How to insulate a roof with foam plastic. Reliable packing of a private house for the winter or insulation of the roof with polystyrene foam. Thermal insulation of flat roofs

What is this material
Disadvantages of polystyrene foam as insulation
Thermal insulation made of polystyrene foam
Technology for laying thermal insulation from foam plastic
How to properly insulate a pitched roof
Insulation technology flat roof
We insulate inner part flat roof

Polymer-based heat insulators are one of the most popular materials for insulating roofs of various structures.

You can insulate a roof with foam plastic very quickly, and all the work can be easily done with your own hands. In this article we will talk about the technology of roof insulation with foam plastic, and also indicate the points that you should pay attention to first.

Polystyrene foam is foamed polystyrene, which consists almost 100% of glued air bubbles, enclosed in a polystyrene shell - this makes the material very light.

The main advantages of polystyrene foam include:

• extremely low weight;
• low thermal conductivity;
• is not afraid of moisture and temperature changes;
• does not cause allergies and does not harm the environment;
• fungus does not develop on it, and rodents do not damage it;
• ease of processing and installation;
• does not deform over time;
• long service life - up to 25-80 years;
• minimum price.

The disadvantage of polystyrene foam is its sensitivity to external factors, as well as the fact that its transportation must be carried out with extreme caution.

The material should be laid in such a way that the material is protected from mechanical damage and is not exposed to direct sunlight.

Before insulating the roof with polystyrene foam, you need to decide on the right choice, everything must be taken into account specifications material and various brands were studied.

Roof insulation with foam plastic: the secrets of a popular material

• PSB-15 (15 kg/m3). It comes in a thickness of 50-100 mm, and is used for thermal insulation of pitched and mansard roofs, as well as ceilings.
• PSB-25 (25 kg/m3). Used for wall insulation. The thickness is the same.
• PSB-35 (35 kg/m3). Designed for installation in places where it is necessary to withstand large mechanical loads; Suitable for thermal insulation of flat roofs, floors, and attic floors.

Disadvantages of polystyrene foam as insulation

Quite often, people wonder whether it is possible to insulate a flat roof with extruded polystyrene foam?

Polystyrene vapors are toxic, but the finished material does not emit harmful elements. A slight danger may arise when polystyrene boards are exposed to an open flame. However, for insulation residential buildings self-extinguishing foam is used, which is not a fire hazardous material.

Naturally, insulating a flat roof with polystyrene foam will be an excellent solution.

However, it is slightly inferior to cotton insulation in terms of functionality, since due to its dense structure, foam sheets cannot always close the gaps between structures, as a result of which cold bridges arise in them, and moisture also collects.

This problem cannot always be eliminated even by processing the joints. construction foam or sealant. As a result, wooden structures may begin to collapse.

Expanded polystyrene has fairly high sound-insulating properties, however, it is not entirely advisable to use it in noisy metal roofs, since cotton insulation copes better with this.

Thermal insulation made of polystyrene foam

The technology for installing polystyrene foam and extruded polystyrene foam is practically the same, because in both cases we are dealing with foamed polymer insulation in slabs.

The only difference is that they have different performance characteristics.

Polystyrene foam is made by repeatedly exposing polystyrene to steam.

As a result, the granules significantly increase in volume and interconnect. And yet, polystyrene foam has low fracture strength, and due to significant mechanical stress it crumbles into granules.

The extrusion method involves first melting the granules and then exposing them to freon and carbon dioxide. As a result, extruded polystyrene foam acquires strength and a solid structure in which the gas cells have a closed shape. Extruded polystyrene foam is the latest technological material with a long service life, and its functional properties are much better than those of polystyrene foam.

It is worth paying attention to this when making roof insulation from polystyrene.

Today, penoplex is a common noun; it is often indicated when designating expanded polystyrene.

Technology for laying thermal insulation from foam plastic

To insulate a roof with polystyrene, its base must first be thoroughly cleaned and dried.

By and large, such material can only be laid with waterproofing, but if you want to maximize the life of the roof, it is strongly recommended to additionally include a layer of vapor barrier, otherwise moisture will begin to condense from inside the insulation.

This will not affect the foam in any way, but wood elements may become moldy and rot over time.

Roof insulation with extruded polystyrene foam can be done in several ways:

• gluing, for example to mastic, liquid nails or facade frost-resistant adhesives;
• mechanical fixation;
• flooring method;
• laying in the lathing.

If the situation requires it, fixation methods can be combined.

How to properly insulate a pitched roof

If you are still deciding how best to insulate your roof with penoplex, then it is better to decide on its type at the time of designing the roof.

This way it will be possible to match the width sheet material and the step of the rafters. By insulating your roof with foam plastic, you will significantly reduce your costs for the material. On sale you can find sheet insulation that allows you to lay it without gaps between the rafters in increments of up to 2 m.

Also, do not forget about taking into account the climatic features of your region in the technological calculation. This will make it possible to correctly calculate the required thickness of the thermal insulation layer - as a rule, it is at least 10 cm.

Extruded polystyrene foam for roofing is laid on the sheathing between the rafters. To make the adhesion as reliable as possible, you can use glue and dowels.

Most likely, minor gaps will form between the slabs and the construction legs. They are either filled with sealant or carefully blown out with foam. If this is not done, cold bridges will subsequently form in such places, in which moisture will condense, which will have an extremely negative effect on the wooden elements of the rafter system. After this, if desired, a vapor barrier is laid, and everything is sheathed with plasterboard or clapboard.

Flat roof insulation technology

Insulating the roof with extruded polystyrene foam from the outside is a fairly popular method.

The roof base is thoroughly cleaned and covered with waterproofing film. Expanded polystyrene boards can simply be laid, glued or fixed with dowels.

It is desirable that no gaps form between the plates, and that they are joined with maximum density.

A vapor barrier membrane can be laid on top of the heat insulator, followed by polystyrene foam boards. Next, the base is covered with expanded clay, and a cement mortar screed is poured on top.

Insulation with polystyrene foam can be done, for example, in the following roofing pie:

• reinforced concrete base;
• bitumen-polymer waterproofing;
• slab heat insulator;
• geotextiles;
• gravel backfill.

Thanks to this, you can create a roof that can withstand heavy loads.

There are also more complex roofing pies, in which the top layer is a layer of soil for planting.

We insulate the inside of a flat roof

There are situations when, during the operation of a finished roof, it is necessary to install additional insulation. Therefore, if you asked yourself the question whether it is possible to insulate the roof with foam plastic from the inside, so as not to disassemble the roofing pie, then in this case the answer will be positive.

You just need to decide on the thickness of the insulation.

Insulating a roof with polystyrene foam from the inside involves fixing the sheets to the ceiling with glue or dowels. The main thing is to properly treat the base before doing this to ensure the best adhesion of the material. Pay special attention to the tight fit of the sheets to each other.

To eliminate voids formed at the joints during mating, use sealant.

For subsequent finishing of the ceiling, you can install a tension or suspension system.

If you plan to use plasterboard or other materials, then before this the ceiling is sheathed with a wooden frame, the slats of which must have a thickness exceeding the thickness of the insulation.

Sometimes the technology of roof insulation with polystyrene foam is violated.

Most often, experts make the following mistakes:

1. Damaged sheets are laid or damaged after installation. As a result, depressions appear in which cold bridges form over time.
2. The wrong width of the heat insulator is used, as a result of which the quality of the seal decreases.
3. Instead of a vapor barrier membrane, a polyethylene film is laid, which is why condensation subsequently accumulates on it.
4. Obviously low-quality material is purchased, and there is also a failure to comply with the general rules of roofing work.

To visualize how to properly insulate a roof with foam plastic, you can study the step-by-step video instructions.

