Any roof for a building is an enclosing structure. Being in direct contact with external environment, she regularly has to bear the consequences of serious temperature changes of several tens of degrees. If you consider that the thickness of the ceiling is some 40 cm, it becomes clear what high loads each of the elements of the roofing system is subjected to.
To neutralize such a detrimental effect of such changes, it is necessary insulation flat roof
. This event is aimed at improving its heat-saving, sound and waterproof characteristics.
A flat roof is called conventionally, since any of them has a slope to drain precipitation from its surface. Creating a slope can perhaps be considered the first step for insulating the floor. The issue of slope is solved, for example, by filling with expanded clay or using reinforced concrete structures.
Flat roofs can be used or not. In the first option, this is a platform on the roof of a building, which is used for various needs. When using the building's floor as additional area, it is necessary to place a concrete screed on top of the heat-insulating layer. In the case of an unused roof, there is no need for such a screed.
Today, two main types are used for flat roof insulation: standard schemes devices: single-layer and double-layer. Schemes and installation technology for various roofing bases (reinforced concrete, corrugated sheets and others) are generally the same.
This scheme is especially common for installing thermal insulation during repairs or new construction of industrial buildings, warehouses, and garages. The layer of insulation used is made entirely of thermal insulation material same density. If the flat roof is intended to be used for its purpose and design, then the thermal insulation layer is covered with a concrete screed.
When installing a flat roof thermal insulation system on new buildings, a two-layer one is mainly used. This system has two layers of thermal insulation material - lower and upper. The insulation material used for the bottom layer is considered the main one. It must have maximum thermal resistance with low thermal insulation strength. Its thickness is 70–170 mm. Due to the top layer, the mechanical load is redistributed completely onto the flat system. The material of the upper layer is much thinner than the lower one - its thickness is only 30–50 mm, however, it has greater compressive strength and strength. This functional redistribution between layers of thermal insulation material can significantly reduce the weight of the insulation and, accordingly, the flat roof system.
Any element of the roof structure is subject to several loads, and therefore must satisfy fairly stringent requirements. In particular, flat roof insulation appears directly under the following loads:
The amount of snow in regions with heavy winter precipitation requires special attention. The mass of wet snow accumulated on the roof can reach several tens of tons. That's why insulation for flat roof must be reliable, with excellent properties, physical and chemical. Since the possibility of moisture getting inside the ceiling cannot be excluded, the thermal insulation must also be moisture resistant.
An important characteristic of roofing thermal insulation is its compressive strength. Thermal insulation of the roof, based on the technology of constructing a flat roof, actually performs the functions of the under-roofing material of its base, therefore its compressive strength and density should be quite high. Any deformation during operation or installation may cause damage to the waterproofing layer.
Thermal insulation material in a single-layer insulation structure or upper layer in a multilayer one it must have a high density, about 200 kg/m 3, which provides the material with special strength (you can safely walk on it).
Insulation of a flat roof considered difficult technological process, one of the important components of which is the use of high-quality modern materials.
The approximate composition of a thermal insulation “pie” for a flat roof looks like this:
The materials used for thermal insulation of a flat roof must meet the requirements of high vapor permeability, reduced thermal conductivity and water absorption, and fire safety.
Thermal insulation slabs are attached to the base using specific dowels or glued to a reinforced concrete slab, but only if the bonding strength of the glue is greater than the peeling strength of the insulation layers. If the presence of a protective layer of cement-sand screed is assumed, the issue of fastening naturally disappears. In the case of using a two-layer system, special disc fasteners are used for the second top layer, which plays a protective function. Their length should be sufficient to pass through the mineral wool mass and go deeper into the base by more than 50 mm.
Other popular ones. It can be said to consist entirely of air bubbles, which are enclosed in closed cells made of polystyrene. During the manufacturing process, a fire retardant is added to the material. Expanded polystyrene is distinguished by excellent thermal characteristics, performance qualities and high strength. This thermal insulation material.
