Bridges of cold: what it is, features and elimination
Cold bridges are also called temperature bridges and represent a section of the building envelope which has a reduced thermal resistance. Among these sites, you can select the joints of the walls and the end of the concrete element. This should include the joint between the structural element or parts of the structure, which are based on materials characterized by a greater degree of thermal conductivity.
These areas are cooled more than other parts of the fence, so they are called cold bridges. Their presence reduces the effectiveness of thermal protection of the building. This circumstance acts as a cause of condensation. And as you know, moisture can cause many problems when it comes to the question of its impact on materials.
Description of cold bridges
Temperature bridges can be material or geometric.The latter occur in those places where the heat-absorbing inner surface is smaller compared with the exothermic outer surface. There are such bridges in the bends of surfaces, namely on:
- bay windows.
Material bridges appear when using high and low heat conductive materials. You can find them with a thermal imager. As examples of cold bridges should be highlighted:
- door and window lintels;
- concrete elements in block or brickwork;
- thermal insulation fastening elements, for example, dowels and racks in frame houses;
- space between the slab and balcony slab.
Temperature bridges can adversely affect the building, as a result, there is a likelihood of condensate formation and accumulation, increased energy consumption for heating, there is a risk of damage to building elements and the risk of fungus formation with health risks. Prevent the formation of cold bridges by arranging the surround double frame, which will have offset racks, as well as the introduction of effective thermal insulation of the type of mineral wool.
Features of temperature bridges
Temperature bridges have the main features that consist in the occurrence of moisture on the walls from their inner side. Among other things, bridges may indicate cracks in the plaster layer. Black mold appears on the wallpaper when peeling off. Doors and windows are the weakest points because it is heat that escapes through them.
Thermal parameters of windows are worse than the walls, due to design features. In short, any window is a temperature bridge. The gaps between the walls and windows is important to properly seal. It is necessary to choose a double-glazed window and frame, as well as a professional approach to installation. The window construction with the wall must be well-fitted and sealed. The joints should be filled with foam or heat insulation.
Work on the elimination
Warming of cold bridges is carried out in several ways. Outside the house must be insulated with a continuous layer of material, namely:
- polystyrene foam;
- mineral wool;
- gas concrete slabs.
A rather effective material for eliminating temperature bridges isextruded polystyrene foam. It is used for local insulation of the basement, jumpers and monolithic belts. The elimination of cold bridges should also be carried out in modern houses, which are distinguished by quite impressive energy efficiency. Temperature bridges here are places of the walls, which have a heat transfer coefficient of 0.3 W / m2° С and more.
If you want to achieve a more effective result, then eliminate the temperature bridges needed at the design and construction stage of the house, and not during its operation. In order for the insulation layer on the walls not to burst and not to collapse, the insulation should be laid in two layers so that the joints of the first layer are blocked.
Fighting temperature bridges in the area of openings
Eliminating cold bridges in the premises, you should pay attention to the window openings. It is necessary to seal the window under the window sill and around the perimeter. Its typical size should be equal to 1.5x1.5 m. If the house has an average size, then there should be about 10 windows in it and no more. In this case, the length of the cold bridges can be significant, so there is something to fight with.
In energy-efficient homes to seal the openings should use a three-layer system, which consists of an internal protective layer from moisture, the middle insulation layer and the outer layer. The first may consist of silicone and tape, the second - from polyurethane foam, while the third - from foil and tape.
About temperature bridges in the walls
Metal bridges of cold can cause mold and mildew, as well as corrosion of the material. To prevent their presence during construction, metal and high-heat conductive structures should be avoided, which could become part of the walls from the street. It is important to calculate the length of fasteners when installing antennas, gutters and air conditioners. This parameter should not be so large that the element reaches the boundary of the formation of dew in a wooden wall or brickwork.
In the latter case, the temperature bridge may be the seams. In order to make them warmer, the solution should be made less thermally conductive using perlite sand. If the walls are laid out from the foam block, claydite-concrete blocks or gas silicate products, the heat-saving indicators fit into the standards. In this case, the blocks should have a thickness in the range from 40 to 50 cm.
However, in such a wall will be a huge number of cold bridges in the form of seams of cement mortar. The wall in this case must be insulated. The warm construction can also be obtained from claydite-concrete blocks, which are made according to the thorn-groove system. In this case, thermal insulation is not required.
Temperature bridges on the balcony
If you want to get a house without cold bridges, then you should think about the insulation of the balcony. Architects often complement homes with loggias and balconies, because these elements are considered functional and attractive. This would be fully so if the reinforced concrete slab, on which the described construction rests, did not act as the most common solution during construction. In this place there are bridges of rather impressive length.
The damage caused by them is often compared with the effect of an unheated wall, the length of which can reach 6 m. In depth of the room, the effect of such bridges can extend to 1 m. , also on the ends.The attractiveness of such a plate will be very doubtful, and the mounting points of the balustrade posts will still become places for the emergence of cold bridges. In order to eliminate such a temperature bridge, the balcony plate must be supported on independent pillars, in which case it will be possible to use any material, such as:
Thermal bridges can be avoided if you remember that the insulation layer should be located over the entire outer surface of the wall. In addition, it must be continuous. To achieve the maximum effect of energy saving, it is necessary to observe the principle of a closed thermal circuit, which excludes the presence of unprotected areas. In theory, this rule seems simple, but in practice it is not always possible to observe it.
The most unreliable in this matter are the joints of the walls with the roof and floors, as well as the slopes of the windows and those places that are located under the window sills. The reason for the temperature bridge may be a loose fit of the material and not enough impressive thickness of the insulating layer.