Finishing 

A quick way to insulate the roof with polystyrene foam using a special technology. We make roof insulation with foam plastic correctly How to properly insulate the roof with foam plastic from the inside

fibreboard in the common people is simply called fiberboard
and is not essentially a heater and 217 rubles per sq. m. expensive, I can offer 168 rubles per sq.m
type in Yandex "DVP"
it is full of where they sell it, nothing new

Fiberboard-? Have you compared features? Is fiberboard thermal insulation? Fiberboard is soundproofing, and in the end, fiberboard does not burn? What is its basis (the basis of fiberboard)?

Fiberboard-? Have you compared features? Is fiberboard thermal insulation? Fiberboard is soundproofing, and in the end, fiberboard does not burn? What is its basis (the basis of fiberboard)?

And more, my friend. What is the maximum thickness of fiberboard?
If there is time and desire, then:





Fiberboard is also used for thermal insulation of buildings and structures. The thermal resistance of this material qualitatively increases in the case of the use of two- and three-layer options using polystyrene foam or mineral wool boards. The three-layer slab consists of a layer of expanded polystyrene or mineral wool insulation, covered on both sides with a fiberboard layer 15 mm thick. Plates with a higher bearing capacity are also produced, with a total fiberboard thickness of 25 mm. The fibrolite layer bears the load of the plaster, promotes vapor diffusion (the wall “breathes”), and increases the fire resistance of the room. When erecting internal walls and partitions, fiberboard reinforced with slats is used, which ensures the preservation of geometric shapes when laying concrete. The peculiar structure of the fiber mat can be made attractive by a variety of color tones, and thus, additional processing is not necessary. From this point of view, fiberboard is simply ideal for finishing large structures (sports complexes, industrial premises, swimming pools, etc.), painted fiberboard with embedded wooden slats combined with styrofoam or mineral wool boards create spectacular walls and coverings.

Rarely is there a material that can be used as multifaceted at the same time as FIBROLIT. And the formwork, and the roof, and partitions are different for you, and even the decoration of the premises is original, and much more. And all this with relatively small physical, construction and financial costs.
I must say, FIBROLIT is not a special novelty. In its manufacture, not chips are used, but wood fiber, due to which high compressive and bending strength is achieved. The density of fiberboard is from 208 to 570 kg per sq.m. The material has low thermal conductivity and high sound absorption coefficient, making it good sound insulation.
Other remarkable qualities of fibrolite are biological stability, low thermal conductivity, high sound insulation characteristics, long service life, do not spoil rodents and insects, do not rot. It is easy and convenient to work with this material: sawing, drilling, driving in nails, chasing, milling. Convenient finishing with plaster, you can paint, glue wallpaper.
One of the applications of fibrolite is fixed formwork in monolithic housing construction, for example, in the construction of cottages, multi-storey buildings, outbuildings, as well as in the reconstruction and repair of buildings. The use of fixed formwork reduces the construction time by 1.5 times compared to other methods.
In Western Siberia, where the heat lasts only 3-3.5 months, the builders managed to build "boxes" of houses in a monolithic way. Can be used with fibrolite different types concrete.
The great advantage of fibrolite is that its use is possible with low temperatures. In the conditions of the Far North, this unique material is used in a complex way according to the Intra-Bau system. Its high heat-insulating properties made it possible to significantly reduce the cost of heating concrete, to carry out pouring of concrete solution immediately on the whole floor of the building in winter conditions.
Fiberboard is also used for thermal insulation of buildings and structures. The thermal resistance of this material qualitatively increases in the case of the use of two- and three-layer options using polystyrene foam or mineral wool boards. The three-layer slab consists of a layer of expanded polystyrene or mineral wool insulation, covered on both sides with a fiberboard layer 15 mm thick. Plates with a higher bearing capacity are also produced, with a total fiberboard thickness of 25 mm. The fibrolite layer bears the load of the plaster, promotes vapor diffusion (the wall “breathes”), and increases the fire resistance of the room. During the construction of internal walls and partitions, fiberboard reinforced with slats is used, which ensures the preservation of geometric shapes when laying concrete. The peculiar structure of the fiber mat can be made attractive by a variety of color tones, and thus, additional processing is not necessary. From this point of view, fiberboard is simply ideal for finishing large structures (sports complexes, industrial premises, swimming pools, etc.), painted fiberboard with built-in wooden slats in combination with polystyrene foam or mineral wool boards create spectacular walls and coatings.

