Fastening insulation to a flat roof. Roof insulation: diagrams and materials. Classification of thermal insulation of flat roofs

Insulating any roof, including a flat one, is considered an effective method that can significantly reduce heat loss. Moreover, a significant effect is achieved with fairly modest heating costs. And this is not the only benefit that thermal insulation provides. But how to choose the right insulation for a flat roof and install it.

The nuances of insulating a flat roof

The principles of thermal insulation for a flat roof are fundamentally different from the approach to insulating pitched roofs. The flat structure does not have rafters between which a thermal insulation layer could be placed. There is nothing to stuff the sheathing on, so the formation of ventilation gaps of the components roofing pie, how in pitched roofs impossible. The analogy can be traced, perhaps, only in the order of layers. It consists of the following components:

Vapor barrier. The layer is laid on the side of the premises and blocks the path of household fumes.
Thermal insulation. This is a barrier to the passage of heat from inside the house to the outside and vice versa. At the same time, it plays the role of sound insulation.
. It protects the thermal insulation layer from the outside from precipitation.
Finish coating. For ballast roofs, the waterproofing layer is covered with gravel or laid on top of it paving slabs or a layer of soil under vegetation and more.

If the sequence of laying layers, as well as the rules of construction, are violated, deplorable complications arise that force owners to spend impressive sums for renovation work, and sometimes for a major reconstruction of the roof.

However, it should be noted that the need for such a design arises only if it is necessary to ensure heating efficiency, that is, to retain heat in them. So when it comes to the roof summer kitchen or ancillary buildings, there is no point in insulating a flat roof.

In such cases, proceed, for example, as follows:

in the concrete roofing pie there is only waterproofing:
on corrugated sheets - prefabricated screed and waterproofing,

Classification of thermal insulation of flat roofs

Attics. There are two subtypes of structures: attic floor with a low-weight superstructure or separate superstructure and ceiling structures. If in the first case only the ceiling is thermally insulated, then in the second - the ceiling or superstructure.

Attic structures can be easily inspected, which allows for timely identification of future leaks. The roofing cake can be dried by simply ventilating the attic. We especially note that insulation can be carried out on an already finished roof. Construction attic structure costs an impressive amount, but the long service life and rare need completely pay for it.

Insulation for flat roofs: technical nuances

To insulate a flat roof, use almost any material that is suitable for thermal insulation of the ceiling and walls. The following are especially in demand:

On a note

Wedge-shaped insulation cannot be considered as a worthy replacement for a layer of thermal insulation. Wedge-shaped slabs solve exclusively drainage issues.

Choosing a thermal insulation method

The method of insulation, as well as the characteristics of the required material, depends on the type of base:

Reinforced concrete. The insulating material, most often mineral wool, is selected with a compressive strength of 40 kPa or more. The deformation parameters should not exceed 10%. A layer of thermal insulation is poured on top cement-sand reinforced or prefabricated screed.
Profiled sheeting. The insulation system has a two-layer structure. The lower tier with a strength indicator of 30 kPa or more is laid on top of the profiled sheet. For the upper tier, this parameter should not be less than 60 kPa. Possible deformation is within 10%. When installing a roof, the coating is laid directly on the insulation system.

The insulation must rest on the flat part of the corrugated sheet for at least 30% of its own area. Therefore, if the thickness of the thermal insulation board is twice the distance between the corrugations, the thermal insulation can be laid directly on the galvanized base. Otherwise, a preparatory leveling layer of CBPB slabs or flat slate is required.

How to lay insulation

Placing rigid roof insulation on a flat roof begins from the low area of the roof, more precisely from its corner. If for some reason the slope of the structure when construction work was not observed, then you need to start from the installation sites of the gutter or.
For profiled sheets thermal insulation boards placed in such a way that the corrugations and their long sides are mutually perpendicular. In this case, fastening can be done through different ridges.
Plates in multilayer thermal insulation are arranged according to the principle brickwork, that is, the seams are spaced apart. In addition, the seam lines and crosshairs in the upper tier cannot coincide with those in the lower row.

Below is one of the options for cutting and laying insulation.

Mounting options

To fix the insulation layer on a flat roof, the following methods are used:

Mechanical.

Fastening is done using so-called telescopic fasteners. They consist of a flange with a smooth outer surface and a tubular rod. The various standard sizes of disc dowels available on the market allow you to fasten roofing pies of various thicknesses.
IN concrete floors Anchors are hammered in and secured to the screed with screws with plastic sleeves.
To calculate the required number of fasteners for an insulated flat roof, the default condition is taken as a basis: two units of fasteners for each slab.
For concrete roofs, the coating and insulation are fixed simultaneously. If the base is made using profiled sheets, separately.
On certain areas(, interface lines with vertical planes, etc.) the fastener installation step is reduced.

Glue.

All layers of the roofing cake, including thermal insulation, are glued to hot mastic, most often. The insulation must be glued evenly. At the same time, the total area of contact areas thermal insulation material with the base should exceed one third of it.
If the roofing pie is completed with bitumen or bitumen-polymer material, then the installation of the roofing system cannot be carried out during the rainy period, since excess moisture will accumulate in the insulation without the ability to escape outside. But when used as finishing coating You can glue it throughout the year, since the membrane allows excess moisture accumulated in the insulation to pass through.

The insulation is laid on a flat roof and covered with a waterproofing carpet. A mixture of gravel and pebbles is poured over the waterproofing layer or paving slabs are laid on plastic supports. The components of the roofing pie lie freely. The pie is fixed exclusively around the perimeter, as well as around the roof penetrations.

