which are glued directly to the foam, and then the vapor barrier and finishing materials are mounted.

Video: rules for insulating a roof with foam

Flat roof mounting

Private apartment buildings with flat roofs are rare. However, foam insulation is suitable not only for residential, but also for industrial or auxiliary buildings with a low roof slope. Before insulating such surfaces, it is necessary to waterproof the plane with bituminous mastic, applying it in several layers after each previous one has dried.

Spread the mastic evenly over the entire surface

This method is simple, but it is also possible to lay roofing material or rolled deposited material "TechnoNIKOL" with a bituminous layer. What is a gas burner for? Although on large roofs, this type of waterproofing is expensive, so mastic is a simple and effective solution.

After the mastic has dried, the entire roofing cake is sequentially laid:

  1. If the foam sheets do not have a locking fastening in the groove, then the material is laid in two layers. In this case, the slabs of the second layer must always overlap the joints of the lower layer. If the plates are fastened together, then one layer of material of the required thickness is mounted.
  2. Typically, the foam is glued to an extra layer of cold mastic. If dowels are used, then they are placed every 40-50 cm.
  3. After the second layer has been laid and dried, all the gaps between the insulation elements and the wall are carefully sealed. For this, outdoor foam or mastic is suitable.
  4. Next, geotextiles are mounted, and then a screed is made, on which roofing material with a bituminous base is laid. Although it is also possible to install OSB boards, on top of which rolled protective materials are fixed in the same way.

Waterproofing the top layer of the roof is required to protect the insulation

After such installation of thermal insulation, the flat roof will have sufficient strength and withstand any snow loads. But a prerequisite is the device of a drain, because its absence will lead to damage to the roofing and insulation.

Video: an example of insulation and waterproofing of a flat roof

Among the variety of materials for insulation, foam plastic is distinguished by its low price and ease of use. Reliable protection of such slabs when insulating the roof will allow you to keep warm in the house and avoid a quick renewal of the protective coating.

Insulation of the foundation with extruded polystyrene foam

Each owner of the site seeks to have a warm summer cottage. But not everyone knows that it is necessary to insulate every part of the building, especially attention should be paid to the foundation.
For insulation of the base of the structure, expanded polystyrene is very often used. With this modern material, the thermal insulation properties of the entire room can be increased very quickly and easily. The material also prevents freezing of the base. Expanded polystyrene is the same foam made according to the latest technological processes. Insulation of the foundation with extruded polystyrene foam can be done independently. Such work does not require skills and special equipment.

Why is it recommended to carry out insulation of the house outside

According to the sanitary norms and rules of SP 23-101-2004, the walls should be insulated from the outer part of the building, although there is no specific prohibition on the performance of internal work. Moreover, in some cases it is impossible to carry out facade work. For example, if a building is on the list of architecture houses and the bureau responsible for it does not give permission to work, if the facade is a complex decorated structure.

Preference is given to wall insulation outside, since useful living space is not taken away

Helpful information! If it was decided to insulate the building facade, a continuous vapor-permeable layer in the room should be created. Otherwise, when warm air gets on the insulation, and then on the cold wall, condensation will form, which causes mold and the rapid growth of fungus.

If possible, most owners prefer to insulate the walls from the outside. Firstly, useful living space is not taken away, and secondly, the building frame is reliably protected from negative atmospheric influences. Other functions that are performed by the insulation of facades from the outside include:

  1. Attractive appearance of the building, even if after the construction of the box it did not have a very aesthetic appearance.
  2. Creation of a special microclimate inside the house due to the fact that correctly performed insulation will play the role of a thermos, when cold does not penetrate inside in winter, and heat in summer.
  3. Extending the service life of the carrier box. A frame that is not constantly wet / dry will last much longer.
  4. Elimination of the so-called cold bridges, which inevitably arise when the rules for building walls are violated or when the building material is chosen incorrectly.
  5. Providing reliable sound insulation. An additional layer on the façade prevents excess noise from entering the premises.
  6. Prevention of condensation in the thermal insulation layer.
  7. A simple solution to the problem of sealing joints in a situation where the house is made of panels.

The only drawback of wall insulation outside is the cost of material and work.

Before insulating the facade of a house, you need to know about the shortcomings of external insulation. The main disadvantage can be considered the cost not only for the purchase of material, but also for ordering high-rise works, if we are talking about a multi-storey building. In a private house, for proper installation, you will have to acquire a good "goat", a stepladder or scaffolding if the building has more than one floor.

The choice of the thickness of the material for insulation

The required thickness of foam for insulation of the ceiling is selected depending on the purpose of the room and the method of installation of the insulation (external or internal version). There are products on sale in different thicknesses from 2 cm to 10 cm.

When choosing a heater for this parameter, be guided by the following rules:

  • for internal and external thermal insulation of ceilings, products with a thickness of 50 millimeters are used
  • panels up to 10 cm thick are suitable for insulating roofs and ceilings under an unheated attic
  • external insulation of the roof and ceiling involves the use of slabs with a thickness of 200-350 mm.

If it is necessary to obtain a thickness of the insulating layer greater than the thickness of the thickest plate, then the material is laid in two layers. In this case, the joints of the slabs in the layers should not coincide.