Roof insulation is an important stage of construction own house. These works must be carried out with high quality and in good faith. It depends on how warm and dry it will be in the house when it is damp, cold and uncomfortable outside the window.

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

What is good about this material? First of all, its rather low cost, as well as excellent performance.

  • Durability: The material has a high level of resistance to compression and stretching.
  • Its low specific gravity makes it possible to use it for insulating even dilapidated structures that are unable to withstand the mass of other heavier material.
  • Wear resistance: the material perfectly resists temperature extremes, is resistant to mechanical damage and abrasion.
  • Moisture resistance: foam absolutely does not absorb moisture, therefore, the material is not subjected to deformation under its influence.
  • Fire resistance: the material is not prone to spontaneous combustion. It is best to choose the material of group G1 for roof insulation.
  • Ease of installation: even an inexperienced person will be able to insulate the roof with foam plastic.
  • Durability of the material: the service life of such a heater is from 25 to 80 years.

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

Determine the amount of material

Before starting work on insulating the roof with foam from the inside, you need to calculate the amount of material needed. To insulate a mansard roof, it is not difficult to calculate the optimal amount - you just need to measure the area of ​​\u200b\u200bthe roof, the step between the rafters and determine the size of the foam boards. However, experts recommend purchasing material with a small margin (6-8 plates), since in the process of cutting it there may be a risk of deformation or breakage of the plate.

Mansard roof insulation with foam plastic - tools and materials

For work you will need the following materials and tools:

  • Styrofoam;
  • anti-condensate vapor barrier film;
  • wooden bars;
  • nails;
  • scissors;
  • sharp knife;
  • mounting foam;
  • construction stapler.

The final result entirely depends on how well and conscientiously the main stages of work will be performed.

Roof insulation - basic steps:

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

Surface preparation, waterproofing and vapor barrier

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

Expanded polystyrene perfectly copes with waterproofing. But in order to extend the life of the foam, it is required to lay a vapor barrier.

Please note: it is imperative to leave a gap of at least 2 cm between the film and the crate. 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 bad smell, mold, etc.

In some cases, an anti-condensate vapor barrier film is laid: overlapping directly on the rafters. This is done in cases where the width of the rafters does not make it possible to leave a gap between the polystyrene foam and the plank base. If a we are talking about the finished building - it is quite acceptable to attach this anti-condensate film to the rafters by means of wooden slats and nails. It is also quite possible to use a special construction stapler for these purposes.

Insulation installation

The most common ways of fastening polystyrene boards:

  • gluing (frost-resistant facade adhesives, liquid nails, mastics for gluing tiles to the ceiling, moment-assembly);
  • mechanical fastening (nails-umbrellas, anchors, wooden slats);
  • flooring;
  • investment in the crate.

Sometimes attachment methods are combined. So, the foam is put into the crate, and additionally fixed with umbrella nails. This fastener is also called a foam dowel with a thermal head.

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

Styrofoam on mansard roof

After arranging the vapor barrier layer, it's time to start installing the insulation - foam sheets. Traditionally mansard roof is performed on a rafter frame, between these rafters foam plates should be placed. In the process of choosing those, preference should be given to plates, the size of which is equal to the width of the step between the rafters. But modern materials allow to insulate roofs with a step width of up to 2 m without gaps.

Foam insulation boards should be located between the rafters along the crate 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. In the process of work, the formation of gaps and cracks between the rafters and foam plates is possible. They must be carefully sealed with ordinary mounting foam (it is quite possible to use any type of sealant).

After all these steps, you can exterior finish surfaces - in case you plan to equip an attic room. The best option with the lowest labor and financial costs is the surface finish drywall sheets, which are attached to the rafters with dowels. Further, it is quite possible to paint the surface or paste over with wallpaper.