Green roofs are also classified as ballast roofs. Although it should be noted that the roof with landscaping is inverse, so the order of the layers of the roofing cake differs from the traditional one. The insulation is laid on top of the waterproofing, which simultaneously functions as a vapor barrier. The thermal insulation layer is covered with a geodrainage polymer membrane, on which a soil-vegetative layer is arranged.

Installation of thermal insulation from the inside

Installing insulation slabs from the inside of a building with a flat roof is physically not very convenient, but practical. After all, installation can be carried out in almost any weather. And there is no need to rush to complete the work in a day, because the insulation does not get wet.

The algorithm for installing thermal insulation is as follows:

Along the line where the ceiling meets the wall, screw a strip of wooden block, the thickness of which on one or both sides is equal to the thickness of the insulation.
The same bar is attached on the opposite side.
We screw a block, both or one of the sides of which is equal to the thickness of the insulation board, along the line where the ceiling and wall join.
We install a similar bar made from a bar on the opposite wall.
For internal insulation Rigid polystyrene foam boards are ideal.
The ceiling is conventionally divided into strips.
The polystyrene foam board is glued to the ceiling and the plank on bitumen mastic and press tightly. The marked strip is completely filled with polystyrene foam. If necessary, the outer slabs are trimmed.
On the side of the completed strip of polystyrene foam boards, pressing tightly, another strip is screwed.
Next, the insulation strip is formed and glued again.
Alternating these two operations: screwing the bars and gluing the thermal insulation, fill the ceiling plane.
Fixing them with a stapler, a plastic film is attached to the planks and the ceiling is finished with some convenient covering material, for example, plasterboard.

Which insulation for a flat roof is better to choose?

Expanded polystyrene gradesURSA XPS. The excellent quality of thermal insulation material produced by the international holding URALITA attracts many developers. It contains fire retardants, which increase the fire resistance of the insulation. This material is excellent for inversion thermal insulation. The slabs have cutouts on the sides that guarantee their perfect joining without the formation of gaps.

Russian-made extruded polystyrene foam is produced in the form of slabs, along each side of which there is an L-shaped edge. It ensures perfectly smooth joining and continuity of the thermal insulation layer, which prevents the formation of cold bridges. Penoplex slabs do not absorb water, which means in this case you can do without additional protection from precipitation.

EPPS TechnoNIKOL. A few words about the products of the domestic company - TechnoNIKOL. The following types of materials are suitable for roof insulation:

XPS CARBON ECO – insulation for roofs of low-rise or country houses.
XPS CARBON ECO DRAIN – drainage grooves on the slabs help ventilate the flat roof.
CARBON PROF is an especially rigid and durable polystyrene foam that can withstand enormous loads. Used in roofing pies of high-rise buildings, shops or warehouses.
CARBON PROF SLOPE is no less durable than CARBON PROF, but this material has a special “trick”. It is supplied as a set of five slabs with different inclinations of the top plane. With their help they form.

TECHNORUF 45, 50, 60 and 70 are intended for installation of single-layer thermal insulation of flat roofs. The numbers in the markings indicate the compression density of the slabs. The thermal conductivity of the material is so low that these slabs can be used to insulate parking lot roofs.

TECHNORUF slabs are also used for two-layer thermal insulation: 50, 60, 70 for the top layer and 25, 30, 35, 40 for the bottom.

(10 votes, average: 0,00 out of 5)

Insulation of a flat roof is a necessity caused by the desire to create a comfortable atmosphere in the room. In winter, insulation does not let heat out of the house; in summer, it does not allow hot air to penetrate. In addition, thermal insulation perfectly suppresses external noise.

Types of insulation

Exist different types thermal insulation.

For thermal insulation of flat roofs use:

Expanded clay. Bulk, cheap material, very easy to install. But due to its thermal insulation characteristics, it is rarely used as an independent insulation material. More often, the roof is insulated with basalt wool or expanded polystyrene, and a slope-forming layer is made from expanded clay, thus increasing the thermal insulation of the room.
Mineral wool. Not the most expensive material. Has excellent thermal insulation characteristics. But mineral wool is susceptible to moisture. Also, it does not have a rigid base, which is unacceptable for a flat roof, so a concrete screed is placed on top of it.
Mineral basalt wool. The main difference from ordinary mineral wool is the rigidity of the slabs. Capable of withstanding heavy loads. Impregnated with special water-repellent composition to increase moisture resistance.
Foam glass. The advantages include durability, strength, resistance to ultraviolet rays and high temperatures. The main disadvantage is the high price.
Extruded polystyrene foam. It has excellent thermal insulation characteristics, is resistant to chemicals, has great strength, and is waterproof. The only negative is the high price.
Styrofoam. Not the foam itself in its pure form, but pieces of it mixed with a cement-sand mixture and poured in as a screed. The main advantage is that it is very cheap.

How to choose insulation

The choice of insulation for a flat roof depends on the characteristics of the roof. So, it can be traditional or inversion.

Traditional roofing involves installing thermal insulation before waterproofing. Thus, the insulation will be protected from moisture, which expands the possibilities for choosing a material.

The inversion roofing pie is designed in reverse. Thermal insulation is placed above the waterproofing. More often this type of roofing is used for a roof that is in use. When choosing insulation, it is necessary to take into account that it should be as resistant to moisture as possible and at the same time have high compressive strength.

In addition, it is possible that the slope-forming layer is created from insulation. To do this, you will need special wedge-shaped thermal insulation. It is, of course, expensive, but it is convenient to work with.