We insulate the roof with polystyrene

IN Lately it was especially popular suburban houses have attic rooms, which are used for storing and storing unnecessary items in it.

Today, many are looking to outfit and turn it into part of the living space, so insulating the attic of a home with foam is an important step in this regard.

Polystyrene foam is widely used in construction and for home insulation and is a foam material with a honeycomb structure filled with air.

Basic properties of polyester

Main features and functions:

• Moisture resistance;
• High heat and sound insulation;
• Neglecting the formation of decays and forms;
• Fire safety and environmental compatibility;
• Low thermal conductivity;
• Resistance to various chemicals.

Benefits of using plastic foam

Foam has several positive pages which include:

• Long service life;
• Small mass of slabs;
• Convenient and easy to install;
• Low material cost;
• Mechanical strength.

Characteristics of foam plate selection

This material is mainly produced and sold in the form of plates different sizes and thickness.

To insulate the attic of a house with foam plastic, it is recommended to buy sparkling plates with a thickness of at least 5 cm.

Depending on the grade of the material, its density is determined, at which the use of this material depends on the performance of various parts.

To insulate your attic, you must calculate correctly required amount material.

To do this, measure the total area of ​​the space, the distance between the roof rafts and calculate the number of discs, which will be determined from the previous parameters.

Experts recommend buying small boards to avoid possible property damage when cutting into pieces.

List of required tools

To carry out work in a heating attic, you will need the following tools, which include pieces of wood for the frame, foam and adhesives, blocking steam film and staple gun, hammer and nails, galvanizing with a sharp knife.

Before starting work, you need to prepare everything necessary tools, tools and materials that will be needed for heating.

When choosing polystyrene foam, waterproofing is required to prevent condensation.

Video help:

Preparatory work

At the initial stage, it is necessary to clean the attic of unnecessary objects, dust and all types of pollution.

Carefully check the space for defects and failures, which must be corrected if found.

Particular attention should be paid to inspecting the roof and rafters and chimney outlet points to avoid the risk of fire.

It's best to check your roof in the rain, allowing you to spot potential cracks and water leaks.

Work technology

After cleaning the roof and troubleshooting, continue cleaning the surfaces.

For this purpose, a special housing is used, which serves additional protection and provides better grip.

The next step is to make waterproofing, which uses a protective coating film that serves as protection against foam.

There is a tightly stacked foam panel between the roof rafters, and joints and cracks are sealed and foam-pierced to eliminate thermal bridging.

The seams of the tablet are carefully glued to prevent cold in the room.
Depending on the intended purpose of the attic room in the future, you should choose the final lining.

To maintain this load, it is necessary to calculate the mass of the coating.
Foam insulation technology includes surface preparation, steam and enhanced waterproofing, ventilation systems and tightly packed material to eliminate gaps that must be thoroughly eroded.

Taking all these requirements into account, it is possible to achieve good heat savings and insulate the attic with high quality.

A prerequisite for heating is the installation of a ventilation system, the function of which is to maintain favorable conditions in the room and to avoid the formation of condensation.

Wooden drawer boxes are treated with special antiseptic agents that protect them from the negative effects of moisture and further decay.

Choosing polystyrene as an attic heater requires a comprehensive approach that includes insulating not only the roof, but also the walls and floor.

Therefore, insulating the attic of a house with polystyrene is not difficult and is accessible to everyone, provided that the technological process is properly taken into account.

Help with this process:

This gives us heated, high quality and a comfortable space that can be used as a separate living room.

How to insulate a roof with foam plastic?

Reliable packaging of a private house for the winter or insulation of the roof with foam plastic

The first step is to clean the floor from old backfill and debris. Then steam and waterproofing should be done. After preparatory work it is necessary to lay out foam plastic slabs on the ceiling.

The joints formed as a result of the layout should be treated with polyurethane foam, insulating the roof with foam. It is worth noting that in places where the roof meets the walls, be sure to leave a gap of 3-5 mm for ventilation.

What density should foam have?

Before insulating the roof with foam, you need to make sure whether the attic floor can withstand the expected loads, with the addition of living space.

• polystyrene foam with a density of 15 kg/m3 (PSB15), thickness 50-100mm - for pitched and attic roofs, ceilings
• polystyrene foam with a density of 25 kg/m3 (PSB-25), thickness 50-100 mm - for walls
• polystyrene foam (PSB35) or extruded polystyrene foam - for flat roofs, floors and attic floors with mechanical loads

Roof insulation

To prevent condensation from forming on wooden structures, it is necessary to lay a vapor barrier membrane.

This should happen during the installation of the rafter system before insulating the roof with foam plastic.

If the insulation process occurs in parallel with the construction of the roof, then it is necessary to fill the rafters with sheathing from below, which will serve as a support for the foam plastic boards. The slabs are installed tightly between the rafters. Then they are covered from above with waterproofing material.

It can be ordinary roofing felt or new materials based on foamed polyethylene.

The process of attaching a waterproofing film or roofing felt to the rafters is carried out construction stapler. But we should not forget that the waterproofing material should not be stretched, but rather, it should sag slightly.

After the above work, lathing is made for laying the roofing itself.

A layer of vapor barrier is laid over the foam boards, which are located from the inside of the roof (read: “How to properly install a vapor barrier on the roof”). Then the process is carried out finishing from sheets of plasterboard, lining, or plastic panels. When laying a vapor barrier, it should be taken into account that the moisture-proof side should be facing the rafters (read also: “How to choose roofing insulation”).

About the dangers of polystyrene foam as insulation

Many developers often ask the question: is polystyrene foam harmful because of its toxic fumes, and is it possible to insulate the roof with polystyrene foam?

It is also noted that polystyrene foam, which is used for insulation of residential premises (PSB), is self-extinguishing (that is, it does not support combustion). Its flammability class belongs to category G1 (fireproof material).

When working on a pitched roof, many experienced builders use mineral wool or basalt slabs.

This is due to the fact that polystyrene foam is a rigid material and does not fill all the space under the roof. The voids that arise due to this are filled with cold bridges, and condensation occurs. This, in turn, entails the destruction of the rafter system and corrosion of the metal elements of the roof. Read also: “How to insulate a roof with polystyrene foam, polystyrene foam - step-by-step technology and instructions."

Roof insulation with foam plastic, detailed video instructions:

If you choose polystyrene foam for roof insulation, be sure to check the thickness of the insulating layer for your region.

When making calculations, you should keep in mind both the roofing material used and the climate zone. General rule: do not use insulation materials with a thickness of less than 100 mm (read: “Thickness of roof insulation and insulation methods”).

If two layers of foam are higher than the size of the rafters, then you will have to build them up. Because it is not advisable to nail the frame for plasterboard boards in the future. In addition, attaching foam sheets will be problematic.

In the following articles you will learn how to insulate a roof with foam insulation.

The market for modern materials for insulating low-rise buildings is actually divided into two camps - supporters of mineral fiber insulation and those who prefer foam materials. If many years of experience in insulating roofs and floors with mineral fiber speaks for itself, then insulating roofs with foam plastic is not yet so popular among developers and construction companies, although this attitude is clearly undeserved. There are many reasons for a reserved attitude towards foamed polymers, therefore, before answering the question for yourself whether it is possible to insulate a roof with foam plastic, it is worth understanding them in more detail.

Why use foam plastic for roof insulation?

From time immemorial, thick mats made of pressed mineral fiber have been used to insulate roofs. Anyone who has worked with mineral wool at least once in their life will confirm my words: even when using protective equipment, working with such insulation is far from easy. In addition, if a hole forms in the roof, the waterproofing is damaged, or condensation flows into the body of the fiber insulation, all the work is in vain.