Laying flat roofing is used in the construction of both residential buildings and industrial and administrative facilities. The insulation of a flat roof has its own specifics, and the effectiveness of thermal insulation depends on the quality of materials and technology of work.
The difference between the insulation of a flat roof and a pitched roof is that it is done in a special way, since the design does not allow the insulation to be placed among the elements in the usual way rafter systems due to their absence. In addition, there is no ventilation gap; instead, if necessary, channels are installed in places where the coating is partially adhered to the underlying base. A flat roof can be insulated from the outside and inside.
Insulation of a flat roof is carried out using not only thermal insulation, but also vapor barrier material. This is necessary because the vapor barrier membrane must remove condensate formed from the thermal insulation and help it evaporate. If this does not happen, condensation formed when the cold outside air collides with the warm air coming from the house, will contribute to the rapid wear of wooden elements and layers of roofing.
The procedure for installing thermal insulation and vapor barrier depends on the type of flat roof. They come in two types: classic and inversion. The thermal insulation device of a classic flat roof consists of the following layers:
The waterproofing layer serves as both a waterproof and finishing coating. The classic type of flat roof, in turn, can be used or not. In the first case, its design is designed for increased loads, since it can accommodate winter Garden, summer playground, etc., for this the heat-insulating layer must be thicker and stronger than when insulating an unused roof.
Insulation of an inversion type flat roof is carried out as follows:
The difference is that when insulating an inversion roof, the thermal insulation is laid above the waterproofing - this allows you to protect the hydrophobic coating from negative impact sunlight, mechanical damage and temperature changes.
Insulation methodsIt is possible to insulate flat roofs in one or two layers. Single layer insulation is usually used for industrial buildings, warehouses and unused roofs. Its distinctive feature is that the insulation is laid in a uniform layer over the entire roof area. If a single-layer insulation of the roof in use is planned, it is necessary to lay a concrete screed and finishing coat. But, in order to create comfortable insulation for a residential building, thermal insulation should be laid in two layers. This system involves laying insulation in different planes. In this case, the bottom layer performs the main thermal insulation function; its thickness ranges from 70 to 170 mm. The top layer performs a protective function; it evenly distributes the mechanical load, and is therefore denser and more durable. Its thickness is on average 50mm. Such an insulation system creates more reliable protection from external influences, but has a higher cost.
Insulation for a flat roof should be as hydrophobic, vapor-permeable, dense, and light in weight as possible. The following materials are currently used:
The technology for thermal insulation of a flat roof should include high-quality installation of waterproofing, which is used as waterproofing membrane(film) or mastic (bitumen, acrylic, silicone, rubber). A reliable way is to combine mastic with roll material, as well as the use liquid rubber, which is excellent for reinforced concrete foundations.
Depending on the type of base, the insulation method is selected. Mineral wool slabs are laid on a reinforced concrete base and covered with a screed on top. In this case, the thermal insulation is made in two layers, the same as when insulating the base from a corrugated sheet. If a galvanized base made of corrugated sheets has a distance between the corrugations less than the thickness of the insulation board, it can be laid without the use of a leveling layer.
The insulation coating is fastened differently depending on the base: with a concrete base, the insulation is attached together with the coating, and when attached to a profiled base, the insulation is fixed separately from the waterproofing.
Thermal insulation boards are laid on a profiled base from the corner of the building so that their long side is perpendicular to the corrugations of the base, while the seams of the upper level should run counter to the seams of the lower level.
Flat roofing is an inexpensive and practical way arrangement of any building. Often it is erected above multi-story residential buildings, industrial facilities, garages and extensions (verandas, terraces). In case of residential buildings A flat roof must be insulated, otherwise it will be of little use. This is exactly what we will talk about in today’s article – insulating a flat roof with your own hands.
The need to insulate a roof, including a flat one, is obvious - any person familiar with the concept of convection from a school physics course should understand that the air, when heated, rushes upward. If he does not meet a worthy obstacle at the top, he will leave the room without hindrance. In other words, all efforts to heat a house under a flat roof will be nullified.
