Flat roof without "cold bridges"

By Admin | Building
02 June 2016

reason for the high popularity lies in the efficiency of flat roofs: the large area it requires a much lower cost than the device pitched roof.In addition, the flat roof - it's always more space that can be efficiently used in modern architecture.

to flat roofs are presented fairly high requirements for thermal protection, and no wonder: indoor climate in any building depends strongly on the quality of the roof, and its good thermal insulation to reduce heating costs.

However, in the construction of the roof, there are always the so-called "cold bridges" (or "thermal bridges") - areas where due to various causes are possible heat distribution in two or three areas, which significantly increases heat loss from the building.Avoid "cold bridges" is impossible, because any design with something connected, and the use of different materials is almost inevitable.But the influence of "cold bridges" can be reduced to a minimum - in particular, through the use of high-quality insulating material.

flat roof design.The basic scheme of the device roofing
basis of a flat roof support plate is made of reinforced concrete monolith or profiled metal sheet.On top of it is placed paroizoliruyuschy material whose main function is to protect the insulation from water vapor that prevents it from getting wet, swelling and ensures the preservation of all of its properties.To protect the insulator against moisture, tend to use polyethylene film or bitumen and bitumen-polymer materials.Then fit the roof heat insulator, protected from atmospheric precipitation waterproofing carpet.There are outer and inner roof insulation methods, and apparatus for flat roofs is possible to use any of them.

practice, however, because of its simplicity, a method often used outdoor.There is also a single-layer and double-layer flat roof insulation system.In modern construction is the most frequent use of a two-layer system.According to the technology, the lower layer takes the brunt heat insulating function, the upper layer of the "responsible" mainly due to the redistribution of the mechanical load.If the first layer has a thickness of 70-170 mm, the second - only 30-50 mm, however, it has high compressive strength and density.Such "specialty" soft roofing layers significantly reduces its weight and consequently the load on the overlap.Recently, there are also solutions that combine the two layers into one plate, for example, RUF Bats EXTRA company ROCKWOOL.The top layer of hard plates and the bottom - softer.This combination of different properties in a single plate significantly reduces installation time the roof, as well as to avoid typical mistakes and optimize the cost of construction and installation works.

When single-layer flat roof insulation system whole insulating layer is made of single-density insulation, and today this technology is used, usually in the reconstruction and repair of old roofs.The materials used for roof insulation.

Benefits of mineral wool insulation material
used in the device flat roof must meet certain requirements.This fire safety, low thermal conductivity, low water absorption (the roof is exposed to the action of rain) and high vapor permeability.The roof of the building is always exposed to high loads, and the use of unsuitable or poor quality material for its device is fraught with the destruction of the roof and the subsequent costly repairs.The most frequently used flat roof insulation extruded insulation, mineral wool, foams, and sprayed polyurethane foam insulation.A major shortcoming of the foam is its fragility, it can be very critical for the device roofs, repairs are very expensive.

As for modern foam (extruded) material, the main advantage is the small layer thickness required for high-quality insulation.However, their use should take into account that the flammability of materials ranging from the first to the fourth group, depending on the brand.Note that the smaller the group number, the lower the flammability of the material, and the material ascribed to the fourth group, with the release of burning acrid black smoke and burning droplets.

In terms of fire safety advantage is stone wool: it is non-flammable and can withstand temperatures up to 1000 ° C.Thus, this material, in addition to its main insulating properties improves fire resistance of the construction, and also enables direct laying modern fusion roofing material by gas burner flames its temperature is about 600 ° C, and thus rock wool boards are not damaged.In choosing the material for the device flat roof must remember that the inner surface of this design usually corresponds to the temperature in the room and outdoor temperature difference is subjected to serious: -50 ° C in winter and + 80 ° C on a sunny summer day.Thus, a heat insulator used on roofs, increased demands on endurance.It is very important, and indicators such as high compressive strength, the peel layer and resistance to point loads: otherwise there is a risk of heat disorders and waterproofing layers.

