Disadvantages: The insulation effect is poor (because the insulation layer is not completely covered), and there will be condensed water (because the cold insulation layer of the wall is hot, and the temperature difference between inside and outside forms condensed water), which will affect the decoration (the insulation layer is inside, and the wall decoration will destroy the insulation layer during decoration) and affect the interior area of the suite (the calculation rule of building area).
Advantages of external thermal insulation: good thermal insulation effect and no occupation of indoor space.
Disadvantages: high cost, difficult construction (especially for high-rise buildings) and high technical requirements, which affect the external wall decoration (high technical requirements for external wall bricklaying).
External wall insulation 1. Definition: refers to the engineering practice of adopting certain fixing methods (bonding, mechanical anchoring, pasting+mechanical anchoring, spraying, pouring, etc.). ) Fix the thermal insulation material with low thermal conductivity (good thermal insulation effect) with the building wall to increase the average thermal resistance of the wall, so as to achieve the effect of thermal insulation or heat insulation.
Second, compare the advantages and disadvantages of commonly used thermal insulation materials.
1 expanded polystyrene board (EPS board)
The thermal conductivity is 0.038-0.04 1, with good thermal insulation effect, low price and slightly poor strength.
2 extruded polystyrene board (XPS board)
Thermal conductivity of 0.028-0.03 has good thermal insulation effect, high strength, moisture resistance and high price, and the surface needs to be treated during construction.
3 rock wool board
The thermal conductivity is 0.04 1-0.045, and it is fire-proof, flame-retardant, moisture-absorbing and poor in heat preservation.
4 rubber powder polystyrene particle thermal insulation slurry
The thermal conductivity is 0.057-0.06, which has good flame retardancy, unsatisfactory heat preservation effect of waste reuse and high construction requirements.
5 polyurethane foam material
Thermal conductivity of 0.025-0.028, good waterproof performance, good thermal insulation effect, high strength and high price.
6 Perlite and other mud
Thermal conductivity of 0.07-0.09, good fire resistance, poor high temperature resistance and heat preservation effect, and high water absorption.
Third, the development of external wall insulation in foreign countries:
External wall thermal insulation system is called EIFS system abroad, that is, external wall thermal insulation decoration system. It can provide excellent energy utilization efficiency and high design flexibility and creativity; It is a light, environment-friendly and non-load-bearing building wall system, which has the effects of energy saving, heat preservation, sound insulation and decoration.
It began to be used in Germany after World War II and was introduced to the United States 60 years later. After the world oil crisis in 73, it was paid attention to and began to be widely used.
The successful application of various external wall insulation technologies in some developed countries such as Europe and America for nearly 30 years shows that the application of external wall insulation-decoration system in the field of building energy conservation is safe, reliable, economical and has good social benefits as long as the materials are properly selected, the formula is reasonable and the construction is strictly standardized.
Fourth, the development and application of external wall thermal insulation technology in China:
The research of wall thermal insulation material technology began in the early 1980s, mainly in scientific research institutes, mostly for internal thermal insulation technology;
In the early 1990s, foreign enterprises began to enter China to guide government decision-making, introduce technology and carry out pilot projects.
In the middle and late 1990s, a group of local enterprises with vision began to study technology and constantly improve technology and materials.
In the late 1990s, it was widely used in Beijing and Northeast China. Among them, Beijing accumulated 50 million m2;
Since 2005, all provinces and cities in severe cold areas, transitional areas and hot summer and warm winter areas have enforced the standard of 50% energy saving.
On June, 2006, 65438+ 10/day, the Regulations on Energy Efficiency Management of Civil Buildings came into effect.
In 2006, the Sino-German cooperative renovation of existing buildings was successfully piloted in Tangshan, Hebei Province.
June, 5438+October, 2007 10, the state issued a document, requiring new buildings all over the country to be insulated and existing buildings to be rebuilt within a time limit.
Five, the form of external wall insulation and its advantages and disadvantages
1. External wall insulation form
Single material thermal insulation external wall: aerated concrete, sintered thermal insulation brick.
Composite thermal insulation external wall:
According to the different setting positions of thermal insulation materials, it can be divided into internal thermal insulation,
External wall insulation and sandwich insulation external wall.
Others: thermal insulation blocks, etc.
2. External wall internal insulation technology
Thermal insulation in the wall is to place thermal insulation materials on the inner side of the outer wall.
