The external wall insulation technology has been applied in foreign countries for a long time, and has withstood the test of various climatic environments. There are still some differences in the application of technology under different climatic conditions, such as cold regions and severe cold regions. We will introduce below. It is also the application of external wall insulation technology in these two climates.
The external wall insulation system is composed of a composite external wall insulation system and a single material external wall insulation system. The composite external wall insulation system is composed of a base layer, a bonding (anchor) layer, an insulation layer, a protective layer and a decorative layer. In addition, there are internal insulation, external insulation and sandwich wall insulation systems. These external wall insulation systems have been or are being applied in cold and cold areas.
The climatic characteristics of cold and severe cold regions are cold in winter (the coldest month average temperature is 0～10°C and <-10°C), the building's outer structure is subjected to low temperature and wind and snow intrusion, and the summer is hot, and the building's outer structure is protected. High temperature and intrusion of solar radiation and rain. The requirements for building energy-saving design standards for external wall insulation performance are also higher than those of other regions. Therefore, the requirements for external wall insulation systems are that they can withstand the changes of external natural environment temperature and humidity for a long time, under the influence of solar radiation and rain, snow and wind. The properties of the various layers of the system are stable and do not cause any damage and loss of function. The materials for each layer have their own performance requirements according to their functions, but they are influential and related to each other.
For the composite exterior wall insulation system, the role of this layer is to ensure the safety of the system. Although the composite external wall insulation system does not undertake the task of structural load bearing, it should also have sufficient mechanical properties to withstand the effect of the system's own weight on the negative wind pressure. The main structure is deformed normally and has sufficient safety reserves to ensure that it does not crack or fall off during the service life. The technical indicators are reflected in the tensile strength of the adhesive material and the base layer and the insulation layer under normal temperature and water resistance conditions, the bonding area, the pullout resistance of the anchor, the anchoring depth, the number of anchors and the anti-rust treatment of the anchor. .
Insulation layer is the main material layer that meets the requirements of building energy-saving design. It is the object of protection. Firstly, it should have good thermal performance. At the same time, it should have certain strength due to the correlation with other layers to achieve the stability of overall performance. The technical indicators are reflected in the thermal conductivity, thermal resistance, apparent density, dimensional stability, water vapor permeability coefficient and water absorption of the thermal insulation material.
The protective layer of the external thermal insulation system is not affected by the outdoor environment indoors. Therefore, it is only required to avoid the exposure of the thermal insulation material and maintain its characteristics under the impact of normal use conditions. The protective layer of the external thermal insulation system shall bear the effects of resisting outdoor temperature and humidity changes, solar radiation and rain, snow and wind, and ensure the impact of the system under normal use conditions and the accidental impact of general accidents. No damage is caused, and the entry of outdoor moisture occurs when the maintenance equipment is supported thereon without causing cracking or perforation of the protective layer.
The technical indicators are expressed in the tensile strength, compressive strength, flexibility and compatibility with the insulation layer and the facing layer under normal temperature, water resistance and freeze-thaw resistance. And the performance requirements of the reinforcement material.
Let us introduce the application of the outer wall insulation technology in the decorative layer, which is different from the direct installation on the main structure, the bonding property with the protective layer under weathering conditions, water resistance, alkali resistance and compatibility.
This is an external thermal insulation system for public buildings. Since the promulgation and implementation of the national standard “Energy Efficiency Design Standard for Public Buildings”, the insulation of the external walls of public buildings has become one of the main contents of energy conservation in public buildings. The standard design atlas "Energy-saving construction of public buildings", there are many types of public buildings, most of which can be applied to the external wall insulation system of residential buildings, but the external wall insulation of large public buildings has its characteristics, one feature is the variety of exterior decorative materials. The metal plate, the pressure cement board, the clay board, the stone, etc. are fixed on the main structure of the outer wall by the keel, and form a certain air layer with the heat insulating material. There are also closed and ventilated, another feature is the wide range of applications of insulation materials, organic materials - molded polystyrene board, extruded polystyrene board and polyurethane, inorganic materials - glass wool, rock (mine) cotton and foam The glass can be fixed to the outer wall by bonding and anchoring. If the outer decorative material of the opaque curtain wall and the heat insulating material are sealed, the water vapor permeation path should be left, or the steam insulation material should be provided on the indoor side. The air layer between the materials is ventilated and ventilated. The windproof, moisture-proof and ventilating measures should be taken on the outside of the thermal insulation material. Some curtain wall design is used to set a metal plate for the windproof and moisture-proof materials outside the thermal insulation material, although it has played a windproof The role of moisture protection, but blocking the passage of water vapor permeation, so that the insulation material is affected by moisture. In fact, the practice of the South is used in the northern region. Effective wind, moisture and venting construction measures or materials should be adopted in cold and severe areas. Windproof and breathable membranes are one of the options.
Another point is the treatment of the "cold bridge" of keel formation. Firstly, the thermal insulation material should be tightly fixed to the outer wall by means of bonding and anchoring, and should not be floated between the keels. Under the premise of ensuring safety, a strong thermal insulation material is arranged between the keel or the fixing member and the wall. On the other hand, in calculating the heat transfer coefficient of the opaque curtain wall exterior insulation system, it should be corrected according to the size and spacing of the keel and the treatment method of the "cold bridge".
The basic process of the prefabricated thermal insulation board exterior insulation system is to combine the protective layer and the outer decorative layer with the thermal insulation material into a thermal insulation decorative insulation board or a prefabricated thermal insulation board which does not include the outer decorative layer, through bonding and anchoring. The method is to fix and assemble the insulation board on the outer wall. The protective layer is made of a metal plate or a pressure cement plate.
This type of exterior insulation system is characterized by industrial production, the quality and performance of the protective layer and insulation materials are easy to control, and the construction process is simple. However, compared with the practice of polystyrene board reinforced polymer mortar, the strength of bonding and anchoring of this system to the wall should be higher, and the insulation between the board and the board should be continuous. If there is a “cold bridge”, the overall insulation should be maintained. Performance is corrected. And handle the waterproofing of the seams.
As can be seen from the above, our emphasis on building insulation construction, the market space of external wall insulation materials is also increasingly broad, although due to the short development time of our external wall insulation technology, and the real estate business awareness of energy conservation and environmental protection is weak, the economy is relatively backward The region is less used. As the country distributes mandatory building energy policies, more companies are beginning to focus on and invest in the building exterior insulation market.
Source: mortar and insulation