Fortunately, there are modern solutions to achieve a warm and yet very robust roof.In particular, rock wool, with excellent thermal insulation values, is highly resistant to damage.For the previously mentioned panels RUF Bats EXTRA developed by ROCKWOOL specifically for the device of flat roofs, the compressive stress at the point load, creating a deformation of 5 mm, is about 100 kPa.In comparison, the pressure on the roof of her walking on the employee causes point loading of about 45 kPa.

errors when installing flat roofs
but not enough to simply choose a high-quality thermal insulation materials for the device roofs, and more important to avoid mistakes in the design and construction work, one of the likely consequences of which could be the emergence of so-called "cold bridges", ie.e.limited by the volume of the construction elements, through which the increased heat."Thermal bridges" are building elements of concrete brick or block masonry, window and door lintels, and often - heat insulation fasteners to the supporting base (anchors).There are several reasons for the emergence of "cold bridges", and accordingly, they are divided into geometric and material.Geometrically caused "cold bridges" arise where the inner surface of the lower heat absorption isothermal outer surface.Due to such a constructive errors at this point the temperature of the inner surface is lower than that of the adjacent building elements.Most of these "cold bridges" bend locations found in the surface of the building: its corners, protruding balconies, canopies and bay windows.With regard to the flat roof, the geometric "thermal bridges" often appear in their attics.

Material "cold bridges" arise where there had been in the construction of a combination of low- and highly conducting materials.

problem is that visually "cold bridges" is not usually defined, and heat engineering defects detected only with the thermal imager.Thermal - opto-electronic measuring device designed for non-contact monitoring and recording of temperature distribution investigated surface.In the construction and utilities, it is used to evaluate the thermal insulation properties of structures - with the help of a thermal imager can be quickly and clearly identify areas of heat loss in buildings.However, such a device is quite expensive (from 100 thousand. Rubles), and they only have a professional construction company.

Increased heat transfer through the "bridges cold" leads to a number of negative consequences.The first of them - excessive loss of heat, which can reach 50%, as a consequence - a significant increase in the cost of building maintenance.Also, the presence of "cold joints" can lead to the formation of condensate, and it in turn - the appearance of mold.But that's not all: with a large number of "cold joints" there is a possibility of deformation of the building and reduce its service life as a result of non-uniform stress.

solutions to avoid "cold bridges»
Fortunately, modern technology allows a large number of cases, to avoid the appearance of "cold bridges".So, one of the most common causes of "cold bridges" are anchors, which is attached to the roof insulation.To avoid the seemingly inevitable heat loss in this case is still possible, if used as a stone wool insulation.So, to prevent the emergence of "cold bridges" You can renounce the use of anchors - will be enough to glue, which, however, need to carefully choose: it is necessary to bond strength was higher than the tensile strength of the heat-insulating material in layers.In other instances, the fastener would not be "cold bridges" because of design features: for fixing stone wool is necessary to use a special plug for insulation with plastic core (sleeve).This design eliminates the possibility of fixing the increase of heat loss in the attachment plates of stone wool.Also, avoid unnecessary heat loss can be by using two-layer insulating ceilings.When the device flat roof made of traditional materials there is the possibility of errors due to the action of the human factor: each of the two layers of the modern roof it must be laid perfectly, which is possible only if there is a lot of experience in producing the work of specialists, particularly need to take care of the joints plates.The use of double-layer thermal insulation materials twice simplifies the process and eliminates the "cold bridges" formed in the joints of insulation boards: the joints of the lower layers of the upper plates overlap.

If the slab of stone wool used in large formats, manages to minimize the number of joints between the boards and thus considerably reduce the heat loss.

There is a rule that should cover the heater plate vertically arranged layer of thermal insulation of the walls.In this case also possible to avoid "cold bridges".

Finally, to the roof to have a truly warm, even at the stage of its design should use special correction factors that take into account the impact of possible "cold bridges".This technique is used in the design of the building.