Advantages:
1) The requirements for waterproof and weatherability of facing and thermal insulation materials are not very high, so gypsum board and plastering mortar can meet the use requirements, and the materials are convenient;
2) Internal thermal insulation materials are separated by floor slabs, and construction is only within a height range, without scaffolding;
3) In areas with hot summer and cold winter and hot summer and warm winter, internal insulation can meet the requirements;
4) For the energy-saving renovation of existing buildings, especially if it is difficult to unify the renovation of the whole building or the whole community after the house is sold to individuals, it is only possible to adopt internal insulation. Therefore, in recent years, external wall internal insulation has also been widely used.
Disadvantages:
1) Because of ring beam, floor slab, constructional column, etc. It will cause thermal bridge and large heat loss;
2) Due to material, structure, construction and other reasons, the facing layer is cracked;
3) it is inconvenient for users to carry out secondary decoration and hanging ornaments;
4) occupying indoor use space;
5) The energy-saving renovation of existing buildings will greatly interfere with the daily life of residents.
6) The wall is greatly influenced by the outdoor climate, and the temperature difference between day and night and between winter and summer is large, which is easy to cause the wall to crack.
3. Exterior wall sandwich insulation technology
Exterior wall sandwich insulation is to place insulation materials between the inner and outer wall sheets of the exterior wall, and the inner and outer wall sheets can use concrete hollow blocks.
Advantages:
1) can effectively protect the interior wall and thermal insulation materials, and has low requirements for the selection of thermal insulation materials, such as polystyrene, glass wool and urea-formaldehyde on-site casting materials;
2) The requirements for the construction season and conditions are not very high, which will not affect the winter construction. It has been used in cold areas such as Heilongjiang, Inner Mongolia and northern Gansu.
Disadvantages:
1) In the non-severe cold area, this kind of wall is thicker than the traditional wall;
2) The inner and outer wall panels need to be connected by connectors, which is more complicated than the traditional wall;
3) There are many "thermal bridges" in the shell. In the earthquake area, there are many "thermal bridges" in the setting of ring beams and structural columns of buildings, and the efficiency of thermal insulation materials has not been fully exerted.
4) The external wall is greatly influenced by the outdoor climate, and the temperature difference between day and night and between winter and summer is large, which is easy to cause wall cracking and rainwater leakage.
4. Heat insulation block
5. External thermal insulation technology of external wall
Advantages:
1) has a wide application range and is suitable for building insulation in different climatic zones;
2) the heat preservation effect is obvious, and the influence of "thermal bridge" is small;
3) it can protect the main structure and greatly reduce the influence of natural temperature, precipitation and ultraviolet rays on the main structure;
4) it is beneficial to improve the indoor environment;
5) Expand the indoor use space. Compared with internal thermal insulation, the use area of each household is increased by about1.3 ~1.8m2;
6) It is beneficial to the renovation of old houses and has little interference to people's daily life.
7) It is convenient to enrich and beautify the facade.
1. External insulation
External insulation materials include rock (mineral) wool, glass wool felt, polystyrene foam board (EPS and XPS for short), ceramsite concrete composite polystyrene imitation stone decorative insulation board, steel wire mesh sandwich wallboard and so on. Among them, polystyrene board has been widely used in external wall thermal insulation plug-in technology all over the world because of its excellent physical properties and low cost. Extrapolation technology is to use bonding mortar or special fasteners to stick the thermal insulation material on the external wall, then apply anti-crack mortar, press glass fiber grid cloth to form a protective layer, and finally add it as a decorative surface.
Another way is to fix all kinds of insulation boards that are not easy to absorb water on the external wall with special fixing pieces, and then hang aluminum plates, natural stones, colored glass and so on. The decorative surface is directly formed on the precast keel. This design is used for the external insulation of the office building of China Bank Head Office designed by Mr. I.M. Pei. This kind of external insulation installation takes a long time, the construction is difficult, and the construction takes up the dominant construction period, and the construction can only be carried out after the main body is accepted. In the construction of high-rise buildings, the safety of construction workers is not easy to be guaranteed.
2. The polystyrene board and the wall are cast in one step.
In this technology, polystyrene board is built into the building template in the concrete frame-shear system, outside the wall to be poured, and then concrete is poured, and the concrete and polystyrene board are poured into a composite wall at one time. This technology solves the main problems of external wall insulation and has obvious advantages. Because the main body and insulation layer of the external wall survive once, the work efficiency is improved, the construction period is greatly shortened, and the safety of construction personnel is ensured. Moreover, in winter construction, polystyrene board plays the role of heat preservation, which can reduce the external heat preservation measures. However, when pouring concrete, attention should be paid to uniform and continuous pouring, otherwise, due to the influence of concrete lateral pressure, polystyrene board will be deformed and dislocated after formwork removal, which will affect the subsequent construction.