Styrofoam on a flat roof

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

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

Expanded polystyrene is often involved in the creation of a roofing "pie":

Option 1

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

Option 2

Option 3

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

The use of the above technologies makes it possible to equip such oases on the roofs of houses. This is called an inverted roof. For its arrangement, expanded polystyrene is material No. 1.

How to insulate the roof with foam and avoid common mistakes?

Installation of insulation, performed incorrectly, in the near future will make itself felt with unpleasant consequences. Leaks, which are formed as a result of poor-quality work, will not only violate the aesthetic picture, but will also contribute to the process of rotting of the rafters.

Let's look at the main 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, it is necessary to avoid the appearance of such defects;
  • incorrectly selected width of the insulation plate also leads to a violation of tightness with all the ensuing consequences;
  • the use of cellophane film instead of anti-condensation vapor barrier is perhaps the most common mistake that can cause many troubles and troubles.

In order for the house to always be warm, dry and comfortable, do not neglect the rules and standards during the installation of insulation. All work must be carried out strictly in accordance with generally accepted canons. Also, special attention must be paid to the quality of the materials used.

Many owners of private houses are wondering if it is possible to insulate the roof with polystyrene foam. 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, should be operated at -50 ... + 75 degrees, its installation provides for the presence of gaps that need to be further processed.

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

September 5, 2016
Specialization: Capital construction works(laying the foundation, erecting walls, constructing the roof, etc.). Internal construction works (laying of internal communications, rough and fine finishing). Hobbies: mobile communications, high tech, computer technology, programming.

Among all possible ways thermal insulation of the roof of a residential building, in my opinion, the cheapest, in my opinion, is the insulation of the roof with foam plastic. The technology is as simple as possible, so all the work is easy to do with your own hands, even if you do not have specialized education or relevant skills.

The instruction prepared by me describes in detail how to insulate the under-roof space from the inside with polystyrene foam (which, by the way, can be easily replaced with foam plastic if desired).

Benefits of foam roof insulation

Let's first figure out whether it is possible, in general, to use polystyrene foam for thermal insulation of the roof.

I will not answer this question directly. It’s better to tell you a little about this material and its features in terms of use for roofing insulation.

Expanded polystyrene, as it is correct to call polystyrene, is a polymeric material consisting of separate closed cells filled with air. It comes in slabs of various thicknesses and sizes.

I have prepared a small table that describes the benefits of Styrofoam.

Peculiarity Description
light weight Due to the fact that the insulation consists of 97 air, it itself weighs very little and, after installation between the rafters, it practically does not exert additional load on the supports roofing material, attic floor and load-bearing walls.
Security Under normal operating conditions, the foam does not emit chemical compounds dangerous to humans into the air. However, the material in question must be carefully protected from ultraviolet rays, under the influence of which it decomposes into toxic substances that can be harmful to health.
Low thermal conductivity Styrofoam in its cells contains a large number of air, which is an excellent thermal insulator. Therefore, even a thin layer of this insulation can significantly reduce unproductive heat loss through the roofing material.
Good sound insulation A polystyrene heat insulator, installed between the rafters, well insulates the living quarters of the house from the noise created by water drops beating on the hard roofing material during rain. However, if you want to reach maximum comfort in attic room, it is better to use more effective soundproofing materials (for example, mineral wool).
Long service life The material, subject to the technology of installation and operation, can last several decades. But the peculiarity of the foam is that during this entire period it retains its specifications and performance properties. Expanded polystyrene does not lose the coefficient of thermal conductivity, does not change the geometric dimensions.
High moisture resistance Due to the closed cell structure, the material has a minimum water absorption coefficient. In direct contact with liquid, the foam absorbs no more than 4% of its own volume. Therefore, when laying it under the roof, it is not necessary to take additional waterproofing measures using polymer membranes.
Good strength Expanded polystyrene perfectly tolerates significant dynamic loads, especially in compression. When insulating a roof with an attic and ventilation gaps under the roofing material, it does not need to be protected with a windproof film (as is the case with basalt mats).
Antiseptic The insulation has antiseptic properties, so mold and fungus do not appear on its surface and inside the insulation layer, insects do not start. However, rodents like to make moves and build nests in foam plastic. This should be taken into account when choosing a heat-insulating material for a country cottage.
Chemical resistance Styrofoam well tolerates exposure to chemicals contained in most building materials. We are talking about paints, adhesives, silicone, cement and plaster, lime and so on. However, expanded polystyrene breaks down under the influence of acids.
Resistance to temperature fluctuations Features of the internal structure of the material allow it to endure numerous successive cycles of freezing and thawing without destroying the internal structure and loss of operational properties. However, the foam is destroyed by the action of sunlight.