In this sense, roof insulation with foam plastic is simply a gift of fate:

• Lightweight and durable foam boards can be laid under rafter sheathing two to three times faster and easier. Even if the polystyrene foam was caught in a rainstorm or lay in an unheated attic for a couple of years, it has not lost its qualities and can last for several more decades;
• Allows you to obtain higher thermal insulation parameters; even with a sheet thickness of 15-17 cm, heat loss through the roof slopes can be reduced by up to 97%;
• Repair and replacement of insulation on the roof, if necessary, is carried out five times faster than when using mineral wool.

For your information! The cost of insulating one square meter of roof will be 30% cheaper than using mineral slabs.

The material is easy to cut with a knife or a hand saw, does not delaminate, and in its normal state does not absorb or emit volatile substances or odors. It can be glued, painted, treated with special primers and even plastered with cement-sand or gypsum mixtures.

Logic dictates: if polystyrene foam is used to insulate walls both indoors and outdoors, houses are built from sip panels based on polystyrene foam and expanded polystyrene, then why can’t foam plastic sheets be used to insulate the roof?

The answer sounds quite simple - polystyrene foam has its own characteristics and disadvantages that must be taken into account when planning roof insulation.

Features of arranging roof insulation made of foam plastic

Foamed polystyrene, which is polystyrene foam, has its own hidden disadvantages that must be taken into account before insulating the roof with polystyrene foam:

1. Foamed polymer practically does not conduct water vapor, therefore, to prevent watering of the wooden elements of the roof rafter system, it will be necessary to cover the insulation layer on the side of the attic with a vapor barrier film;
2. Similarly, the plane of the foam sheets on the side adjacent to the roofing material of the roof must be covered with a waterproofing sheet or film;
3. The main disadvantage of polystyrene foam, which prevents the widespread use of foam material as a basis for insulation, is its poor thermal resistance and flammability.

For your information! The manufacturer of foam materials tried to minimize the susceptibility of the foam to ignition using special additives in the form of iron and chromium salts.

Such brands of polystyrene melt even when in contact with an open flame, releasing polystyrene decomposition products, but a stable combustion front does not form at temperatures up to 370-400 o C. Wood, widely used for the manufacture of roof rafters, begins to char and steadily smolder even at 270 o C. Therefore, for roof insulation, it is recommended to use foam grades with index C.

To equip insulation systems, foam plastic with a density of 20 to 45 kg/m 3 is used. The heaviest brands have always been the most durable and, accordingly, the most expensive. The lower specific gravity, the lower the thermal conductivity coefficient, but the strength of the material also decreases.

Since the foam sheets laid in the rafter roof insulation system do not experience loads, as, for example, when installing a concrete floor, there are no special requirements for contact or bending strength. But this does not mean that almost any material can be used to insulate the roof, for example, sheets from foam packaging or thermal insulation of industrial refrigerators. This foam will crumble into granules in the second or third year of service. For insulation, use foamed polystyrene grade C with a density of 30 kg/m 3 or more.

Technology for arranging roof insulation based on foam plastic

The sequence of laying an old, long-built house may differ slightly from the scheme for arranging insulation for a newly assembled rafter system of a new building. The difference lies in the use and location of the waterproofing film or membrane. Of course, work on laying a foam insulation system is carried out only after processing all, without exception, wooden parts of the roof rafter system.

Arrangement of insulation for an old building

Most often the question effective insulation rises specifically for houses where the roof is assembled ready-made and has been serving properly for quite a long time. Such a roof, as a rule, already has its own insulation layer laid during construction. If the audit showed the good condition of the materials used, the absence of soaking or destruction of steam and waterproofing, then you can simply supplement the existing layer with upholstery with OSB boards and an additional layer of polystyrene foam 70 mm thick. The installed insulation can be covered with a layer of aluminized film.

• The remains of the roof waterproofing and insulating material are removed;
• The surface of the wood of the rafters and sheathing is thoroughly cleaned with an electric brush, after which it is treated with protective antifungal compounds;
• A new layer of waterproofing is applied to the sheathing and rafters; even the rafter beams must be wrapped in insulation and secured with a stapler;
• Foam blocks are cut with a width equal to the pitch of the rafters, and applied to the end surface polyurethane glue, and the material is laid with inside roofs are like bricks.

In the lower part of the roof it is necessary to lay polystyrene foam with a minimum number of seams; in the area adjacent to the ridge, you can collect insulation from pieces and scraps, but be sure to glue and foam the seams. Foam plastic up to 50 mm thick can be easily cut with a knife; for thicker slabs it is best to use a carpenter's saw with teeth ground on the sides. In this case, the cut is thin and neat.

When cutting, tiny dust and foam balls become highly electrified and stick to your hands, so when cutting the material, a vacuum cleaner is usually used to collect the chips. It is advisable to work in an apron and sleeves, since dust, balls and small pieces of foam are very difficult to remove from the surface of clothing.

Excess foam is trimmed and protected. After laying the insulation layer, a vapor barrier material is applied to the surface. It is best to use rolled material with an aluminized surface such as penofol or isopol. The vapor barrier is covered with clapboard sheathing or moisture-resistant plywood treated with a fire-retardant compound.

Roof insulation with foam plastic for new buildings

The technology for constructing insulation for a newly constructed building differs only in the method and location of attaching the top layer of waterproofing. The film or membrane is rolled out horizontal stripes on the roof rafters after filling the sheathing. Laying the canvas begins from the lower edge of the roof slope, each subsequent row is laid out overlapping the previous one. The material is stapled to the rafters; the joints must be taped. A counter lathing is placed on top of the membrane to form vents. The remaining insulation elements are performed similarly to the previous case.

Most important point building an insulation system is the arrangement of a roof covering passage unit chimney. It doesn’t matter what material the chimney pipe is made of, it will have to be insulated with basalt fiber and covered with a protective casing made of thin sheet metal. The box in which the pipe is attached to the rafters is also filled with a mineral thermal insulator; the lathing or cladding covering the layer of foam plastic in close proximity to the pipe, at a distance of 40-50 cm, must be sewn up with a metal sheet.

Roof insulation is an important stage in building your own home. This work must be carried out efficiently and conscientiously. This determines how warm and dry the house will be, when outside the window it will be damp, cold and uncomfortable.

Modern construction supermarkets and markets offer a huge variety of various materials for roof insulation: mineral wool, fiberglass, basalt slabs, polyurethane foam and a host of other materials. But the invariably leading position is still occupied by polystyrene foam, or, as it is popularly called in the old fashioned way, polystyrene foam in slabs. The most suitable brand for roof thermal insulation is PSB-S-25 and PSB-S-35.

What's good about this material? First of all, due to its rather low cost, as well as excellent performance characteristics.

• Strength: the material has an increased level of resistance to compression and tension.
• Its low specific gravity allows it to be used to insulate even dilapidated structures that cannot withstand the weight of other heavier materials.
• Wear resistance: the material perfectly resists temperature changes, is resistant to mechanical damage and abrasion.
• Moisture resistance: foam plastic does not absorb moisture at all, therefore, the material is not subject to deformation under its influence.
• Fire resistance: the material is not prone to spontaneous combustion. It is best to choose material from group G1 for roof insulation.
• Ease of installation: work on roof insulation with foam plastic can be done even by an inexperienced person.
• Durability of the material: the service life of such insulation is from 25 to 80 years.

Relatively recently appeared on the shelves liquid foam. This material has the same characteristics as polystyrene foam in slabs, but is fundamentally different in the method of application: penoizol is sprayed over the surface using a special installation. Thus, a seamless continuous layer of thermal insulation is formed on the surface. The only negative this method is the need for additional fixation of the surface by installing thin sheets of ordinary polystyrene foam or drywall.

Determining the amount of material

Before you begin work on insulating the roof with foam plastic from the inside, you need to calculate the amount of material required. To insulate an attic roof, calculating the optimal amount is not difficult - you just need to measure the roof area, the pitch between the rafters and determine the size of the foam boards. However, experts recommend purchasing material with a small reserve (6-8 slabs), since in the process of cutting it there may be a risk of deformation or breakage of the slab.