We have conducted an experimental study on the one-time molding of meshless concrete polystyrene composite wall. The test results show that it is completely possible to directly use concrete as adhesive to stick polystyrene board under the condition that the amount of cement slurry in concrete is appropriate. When we treat the back of polystyrene board, its adhesion with concrete is further improved (its average adhesion strength can reach 0.07Mpa, and the failure occurs on polystyrene board). This technology cancels the steel wire mesh frame, improves the thermal insulation performance and reduces the cost of the plate. After demonstrating its long-term durability, it can be popularized in engineering.
3. Exterior wall insulation with polystyrene particle thermal insulation slurry
Waste polystyrene plastics (EPS for short) were crushed into 0.5~4mm particles, which were used as lightweight aggregate to prepare thermal insulation mortar. The technology includes insulation layer, anti-crack protection layer and anti-seepage protection surface layer (or anti-seepage and anti-crack mortar layer on the surface layer). Among them, ZL rubber powder polystyrene particle insulation material and technology were listed as national construction method by the Ministry of Construction 1998. This construction method is widely regarded as external wall insulation technology.
The construction technology is simple, which can reduce the labor intensity and improve the work efficiency. Not affected by structural quality differences, the defective wall does not need to be repaired and leveled, but can be directly repaired with thermal insulation slurry, which avoids the phenomenon that other thermal insulation construction processes fall off due to too thick leveling and plastering. At the same time, this technology has solved the problems of easy debonding and hollowing of interface layer and easy cracking of surface layer caused by poor service conditions in external wall thermal insulation engineering, and achieved an important breakthrough in external wall thermal insulation technology. Compared with other external insulation, the cost is lower, and the construction cost can be reduced under the condition of achieving the same insulation effect. For example, compared with polystyrene board external insulation, 25 yuan can be reduced per square meter. This technology was adopted in the high-rise external wall insulation project of Yunlang New Residence in Tianjin. In addition, in the energy-saving thermal insulation wall technology, the wall is made into an interlayer, and perlite, sawdust, mineral wool, glass wool, polystyrene foam plastic and polyurethane foam plastic (which can also be foamed on site) are filled in the interlayer to form the thermal insulation layer.
Second, the external wall thermal insulation and energy-saving materials
Commonly used thermal insulation materials mainly include: polystyrene foam plastic board (EPS and XPS), rock (mineral) wool board, glass wool felt and ultra-light polystyrene particle thermal insulation slurry. All the above materials have a common feature, that is, there are a large number of closed pores in the materials, and the apparent density is small, which is also necessary as thermal insulation materials.
Rock (mineral) wool and glass wool are sometimes collectively referred to as mineral wool, both of which belong to inorganic materials. Rock wool does not burn and its price is low. It can not only meet the thermal insulation performance, but also have a certain sound insulation effect. However, the quality of rock wool is uneven, the density with good thermal insulation performance is low, the tensile strength is low and the durability is poor.
Glass wool and rock wool have many similarities in performance, but their handfeel is better than rock wool, which can improve workers' working conditions. But its price is higher than rock wool.
Polystyrene foam is a kind of material with many closed micropores, which is made of polystyrene resin as the main raw material and foamed by foaming agent. It has the advantages of low apparent density, low thermal conductivity, low water absorption, good sound insulation, high mechanical strength, high dimensional accuracy and uniform structure. Therefore, it occupies a high share in external wall insulation.
Decorative thermal insulation decorative board with organic material and metal on the surface. Commonly used is metal decorative insulation board. It is also an excellent material on the market. See the website: /00 1xhj for specific parameters and introduction.
Verb (abbreviation of verb) external wall insulation system
A.JCTA-950 inorganic thermal insulation mortar system
1, system introduction
JCTA-950 inorganic thermal insulation mortar is a new type of thermal insulation and energy-saving mortar material for building interior and exterior walls. Inorganic lightweight thermal insulation particles are used as lightweight aggregate, and dry powder mortar composed of cementing materials, stone powder, anti-cracking additives and other fillers is added.
2. A new inorganic thermal insulation material-vitrified microbeads
Vitrified microspheres have an irregular spherical structure and a closed shell, but they also have a microporous structure and a glassy surface. It has the remarkable characteristics of light weight, heat insulation, fire prevention, high temperature resistance, aging resistance and low water absorption.
3. Advantages and characteristics
1. With vitrified inorganic beads as the main energy-saving material, it has high strength and low water absorption, which overcomes the phenomena of high water absorption, easy powdering, large volume loss during slurry mixing, easy to cause the later thermal insulation performance of products to decrease, hollowing and cracking.
2. As an inorganic thermal insulation material, vitrified microspheres have Class A incombustible combustion performance, which makes up for the defects of poor fireproof performance, low aging resistance, low weather resistance, large construction rebound and easy to be eaten by insects and ants.