If we talk about the shortcomings, then I see two of them:

  1. High fire hazard. Classic foam plastic ignites upon short-term contact with an open fire and contributes to the further spread of the flame. In addition, in the event of a fire, the material emits toxic fumes which may cause injury or death.
    Therefore, for thermal insulation of the roof, it is necessary to use material marked "C", which means that fire retardants are added to the expanded polystyrene during production, which increase the level of fire safety of the insulation.
  2. Low vapor permeability. The material practically does not allow air to pass through itself, therefore it disrupts the natural infiltration of air through the building envelope. As a result, a large amount of moisture accumulates in the attic or attic, which negatively affects the microclimate of the room and the finishing materials of the room.
    To avoid this, it is necessary to design in the under-roof space effective system ventilation, which will bring moist air outside, replacing it with fresh.
    If you still ask my opinion, then I can say that polystyrene, albeit with some reservations, can be used to insulate the roof. Moreover, all possible shortcomings are justified by the low price of the material.

I advise you to buy a heater marked PSB-S-25 for work. Due to this foam density (25 kg per cubic meter), it has a fairly low thermal conductivity. And the strength of the heat insulator does not play a big role, since in pitched roof between the rafters, it will not experience significant loads.

Never use packaging coarse-grained foam for insulation. With it, you will not achieve the desired effect, and the material itself can release toxic substances when heated or in contact with some building materials.

Warming technology

Now I will move on to a description of how the roof is insulated from the inside with foam. The work consists of several stages, each of which I will describe in detail.

I note right away that despite the use of foam, I will install hydro and vapor barrier films. They are needed not so much to isolate the insulation layer, but to prevent moisture from the wooden roof rafters.

After all, if the wood is exposed to constant wetting, its service life will be significantly reduced.

Schematically, the whole process can be divided into several stages, which are presented in the illustration below:

Purchase of material

It all starts with the purchase of a heater. As I said, it is better to purchase material with a density of 25 kg. per cubic metre.

Typically, such foam is sold in 100 by 50 cm slabs. Therefore, if you only plan to build a roof with insulation, it is desirable that the distance between the rafters be 50 or 100 cm. Then there will be no need to trim the slabs.

I want to say a little about the thickness. For central Russia, the thickness of the insulation layer should be 10 cm. Such plates are available for sale, but I advise you to purchase foam plastic 5 cm thick and put it between the rafters in two layers with overlapping seams.

Thus, it will be possible to avoid the appearance of cold bridges in the intervals between the individual parts of the insulation.

In addition to foam, you will need other materials:

  • polyurethane adhesive for polystyrene foam - sold in metal cylinders and resembles ordinary polyurethane foam (I can recommend Tytan Styro 753 as an example);
  • waterproof film for installation under roofing material (for example, Juta Windscreen);
  • vapor barrier membrane - in the case I am describing, I will use foil foamed polyethylene so that it remains possible to equip a cozy room in the attic, turning it into an attic;
  • plywood - with its help, the interior decoration of the attic is carried out (instead of plywood, you can use any sheet - OSB boards, drywall - or decorative materials- lining, plastic).

Preparing the truss system

The technology of roof insulation with foam plastic necessarily provides for the preliminary preparation of the truss system for this operation. Otherwise, neither the insulation layer you designed, nor the roof in general, will last long enough.

The sequence of actions is as follows:

  1. I free the attic from foreign objects. Usually, a lot of rubbish is stored in the attic in a residential building, which not only interferes with work, but also poses a certain danger in terms of fire safety. Therefore, all things need to be removed, especially since in my case, further arrangement of the room is planned.
  2. I examine the rafters for traces of biocorrosion. Get rid of mold, fungus and other similar manifestations. To do this, you need to either clean the surface with a grinder or sandpaper, or process wooden details antiseptic.