Thermal insulation can be laid in one or two layers. This depends on the floor slabs, which are often made from reinforced concrete slabs and profiled sheets.

In the first case, it is permissible to lay the insulation in one layer, and it must have a compressive strength of at least 40 kPa, after which a screed is poured on top of it. In the second case, two-layer thermal insulation is required. The first layer must have a strength of at least 30 kPa, the second - at least 60 kPa. If desired, it is also possible to install thermal insulation of the roof on a reinforced concrete base. This will improve its quality.

Installation of mineral wool

If we are talking about a traditional roofing pie (namely, it is used most often), then preliminary stage the work will be as follows:

If corrugated sheeting is used, its lower wave must be filled with insulation. If the thickness of the insulation is twice the width of the wave, this step can be skipped.
Vapor barrier device. The film must be applied to the parapet to the height of the future thermal insulation layer. The longitudinal overlap is 10 centimeters, the transverse overlap is 15 centimeters. The joints must be taped with tape.
Inspection of thermal insulation boards. The rigidity should be uniform over the entire sheet area. There should be no moisture.

Insulation of a flat roof using mineral wool is carried out as follows:

Installation starts from the corner. It doesn't matter which one.
Mineral wool can be fastened using mastic or special dowels, with a minimum calculation of 2 dowels per slab. In corrugated sheeting, fasteners are screwed exclusively into the upper wave, so as not to pinch the insulation. It is permissible to glue mineral wool to a concrete base with mastic.
Next, lay the top layer of thermal insulation. In this case, the joints should under no circumstances fall on top of each other - this will lead to the formation of cold bridges. It is better if the upper plate overlaps the lower one by 1/4.
The top layer is fastened in the same way as the bottom layer, using special dowels. To ensure that the fasteners get into the upper wave of the corrugated sheet, orient yourself along the parapet. There you can apply markings in advance. The minimum fastening calculation is 2 dowels per sheet. But it is better to perform additional fixation to ensure a tight fit of the layers one to one. It is important not to pinch the self-tapping screw inside the dowel - this will compromise the integrity of the insulation, which will lead to the formation of cold bridges.
Seams more than half a centimeter wide are filled with insulation.
The next step is the installation of waterproofing.

To insulate a residential building, mineral wool with a thickness of at least 20 centimeters is laid. For outbuildings - at least 12 centimeters thick.

Installation of extruded polystyrene foam

Thermal insulation of a flat roof using extruded polystyrene foam is carried out as follows:

Cleaning the base from dirt and dust.
Installation starts from the corner.
It is not necessary to lay a vapor barrier under polystyrene foam; it is completely moisture-proof and is not afraid of condensation. Therefore, this insulation is often glued to the base using cold mastic or special glue. As a last resort, use polyurethane foam. There is no need to apply glue or mastic over the entire base of the slab, just coat a few points. It would be a good idea to coat the end with glue to ensure a tight fit of the insulation to the parapet on one side, and to securely connect the seams on the other.
Possible cavities are sealed with polyurethane foam. Do not overdo it so that the foam does not squeeze out the insulation.
The seams must be taped to prevent cement laitance from penetrating into them, which can cause cold bridges to form.
If the waterproofing is subsequently glued using gas burner, a concrete slab is placed on polystyrene foam, the minimum thickness of which is 3 centimeters.
Next, wait a few days for the screed to dry completely and waterproof it.

The thickness of the expanded polystyrene layer is the same as the thickness of mineral wool.

Foam glass installation

Insulation of a flat roof with foam glass is carried out using the following technology:

Cleaning the base from dirt and dust.
Installation starts from the corner.
Foam glass also does not require a vapor barrier. The insulation is secured using cold mastic or hot bitumen. There is no difference in the process.

Foam glass can be used both on reinforced concrete slabs and on corrugated sheets. In the first case, mastic or bitumen is rolled out along the base of the roof using a notched trowel to ensure reliable fixation of the insulating layer. Sheets of insulation are coated along the edges to ensure a tight fit to each other and to the wall.

In the second case, the foam glass slabs are soaked in the adhesive on all sides except the top. This is necessary to avoid overconsumption of bitumen or mastic. Your hands should be protected with rubber gloves, but even so you shouldn’t put them in the bitumen, and therefore it’s better to hold the sheet in any convenient way; even wooden sticks are suitable for this.

Upper layer mounted on the same principle as the lower one on reinforced concrete slabs. First, glue is rolled out along the base, and then the insulation is laid, not forgetting to coat the edges. When the sheets are pressed tightly one to one, mastic or bitumen should protrude outward.
If there is a loose fit between the foam glass slabs and the formation of wide seams (more than 5 millimeters), they need to be sealed. To do this, the edge of one of the sheets is cut at an angle of 45 degrees and moved towards the unsealed seam, after soaking it in bitumen.

Insulation with expanded clay

Expanded clay is rarely used as independent thermal insulation for flat roofs. Rather, it is simply an addition to the main insulation.

In addition, expanded clay is often used to create a slope-forming layer. Therefore, the order of work is as follows:

Installation of basic thermal insulation made of mineral wool or expanded polystyrene.
Marking the angle of the roof, tightening the laces.
Delivering expanded clay to the roof and stretching it along a cord, a rule is used for this.
Excess material is pulled away along the edges to ensure good moisture removal from the parapet.
A concrete screed is placed on top of the expanded clay.

The thickness of the thermal insulation layer of expanded clay depends on the angle of inclination of the roof. Expanded clay should not affect the thickness of the main insulation layer.

