How to achieve the required construction quality of the external wall insulation construction method
Some improper methods in the design, construction and other aspects of the external wall insulation system cause problems in construction quality. So, how can we make the building insulation to meet both the insulation requirements and the construction quality requirements?
First of all, because the external insulation keeps the building structure in the protection of the insulation layer, the temperature environment of the building structure is stable, which is conducive to the protection of the building structure and enhances the durability. In addition, the external insulation will be wrapped outside the building, a large area of ??insulation, more conducive to insulation and energy saving. With regard to the problem of external wall insulation cracking, we can improve the external insulation materials and construction methods to achieve the required construction quality.
The specific method is as follows:
The external insulation of the building should be the entire external insulation of the entire building
Due to incomplete external insulation, cracks occur in components such as the awning of the building. Therefore, in order to avoid cracks, the building should be fully insulated, including awnings and other components.
The main reason for external wall insulation cracking is due to the difference in the linear expansion coefficient between the insulation material and the exterior decoration material. The principle of our prevention of cracks is: by reducing the external insulation material of the building structure with the external decoration, leveling the mortar, the outer surface and other materials The linear expansion coefficient ratio is a gradual layer-by-layer gradient between materials, and flexible release of stress to play a role in preventing cracks.
Insulation material selection
In the construction currently under construction, the use of heat-insulating materials is mainly based on dense benzene board, polystyrene board, and polystyrene heat-insulating material. Compact benzene board has the advantages of high density, small thermal conductivity, etc. Its thermal conductivity is 0.029W/mK, and the thermal conductivity of cracking mortar is 0.93W/mK）。 The thermal conductivity of the two materials is different by 32 times, while The thermal conductivity of the benzene plate is 0.042 W/mK, which is 22 times that of the anti-crack mortar. Therefore, compared with the polystyrene board, the crack resistance of the benzene board is weaker than that of the polystyrene board. Polyphenylene granules as the main raw material of the thermal insulation material is made of rubber powder and rubber powder polyphenylene granules, and the powdered powder material as the binding material of polyphenylene granules is generally used slaked lime powder - fly ash - silicon powder - cement is The main component of the inorganic gelling system, the thermal conductivity of such materials is generally 0.06W/mK, a 16-fold difference compared with cracking mortar. Compared with compact benzene plates and polyphenylene plates, the thermal conductivity of this kind of material is much smaller, so it can alleviate the accumulation of heat in the anti-crack layer, and the system can be released quickly due to the thermal load and stress caused by sudden temperature changes. Improve the durability of crack resistance.
Enhanced network choice
The application of glass fiber mesh cloth as a key reinforcement material for crack resistance of the crack protection layer in the external thermal insulation technology has been rapidly developed. On the one hand, it can effectively increase the tensile strength of the protective layer, and on the other hand, it can effectively disperse. Stress, the original cracks can be dispersed into many finer cracks, thus forming a crack resistance. As the outer protective cracking mortar of the insulation layer is alkaline, the long-term alkali resistance of the glass fiber grid cloth has a decisive significance to the cracks. From the durability analysis, the high alkali-resistant fiber mesh cloth is much more durable than the alkali-free mesh cloth and the alkali-base mesh cloth, and it can meet at least 25 years of use requirements. Therefore, the selection of the enhanced network is It is recommended to use a high alkali-resistant mesh cloth.
Protective layer material selection
Due to the high strength of the cement mortar, large shrinkage, and insufficient flexibility deformation, it directly acts on the outside of the insulating layer, resulting in poor weatherability and cracking. In order to solve this problem, special anti-cracking mortar must be used and supplemented with a reasonable reinforcement net. The appropriate amount of fiber should be added to the mortar. The cracking resistance of the anti-crack mortar is less than 3. If the exterior facing is a tile, the steel wire mesh light can also be added to the cement crack resistance mortar. The hole spacing of the steel wire mesh should not be too small and should not be reached. The short side of the tile should cover at least two holes on the Internet. Wire mesh should use anti-corrosion hot galvanized steel wire mesh.
No cavity structure improves system stability
In the design of polystyrene board for external insulation, the insulation layer is mainly subjected to gravity and wind pressure. Due to the limitation of the strength of the polystyrene board, the insulation layer is cracked or even shed. In order to increase the strength of the insulation board, the bonding area should be increased as much as possible, and no cavity is used to meet the requirement of wind pressure destruction.
Building external wall insulation is an emerging construction method in recent years. Because of the defects in the design of internal insulation, mixed insulation and other methods, it is recommended to use external insulation, and in accordance with the principle of layer-by-layer gradual and flexible release of stress, choose materials and construction methods. To achieve the purpose of insulation and crack resistance. Since the external wall insulation system is an organic whole, the synergy of the various related layers required not only requires a gradual change in flexibility, but also a certain degree of compatibility and synergy to form a composite whole.
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