  1. Troubleshooting and troubleshooting rafters. If a section of rafters is found that has already rotted or broken, it is necessary to repair the damaged part. In some cases, it is advisable to completely replace one or more beams, which, as a result of destruction, have ceased to fulfill the tasks assigned to them.
  2. I get rid of parts and accessories that can damage the insulating polymer films. Usually we are talking about self-tapping screws, nails, wire and other products that were used in the construction of the roof and fixing the roofing material. All sharp ends must be bent so that they do not tear the film.
  3. I am priming wooden rafters. To do this, I use a composition with antiseptic properties (for example, Kompozit Universal Bio Concentrate), thanks to which wooden parts will be reliably protected from the appearance and development of various microorganisms on the surface and inside. I do the processing in two layers with a brush. Before applying the second coat of primer, the wood must be allowed to dry, which takes 3 to 4 hours.

  1. I carry out all engineering communications in the attic. We are talking about ventilation pipes and electrical wiring. The first ones need to be insulated with foam shells, and the wiring should be placed in special plastic channels that will protect the house from fire in the event of a short circuit.

This completes the preparation and you can proceed to the installation of a waterproof film.

Arrangement of waterproofing

The most effective way of laying waterproofing is on top of the rafters under the roofing material. That is why I will describe it.

The scheme is this:

  1. Installing waterproofing membranes. You can use plastic wrap, since air infiltration will still be hindered by the foam laid between the rafters. I always start work from the bottom of the roof, gradually moving towards the ridge.

  1. I fix the film with a stapler. The film is shot to the rafters with brackets. Instead, you can use nails with spacers or wide heads that will hold the material in place and not tear it.
  2. I seal the seams of the plastic film. To do this, the top sheet of waterproofing must be placed so that an overlap is formed on the bottom one at a distance of up to 10 cm. Then I glue the joint with adhesive tape to prevent moisture from getting inside. For polystyrene, this is not scary, but the rafters can be damaged during operation.
  3. I stuff a crate on the rafters. To do this, I use wooden bars with a section of 5 by 5 cm. This stage is needed to form a gap between the insulation layer and the roofing, through which the moisture condensed inside will be removed to the outside. At the same time, these bars help to secure the waterproofing more firmly.

  1. Installing roofing material. In my case, it was a metal tile. If you are going to install a flexible roof (for example, shingles), then OSB boards or plywood should be additionally attached to the crate, and already put on them roofing.

If the house and its roof have been built for a long time, then the waterproofing will have to be carried out from the inside. To do this, the film is placed in the gaps between the rafters as close as possible to the roofing, and the beams are, as it were, wrapped in a film.

The film is fixed using a conventional stapler with staples. You can also use wooden planks, which are nailed to the side surfaces of the rafters.

The bottom line is not to miss the leaking moisture to the insulation. However, the material itself is waterproof, and you do not protect the rafters that way. Therefore, the need to use such waterproofing in tandem with foam is questioned by many.

I still recommend sticking with tape. There are few hassles and costs, but on the other hand, you protect the attic room from a possible flood during a heavy downpour.

Insulation laying

Well, now we directly insulate the roof with foam. That is, we fix polystyrene foam in the space between the rafters.

Here the sequence of actions is as simple as possible:

  1. I take measurements and mark out the foam boards. It is necessary to make sure that the insulation enters the space between adjacent rafters as tightly as possible, without forming gaps, which can subsequently cause the formation of cold bridges.
  2. I am cutting the heat insulator. To do this, you can use a metalwork knife or a hacksaw with small cloves. I also have a heated wire attachment that allows you to quickly and accurately cut foam.

  1. I clean the ends of the foam using a special grater. Instead, you can use sandpaper, which is put on a plaster grater. It is necessary to make the ends of the sheets as smooth as possible so that they fit well to the side surfaces of the rafters.
  2. I install the first layer of thermal insulation material between the rafters. To fix the foam sheets in their places, I use polyurethane glue from a can, which I apply with a gun.