Foam insulation

Before you insulate a flat roof with polystyrene foam, you will have to work hard and break the insulation into small pieces. Foam plastic of any density, any type and any shape is suitable. The average size pieces 3*3 centimeters. To insulate the roof, polystyrene foam is mixed with regular concrete mixture and poured onto the roof as a screed. The screed must be reinforced so that the concrete does not disintegrate later.

The main problem is that for a flat roof you will need a lot of pieces of foam. Also, this type of insulation will not be very effective. Rather, it can be used as additional thermal insulation.

The answer to the question whether there is a need to insulate a flat roof should definitely be positive. Any schoolchild knows the law of convection, according to which warm air rises up. As a result, maximum heat loss occurs through the roof structure. However, this is not the only reason for the need for insulation.

A cold surface without insulation, when in contact with heated air, will lead to its sharp cooling, resulting in the formation of condensation, which will destroy the roof. This process proceeds slowly and imperceptibly, but in the end it can cause a complete collapse of the entire structure.

In the case of a combined roofing option, condensate will drain into the interior.

An insulated flat roof creates a cozy atmosphere in the rooms located directly below it.

Features of insulation of flat roofs

Flat designs are divided into classic and inverse

The classic version is often called a soft roof. Its components are load-bearing slab, on which thermal insulation material is laid above the vapor barrier layer. It, in turn, is protected from the effects of rain, melt water, and snow by a carpet waterproofing coating created on the basis of rolled bitumen-containing materials.

A traditional flat roof is a kind of multi-layer cake, the main layers of which are:

Floor slab
Fastening insulation material
Vapor barrier layer
Insulation layer
Waterproofing
Additional insulation

Traditional flat structures are widely used in residential and industrial construction. For example, most residential high-rise buildings have just such a layout. Classic roofs can be used or not.

The inversion type of flat roof is an improved design solution of the traditional version. It is arranged according to the following scheme:

Gravel layer - its thickness should be at least 50 mm.
Filter material
Insulation layer (for example, extruded polystyrene foam)
Carpet waterproofing
Screed
Floor slab

The fundamental difference between the inversion design and the classical one is the location of the layer of insulating material above the waterproofing, and not under it. This design feature allows you to protect the waterproofing carpet from negative impact solar ultraviolet radiation, significant temperature fluctuations, freezing and thawing, mechanical damage. As a result of the listed advantages of the inversion layer arrangement, the service life is significantly increased compared to the service life of traditional soft roofs.

The design feature of the inversion roof makes it possible to use it as an operational one: it can be used to organize recreation areas, parking lots, summer cafes, pedestrian zones, etc.

Thermal insulation requirements

The load-bearing part of a flat roof is the covering slab. It is made on the basis of reinforced concrete or corrugated sheets.

The roof slope is created in various ways: using reinforced concrete ties, structurally, by filling with expanded clay, etc. The main feature of a flat roof structure is the increased requirements for all its elements.

The layer of thermal insulation material will be affected different types loads: snow, wind, installation, operational, etc. For this reason, particularly stringent requirements are imposed on the material in terms of their physical and mechanical characteristics.

Since it is impossible to completely prevent the penetration of moisture into the roof structure, the thermal insulation layer must certainly be hydrophobized.

Single-layer and double-layer thermal insulation

Single-layer thermal insulation system

Its main distinctive feature is based on insulation for flat roofs of the same density. When planning the creation of an exploitable roof, as already mentioned, a concrete screed is laid over the heat-insulating layer. The use of such a system is advisable in case of repair of an old structure or during the construction of warehouses and buildings industrial purposes, garages.

Double-layer thermal insulation system

Its structure is completely different. The top layer should be made on the basis of an insulating material characterized by increased density and significant strength. Its main task is to redistribute mechanical load. The thickness of this layer should be 30-50 mm.

The purpose of the bottom layer is to perform the main heat-insulating function. Its thickness remains within the range of 70-170 mm.

This design significantly reduces the weight of the roof, thereby reducing the load on the floors. This point is extremely important when renovating old buildings.

Today, the construction market offers new generation materials that combine the quality characteristics of both layers. The upper edge of such insulation is characterized by significant rigidity, while the lower edge is much softer. Installation of such slabs takes very little time and is not associated with any difficulties.

The importance of vapor barrier for high-quality roof insulation

The vapor barrier layer laid on the base must have excellent vapor-retaining properties in order to prevent vapors rising from the interior to the roof from penetrating the insulation. As you know, as insulation becomes saturated with moisture, its thermal conductivity decreases. In addition, steam accumulations lead to the formation of swellings in the waterproofing carpet, which over time provoke the destruction of the coating. For this reason, the issue of choosing a vapor barrier must be taken very seriously. It comes in two types:

Film - polyethylene or polypropylene film is used for insulation. The main disadvantage of these materials is the presence of seams: moisture can seep through them.

Fused - created on the basis of materials of the welded type - for example, bitumen or polymer bitumen. The absence of seams when constructing such a vapor barrier guarantees the tightness of the coating. Its other advantages are the significant thickness of the deposited layer and increased tensile strength.

Thermal insulation materials

When constructing a thermal insulation layer, the most different materials: they all differ in physical and mechanical qualities and installation method.

Most affordable insulation, still used in private and urban construction, is the use of backfill materials. The main ones are perlite sand and expanded clay. The main and, perhaps, the only advantage of using these materials is their low cost. In all other properties, they cannot compete with modern gas-filled polymers and fiber insulation.