Important! For external thermal insulation of ceilings, panels with a thickness starting from 100 mm are suitable. For internal insulation and ceilings, above which there is a warm attic, a material with a thickness of 5 centimeters is used.

When choosing a heater, pay attention to its density. Use the following slabs depending on the location and type of insulator installation:

  • for external insulation, the optimum density of the material is 25 kg / m³
  • for internal thermal insulation, plates with a density of 15 kg / m³ are used.

Advantages of external insulation of a wooden house over internal

Choosing the right way to carry out work on the insulation of a wooden house is a guarantee of a high-quality result. Internal insulation of houses is used extremely rarely, since a thick layer of material will significantly reduce the area of ​​the room. In addition, the insulation of walls in a wooden house from the inside will lead to the fact that the outer side of the walls will still be exposed to cold, which will lead to freezing of wood.

Incorrectly carried out work and non-observance of the technology of warming a frame house can lead to the fact that the tree begins to rot from the inside and becomes a favorable environment for the life of fungi and mold. That is why the method is no less important than the choice of a material suitable for this purpose.

Insulation of a wooden house is better done outside than inside

But with outdoor insulation, it is also important to ensure that couples are free to go out. Otherwise, the wood will deteriorate and it will be impossible to control the condition of the walls.

The main mistakes made in the process of warming the attic

The end result of the work, which is carried out with your own hands, directly depends on how accurately the technology and all the prescribed rules are followed. It is especially worth considering the procedure for laying the waterproofing layer, since materials that are capable of absorbing moisture later dry up, which often becomes the cause of cold in the room.

Here are some recommendations from experts, using which you can minimize negative consequences:

  • if the angle of inclination of the roof does not exceed 13 °, it will delay precipitation on the surface. The result is rust and leaks. All this can negatively affect the condition of the insulation, so it is important to make sure that the angle of inclination is large enough before starting work.
  • installation of thermal insulation material on walls and roof is not all the necessary work. It is also necessary to take care of window insulation (according to Swedish technology). To do this, it is best to invite specialists in order to surely avoid a leak. Especially when tilted windows are required

Installation of thermal insulation material on walls and ceilings can be done independently or with the help of specialists.

  • in order to provide the thermal insulation material with ventilation and the ability to dry out if it gets wet, it is advisable to leave a gap of about 2-3 cm between the material and the roof
  • it is strictly forbidden to skip at least one of the necessary layers of steam or waterproofing materials
  • if the insulation material is thicker than the rafters, then their height can be increased by independently filling additional slats.

These simple recommendations can help in the process of work, significantly improving the quality of insulation. However, if for any reason there are doubts about the strength and experience, it would be better to invite a specialist. Of course, you will have to pay for this, but in this case you will not have to redo everything twice.

Insulating the attic pediment from the inside is far from the most difficult task that a home owner may face. Often, on the top floor, the owners want to place a balcony, the insulation technology of which also has its own characteristics.

As well as for walls, a wide variety of materials can be used to insulate the ceiling on the balcony, although it is worth noting that the technology for insulating loggias, which has not been mentioned before, is often used here. To understand in detail the features of this process, the step-by-step instructions "Do-it-yourself balcony insulation from the inside" will help you figure it out.

Attic temperature circuit diagram

Heaters for the mansard roof

It should be noted that the slope of the slopes defining the walls of the attic is a cellular structure formed by rafter legs. It is between them that the insulating material will need to be laid. Therefore, the main requirement for the latter is to be dense with clear shapes. This means that to insulate the attic roof of a private house, it will be necessary to choose plate material. Such heaters include mineral wool in mats and expanded polystyrene plates, it is also high-density foam.

But, as mentioned above, today the market offers completely unique technologies for insulation that do not use dense materials. One of them, which has shown itself from the most positive side, is liquid polyurethane foam. Let's start in order and consider each insulation separately.

Mineral wool

The definition of mineral wool includes several varieties of this building material: glass wool, slag wool, stone variety. When the conversation comes about the attic insulation, then we must talk about the basalt variety, as the best for today. It is its technical characteristics that we will consider.

Characteristics Thermal conductivity, W / m × K Density, kg / m³ Temperature range, ° С Hygroscopicity
Indicators0,035-0,04275-200-190 to +1000Low

Mineral wool in a roll

Basalt wool is mainly divided by density. There are four positions:

  • P-75 - used for insulation of pipes and horizontal surfaces
  • P-125 - this is exactly the same material that is used to insulate the walls of the attic from the inside with your own hands
  • PZh-175 - for thermal insulation of metal and concrete structures
  • PPZh-200 - a very dense material used for thermal insulation of rigid load-bearing structures.

Expanded polystyrene plates

This material is often called foam, which is true. Simply from the variety that is used for packaging, polystyrene foam plates differ in density. Therefore, the material itself is very hard and durable, withstanding mechanical stress and moisture well.

Characteristics Thermal conductivity, W / m × K Density, kg / m³ Flammability class Vapor permeability, kg / m × h × Pa

Let's make a reservation right away that such material is not recommended for insulation due to its high flammability and the love of rodents. But if you still intend to use it, then it is better to take plates of expanded polystyrene with a density of at least 25 kg / m³ to insulate the attic roof.