  1. I seal the joints between the foam sheets and the rafters with polyurethane adhesive. It is necessary to ensure that the mass fills the entire space, leaving no voids. In some cases, gaps can be sealed with foam scraps.
  2. I install the second layer of foam. I am working as described above. But the sheets must be positioned so that the second row of insulation overlaps the seams of the first. Then you need to re-seal all the cracks in the insulation layer.

As a result, you should have an insulating layer of foam, which is mounted flush with the rafters (at least it turned out that way for me). This is necessary so that a gap does not form between the vapor barrier and polystyrene foam, in which moisture can accumulate.

Having finished with this work, you can proceed to the installation of penofol.

Vapor barrier installation

Penofol I will replace the standard vapor barrier membrane. I install it not so much to protect the heat-insulating layer, but to equip an additional thermal screen that increases the efficiency of the heating devices that will be used to heat the attic.

The scheme of work for the installation of penofol is as follows:

  1. I roll out the first layer of foil-wrapped polyethylene foam. You need to install it with aluminum foil towards the room. You can fix it on the rafters using metal staples and a stapler or self-tapping screws with hats. I recommend using foam type A with a thickness of 5 mm.
  2. I roll out and fix the second layer of foil insulation. It must be attached so that it does not overlap, but is located as tightly as possible to the previous foam sheet.
  3. I seal the joints of the heat-reflecting layer. To do this, I glue the gaps between the sheets of penofol with metallized adhesive tape.

  1. I mount an additional crate on the surface of the penofol. Wooden bars are used, pre-treated with an antiseptic. They will help to design a ventilation gap between the decorative finishing material and the heat-reflecting layer.

That's all. Now you can move on to decorative trim.

Finishing

In the photo - the walls of the attic, finished with plywood.

I will not describe this stage in detail, since the sequence of actions depends on what material you will use.

I fixed plywood sheets on the crate, which I will then sew up with eurolining. There is one feature here. Glued veneer sheets should be positioned so that there is a gap of 2-3 mm between them to compensate for the expansion of the plywood during use.

Summary

After reviewing the material I have proposed, you yourself could see for yourself that roof insulation with foam plastic and foam plastic is not so difficult process as it seems at first glance. But in no case should you approach him through the sleeves.

By the way, there are other ways to insulate the attic. One of them is described in the video in this article.

And I wanted to ask, did you insulate the roof with foam or did you use another heat-insulating material for this? How do you evaluate the effectiveness and safety of using expanded polystyrene for these purposes? You can post your answers in the comments to the material.
Or you can also read about mineral wool roof insulation.

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

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

But the material also has disadvantages - vapor tightness and flammability. Therefore, when using polystyrene foam as a heater, it is imperative to install ventilation in the attic room and strictly observe all fire safety standards.

Difficulties with foam insulation

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

While 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. There is a formation of voids into which cold penetrates, as a result of which condensation forms. Due to condensate, the truss system is destroyed, and the metal elements in the roof rust.


To avoid condensation, when choosing foam for the thermal insulation of the roof of a private house, it is necessary to specify such an indicator as the thickness of the heat-insulating layer for the area in which you live. When calculating, you need to focus on the type of roofing material used and the climatic zone. One thing is common for the choice of foam: it is not recommended to use foam less than 10 cm thick for work.

Expert opinion

Konstantin Alexandrovich

Ask an expert

In cases where the insulation needs to be laid in two layers, and the thickness of the rafters does not allow, it will be correct to fill a 50mm by 50mm beam horizontally, stepping under the sheathing material (drywall, OSB and various moisture-resistant boards).

Styrofoam characteristics


Polyfoam among other materials is distinguished by the following advantages:

  • light weight, which reduces the load on the bearing parts of the roof;
  • ease of installation and processing with tools;
  • resistance to temperature extremes and certain mechanical loads;
  • low thermal conductivity due to the high air content - 98 percent;
  • long service life;
  • preservation of properties and form when high humidity, he is not afraid of mold and fungus;
  • affordable cost;
  • environmental friendliness;
  • fire safety (polystyrene can only melt, not ignite);
  • hypoallergenicity.