Absolute horizontality of flat roofs is unacceptable.

In accordance with technological requirements, they must have minimum slope 2-4 degrees. Choosing as insulation expanded clay, it is extremely difficult to level the surface in such a way as to create a smooth slope and achieve the same screed thickness throughout the entire roofing plane. Working with expanded clay significantly increases costs and increases construction duration.

Insulation based on mineral wool in most cases, it does not have a sufficient level of strength to create a full-fledged base for a waterproofing carpet. For this reason, in order to strengthen it, new Constructive decisions. In this case, a screed device is used above the insulation. It helps to distribute the load evenly and create a base of the required rigidity for laying a waterproofing carpet. There are two types of screeds:

Prefabricated screed– created from flat or asbestos slate sheets covering the insulation. The installation of such a coating is quite expensive and significantly increases the cost of the work carried out.
Wet screed- essentially it is a simple cement-sand mortar. Is over budget option, but has one big drawback: its use can lead to moistening of the insulation. For this reason, when choosing this method, it is placed under the screed separation layer based on kraft paper or glassine.

Another disadvantage of this method is the significant drying time of the cement-sand composition. If waterproofing is applied to a mixture that has not completely dried, bubbles appear on the surface of the finished roof, significantly reducing the service life.

The obvious fact is that screed is by no means an ideal way to obtain a rigid base if you choose not very durable insulation. In addition to increasing the financial costs associated with construction, it also increases the weight of the coating, increasing the load on the floors.

For this reason, it is recommended to choose very durable thermal insulation slabs made from mineral wool, which is obtained from basalt rocks. In their production it is used special technology with double orientation of fibers, significantly increasing their rigidity.

Rigid slabs based on basalt fiber have a number of advantages:

ease of installation;
excellent thermal insulation properties;
increased fire safety.

A significant disadvantage of fibrous materials is their significant hygroscopicity. If the waterproofing layer is damaged due to cracks formed in the screed, moisture penetrates into the insulation layer. As materials with a fibrous structure become wet, they lose their thermal insulation characteristics, resulting in insulation becoming of lesser quality.

The listed materials are used for insulation of flat roofs of classical design.

When insulating inversion roofs materials such as foam glass or extruded polystyrene foam are used. Their advantages over mineral wool are non-hygroscopicity and high mechanical strength.

Foam glass- a relatively new heat-insulating material, which has become widespread in the creation of flat structures due to its exceptional qualities.

The distinctive properties of foam glass are:

resistance to high temperatures;
mechanical strength;
resistance to ultraviolet rays;
non-susceptibility to biocorrosion;
excessively long service life (it is practically unlimited);
preservation of the geometric shape is achieved due to the low coefficient of thermal expansion.

As a result of the presence of the last of these qualities, the mechanical loads exerted on the waterproofing membrane are significantly reduced, as a result of which the material retains its quality characteristics throughout its entire service life.

Its disadvantage is considered to be its high price compared to other insulation materials.

Extruded polystyrene foam (or extruded polystyrene foam) is a new achievement in the field of thermal insulation technologies. The material has a uniform structure and is composed of completely closed small cells (0.1-0.2 mm). During its production, polystyrene granules are mixed under high pressure and at high temperature, a special foaming agent is introduced into the composition, and then extruded from the extruder. We can confidently say that in terms of quality characteristics this material has no analogues in the world. Extruded polystyrene foam has:

the lowest thermal conductivity among analogues;
resistance to chemical agents;
increased compressive strength;
resistance to the formation of mold and mildew;
steam and waterproof.

According to the results of a number of studies, the degree of water absorption of the material is a maximum of 0.2 percent by volume. It is also important that moisture does not penetrate inside: only the cells located on the surface are filled. Thanks to this quality, when installing thermal insulation on a flat roof, there is no need for additional protection material.

Subtleties of insulation fastening

When choosing any material a necessary condition is its strong attachment to the base. For this purpose, two methods can be used:

Bonding to bitumen. This process is labor-intensive and quite expensive. Its use is advisable only if there is a concrete base, since in this case there is no need for more expensive specialized dowels and drilling holes for them.
Mechanical fastening method using special telescopic dowels. Their special feature is a very wide cap, thanks to which the fastening elements do not pierce the waterproofing carpet and the tightness of the roof is not compromised.

There is a construction rule, according to which the waterproofing carpet is attached to the insulation using the same method in which it is mounted to the base.

For mechanical fastening, it is recommended to use a polymer-bitumen weld-on material as a vapor barrier. Thanks to its elasticity, small holes, which are made by dowels on which the insulation is attached, are tightened without consequences.

When using two-layer insulation, the slabs are laid “staggered”: the joints of the slabs forming the bottom layer must be covered by the top ones. If this requirement is observed, the formation of “cold bridges” can be avoided. At least two dowels are used to fasten each insulation board.

Proper insulation will provide a cozy and comfortable atmosphere inside the house.

CONCLUSIONS:

The need for insulation is due to maximum heat loss through the roof structure.
The fundamental difference between the inversion design and the classical one is the location of the layer of insulating material above the waterproofing.
Particularly stringent requirements are imposed on insulating materials in terms of their physical and mechanical characteristics.
When installing roofs in use, a concrete screed must be laid on top of the insulation layer.
Insulation of a flat roof can be done by laying one or two layers.
The vapor barrier layer laid on the base must have excellent vapor-retaining properties in order to prevent the insulation from moistening.
When constructing a thermal insulation layer, different materials are used, differing in physical and mechanical properties and installation method.
For insulation classic roofing Expanded clay, mineral wool, and rigid slabs based on basalt fiber are used.
When insulating inversion roofs, foam glass or extruded polystyrene foam is used.
When choosing any material, a necessary condition is its strong attachment to the base.
Fastening is carried out by gluing to bitumen or mechanically using special telescopic dowels.