Expanded polystyrene plates of different thicknesses

Polyurethane foam (PPU)

It is a two-component thermal insulation material composed of polyol and polyisocyanate. The two components are supplied separately in different containers, but during application they are mixed in one container and under pressure are supplied to the thermal insulation areas through a hose and a spray gun. In fact, polyurethane foam is a liquid substance that quickly hardens in air, turning into a hard and sufficiently durable coating.

Characteristics Thermal conductivity, W / m × K Density, kg / m³ Water vapor permeability, kg / m × h × Pa Fire resistance

The quality of insulation is based on the characteristic of thermal conductivity. Comparing the three types, it can be noted that the weakest among them is mineral wool, the most ideal is polyurethane foam.

Polyurethane foam is a liquid material that turns into a durable and hard coating when exposed to air

But this does not mean that everyone should use the PPU. This material is not the cheapest, and special equipment is required to apply it. However, it should be noted that equipment manufacturers today offer mini-stations, the weight of which is only 30 kg. It contains two containers with components, hoses and a nozzle. The compressor will need to be purchased separately, but it is better to take it from friends or rent it.

And a few more varieties of heat-insulating materials, which are less often used in the insulation of the roof from the inside with their own hands.

Glass wool

Characteristics Thermal conductivity, W / m × K Density, kg / m³ Fire resistance Water vapor permeability, kg / m × h × Pa
Indicators0,038-0,04711-25NG or G10,6


Characteristics Thermal conductivity, W / m × K Density, kg / m³ Fire resistance Water vapor permeability, kg / m × h × Pa

Ecowool - cellulose-based insulation, spray-on type


Characteristics Thermal conductivity, W / m × K Operating temperature, ° С Thermal reflection,% Water absorption,% Water vapor permeability, kg / m × h × Pa
Indicators0,037-0,049-60 to +10095-970,35-0,70,001

Penofol - polyethylene insulation, covered with foil on one or both sides

Insulation of a private house with foam

Hello dear friends!

There is a good reason to start insulating your home - our homes need heating for most of the year, and the cost of heating continues to rise. In order for energy saving efforts to have the maximum effect, a residential building needs to be insulated from the roof to the foundation. But in practice, insulation work begins from the walls of the house, since this has another important goal - to update the appearance of the facade.

The qualities of foam as insulation

You can use polystyrene foam as insulation. This material is so light that its weight practically does not create a load on the supporting structures of the house, so the foundation of the building and its walls do not need additional reinforcement, even if they are not designed for additional loads.

Polyfoam is an airtight material, therefore, in a house insulated with it, it remains cool in summer, and warm in winter. But, without letting in air, it does not let in steam either, so rooms with high humidity, for example, a bathroom or a kitchen, must be provided with good ventilation.

Foam sheets are available in different thicknesses - from 2 to 10 centimeters, and different densities. There are also polystyrene foam boards that have a higher density than polystyrene foam, but they are thinner. The thicker the material and the higher its density, the more effective its properties as insulation. But you need to know that even the densest and thickest foam has no sound insulation properties.

Foam bonding technology

Work on the insulation of a private house with foam must be carried out in dry weather at an air temperature above zero. In wet or frosty weather, at the place of work, you need to create an air corridor made of plastic wrap and supply heated air inside.

In practice, any walls can be insulated with foam plastic - brick, concrete, block and others, but they must be dry, durable, free from loose plaster, and, if possible, leveled. Foam boards are glued with a special glue for working with foam. It is applied to the wall with a notched trowel and the board is glued on top. If the wall is uneven, the sheets are glued only along the perimeter and in the middle. The plates are also glued together - for this, their joints are coated with an adhesive solution. After that, the glued foam is sewn to the walls with dowels with hats and umbrellas using a perforator or drill. Five dowels should go to one sheet - four in the corners, and one in the center.

The next step is to glue the reinforcing mesh, which is attached to a special reinforcing glue designed for this purpose. You need to start the sticker process from the top. First, a strip in the width of the mesh is coated with an adhesive mixture, a mesh is applied to it, and pressed down with a spatula, and the protruding glue is evenly distributed over the wall surface. Perforated corners are attached to the corners of the slopes and walls on top of the mesh, which will align them and protect them from accidental chips. This completes the rough work, and you can proceed to the final finishing of the walls.

Decorative finishing of the building

On top of the first layer of plaster, after it dries, a second layer is applied, but it is more carefully leveled with a spatula or metal scraper. When it dries, all remaining irregularities are removed - this is done with an abrasive mesh. If the walls are simply painted with acrylic paint for outdoor use, then the house will look very attractive, but the painting will sometimes need to be updated, or you can decorate the building in a different way - make decorative plaster, for example, a bark beetle.

The final finishing of the building can be completed with decorative moldings on the eaves and under the roof edge.

After spending insulation of a private house with foam and by updating it in this way, you can achieve comfort inside the home and originality outside.

Watch the video: How to Insulate a Cathedral Ceiling in an Existing Home with Foam Insulation. Foam University

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