3. Vitrified microbead thermal insulation mortar is a kind of one-component thermal insulation material, with stable and reliable quality, good cohesiveness, early strength and quick drying, short construction period and easy guarantee of construction quality, which greatly reduces the cost of thermal insulation system and reduces the construction process and labor intensity.
Inorganic thermal insulation mortar has good crack resistance, fire resistance and weather resistance, and has strong ability to resist the erosion and destruction of thermal insulation layer by external environment in application, so the product has long service life and can be applied to internal and external wall thermal insulation and energy-saving projects.
4, the implementation of standards and dosage
Shanghai implements Type 80 requirements in DB3 1/T366, while other provinces and cities implement GB20473 requirements. Generally, the water-cement ratio is1:1.1~1.3, and the dosage per square meter with a thickness of 3 cm is about 12.5Kg.
Step 5 write a composition
Table 3.1.5 Composition of JCTA-950 Inorganic Thermal Insulation Mortar System
Decorative interface layer, insulation layer, protective layer and decorative layer.
Coating finish JCTA-400F JCTA-950(SB- 1 anti-seepage agent) JCTA-920A+ grid cloth +JCTA-920A JCTA-600-4+
WB-2-4+ coating
Brick facing JCTA-920A+ grid cloth +JCTA-920A+ anchor JCTA-900- 1A+
JCTA-360F
As shown in the above table:
2.6, authentication and application
JCTA-950 inorganic thermal insulation mortar won the certificate of transformation of scientific and technological achievements in 2007, key new products in Shanghai in 2006 and product promotion in Shanghai, Zhejiang, Jiangxi, Anhui, Guangzhou and Shenzhen. The novelty retrieval work of Shanghai Institute of Science and Technology Information has reached the leading level in China.
At present, it has been successfully applied to many projects such as Changjiang Business Center, Jinsha Yayuan, Film Garden, Xingye Square, Jebsen International Apartment, Maanshan, Zhenjiang and so on, and has been widely praised by users. The technical specification of JCTA-950 inorganic thermal insulation mortar application is compiled, and the construction method, nodes and details are defined, which ensures the construction quality of external wall thermal insulation.
B.JCTA-920 polystyrene particle thermal insulation mortar system
1 system introduction
The exterior insulation system of rubber powder polystyrene particle exterior wall is a structural system set outside the exterior wall, which is composed of interface layer, rubber powder polystyrene particle insulation layer, anti-crack protection layer and decoration layer, and plays the role of insulation, protection and decoration.
2 System functions:
1. The thermal insulation effect is good, and the thermal conductivity is less than 0.06.
2. Light deadweight, dry density 180 ~ 250.
3. The thermal insulation mortar has high strength, and its compressive strength is above 0.4 MPa.
4. Good weather resistance and long effective service life. At present, it has a wide range and is a mature product.
5. When in use, just add water and stir, with convenient construction, low cost and high cost performance.
3. The system structure is divided into coating veneer and ceramic tile veneer.
Table 3. 1.3 JCTA-920 polystyrene particle thermal insulation mortar system structure
Decorative interface layer, insulation layer, protective layer and decorative layer.
Coating finishing JCTA-400F JCTA-920 JCTA-920A+ grid cloth (standard) +JCTA-920A+ anchor JCTA-600-4+
WB-2-4+ coating
Brick facing JCTA-920A+ grid cloth (reinforcement) +JCTA-920A+ anchor JCTA-900- 1A+
JCTA-360F
JCTA-400F is specially developed for thermal insulation mortar system to prevent hollow drum and shell formation of thermal insulation mortar base. Sawteeth must be pulled during construction, and thermal insulation mortar can be constructed at the same time.
JCTA-920 thermal insulation mortar can be made into 3 cm thick and 3.6 square meters by mixing 22 kg rubber powder+154 liter polystyrene particles +24 kg water. 1 cubic rubber powder particles can be used to make insulation mortar with a thickness of 3cm and about 24㎡.
JCTA-920A is a flexible polymer modified plastering material, which has strong crack resistance and plays a good role in protecting thermal insulation mortar. Compression-folding ratio ≤3.0.
JCTA-900- 1A thermal insulation system has good flexibility and bonding performance. JCTA-360F caulking agent is used to bond ceramic tiles, which is flexible, breathable, hydrophobic and alkali-free.
JCTA-920 system was tested according to the industry standard JG 158-2004, and passed large-scale tests such as wind pressure resistance and weather resistance, as well as a number of provincial promotion certificates. Has a strong scientific research force and inspection equipment synchronized with the Academy of Sciences. Raffles city, Yijing Yayuan and Jinsha Yayuan all adopt JCTA-920 system.