How to insulate a flat roof with mineral wool, see the video.

In construction, the opinion is becoming increasingly stronger that a flat, usable roof is the only way it should be. Many are confused by the complexity of its technical structure, but gaps in knowledge are easily eliminated. Let's look at the main principles of flat roof insulation.

What are the requirements for thermal insulation of flat roofs?

A flat roof is almost always installed in the absence of a warm attic. Between the habitable area and the street there is only one fairly thin partition, which cannot boast of good heat transfer resistance.

The problem, as in most cases, is solved by adding a layer of material that conducts heat poorly. Simple at first glance, but in the practical implementation of such projects a lot of questions arise: where exactly to lay the insulation, how much and what kind, how to ensure its protection and long service life?

They bring their own specifics and individual characteristics the roof itself, because it is often exploitable, and sometimes even has a bulk structure and its own landscaping. Agree that a 30 cm layer of expanded clay or lawn soil itself serves as a pretty good heat insulator, which means you can avoid increasing the thickness of more expensive insulation.

We must not forget about the fact that the conditions for using insulation on a flat roof are radically different from all other insulation systems. If, in general, the insulation, be it mineral wool or polystyrene foam, remains locked in the protected layer and is completely immobilized, then the influence on the roof in use dynamic loads expressed very clearly. But most insulation materials are lightweight porous materials that do not withstand mechanical stress very well over a long period of time.

Insulation pie device

We also cannot help but note that the trend towards technological improvement in construction forces us to look for materials and systems whose service life is comparable to the interval between major repairs of the building. And even if the material itself is in its own way physical and chemical properties looks quite durable, incorrect conditions for its placement will negate all these advantages. That's why correct composition flat roofing is one of the key design points.

In the classic case, a flat exploitable roof is installed on a solid reinforced concrete base. Here it is worth paying attention: the walk-through roof along the profile steel sheet It only looks like it is being used, but in fact, passage is only possible for the purpose of maintenance. The main reason for such a complex device is the requirement to place a layer of thermal insulation on the outside.

1 - floor slab; 2 - vapor barrier; 3 - insulation; 4 - waterproofing; 5 - reinforced screed; 6 - waterproofing; 7 - tile; 8 - expanded clay; 9 — aerator; 10 - roof funnel

The concrete base is covered with slab insulating materials - from polystyrene foam to basalt wool with a density of 80-100 kg/m 3. They leave in the parapets ventilation holes, and on the main surface one fan deflector is installed for every 60-100 m2 of surface. Another layer of reinforced material is poured on top of the insulation steel mesh sand concrete, which gives the roof high operational stability. Even higher there is a layer of waterproofing and, finally, a hydrophobic serviceable coating, forming a sealed bowl with outlets for the storm system at the lowest points.

Quite a clear system, isn't it? However, the idea of flat roofs changes dramatically when considering inversion roofing systems. The fact is that “face” coverings for flat roofs perfectly retain any moisture, but do not tolerate temperature changes and year-round exposure to UV radiation. In light of the above, it looks interesting solution Unfold (invert) the layers of the cake in reverse order.

1 - floor slab; 2 - gravel; 3 - waterproofing; 4 - slab insulation; 5 - drainage material; 6 - gravel; 7 - geotextile; 8 - turf with lawn grass

Coming from above gravel bed and paving covering, below is a drainage system (cellular membrane, for example) and slab insulation, characterized by close to zero water absorption. And already under them there is a waterproof layer with elements of a stormwater system and a preparatory backfill with gravel, due to which the correct “slope” of the absolutely flat ceiling of the upper floor is achieved.

The inversion roofing system can rightfully be called a record holder for durability among other types of roofs, including pitched ones. The only negative is the highest known complexity of the device:

only high-quality and certified materials are required;
All vertical connections and the folds of the waterproof layer must be protected from external influences;
delivery of an impressive amount of building materials to the roof is required;
low maintainability: the roof is done once and for a long time, it is very difficult to disassemble and eliminate installation flaws.

Protection of thermal insulation materials

The described device is too idealized: using materials that are resistant to wetness is quite expensive, and not everyone is ready for such investments, despite the multiple payback of such projects. What if you use ordinary mineral wool for insulation?

We mentioned above the most important method of protecting such materials. Ventilation with air at outside temperature prevents the formation of condensation, the wool clumping and the loss of its heat-insulating properties.

The authors of flat roof systems offer unique implementations for each solution: the type of ventilation system, the number of supply openings and deflectors are determined individually, depending on the properties of the insulation, the slope of the roof, its area and the thickness of the thermal protection. But in all cases, the location of the vapor barrier remains unchanged: it is rolled out directly on top of the concrete base and traps the remaining moisture seeping out of the building along with the warm air.

Sufficient protection from mechanical stress is achieved by installing an intermediate hard layer in front of the front hydrophobic coating. And yes - a roof insulated with cotton wool materials, by definition, cannot be inversion, only bulk. By the way, the thickness of the intermediate screed can be significantly reduced by combining wool and slab incompressible materials. When laid on top of looser insulation, they will create a fairly flat supporting plane and serve as formwork while the sand concrete sets.