However, the beneficial aspects of roof insulation do not end there. In addition to the fact that thermal insulation delays warm air, it prevents sudden temperature changes inside roofing pie. Let's turn to the same school physics course. When cold outdoor air encounters heated air rising from the home, the reaction creates condensation—tiny droplets of water. As condensation accumulates, it impregnates the layers of the roofing pie and wooden elements, causing their rapid wear. For this reason, laying only insulation under the roof sheathing is not enough - it is necessary to protect it vapor barrier membrane, which will remove condensate from the thermal insulation and promote its rapid evaporation.
It turns out that the device for insulating a flat roof involves the use of not only thermal insulation material, but also a vapor barrier. The order of installation depends on the type of roof. Flat roofs come in classic and inversion styles. In the first case, the base is a load-bearing slab, on which a vapor barrier is laid, and then insulation. It, in turn, is closed roll waterproofing based on bitumen. It simultaneously protects the insulation from moisture and serves as a finishing coating. Such roofs can be found on multi-story buildings in any city. It is also worth mentioning that classic roofing can be used or not. As the name implies, you can use the exploited roof, that is, place equipment, furniture there, make add-ons, in general, use it to the full as an additional surface. The covering of an unused roof is not adapted to increased loads, but insulation of both types follows the same scenarios.
Inversion roofing in technical design is much more advanced than traditional roofing. First, a layer of gravel, expanded clay or crushed stone is poured onto the supporting slab. The thickness of the powder should be at least 5 cm. Waterproofing is placed on such a drainage pad, then insulation, everything is poured with concrete and the screed is covered finishing material. The main difference is in the installation of insulation over the waterproofing, which allows you to protect the hydrophobic layer from harmful ultraviolet rays, temperature changes and mechanical damage. As a result, an inversion flat roof lasts much longer than a traditional one and automatically becomes usable - a durable concrete screed (especially if it is reinforced) allows you to create areas for recreation and sports in the open air.
It should be taken into account that the insulation, like all other layers of the roofing pie, will be subject to various types of loads: the weight of snow, wind force, the mass of overlying materials, etc. Therefore, increased physical and mechanical requirements are placed on insulation for flat roofs. In addition, experts strongly recommend choosing the most hydrophobic material, since it is impossible to guarantee 100% protection from moisture. We'll talk more about choosing insulation a little later.
Insulation of flat roofs is carried out according to one of two schemes: in one or two layers. Single-layer insulation is relevant for industrial buildings, garages and warehouses. Suitable for used and unused roofs(in the first case, reinforced concrete screed finishing layer). Placing the insulation in one plane provides moderate protection against condensation and excessive heat loss, however, only two-layer insulation can create a microclimate that is comfortable for a cozy life.
A two-layer insulation scheme, as you might guess, involves laying two layers of heat-insulating material in different planes. The lower main layer should be thermally stable with low strength and a thickness of 70 to 170 mm. The top layer is responsible for distributing the mechanical load over the entire surface of the system. Its thickness is significantly less than that of the bottom layer, ranging from 30 to 50 mm, but at the same time it has high compressive and tensile strength. Such a functional distribution of two layers of insulation significantly reduces the mass of the roofing pie as a whole, thereby reducing the load exerted by the roof on the floors and foundation.
To insulate a flat roof from the outside, the most different materials, but after studying the above information we can already identify several main selection criteria. Firstly, maximum hydrophobicity. Secondly, strength and density. Thirdly, keep the weight as low as possible. Let's look at the materials used in modern construction.
Most often, backfill materials are used in urban and private construction due to their availability and low cost. It's about about expanded clay (clay foamed under high pressure) and perlite (light coarse sand with good thermal insulation characteristics). Unfortunately, the advantages of these materials are limited by their low cost and availability - in other respects they are not able to compete with fiber or polymer insulation. They are relatively heavy, and it is ideal to create flat surface It's quite difficult on a slight slope.
The second most popular are mineral wool boards and polystyrene foam. Mineral wool retains heat well, is easy to use, does not burn, but needs high-quality waterproofing– if it gets even a little wet, it will no longer protect against heat loss. Extruded polystyrene foam is not afraid of water, is characterized by high strength, ease of installation and relatively low cost. However, it is better to use it to create an inversion roof, since the material is very sensitive to ultraviolet radiation and is flammable.
Not long ago, mineral wool in slabs made from basalt rocks appeared on the market. It is much stronger in compression and tearing than older analogues, is not so afraid of water and allows you to create a fairly durable coating without installing a heavy concrete screed.
And finally, the newest, high-quality and expensive insulation material is polyurethane foam. A special composition is applied to the prepared surface by mechanical spraying, after which it foams, hardens and creates a durable waterproof crust that perfectly retains heat and is impervious to ultraviolet radiation. In the West, polyurethane foam has long been used to insulate roofs, including flat ones. In our latitudes its advantages have only just begun to be appreciated.
Positive aspects of using polyurethane foam for roof insulation:
Thus, polyurethane foam replaces insulation, vapor and waterproofing. The only drawback is that you won’t be able to do this kind of work yourself, since this requires special equipment and skills in handling two-component material.
It's time to tell you how to insulate a flat roof yourself. Since the disadvantages of bulk insulation do not allow us to talk about them as the best options for arrangement, we will touch on the use of mineral wool boards and extruded polystyrene foam.
Let us immediately make a reservation that not all mineral wool slabs can be used to insulate a flat roof in use or a classic one. soft roof. Best suited for this purpose basalt slabs, the fibers in which are directed in different sides- this allows them to withstand high loads. Of course, you can protect fragile insulation with a screed (dry or wet), but this will create additional load on the supporting structures.
Mineral wool insulation technology:
Video about insulating a flat roof with mineral wool:
Extruded polystyrene foam is highly durable and waterproof, and therefore is most often used for insulating inversion roofs. The slabs have slot locks that provide a very dense surface, but for greater reliability, it is recommended to glue all joints with construction tape.
The beauty of polystyrene foam is that working with it is very simple and quick:
Insulating a flat roof is not so easy, but this measure is considered necessary if you want to live in a warm house and not overpay for heating.
1.
2.
3.
4.
5.
Flat roof is one of the most popular structures used in the construction of various technical structures, industrial buildings and outbuildings. This option is distinguished not only by its relatively low cost, but also by its high practicality. At the same time, it is worthwhile to insulate a flat roof as responsibly as possible, since otherwise all the advantages of such structures may come to naught.
Thus, timely and proper insulation roofing contributes not only to better preservation of the entire structure, but also to the creation necessary conditions for productive activities and storage of tools and materials. At the same time, it should be remembered that the insulation process itself and the choice of thermal insulation materials are influenced by factors such as the design features of the structure, the type of roof and the form of thermal insulation.
Any roof includes the following constituent elements:
It is worth noting that today there are two main types of flat roofs used - traditional and inversion. The sequence in which all of the above layers will be laid depends on which type is chosen. So, if the traditional option is used, then the waterproofing is spread over the insulation, and with the inversion type, the insulation is already placed on top of the waterproofing. The choice of one or another installation option depends on future fate roofs. If it will be used for gardens or recreation areas, then the inversion type looks preferable, and if no additional load is expected, then you can limit yourself to the traditional option.
When looking for the main ways to solve the problem: “How to insulate the roof?”, it is worth, first of all, to understand the main modifications.
Today we can distinguish two main types of thermal insulation, the most optimal for Russian conditions:
Single-layer and two-layer roof thermal insulation systems have both their advantages and disadvantages. If the first is characterized by low cost and speed of construction, then the main advantage of the second can be called the absence of through seams and more effective protection from external influences.
The choice of thermal insulation must be made using the entire amount of available information. The main task of insulation is to retain water vapor under the roof without damaging the waterproofing layer itself. After all, as you know, water vapor absorbed into the insulation over time can lead to serious deformation of the thermal insulation layer, which will have an extremely negative impact on the condition of the entire roof.
The main layer of thermal insulation can consist of the most various materials: here a lot depends on the type of roof, as well as on design features building. Most often, the roof is insulated with extruded polystyrene foam, foam glass or mineral wool. The main advantage of the first material is that it always remains dry under absolutely any circumstances. At the same time, the main disadvantages of expanded polystyrene include its flammability and destructibility under the influence of ultraviolet rays. The same applies to foam glass, which is also quite expensive and causes significant damage to the family budget.
Insulating a flat roof with mineral wool - expert advice:
Insulating a roof with basalt wool is a more affordable and common option, however, it is also fraught with several dangers and disadvantages. Firstly, this type of insulation is very fragile, so it almost never serves as the basis for waterproofing. To strengthen it, it is necessary to install special ties that will give sufficient rigidity to the coating. Secondly, if insulating a flat roof with polystyrene foam allows you to forget about the problem of roof waterproofing for a sufficiently long period, then in the case of mineral wool, the first repair will have to be carried out within a few years.
Modern market construction and finishing materials constantly offers its customers new technologies and ways to solve certain problems. Thus, a new word in roof insulation has become special sandwich panels with mineral wool insulation, which are devoid of many of the disadvantages of ordinary mineral wool and, in addition, have unconditional aesthetic advantages.
After constructing a reliable roof, you need to make sure that it does an excellent job of protecting your home from precipitation, and think about its thermal insulation, since heat leaks in most cases occur through the roof. By the way, the process of thermal insulation of the roof is in second place in importance after creating the tightness of the coating. With all the variety of roof designs, the process of insulating it is carried out according to similar principles. And how exactly - now you will find out!
The roof is the weakest element in the design of a residential building in terms of heat loss. The upward direction of heat flows causes much higher heat leaks compared to the walls and basement. Heat loss through an uninsulated roof often reaches 30% of all losses in low-rise buildings. Due to rising heating and energy costs, minimizing such losses brings tangible benefits.
Lack of thermal insulation or improper installation of insulation provokes the formation of condensation on inner surface, which entails a violation of the microclimate in the house, the formation of fungus and mold. In this case, the roof will be heated by heat flows that come from the attic of the building, so in winter the snow settled on the roof quickly melts, flowing down the slope and turning into ice and icicles, as well as deforming the roof and damaging the waterproofing.
One of important factors that influence such indicators are humidity and temperature regime, the maintenance of which is ensured by specific thermal insulation materials. To insulate the roof, materials and thermal insulation techniques are used that ensure the highest quality preservation of heat in the house in accordance with established building codes. The insulation must have low water permeability and a certain vapor permeability - the ability to allow steam to pass through, giving the roof the ability to “breathe”.
In the construction of private houses, the design of cold attics was traditionally used, when the main insulation was carried out along the surface of the floors, i.e. along the attic floor. This approach was associated with a lack of thermal insulation material that could be laid on the rafter structures. The modern approach makes it possible to insulate the under-roof space along the rafter structures themselves, while creating a full-fledged attic and increasing the minimum costs living space.
Particular attention should be paid to the choice of insulation. To insulate the roof, materials are used that differ in thermal conductivity, vapor permeability, level of moisture repellence and mechanical characteristics, durability, fire resistance, ease of use and cost. When purchasing thermal insulation material for roof insulation, you need to pay attention to the following criteria:
The insulation material must be selected so that its thickness ensures the energy loss of the building, in accordance with the requirements of SNiP, therefore it should be determined based on the thermal conductivity coefficient of a certain material. If the thickness is not enough truss structures In order to organize appropriate insulation, then to solve this issue it is necessary to use more efficient insulation with a low level of thermal conductivity.
The main characteristic of insulation is its average density. Thermal insulation materials are divided by density into dense, medium, light and very light. High-density materials will not always provide high levels of thermal insulation, but they can withstand more significant mechanical loads and create increased loads on the load-bearing structures of the insulated house. The density of the insulation is 20 - 200 kilograms per cubic meter. Let's look at the main types of insulation:
At the second stage preparatory work Before attaching the thermal insulation material, it is necessary to check the electrical wiring for serviceability. Repair its damaged parts, replace worn wires, ring switches, carefully check all connectors, connections, fastenings and joints. If the electrical wiring is completely unusable, it should be redone.
In construction practice, there are many methods for installing roof thermal insulation. Which method to use in each specific case will depend on the complexity of the roof structure and the material used for its insulation. Let's take a closer look at them.
There are several methods for laying thermal insulation material:
Internal insulation- This is the most popular thermal insulation option, which is suitable for pitched and flat roofs. Internal roof insulation is carried out using the following technology: first lay interior lining premises, on top of it - a vapor barrier, then - heat-insulating material, after that - wind and waterproofing.
The final thermal insulation layer is the roofing material you have chosen. Remember that the insulation must have the required width and be adapted to certain climatic conditions. But the main thing is to ensure that the material does not weigh down the roof, and to provide the gaps that are required to remove moisture from the structure.
External roof insulation is carried out on the basis of flat roofs using rigid plates, which are therefore pressed concrete slabs or pebbles. When organizing external thermal insulation, it is very important to calculate the strength of the roof in order to protect against roof collapse.
Choosing a thermal insulation technique pitched roof carried out depending on the characteristics of the building. If the house is in operation and you do not plan to dismantle the roofing material, the main or additional insulation of the roof should be carried out along the inside of the roof - directly along the rafter systems.
If the building is just under construction and you have not yet installed the roofing material, then it is worth insulating the outer side of the pitched roof structures, and the internal sheathing will act as a support for the thermal insulation material. To insulate the roof, you can choose one- or two-layer thermal insulation. But at the same time, it is worth using only insulation that has the same density.
It is customary to insulate pitched roofs on rafters with heat-insulating materials, which are characterized by low density (25 - 50 kilograms per cubic meter), designed exclusively for atmospheric influences and temperature. Remember that the materials should not create a large load on the structure.
When building a new house, it is recommended to use a two-layer insulation method to insulate a flat roof. The bottom layer is required for thermal protection, and the top layer is needed to distribute loads over the entire structure. The single-layer method is usually used exclusively for the repair and reconstruction of old roofs.
To insulate flat roofs, it is necessary to use dense insulation materials, which must withstand significant loads from snow and water, since precipitation often accumulates on such roofs. Flat roofs made of corrugated sheets need to be insulated with mineral wool, basalt and polystyrene foam boards, which have a density of about 220 kilograms per cubic meter. The roof on a reinforced concrete slab is insulated with denser materials, for example, PPZh-200 slabs.
Roof thermal insulation is a multi-layer system consisting of an internal vapor-proof layer, insulation and an upper membrane material, which is characterized by one-sided moisture permeability. This type of construction is called a “roofing pie”.
Manufacturers of modern building materials consumers are offered a ready-made “pie,” but you can create it yourself at the proper level of quality. The first layer is a moisture-proof material that protects the insulation layer from excess moisture that comes from the room. Typically, foil, polyethylene and other materials are used.
The material is laid on inside load-bearing elements without gaps in a single layer, gluing the joints with sealant and securing them with strips to wooden structures using galvanized nails or a construction stapler. If it is impossible to lay the material in one layer, you need to create overlaps, which should be more than 100 millimeters.
A vapor barrier top layer is necessary to ensure the passage of moisture outward and prevent it from entering the layer of thermal insulation material. Thermal insulation material is laid directly on the vapor barrier material. At the same time, it must be precisely cut to size, since it is not allowed to crumple.
You can achieve the planned and calculated efficiency of thermal insulation of a soft roof only if you prevent the formation of cold bridges when laying the insulation. To do this, the roofing material must be laid without interruption by other structural elements. Shouldn't be in thermal insulation layer planes and depressions for air passage.
Thus, only high-quality styling thermal insulation. Therefore, it is not recommended to save on it; you need to strictly follow the technology in order to avoid such fatal mistakes as using material of the wrong width or installing insulation of small thickness. Also remember that the maximum possible effect from the roof insulation procedure can be achieved only with an integrated approach to the thermal insulation of the house.