Of course, polystyrene also has disadvantages:

  • if the material is exposed to open fire, it releases harmful substances;
  • capable of absorbing moisture small quantities, because of which the rafters, lathing, finishing materials are covered with mold and fungus, and metal fasteners are rusted;
  • 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 air permeability;
  • polystyrene can be gnawed and inhabited by rodents (the exception is extruded polystyrene foam);
  • solvents, alcohols, gasoline are dangerous for him;
  • destroyed by ultraviolet radiation.

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


A standard foam sheet can be of the following dimensions (mm):

  • 500×1000;
  • 1000×1000;
  • 2000×1000.

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

After studying the characteristics of the foam and comparing them with other materials for thermal insulation, each builder 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 to be waterproofed;
  • polystyrene of the selected type (given the required thickness and size);
  • vapor barrier film or membrane;
  • self-adhesive tape to glue the junction-overlap of vapor and waterproofing materials;
  • mounting foam;
  • construction stapler;
  • scissors and a knife;
  • wooden bars;
  • hammer;
  • material that will be used for final finishing in places of insulation.


After preparation necessary materials and tools, you can begin to insulate the roof with foam.

This happens in the following order:

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


foam boards very often flat roofs are insulated from the outside. To do this, the roof is well cleaned and covered with waterproofing. Polystyrene boards can be laid in the form of flooring, glued, fastened with dowels. An important condition is the laying of the plates 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 the installation of polystyrene foam plates begins, they are covered with expanded clay, on which a cement-sand reinforced screed is laid. Also, with the help of foam, you can create a roofing "pie", consisting of:

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

With this combination, an exploitable roof is created that cannot be destroyed by high loads.


Thermal insulation technology outside:


This option is the most common method of attaching the material to the surface of concrete slabs. This method is suitable for warming 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 and waterproofing. Careful observance of the required rules during installation will allow you to live in any house comfortably and without additional heating costs.

Video on foam roof insulation

Installation of roof insulation is one of the milestones country house buildings.

Measurements and calculations show that, on average, through a roof laid without thermal insulation, up to 30% heat is lost.

You can block the way to these losses with the help of various thermal insulation materials. However more often than others its modifications are now used.

Styrofoam is insulated pitched and flat roofs and ceilings.

The popularity of this material is quite understandable: it is light and easy to process, has a very low thermal conductivity, does not deteriorate by microorganisms and not afraid of water.

However, he has some features that affect the installation and installation sequence, as well as the operation of the house:

  1. Vapor resistance. Styrofoam and other modifications of expanded polystyrene pass only a few milligrams of water vapor per hour through 1 square meter surfaces. They also do not let water into the depth of the material, but due to the porous structure they can collect a certain amount of moisture on the surface. At the point of contact with wooden structures, this leads to rotting of the wood, and the foam itself blackens on the surface. For this reason, all modifications of expanded polystyrene have to be protected with a vapor and waterproofing film, and the room must be ventilated. Under such conditions, this material serves up to 80 years or more.
  2. combustibility. Modern foam brand PSB-S - self-extinguishing material. This means that it lights up, but after the flame is removed, it goes out. However, it is a combustible material, so it must not be laid around the chimney. In this place, mineral wool and expanded clay are used for thermal insulation.
  3. Low elasticity. Unlike mineral wool expanded polystyrene has almost no elasticity. For this reason, slabs are cut out of it, which are only 1 cm wider than the distance between the rafters. Such slabs fit tightly into the opening. If you increase the width of the plate, then during installation it will warp. This leads to the formation of gaps between the plates and the formation of cold bridges. The edges of the plates do not always fit snugly against the wood, so you have to fill the gaps mounting foam.
  4. Sensitivity to sunlight. Expanded polystyrene of all modifications is destroyed by ultraviolet rays of sunlight. This means that when laying it is carefully closed from light rays. The outer side is covered with roofing material, and the inner side is covered with a vapor barrier membrane and trim. It is impossible to leave the foam even on the inside without finishing. The light coming through dormer windows, causes yellowing and destruction of this material.

Choosing tools and materials

Polyfoam is produced in various modifications, the properties of which will have to take into account when choosing materials (according to GOST 15588-86 and SP-50.13330.2012).

The best thermal insulation properties have polystyrene brand PSB-S-35 and extruded polystyrene foam (penoplex). They also withstand significant compressive stress.