Technical details of construction

But do not assume that it is resistant to moisture and chemical exposure polyurethane or polyisocyanurate will be a panacea and that they can be used anywhere. All materials have weak points, but in advanced insulation materials they are more specific.

Violation of work technology, the use of fasteners and construction chemicals other than the design ones, the replacement of insulating materials with cheaper analogues - these are just a few reasons why brave modern projects turn out to be unviable and, rather, discredit the technology than develop it.

As a conclusion, we recommend communicating more closely with material suppliers and paying close attention to standard projects, offered by them. Execution of such solutions with absolute technical precision means a long-term guarantee from the manufacturer and confidence in long-term and problem-free operation of the roof.

IN Lately The fashion for flat roofing is increasingly taking over the CIS countries. The fact is that its arrangement has a relatively low price when compared with the same gable. In addition, so-called exploitable roofs are actively practiced in Europe. They are equipped with workshops, lawns, swimming pools and ornamental gardens. Regardless of whether the roof will be used as additional square meters or this plane will remain untouched, it is important to arrange it correctly. Insulation of a flat roof is an important part, because its type does not provide for the creation of an attic space, therefore, the ceiling will act as a roof and it is impossible to do without thermal insulation.

Options for arranging flat roofs

Insulating a flat roof is an obvious matter. If you listened carefully to your physics teacher, you can probably remember a process called convection. Its essence is that warm air will always be at the top and cold air at the bottom. Therefore, if at the construction stage you do not take care of arranging a thermal insulation layer, warm air will very quickly leave the living space, and large resources will be spent on heating it.

In addition to preventing heat loss, the insulation equalizes the temperature regime in the roofing pie, thereby protecting it from the formation of condensation. Moisture that gets inside the cake has a very negative effect on all its components, but it causes the greatest damage to the insulation boards. A small amount of water can reduce the useful protective properties of the roof by more than 50 percent, and with prolonged exposure it will completely destroy the insulating boards. Without functioning protection, the roofing system will not last long, therefore, it will soon become unusable.

The roofing pie involves the installation of several layers. It is worth noting that flat roofs can be installed using two methods.

Classic
Inversion

If we consider the first type of device, then everything is simple. First, the base is laid, as a rule, it is reinforced concrete slab floors, then there is a vapor barrier layer, on top of which insulation boards are laid. After the installation process, waterproofing work is carried out. It is customary to use bitumen-based materials. These types of roofs are widespread on all multi-story buildings with a flat roof. Some strengthening of the roofing system can make it usable. But, as a rule, installing such roofs on high-rise buildings is impractical, so they are made unusable.

The second option is practically no different, but is more thoughtful than the previous type. To install an inversion roof, the same reinforced concrete slab is laid as the base, but not a vapor barrier layer is placed on it, but bulk material. It is used as gravel, expanded clay or crushed stone. The thickness of this layer is calculated using some formulas, but the minimum value is 5 centimeters. Waterproofing is placed on the bulk layer, and insulation is closed on top. A cement screed is placed on top of the thermal insulation layer, which will be the final layer of the base.

The essence of this method is to protect the waterproofing layer from exposure external environment. This will allow him to perform his functional tasks longer. Practice shows that this method really works, and many developers prefer it. Inversion roofing can also be created either for use or not. If you decide to install your roof, please note that this requires additional calculations. Pay special attention to the screed, because in addition to the coating, it is a barrier against destructive moisture, which, at the slightest opportunity, will penetrate into the roofing pie.

Insulation for flat roofs, however, like the other layers of the roofing pie, must be selected according to increased requirements. The fact is that if the roof is in use, then in addition to the main loads that will arise during its use, there are additional ones, for example, snow or pressure from its own weight. When purchasing these materials, you should first ask for recommendations from specialists and only then go to a hardware store.

Methods for laying thermal insulation

Insulation of a flat roof from the outside can be carried out in one or two layers.

The first option has found application in industrial buildings, temporary structures. One layer is suitable for both used and unused roofs. It is worth understanding that with increased loads that arise as a result of using the roofing plane, the reliability of a thin layer will not be enough, therefore, to give additional rigidity, it is laid in the base reinforced mesh. Make sure that the insulation boards are located in the same plane, this will prevent temperature changes and the occurrence of condensation.

Two layers of thermal insulation will give the roof required thickness, which will entail more comfortable living in such a building. The material of the bottom layer of thermal insulation should be slightly different from the top. It must have great thermal stability, despite its small size. As a rule, the thickness of such a product ranges from 70 to 170 millimeters. As for the top layer, it will distribute the mechanical loads arising from the elements above. The thickness of the top plates is significantly less than the heat-resistant layer and is about 30-50 millimeters. Despite such small parameters, they tolerate high loads well.

How not to make a mistake when buying insulation for a flat roof

Absolutely any materials that meet certain requirements can be used as insulation products. These include maximum hydrophobicity, high strength properties and good density. So, let's see which materials from the construction industry are most suitable for us.

City and private developers most often use bulk products. They explain this by the fact that this material can be purchased almost everywhere, and at a low price. Expanded clay and perlite are products on this list. The first is the result of foaming clay under pressure, as for the second, its main part is coarse sand, which has high thermal insulation qualities.

In fact, apart from their low price, these materials cannot stand out in any way and are significantly inferior to fiber and polymer insulation. Their significant disadvantages are the large mass and complexity of installation work.

The second place in popularity is occupied by mineral wool slabs and known to everyone Styrofoam. If you use mineral slabs, then you will need high-quality waterproofing. The article has already mentioned that if moisture gets into the thermal insulation layer, it will eventually damage not only it, but also the entire rafter system. The second type significantly wins not only in this matter. Polystyrene foam is not afraid of getting wet, is relatively durable, very easy to install, and has an affordable price tag. And everything would be fine, but it is undesirable to use it on an inversion roof, which is the most common. The fact is that polystyrene foam is very sensitive to direct sunlight and is not safe in terms of fire.

Evolution building materials relatively recently produced mineral wool in slabs, the main components of which are rocks. This product It is characterized by increased strength compared to older analogues, moisture does not have such a strong effect on its characteristics, the structure of the material makes it possible to do without reinforced concrete screed.

If we talk about new products, it is worth mentioning polyurethane foam. Installation of this material is carried out by spraying onto a prepared base. Upon contact with the surface, it reacts and foams, creating a durable, waterproof shield that is resistant to even prolonged exposure to sunlight. It is worth noting that this method of insulation has long been actively used in Western countries, but this material came to us quite recently, and developers have only just begun to appreciate it.

I've asked my colleagues a lot about polyurethane foam and almost no one knows anything about it. After a short search on the Internet, I wrote down the main ones for myself positive traits this product.

Low thermal conductivity. For comparison, let’s compare mineral wool in which this indicator is 0.055 W/m2 and the material in question with a value half as much - 0.022 W/m2
The preparatory processes do not take much time. It is enough just to remove large debris from the surface and sweep
To create the required layer, a small amount of polyurethane foam is enough, only 5-6 centimeters
Minimum risk of leakage due to the creation of a monolithic surface
If you spray it efficiently, then there is no need for waterproofing the roofing pie, therefore, you can save on this
Multifunctionality. This product is an excellent alternative waterproofing materials. It can be installed not only on the roof, but also in other places
Low weight due to low density
Environmentally friendly product
Due to the installation method, it can cover any types of elements, for example, drainpipes
Does not burn or ignite, therefore completely safe
Long service life (about 25 years)
Easy to install

Thanks to the application of polyurethane foam, thermal insulation acquires slightly different properties. It becomes completely impervious to moisture, which will positively affect the shelf life roofing elements. In fact, this material can completely replace the roofing pie.

A significant disadvantage of its installation is the need for special equipment. Therefore, you are unlikely to do the installation yourself.

Technological process of laying insulation

As the materials under consideration, I will take mineral wool boards and polystyrene foam. The point is that I find it inappropriate to use bulk materials In this regard, you cannot install polyurethane foam yourself. Therefore, I will focus on them.

How to insulate a flat roof with mineral wool slabs

Before explaining the installation process, I note that not all types of mineral wool slabs can be used as insulation for flat roofs. The most suitable variety is a basalt-based product. The structure of such boards is that its fibers are directed in opposite directions, as a result of which the strength indicators increase.

Thermal insulation of a flat roof with mineral wool occurs in the following sequence:

Preparing the base. Typically, this process involves cleaning the reinforced concrete slab of excess debris.
Laying a vapor barrier layer. Regardless of the material used and the method of laying the roof, vapor barrier cannot be neglected. This material will be the very first assistant in the fight against condensation. Some developers who forgot or did not want to lay this layer soon paid for their mistakes. Their roof, under the influence of water, began to collapse very quickly. Hardware began to rust and the wood began to rot.

Vapor barrier membranes are available both unidirectional and double-sided. Laying the first ones implies that you have taken care of reliable natural ventilation, which will remove moisture removed by the membrane. Alternative option is polyethylene or bitumen

Installation of mineral wool slabs occurs on top of the vapor barrier. Their construction is best done in two layers. It is worth understanding that a thick roofing pie has quite a large mass, so before laying you should carefully check all the calculations. However, you can get by with just one; as a rule, it is quite enough for warm regions of the country
After spreading the insulation boards on the surface, they are attached to the base. Dowels or bitumen are used as fasteners. If mechanical fasteners are used, the vapor barrier must be securely glued to the base using the fusion method.

When bitumen is used in laying insulation, the entire installation process not only slows down, but also increases in price. Despite this, it is a necessary component for concrete surfaces so that moisture cannot penetrate into the roofing pie

You cannot combine two fastening methods, i.e. if you used dowels, then continue to fasten only with them and do not use bitumen

Quality work done will not only bring satisfaction, but will also have a positive impact on the life of your building. If you find it difficult to perform the above work yourself, then hire experienced workers for this.

Installation of foam plastic as insulation

This material has relatively high strength and is completely waterproof. That is why it is the most popular insulation for inversion roofs.

The technology of laying polystyrene foam is not a difficult job. It is enough to know installation technology.

As with everything, some preparatory work takes place first.
Then, the material begins to be laid on the prepared base, usually a reinforced concrete slab. Please note that the surface is not coated and no additional layer is placed on it. All foam tiles are fastened together with construction tape. If there is a need to build a second stand, lay the tiles in such a way that their seams do not coincide with the previous layer
When this layer is completed, the geotextile is laid. 5-10 centimeters will be enough. It provides reliable protection of the lower layers from dirt and mechanical damage
Next, gravel or small crushed stone is poured, and the entire surface is filled with screed

If you plan to grow any plants on the roof, and for this you need to pour soil on its surface, then to protect the roofing pie it is better to increase the geotextile layer by 15-20 centimeters.

A flat roof is perfect solution for country houses, you save significantly on materials. Modern roofing products make it possible to create a roof that is completely protected from moisture, which will have a positive effect on the service life of the building as a whole.