Insulating an attic roof with foam plastic - tools and materials

To work you will need the following materials and tools:

• Styrofoam;
• anti-condensation vapor barrier film;
• wooden blocks;
• nails;
• scissors;
• sharp knife;
• polyurethane foam;
• construction stapler.

The final result depends entirely on how well and conscientiously the main stages of the work are completed.

Roof insulation - based stages:

• preparatory;
• flooring waterproofing and vapor barrier film;
• installation of insulation;
• interior decoration.

Surface preparation, waterproofing and vapor barrier

The surface on which the foam will be laid must be clean and dry.

Expanded polystyrene does an excellent job of waterproofing. But in order to extend the service life of foam plastic, a vapor barrier must be installed.

Please note: it is imperative to leave a gap of at least 2 cm between the film and the sheathing. If you do not do this, condensation will constantly accumulate on the inside of the insulation, which can lead to the process of rotting of the rafters, the appearance of unpleasant odor, mold, etc.

In some cases, an anti-condensation vapor barrier film is laid: overlapping directly onto the rafters. This is done in cases where the width of the rafters does not allow leaving a gap between the polystyrene foam and the plank base. If we are talking about already finished building- the option of attaching this anti-condensation film to the rafters using wooden slats and nails is quite acceptable. It is also quite possible to use a special construction stapler for these purposes.

Installation of insulation

The most common fastening methods polystyrene foam boards:

• gluing (frost-resistant facade adhesives, liquid nails, mastics for gluing tiles to the ceiling, instant installation);
• mechanical fastening (umbrella nails, anchors, wooden slats);
• flooring;
• investment in sheathing.

Sometimes fastening methods are combined. So, polystyrene foam is placed in the sheathing, and additionally fixed with umbrella nails. This fastener is also called a dowel for foam plastic with a thermal head.

Often they combine gluing foam and fastening it with screws. You can glue polystyrene foam onto brick, drywall, plywood, concrete, and iron.

Polystyrene foam on the attic roof

After arranging the vapor barrier layer, it’s time to start installing the insulation - foam sheets. Traditionally, the attic roof is made on a rafter frame; foam plastic slabs should be placed between these rafters. In the process of selecting such, preference should be given to slabs whose size is equal to the width of the step between the rafters. But modern materials allow you to insulate roofs with a pitch width of up to 2 m without gaps.

Foam insulation boards should be placed between the rafters along the sheathing or on top of them. In order for the insulation to hold more firmly and reliably, experts recommend using glue and dowels at the same time. During operation, gaps and cracks may form between the rafters and foam boards. They must be carefully sealed using ordinary polyurethane foam (it is quite possible to use any type of sealant).

After all these steps you can perform exterior finishing surfaces - if you are planning to equip an attic space. The best option with the least labor and financial costs is surface finishing plasterboard sheets, which are attached to the rafters using dowels. Next, it is quite possible to paint the surface or cover it with wallpaper.

Polystyrene foam on a flat roof

A fairly common method of insulating flat roofs with polystyrene foam. The surface is cleaned and covered with a waterproofing film. Expanded polystyrene can be laid freely on a flat roof, fastened cold or hot, or nailed.

It is important to lay the slabs close to each other.

Expanded polystyrene is often involved in creating the roofing “pie”:

Option 1

If polystyrene foam is laid on a flat roof, then it is combined with geotextiles, after which a layer of gravel of fraction 16/32 with a thickness of at least 5 cm is poured. This type of roofing is increasingly used in modern urban planning. This makes it possible to arrange a recreation area, lawns and even parking lots on the roof.

Option 2

Option 3

The third version of the insulation cake: vapor barrier, polystyrene foam boards, a layer of expanded clay, reinforced cement-sand screed 30-40 cm thick.

The use of the technologies described above makes it possible to equip such oases on the roofs of houses. This is called inversion roofing. For its arrangement, polystyrene foam is material No. 1.

How to insulate a roof with foam plastic and avoid common mistakes?

Installation of insulation done incorrectly will make itself felt in the near future. unpleasant consequences. Leaks that form as a result of poorly performed work will not only disrupt the aesthetic picture, but will also contribute to the process of rotting of the rafters.

Let's look at the main ones possible mistakes, most often allowed during the installation process:

• the formation of depressions and cavities on the surface of the insulation. This can lead to the formation of cold bridges. During the installation of insulation, the appearance of such defects must be avoided;
• incorrectly chosen width of the insulation board also leads to a violation of the tightness with all the ensuing consequences;
• usage cellophane film instead of an anti-condensation vapor barrier - perhaps the most common mistake that can cause many troubles and troubles.

To ensure that your home is always warm, dry and comfortable, you should not neglect the rules and standards during the installation of insulation. All work must be performed strictly in accordance with generally accepted canons. Also Special attention It is necessary to pay attention to the quality of the materials used.

Many owners of private houses are wondering whether it is possible to insulate the roof with foam plastic. Of course it is possible. The material does not harm health, and also has excellent performance characteristics and a fairly reasonable cost. But it is sensitive to resins and oil paints, it must be operated at -50...+75 degrees, its installation requires the presence of gaps that need to be additionally processed.

Comparing polystyrene foam with other types of insulation (mineral wool, penoizol, polyurethane foam), we can definitely say that polystyrene foam is best insulation for the roof, no. But in some cases it is simply irreplaceable, and one of them is the installation of an inversion roof.

Polymer heat insulators are among the most popular materials for insulating roofs of various designs. Roof insulation with foam plastic allows short time Install the thermal insulation yourself.

Features of the material

Polystyrene foam is foamed polystyrene - lightweight material, 98% consisting of air bubbles glued together, which are enclosed in a polystyrene shell. The advantages of polystyrene foam include:

• minimum weight (insulation does not add serious loads to the roof structure);
• low thermal conductivity coefficient due to the high air content, which is an excellent heat insulator;
• resistance to moisture (can be used in humid environment without loss of thermal insulation properties);
• resistance to temperature changes;
• fire safety (the material does not ignite, but upon contact with an open fire it begins to melt);
• environmental safety and hypoallergenicity;
• resistance to biological damage (fungus does not develop, is not damaged by rodents);
• ease of processing with tools and installation;
• lack of tendency to deformation;
• long service life (25-80 years);
• affordable price.

Foam plastic is one of the materials that is sensitive to external influences. It must be transported with care. The material should be protected from mechanical damage and exposure to direct sunlight.

When choosing foam plastic for roof insulation and building structures It is important to take into account the technical characteristics of the material of various brands. Manufacturers recommend using polystyrene foam:

• PSB-15 (density 15 kg/m3) 50-100 mm thick for thermal insulation of pitched roofs, including attic roofs, as well as ceilings;
• PSB-25 (density 25 kg/m3) 50-100 mm thick for wall insulation;
• PSB-35 (density 35 kg/m3), or extruded polystyrene foam - for thermal insulation of flat roofs, attic floors, floors. This material can withstand high mechanical loads.

Disadvantages of polystyrene foam as insulation

The question often arises: is it possible to insulate a roof with foam plastic? Polystyrene vapors are toxic, but the finished material does not emit harmful substances. Expanded polystyrene boards can pose some danger when melted under the influence of an open flame. But it is worth noting that self-extinguishing foam is used to insulate residential buildings - it does not support combustion and is a fireproof material.

To insulate pitched roofs, sheets of expanded polystyrene can be used, but in terms of functionality they are inferior to cotton insulation: rigid slabs made of polymer material They cannot always tightly fill the space between structures, as a result of which cold bridges form and moisture condenses in places where there are voids. Treating joints with construction foam or sealant does not guarantee 100% protection. Condensation causes destruction of wooden structures and metal fasteners.

The soundproofing qualities of polystyrene foam are rated quite highly, but it is not entirely suitable for thermal insulation of “noisy” metal roofs, since it dampens sound worse than cotton insulation.

Thermal insulators made of polystyrene

What is the difference between roof insulation with extruded polystyrene foam and foam insulation? There are no particular differences in the installation principle, since both materials are polymer foamed slab insulation. But despite the close chemical composition, extruded polystyrene foam and polystyrene foam differ in their performance characteristics.

Polystyrene foam is made by repeatedly exposing polystyrene to steam. The initial granules increase significantly in volume and sinter together. It is worth noting that the physicochemical bonds between the granules are quite weak, as a result of which the foam has low fracture strength and can crumble into granules under external influence.

The extrusion method involves first melting polymer pellets and then treating them with freon and carbon dioxide. Thanks to this, extruded polystyrene foam has a strong, solid microstructure, which consists of small closed cells filled with gas molecules. The walls of the cells form a continuous mass of substance. Extruded polystyrene foam is a modern high-tech durable material that surpasses traditional polystyrene foam in its functional parameters. This should be taken into account when choosing a material for roof insulation.

"Penoplex" is one of many brands extruded polystyrene foam. Today, the term “penoplex” has become a household name and is often used to refer to expanded polystyrene produced by extrusion.

Basic principles for installing foam insulation

The foam should be laid on a clean and dry surface. In principle, this material can only be installed in conjunction with waterproofing, but in order to ensure long-term operation of the roof, it is advisable to add a vapor barrier layer, otherwise condensation will begin to accumulate on the insulation from the inside. The foam itself will not suffer from it, but wooden structures may begin to rot and become moldy.

Roof insulation with polystyrene foam can be done different ways, including:

• gluing (on liquid nails, facade frost-resistant adhesives, mastics);
• mechanical fastening (anchors, wooden slats, umbrella nails);
• flooring;
• investment in the sheathing.

If necessary, fastening methods can be combined. For example, sheet insulation is inserted into the sheathing and additionally secured with a dowel with a thermal head (umbrella nail). Or the material is glued to the surface and secured with screws.

Insulation of a pitched roof

It is recommended to select a thermal insulator at the roof design stage so that the pitch of the rafters matches the width of the sheet material. If we insulate the roof with foam plastic, then this approach can significantly reduce material consumption. The construction market offers sheet polystyrene foam insulation, which can be laid without gaps between rafters with a step width of up to 2 meters.

In addition, it is important to perform a thermal calculation taking into account the climatic characteristics of the area in order to determine required thickness thermal insulation layer. The minimum recommended parameter is 100 mm.

Foam boards are laid along the sheathing between rafter legs. To secure the fastening, you can use glue and dowels. There are often small gaps between the slabs and rafters. They should be properly blown out with polyurethane foam or filled with sealant, otherwise cold bridges will form in these places, where condensation will accumulate and have a detrimental effect on the wood of the elements of the rafter system. At the next stage, it is recommended to lay a vapor barrier, and then finish it with plasterboard, clapboard or wood board.

Flat roof insulation

Expanded polystyrene boards are a popular option for external insulation of flat roofs. The roof base should be thoroughly cleaned and covered with waterproofing film. Expanded polystyrene slabs can simply be laid as a flooring, glued, or secured with dowels. It is very important to lay the slabs without gaps, as tightly as possible.

The vapor barrier membrane can be laid under the heat insulator on a concrete base, then polystyrene foam slabs are mounted, covered with a layer of expanded clay, on top of which a cement-sand reinforced screed is laid. Expanded polystyrene as insulation can also be included in such a roofing pie:

• reinforced concrete base;
• bitumen-polymer waterproofing;
• slab heat insulator;
• geotextiles;
• gravel backfill.

This allows you to create a serviceable roof designed for high loads.

There are more complex versions of the roofing pie, upper layer which is the soil for planting plants. Roof insulation with penoplex is widely used to create such inversion roofs.

Insulating a flat roof from the inside

During operation, it may turn out that a flat roof needs additional insulation. In order not to dismantle the roofing pie, it is recommended to insulate the roof with foam plastic from the inside. You should select insulation of the required thickness.

Foamed polystyrene sheets can be attached to reinforced concrete ceilings using glue and dowels. It is important to prepare the base surface to ensure high adhesive adhesion. When laying slabs, the elements should fit tightly to each other. It is advisable to use a sealant during the process so that there are no voids at the joints between the sheets and at the points where they meet the walls.

To finish such a ceiling, you can use a tension or hanging system. If it is planned to cover it with plasterboard or other materials, a wooden sheathing is first attached to the ceiling, the thickness of which should be no less than the thickness of the insulation.

The most common mistakes when insulating with polystyrene foam

1. Installation of sheets with defects or damage to mounted slabs - depressions and cavities contribute to the formation of cold bridges.
2. An incorrectly selected width of the heat insulator also causes a leak.
3. The use of polyethylene film instead of a vapor barrier membrane provokes the formation of condensation.
4. Use of low-quality materials, violation of work technology.

Roof insulation with foam plastic (expanded polystyrene) from the inside, video

Watch how to insulate a roof with polystyrene foam and extruded polystyrene foam from the inside in the video. Advantages and disadvantages of polystyrene foam, is it possible to insulate a roof with it?

Roof insulation with foam plastic: types and classification of insulation materials. Thermal insulation of a gable roof

Today, when building houses, and later finishing them, the question arises of how to make it warm. After all, building is only half the battle; it is important to reduce heat loss as effectively as possible. Moreover, by insulating not only the walls and floor, but also insulating the roof with foam plastic from the inside, or choosing another insulation.

Modern insulation technologies allow you to avoid heavy weighting of the roof. A reliable degree of protection against heat loss is provided by the fairly lightweight thermal insulation materials that exist today.

Completed view of attic insulation

The insulation process depends on its type and plans for using the attic space. So it makes sense to insulate the roof slopes if the attic will be frequently used or equipped as a living space.

For these purposes they began to use various insulation materials that effectively cope with this task. And at this stage, the question usually arises: is it possible to insulate the roof with foam plastic or use another material for this purpose, such as mineral wool.

Some prefer the first option, others the second, based on their work experience or the advice of friends. Still others simply doubt and do not know what to give preference to. So what is better to insulate the roof with foam plastic or mineral wool? Let's try to figure it out and decide what to choose.

Types and classification of insulation

Let's consider all types of insulation that are used for these purposes. Various materials are used in roof insulation.

The most commonly used insulation materials are:

• light weight;
• easy to install;

Considering all the disadvantages and advantages, we can say that polystyrene foam is the best option for insulation, which will keep the house warm.

mineral wool insulation;

• expanded clay

All of the listed materials have their pros and, of course, cons. Let's figure it out and determine which material has the best qualities.

Expanded clay is environmental material with good thermal insulation qualities and inexpensive price. The big disadvantage is that it is difficult to work with. The main difficulty is that it is difficult to fix and distribute evenly on non-horizontal surfaces.

Expanded polystyrene has good properties thermal insulation and sound insulation, strong and durable material. But it does have its drawbacks: it melts, releasing harmful substances upon contact with an open fire, and has a low vapor barrier coefficient.

Mineral wool has a low material density and therefore it is considered that its thermal insulation abilities are lower than those of polystyrene foam. Also, its water-repellent properties are not great. Otherwise she is good material for insulation.

Polystyrene foam is a lightweight material that consists of ninety-eight percent air bubbles enclosed in a polystyrene shell.

Its advantages are as follows:

• light weight;
• low thermal conductivity coefficient;
• easy to install;
• has good sound insulation properties;
• it is an environmentally friendly insulation material;
• optimal price-quality ratio;
• does not burn on contact with open fire.

Also, the advantages of foam insulation include its moisture-repellent property - you do not have to additionally install moisture- and vapor-protective membranes. Insulation with foam plastic is much cheaper than with mineral wool mats, but requires more care and experience.

In conclusion

We tried to tell you about all the ways to insulate a roof with foam plastic. We hope that you have learned a lot of useful things from this article and now you can independently insulate the roof with foam plastic without resorting to the services of construction organizations, and most importantly, you can save money that you will subsequently spend on your needs.

Do-it-yourself insulation of the roof from the inside with polystyrene foam, how and what is the best way to insulate the roof, is it possible to use mineral wool, instructions, photo and video tutorials, price

Do-it-yourself insulation of the roof from the inside with polystyrene foam, how and what is the best way to insulate the roof, is it possible to use mineral wool, instructions, photo and video tutorials, price

How to insulate a roof with foam plastic: answers to all questions

The constructed house is already protected by the roof from seasonal precipitation and wind loads. If the roof is insulated, thermal insulation is added to the functions of the roof. The uninsulated ceiling of the upper level of a residential building and its roof causes the loss of a fifth of the building’s heat. Roof insulation helps to avoid energy losses, save on heating costs, and get additional square meters comfortable space for all-season living.

With a wide range of bulk, roll, sprayed and produced insulation boards, the most popular and affordable is roof insulation with foam plastic.

Are polystyrene foam and polystyrene foam the same thing?

Expanded polystyrene is superior to polystyrene in all respects and is therefore more expensive

Both materials are produced from polystyrene using different technologies. The classic foam plastic we are familiar with is obtained by steaming in the form of microgranules, which increase from high temperature and fill the volume of the block mold. The result is a lightweight material from polystyrene shells sintered together and filled with air.

Expanded polystyrene, produced by extrusion, is a material with a solid structure, including small gas-filled cells. Thanks to the technology, a more dense, waterproof, durable material is obtained. Insulating a roof with expanded polystyrene will cost more, but will allow you to get a thinner layer of thermal insulation with good sound absorption, better fire resistance and a longer service life. This material is practically irreplaceable when thermal insulation of a flat roof and floors is being used. Expanded polystyrene is good not only for roofing, but also for insulating gables gable roof without large losses of useful living space.

The operating technology is the same for both materials. In the future, insulation of building roofs with foam plastic will be considered.

Features of the material

Foam boards come in different thicknesses

• light weight, reducing the load on the load-bearing elements of the roof structure;
• ease of installation and processing with working tools;
• resistance to temperature changes and certain mechanical loads;
• low thermal conductivity due to 98% air content in the material;
• long service life;
• retains its properties and shape in a humid environment, is not afraid of mold and mildew;
• affordable price;
• environmental friendliness;
• fire safety (the material melts without ignition);
• hypoallergenic.

• release of harmful substances when exposed to open fire;
• the ability to accumulate a small amount of moisture, which can cause the formation of mold and mildew on rafters, sheathing, finishing materials and corrosion of metal fasteners;
• the impossibility of completely filling the niche between the rafters due to rigidity; this leads to the appearance of condensation and cold bridges;
• the material is almost impervious to air;
• rodents can live in polystyrene foam (this does not apply to extruded polystyrene foam);
• afraid of contact with solvents, alcohols and petroleum products;
• ultraviolet radiation destroys the foam.

Standard foam sheets have dimensions:

The thickness of the insulation falls within the range of 10-100mm. In the marking of foam plastic, the number indicates the density in kg/m³. When insulating a roof from the inside or outside, the PSB-S-15 and PSB-S-25 brands are more often used.

After studying the characteristics and comparing them with other types of heat insulators, each owner independently decides whether it is possible to insulate the roof with foam plastic, or whether another material is suitable in his case.

Methods for fastening foam boards

The set of insulation sheets depends on the chosen installation method. necessary materials, devices and tools that will be required for work.

Fastening polystyrene foam using regular polyurethane foam

• glue with special frost-resistant glue, liquid nails, mastic;
• lay - when insulating the attic floor or flat roof outside;
• put battens into the niche;
• secure mechanically using wooden slats, umbrella nails or anchors.

For greater reliability, ease of operation, or if necessary, it is possible to combine the proposed fastening methods.

Required materials and tools

To work you need to prepare:

• waterproofing material;
• polystyrene foam of the selected brand with the required thickness and size of the plate;
• vapor barrier film or membrane;
• self-adhesive tape for gluing joints or overlaps of vapor and waterproofing fabrics;
• polyurethane foam;
• construction stapler;
• scissors, knife;
• wooden blocks;
• hammer;
• material for finishing insulation places.

Now you can start insulating the roof with foam plastic.

Insulation of a flat roof

Insulating a flat roof with foam plastic and bypassing communications

1. The waterproofing film is first laid on the previously prepared, clean and dried surface of the flat roof.
2. Then the foam plastic slabs are tightly laid (for a roof that will be loaded during operation, it is advisable to choose polystyrene foam) and the joints are taped with special tape. If there is a second layer of insulation, its slabs must overlap the joints of the lower layer during installation.
3. The insulation is covered with geotextile, on which a layer of gravel, expanded clay or crushed stone (at least five centimeters) is poured.
4. A screed is being made on which the finishing roof covering will be laid.

If you plan to lay out a lawn or flower bed on a used flat roof, then another layer of geotextile is laid on top of the gravel. Now a layer of soil is poured onto it (within 20 cm) and grass or other plant crops are planted.

Roof insulation with foam plastic can also be done from the inside. Most often, foam plastic is glued to the ceiling, so the surface of the latter must be prepared for good adhesion. After fixing the slabs, fill the voids at their joints with sealant. The finishing of the insulated floor can be systems of hanging or suspended ceilings. If the foam will be covered with sheets of plasterboard or other materials, a lathing is attached to the ceiling in advance.

Insulation of a pitched roof

1. Produce necessary preparation and revision of the roof structure frame and the roof itself:

Scheme for insulating a pitched roof with foam plastic

Roof insulation with foam plastic

1. Laying prepared foam boards between the rafters and securing them using the chosen method.
2. Small gaps between sheets of foam plastic are filled with polyurethane foam or other sealant. This operation should be performed carefully and efficiently. Otherwise, there is a high probability of cold bridges occurring with the obligatory formation of unwanted condensation.

For additional insulation, a layer of mineral wool can be installed on the foam.

1. If additional sound insulation is provided, it is laid on foam plastic. Otherwise, move on to the next point.
2. The insulation is separated from the internal attic or attic space by a vapor barrier film, the sheets of which are also taped with special tape at the joints. The vapor barrier is secured to the rafters with staplers and wooden guides for future cladding. The thickness of these guides or profiles will provide the necessary ventilation gap between the vapor barrier and the final finish. When stretching the film, leave a slight sag to avoid tearing due to temperature changes.

1. The work is completed by covering the inside of the insulated attic space with selected finishing materials.

Mistakes when insulating with foam plastic

1. Use of low-quality slabs - with manufacturing defects or damage during installation.
2. Violation of technology and work order.
3. Using ordinary polyethylene film as a vapor barrier.
4. Incorrectly selected width of the installed slabs - this leads to a violation of the tightness of the insulation layer.

Knowing how to insulate a roof with foam plastic, it would be useful to study technologies using other materials. After comparing all the pros and cons, you can make an informed choice.

Roof insulation with foam plastic: can it be used, all the pros and cons

Answers to all questions about roof insulation with foam plastic. How to properly and whether it is possible to insulate a roof with polystyrene foam. The advantages of this method of thermal insulation.

Roof insulation with foam plastic: 5 main questions for an independent master

Are you attracted to roof insulation with foam plastic as the cheapest and easiest option, but you are worried about some opinions about its toxicity, and you don’t really know how to get started with this material? In this article we will reveal the 5 most important issues about polystyrene foam as insulation and will help you understand the technology of its installation with the help of detailed master classes. It will be interesting!

What is hidden under the name “foam plastic”?

Foam plastic is the popular name for expanded polystyrene. But it is worth distinguishing between simply expanded polystyrene and extruded polystyrene foam.

Polystyrene is a product of the polymerization of styrene, which is quite clear from the name alone. In appearance, polystyrene is hard, elastic and colorless. It does not have high mechanical bending or tensile strength, low density. Even lenses are made from this substance, not to mention dishes and other household items.

Expanded polystyrene is foamed polystyrene, which is produced in the form of sheets up to 20 cm thick and can vary in density. It costs much less than extruded polystyrene foam, is more friable and has a more limited scope of application.

The name of extruded polystyrene foam comes from its production method - extrusion, when the raw material is squeezed out through certain holes of the same size. Even more precisely: extruded polystyrene foam is a gas-saturated melt of polyethylene. It is produced in the form of sheets with a thickness of 30 to 70 mm, and varies not only in density, but also in color. Much more durable than conventional foam, it has a tongue-and-groove system along the edges and is easy to install - there is no need to fill the joints. In addition, its thermal conductivity is even lower - in fact, the lowest of all existing insulation materials.

Extruded polystyrene foam is made by extrusion, due to which it has a uniform, closed-porous structure. Each cell has a diameter of no more than 0.1-0.2 mm.

Extruded polystyrene foam in English abbreviation called XPS, in Russian – EPPS. They are also insulated with polystyrene as a sandwich panel when this insulation is closed on top OSB board or metal sheet:

Moreover, working with this material is quite simple:

But one of the most popular XPS products on the Russian market is the light blue Primaplex slabs. This is a fairly durable material with extremely low water absorption, dimensional stability and high frost resistance.

Why is foam plastic better than other thermal insulation?

Now let's look at the popular myths about polystyrene foam.

So, the first and most important quality for which this insulation is valued is its high thermal insulation. This coefficient is 0.035-0.048 W/mK at 25C, and 0.20 W/mK for its individual types, according to manufacturers. But absolutely all foamed plastics are afraid of water and quickly absorb it. And expanded polystyrene, which is made using the non-press method, has a water absorption of up to 350% of its mass. And even this is not the limit! And the more moisture in the insulation, the lower its thermal insulation properties.

But in practice, ordinary polystyrene foam lasts only 10-15 years as roof insulation, after which its heat-protective qualities sharply decrease. But extruded polystyrene foam, abbreviated as EPS, is more durable.

But polystyrene foam has the lowest thermal conductivity among all existing roof insulation materials. Even in severe frost, the temperature of 50 mm thick foam and EPS sheets will be +5°C. Plus the following advantages over other heat insulators:

• Soundproof.
• Stable dimensions throughout the entire period.
• Easy to install and cut to required sizes.
• No need for wind protection.
• Resistance to various types of chemicals.

And quite interestingly, in factory conditions they test the strength of extruded polystyrene foam: they lower it into water, heat it to +40°C and cool it to -40°C. Each such cycle is equivalent to one year of operation. Therefore, manufacturers confidently declare that extruded polystyrene foam can serve as under-roof insulation for 50 to 80 years.

And the most important advantage of extruded polystyrene foam is that it does not reduce its thermal insulation properties even when in contact with water. Whereas conventional insulation works properly for only a few years, and then, if mistakes were made in roof insulation, they gradually reduce their thermal insulation qualities and the house has to be heated more and more. This is not to mention other related problems.

But in a roofing pie, polystyrene foam can be damaged by rodents: they will not live in it, but they will make passages. Unless you hide these sheets outside:

Is polystyrene foam safe as insulation?

Officially, this material is classified as environmentally friendly, i.e. those that do not pollute environment and are not dangerous to humans. But let’s initially determine what influence on the human body can be considered dangerous, and what can be considered prejudice and unnecessary anxiety. You will be very surprised!

Such different concepts

Thus, in the world it is customary to refer to two main concepts for assessing the harm to the human body of certain substances: threshold and linear.

The threshold concept states that all harmful substances in a residential building must be reduced to a certain level for each of them, a threshold, which is fixed by the MPC value (maximum permissible concentration). Those. This is the amount of a harmful substance in the air that can already harm a person. Exceeding this threshold always leads to negative consequences such as illness or even death. Let's give an example: the cheapest foam plastic was chosen as insulation, it was installed incorrectly, there is no normal ventilation in the home. Result: sick liver in the household. But in a well-ventilated house, no one feels harm for a long time. Those. we are talking about the fact that the concentration of a harmful substance below the established threshold does not affect dangerous influence per person, and a healthy body can easily cope with small toxins. It's like inhaling cigarette smoke from your interlocutor once.

In all countries former USSR And modern Russia building codes are based on the threshold concept. But in Japan, Canada, Germany, the USA and Belgium, the linear concept is at the forefront, the essence of which is that the harmful effect on the human body linearly depends on the total absorption of a certain substance. Those. at one time cigarette smoke really will not have a significant effect negative influence on the body, but constant smoking – yes. The same applies to polystyrene foam: if such insulation is on both the roof and the walls, then every day a person absorbs through the lungs permissible norm styrene, which is not so little in a year. In a word, small concentrations of poison with long-term use are also harmful. This is easy to show using the example of modern megacities: all transport exhausts and factory emissions do not individually exceed the sanitary threshold, but still life is not sweet for the city residents.

If, when insulating, we adhere not to the first concept, but to the second, then the value of the maximum permissibility of styrene in a residential area will have to be reduced by 594 times!

Of course, polystyrene is used both in the food industry of our country and in medicine. But remember that its toxicity is calculated according to the same concept - threshold. Just note that polystyrene foam and polystyrene are already being phased out in many countries, and in some even banned.

A substance that is not excreted from the body

Now let us recall that styrene is a condensed aromatic compound that contains benzene in its molecule and is bad because it is not excreted from the human body. And, according to modern scientists, in residential construction the threshold for the presence of styrene in the air should be reduced to such minimum values ​​that any polymerization products (including polystyrene foam) should be prohibited.

Therefore, we conclude: styrene is toxic to humans primarily because it accumulates in the liver. After all, the problem is that with an ordinary toxin human body can really handle it by simply processing it with the help of the liver and throwing it away naturally, but styrene is not removed from the body - it only accumulates. Therefore, a threshold concept cannot be applied to foam insulation - only a linear one.

In addition, according to modern SNiPs, toxicity indicators of combustion products must be determined for combustible materials. And for high-quality expanded polystyrene this value is T2, which means “moderately dangerous”.

99% polymerization

There is one more point that not everyone knows about. The fact is that 100% polymerization of EPS is only a theory, but in practice it does not even reach 98%. In addition, even the polymerization process itself is reversible, because polymers are easily destroyed by ultraviolet rays, ozone, water, oxygen, heat and mechanical stress. Then free styrene begins to separate from the EPS and penetrates into the living room, albeit in a small concentration, but it affects the heart and women’s health quite a bit. And the most common problems from this element - toxic hepatitis, and all due to the cumulative properties of styrene, it accumulates in the liver, but is not excreted.

And finally, special studies of the Russian Academy of Sciences have shown that during its period of operation, polystyrene foam decomposes up to 10-15%, and 65% of the decomposed part consists of styrene.

The solution is ventilation!

But how can the foam used to insulate the roof harm it? If this is insulation from the outside, then, of course, no way. If from the inside, but the attic is not used, then it is necessary to carefully consider ventilation. But if we are talking about a residential attic with such insulation, then things are bad. At least we don't advise you to do this.

Or it’s good to cover the foam in front with other insulation, as in this project:

How to insulate a roof with foam plastic inside and outside?

Basic methods of attaching foam to a surface:

But mainly two methods of fastening are popular. Adhesive:

This is how to properly insulate an attic roof:

As insulation for a concrete roof:

What difficulties may arise during insulation?

But there are many such difficulties, so get ready to study all the nuances of such insulation.

Point 1. Expansion joints

Here is the first stumbling block that may frustrate you when insulating your roof with foam plastic. This is the concept of expansion joints. Seams form over time between thermal insulation materials due to temperature changes, as well as along the perimeter and in places where beams pass. You can notice such problem areas in winter - by a thin strip of ice or snow that does not roll off. And there is a limit for deviations from the norm for these seams, and for pitched roofs it is one, but for flat roofs it is completely different.

Although some home craftsmen simply cut out the foam to the size of the rafters and insert it without any seams:

Point 2. Weathering

But the most alarming thing is that polystyrene foam undergoes weathering, during which gas-containing mixtures are formed. And weathering in an ordinary attic with its ventilation through oppositely located dormer windows- inevitable. It is not advisable to decorate even a residential attic with polystyrene foam, so that in the heat you simply do not inhale the so-called persistent organic pollutants, which, by the way, Western countries under the strict prohibition of the Stockholm Convention.

Point 3. Preliminary plan

Unlike the installation of conventional insulation, before installing foam sheets, you should carefully consider the plan and make sketches. There are other difficulties: for example, such panels cannot be cut and processed mechanically, they cannot be secured with screws - only inserted into the finished structure. Moreover, if you need to carry out certain communications under the roof (electricity, for example), then you will have to organize another mounting layer under the panels, at least 50 mm thick.

Point 4. The need for waterproofing

Despite the fact that polystyrene foam and expanded polystyrene are waterproof, covering roof slopes or flat roofs with them cannot be considered waterproofing. All because of the large number of seams. This is why a waterproofing layer is necessary: ​​it can be bitumen rolled materials, oiled paper, fiberglass or kraft paper.

Have you decided to insulate with this material? Think it over proper ventilation roofs and take care of your health!

Roof insulation with foam plastic: detailed analysis all pressing issues

Myths and truth about foam insulation: how easy, safe and practical it is. Step-by-step instructions with examples of work performed correctly.

The process of insulating a roof with foam plastic is a very popular way to insulate a house. Both pitched and flat roofs can be insulated in this way. Also, foam plastic for insulation can be laid in the attic floors.

Roof insulation with foam plastic has many advantages: it is easy to install and process, it is not afraid of moisture, it does not rot or be destroyed by microorganisms, and it can provide reliable thermal insulation without weighing down the structure.

But the material also has disadvantages - vapor permeability and flammability. Therefore, when using polystyrene foam as insulation, it is necessary to install ventilation in attic room and strictly comply with all fire safety regulations.

Difficulties with foam insulation

Many developers often have a question: are foam vapors poisonous? Is it worth using this material to insulate the roof from the inside? In favor of polystyrene foam is the fact that it is used for thermal insulation in residential premises polystyrene foam (PSB) is self-extinguishing - it does not catch fire. The flammability class of polystyrene foam is category G1, that is, it is a fireproof material.

When working on a pitched roof, many experienced builders use mineral wool or basalt slabs. This choice is determined by the rigidity of the foam, due to which the material cannot be located in the entire space under the roof. Voids appear into which cold penetrates, resulting in the formation of condensation. Destroys due to condensation rafter system, and the metal elements in the roof rust.

To avoid condensation, when choosing foam plastic for thermal insulation of the roof of a private house, it is necessary to clarify such an indicator as the thickness of the thermal insulation layer for the area in which you live. When making calculations, you need to focus on the type of roofing material used and the climate zone. The choice of foam has one thing in common: it is not recommended to use foam with a thickness of less than 10 cm for work.

Expert opinion

Konstantin Alexandrovich

Ask a question to an expert

In cases where the insulation needs to be laid in two layers, and the thickness of the rafters does not allow it, it would be correct to lay a 50mm by 50mm beam horizontally, step under the covering material (plasterboard, OSB and various moisture-resistant boards).

Characteristics of foam plastic

Foam plastic has the following advantages among other materials:

• light weight, which reduces the load on the load-bearing parts of the roof;
• ease of installation and processing with tools;
• durability at temperature changes and certain mechanical loads;
• low thermal conductivity due to great content air - 98 percent;
• long service life;
• preservation of properties and shape at high humidity, it is not afraid of mold and mildew;
• affordable cost;
• environmental friendliness;
• fire safety (foam plastic can only melt and not ignite);
• hypoallergenic.

Of course, foam plastic also has disadvantages:

• if the material is exposed to open fire, it releases harmful substances;
• capable of absorbing moisture, albeit in small quantities, which is why rafters, sheathing, and mold become covered with mold and mildew, Decoration Materials, and metal fasteners are rusty;
• it is impossible to completely position the foam between the rafters, as it is too rigid; in this case, condensation and cold bridges form;
• has low breathability;
• polystyrene foam can be chewed through and colonized by rodents (extruded polystyrene foam is an exception);
• Solvents, alcohols, gasoline are dangerous for him;
• destroyed by exposure to ultraviolet radiation.

Attention! Despite the fact that high fire resistance is one of the advantages of polystyrene foam (it does not spontaneously ignite), if the material burns, toxic substances are released. That is why the installation of polystyrene foam must be accompanied by compliance with all fire safety rules.

Standard foam sheet can be following sizes(mm):

• 500×1000;
• 1000×1000;
• 2000×1000.

The thickness of the insulation varies from 10 to 100 mm. The number contained in the insulation marking indicates the density (kg/m3). For internal or external roof insulation, polystyrene foam of the PSB-15 or PSB-S-25 brands is usually used.

Having studied the characteristics of foam plastic and comparing them with other materials for thermal insulation, each builder himself decides whether to use this material for insulation or replace it with another.

Do-it-yourself roof insulation with polystyrene foam

Before work you should prepare:

• material that will be used for waterproofing;
• polystyrene foam of the selected type (taking into account the required thickness and size);
• vapor barrier film or membrane;
• self-adhesive tape to glue the joints and overlaps of steam and waterproofing materials;
• polyurethane foam;
• construction stapler;
• scissors and knife;
• wooden blocks;
• hammer;
• material that will be used for final finishing in areas of insulation.

After preparing the necessary materials and tools, you can begin to insulate the roof using polystyrene foam.

This happens in the following order:

How to insulate a roof with foam plastic from the outside?

Foam boards are often used to insulate flat roofs from the outside. To do this, the roof is well cleaned and covered with waterproofing. Polystyrene boards can be laid as flooring, glued, or secured with dowels. An important condition is to lay the slabs as tightly as possible so that gaps do not form.

The vapor barrier membrane can be laid at the bottom of the heat insulator, placing it on concrete base, then begin the installation of polystyrene foam slabs, cover them with expanded clay, on which a cement-sand reinforced screed is laid. Also, using polystyrene foam, you can create a roofing “pie” consisting of:

• reinforced concrete base;
• bitumen-polymer waterproofing;
• slab heat insulator;
• geotextiles;
• gravel backfill.

This combination creates a serviceable roof that cannot be destroyed. high loads.

External thermal insulation technology:

This option is the most common method of attaching material to the surface of concrete slabs. This method is suitable for insulating a flat roof. Moreover, you can insulate both a new roof and a restored one.

Conclusion

Regardless of the choice of insulation by the master, the so-called protective “pie” always includes foam plastic and waterproofing. Careful adherence to the required rules during installation will allow you to live in any home comfortably and without additional heating costs.

Video on roof insulation with foam plastic