All of these brands are suitable for roof insulation, but usually used PSB-S-15, since it creates a minimum load on the attic floor. PSB-S-35 and (), as a rule, are used for warming flat roofs, since compression resistance is required there.

You will also need to work:

  1. . It will protect the insulation and rafters from the penetration of steam from the room. It is recommended to choose a two-layer waterproofing membrane Megaspan B. Its rough side keeps drops of condensate on its villi, preventing it from draining. As the air humidity decreases, the condensate evaporates.
  2. Windproof waterproof membrane. This membrane protects the insulation from drops from above when the roof leaks, but passes the steam that forms when it dries. wooden structures. It is advisable to choose a membrane type Megaspan A or other superpermeable membranes.
  3. Wooden bars with a section of 50 × 50 or 40 × 50 mm, treated with antiseptic preparations. They are needed for the construction of the crate.
  4. Nails and hammer for fixing the film and finishing material.
  5. Sharp knife for cutting foam.
  6. Mounting foam without toluene for sealing joints.
  7. Stapler and staples for fixing the film.
  8. Construction tape.

Technology for insulating a gable roof with foam plastic from the inside

It is advisable to lay the thermal insulation under the roof immediately when installing the roofing material. However, the developer is not always able to do this. In such cases, insulate the roof comes from within.

Modern mounting technology roofs provides for the laying of a wind-moisture protective membrane. If it was laid in compliance with all the rules, you can immediately proceed with the installation of insulation.

Styrofoam is cut into plates with a width 1 cm larger than the distance between the rafters so that they fit snugly into the opening.

The slabs are laid in several layers, overlapping the joints of the previous layer with the slabs of the next one. It is recommended to stick with mounting foam one layer to another and fill all the gaps between them and the rafters so that cold bridges do not form.

After filling holes between the rafters, a vapor barrier membrane is fixed with a stapler to their lower surface. Instead of fixing with brackets, the film can be fixed with wooden planks through which the film is nailed to the rafters. It is unfolded and laid from the bottom up, overlapping the edges of the bottom layer by 15 cm.

The joints of the canvases are glued with adhesive tape. Double-sided membrane type Megaspan B is always laid with the smooth side against the foam. After installing the vapor barrier a crate is constructed on the rafters, to which the finishing material is attached. After completion of this stage, an air ventilation layer is formed between the film and the finish.

If the roof has been laid without waterproofing membrane, the work will have to start with its installation. In this case, the membrane is laid around the rafters with a pile to the insulation. Attach it to the rafters and the outer crate. Only after the membrane is fixed, start laying the insulation.

Features of flat roof insulation

This can be done immediately after the installation of the ceiling. Typically, this cover is reinforced concrete slabs that need to be cleaned and fixed with a vapor barrier membrane.

For thermal insulation of flat roofs, choose foam that can withstand pressure well (see above). Sheets of this insulation are glued to the film and attached to reinforced concrete with dowels. Stacking rule the same: each subsequent layer must overlap the joints of the previous slabs.

The foam is covered with fiberglass on top, and then with a waterproofing membrane, on top of which lay geotextiles. Geotextiles can be covered with expanded clay, on which a reinforced cement-sand screed is poured, and then paving slabs are laid.

If laid external thermal insulation for some reason difficult, a flat roof can be insulated with styrofoam from below. If the roof covering is reliable, then the dew point shift towards the room does not matter. First, a crate of wooden bars is mounted on the floor slab, fixing them in the slab with dowels.

Styrofoam boards glued directly to a clean and dry floor slab between the bars, and then additionally fastened with dowels. Joints are also sealed with mounting foam.

Insulation isolate from the steam from below with the vapor barrier membrane pile down. It is nailed to the bars with nails through wooden planks. Further, the insulation is hidden behind a suspended or stretch ceiling.

Thermal insulation of the roof with foam plastic is simple and does not require high qualifications. After studying the properties of materials and mastering the skills of working with them, any home master will cope with such work.

Styrofoam insulation requires thorough hydro and vapor barrier, as well as protecting this material from sunlight.

A master class on roof insulation with foam, see the video: