Combined roof: types, device and features

Combined roof: types, device and features
Combined roof: types, device and features

Combined roof looks like a design that allows you to successfully connect the roof to the attic. Such a roof device is much cheaper, and the assembly of the structure is carried out without complex preparatory steps. However, it is necessary to follow all the rules of construction, regulated by roofing technology. Very often, reinforced concrete components are used for the construction of these structures. Combined roof construction of this type is used in the construction of buildings of multi-storey buildings.

flat roofs

Types of combined roofs

Various materials are used as thermal insulation. However, they all have the only drawback - they are afraid of getting wet. Therefore, roofers use several types of structures that differ in the way they protect the insulation. One of the most common types of combined roofs is a ventilated roof. This model allows you to dry the insulating layer with the help of an air gap.

Next in importance is the non-ventilated type of roofs, in the design of which hydrobarriers are used. Alternatively, in some roofs, a complex option is used, in which the ventilated structure may have non-ventilated segments. This model of combined roofs, photos of which can be seen in this article, is often used in the construction of private houses. A fully non-ventilated roof is more used in commercial projects.

flat combined roofs


The air layer serves to dry the roofing insulation in a combined ventilated roof, while performing additional heat-insulating functions. Such a coating is resistant to external temperature conditions. The use of this model is due to a number of reasons:

  • Maximum security of each insulating layer;
  • no seals or blisters;
  • possibility of using organic-based insulation;
  • Costability of installation design.

For the installation of a ventilated roof of combined coatings, reinforced concrete floor slabs are used, covered with insulating materials, over which an air gap is maintained. Above the insulation, thin roofing concrete slabs are installed, covered with a layer of waterproofing.


This method of combined roofing of roofs involves a more complex composition. When using such a model, the main goal is to insulate inclined planes as much as possible.To accomplish this task, all laid layers are compacted as much as possible. In this way, condensation is completely eliminated.

combined roof

However, this design has some limitations. It is not recommended for use in regions where in winter the air temperature drops below -30 degrees Celsius.

Structurally, this model of a combined roof is as follows. A reinforced concrete floor slab is used as the base. Then a protective layer is laid, consisting of a vapor barrier. After that, the surface is covered with a dense layer of heat-insulating material. In this case, the use of bulk insulation like expanded clay is allowed. At the next stage, the surface is leveled with a cement mortar screed. Next, a waterproofing layer is laid, and at the last stage, roll-type insulating materials are rolled out over the surface.

Partly vented

This type of combined roof can serve as an average solution between the previous methods. For its device, a reinforced concrete floor slab is also laid at the base, which is covered with a layer of lightweight concrete slabs. Next, a layer of rolled waterproofing materials is laid. This roof model has an attic space, even if the attic turns out to be closed and its area does not have to be used. If the latter condition is met, the cost of the project can be reduced by 15 percent.

Types of combined structures

For device varioustypes of roofs use their own types of structures, the most suitable in the circumstances. By type of construction, there are 4 main varieties:

  • horizontal;
  • flat;
  • two-layer;
  • inverted.

Each of these types of roofs has its own production technology and involves the use of a certain group of building materials. Next, consider each of the types in more detail.


This model is used for the construction of non-ventilated roofs and has several assembly variations:

  • flat, used in the construction of private houses;
  • reverse combined, which uses high-density insulation;
  • horizontal reverse.

When using this type of combined roofs, vapor barrier layers are of great importance, which prevent the formation of condensate. In addition, the horizontal roof is not protected from external temperature changes. Therefore, to protect the surface, a regulated layer of crushed stone is spread on top.


Flat combined roofs - this is the most common type of roof, which is used at any opportunity. The following layers form it:

  • base in the form of floor slabs;
  • vapor barrier layer;
  • thermal insulation layer;
  • waterproofing;
  • roofing material.

In these types of roofs, attic spaces are often arranged, addingaesthetic appeal of the facade of the building. For these structures, it is not recommended to use dark tones of roofing materials. Preference should be given to high-density insulation. The flat roof is conducive to the arrangement of terraces and viewing platforms.

flat combined

Double layer

With the use of this type of roof device, two layers of heat-insulating materials are used. Most often, pressed mineral wool slabs are used, protecting them with a layer of waterproofing. The first layer of thermal insulation is laid on the base in thickness twice the next one. This method allows you to protect the roof as much as possible from the influence of external factors, and also helps to reduce the load, significantly increasing the life of the roof. This model is arranged from the following components:

  • base;
  • vapor barrier layer;
  • main layer of thermal insulation materials;
  • top layer of thermal insulation;
  • waterproofing layer.

An additional layer of vapor barrier is sometimes laid between the thermal insulation. The latter helps to avoid excessive compaction of the insulating layers.

combined device


This type of roof structure differs in the order in which the protective layers are arranged. Using this model, use the reverse order of laying waterproofing and insulating materials. Here, the waterproofing layer is maximally protected from various damages and the effects of an aggressive environment. This arrangement assumes the followingsteps:

  • concrete base;
  • cement screed;
  • waterproofing layer;
  • drainage components;
  • insulation layer;
  • geotextile layer;
  • regulated mixture of sand and cement;
  • paving slabs.
combined roofing device

This type of roof is best suited for terraces, open areas and parking areas. The main advantage of this design is its high strength. Ordinary roofs are too susceptible to the influence of the external environment, but for inversion this problem does not pose a threat.

Plus, the simplified method of installation of this type of roof allows it to be used on existing buildings, without much effort and complex preparations. To carry out such a task, it is enough to dismantle the existing insulating coatings and install others using the specified order.


So, we have considered the main types of roofs. As you can see, the combined roof can be very different. Everyone chooses the best option for themselves.

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