At present, as the country vigorously promotes energy-saving and emission-reduction and builds a general trend of conservation-oriented society, building energy-saving as a large-energy-consuming household also has a relatively rapid development, and insulation mortars for various types of external walls are convenient for construction and have a good Thermal insulation effect, so there is more use in the external wall energy-saving project. However, due to specific reasons, the strength of insulation mortar is lower than that of ordinary mortar. At the same time, the insulation layer is relatively thick and has a large porosity. Therefore, once the exterior wall has leakage, it is relatively difficult to determine the leakage. Source, therefore, the key to the prevention of seepage in the application of insulating mortar walls falls on the quality of the external wall construction and construction. In the following, the construction method of the external wall thermal insulation mortar and the anti-crack mortar used for a project constructed by our company effectively increases the anti-leakage effect of the external wall, and combines the thermal insulation mortar and the waterproof material together. A beneficial attempt has been made to improve the anti-leakage effect of the external walls for your reference.
1 Project Overview
The Shuimuyishan project is located in Meilin, Shenzhen. It is a high-rise residential building developed and constructed by our company. The project has a total construction area of ​​65307m2. It consists of a 34-story and a 31-storey high-rise residential building with an external wall construction area of ​​8.2. Million m2, the external wall of the building is decorated with exterior paint, and according to the building energy-saving requirements, the external wall insulation measures are 30mm thick inorganic hollow glass beads insulation mortar. Because the project is located at the height of Meilin, and the surrounding buildings are lower than it and at the same time, it is in a special position. Therefore, when the project is under investigation, the external wall of the project needs to withstand greater wind pressure. The problem of leakage prevention, and the practice of adding insulating layers to the external walls will make it difficult to determine the source of the leakage once the leakage occurs. Therefore, the project's external wall anti-seepage work is a major focus and difficulty of this project.
2 Determine the external wall insulation and strengthen the waterproof construction practices
1) It is determined that the insulation mortar material with relatively high strength is determined by the design company and our company through market inspection and it is determined that this project shall be used in the two types of mortars: polystyrene insulation mortar and inorganic insulating glass insulation mortar insulation mortar. The external wall insulation mortar, through the comprehensive comparison of the indicators of these two types of mortar and combined with the characteristics of the project, we selected the compressive strength, bonding performance and the finished product mortar density is relatively high, more conducive to anti-leakage Inorganic hollow glass beads insulation mortar is the wall insulation material of this project. 2) In order to prevent leakage of thermal insulation mortar cracks and weak places such as construction joints, and to ensure that our entire outer wall is free from leakage and other quality defects as much as possible under strong wind pressure conditions, we decided to use insulation mortar. A 1mm thick polymer cement-based water-repellent coating is applied on the surface of the same brand of crack-resistance mortar with a thickness of 5mm on the surface as a waterproof reinforcement layer for the exterior wall, so that the entire exterior wall waterproofing is in a state of multi-channel fortification. 3) The final practice of the external wall is shown in Figure 1.
Figure 1 Schematic diagram of exterior wall
3Construction process and control points of the external wall construction stage
3.1 Construction Process
Basic wall surface cleaning (concrete wall interface treatment) → external wall hanging line, sleeve, bomb control line, sticking control insulation layer thickness gray cake → layered wipe insulation mortar → Scrape-resisting mortar → brushing polymer cement base Waterproof coating → batch exterior putty → exterior wall paint.
3.2 Primary wall treatment
1) Arrange people to clean up the wall base so that the oil, dirt and other contaminants on the wall surface and other materials that interfere with the bond are all cleaned up and the objects protruding from the wall surface are removed. 2) The concrete structure wall through-hole screw hole must be completely sealed and sealed with 1:2 dry hard cement mortar. 3) For the thickness of local insulation mortar stucco that exceeds the design requirements, leveling with 1:3 cement mortar and roughening the surface of the mortar should be performed first. The roughening treatment method uses a bamboo broom on the surface of the mortar before the leveling mortar has not completely solidified. The brush makes the surface of the cement mortar striped. 4) Hang the wire mesh at the junction of the concrete wall and the block wall, leaving 150mm wide on both sides and fix it with cement nails. 5) The brushing interface treatment agent should be formulated according to the interface agent: medium fine sand: cement = 1:1:1 (weight ratio). Add 1 part of the interface agent first, then add 1 part of medium fine sand and cement, stir into a slurry. Brush evenly with the roller, pay attention to uniform brushing and prevent brush leakage.
3.3 Commodity insulation mortar layer construction
1) Preparation of thermal insulation mortar: The inorganic hollow glass bead insulation mortar dry blended material of the finished product on the market is transported to the construction site and water can be added directly according to the instructions for use of the product. Attention should be paid to the use of a forced mortar mixer for stirring. Mixing time is controlled in 5min ~ 7min so that the insulation can be used as a uniform paste, the water-cement ratio is controlled between (0.85 ~ 1): 1, stirring should be first into the dry mix and then add tap water while stirring, At the same time, it is forbidden to add any auxiliary materials to the material to prevent the chemical materials or physical reactions of the auxiliary materials and thermal insulation mortar from affecting the performance of the thermal insulation mortar. At the same time insulation mortar must be used with the mix, used within 2h, overtime is strictly prohibited.
2) Construction of thermal insulation mortar: The thermal insulation mortar must be separated and survived. The thickness of the first layer must not be less than 10mm during construction. It must be squeezed during construction to ensure firm connection with the base layer. Scrape the squeegee, wait until it is dry, and stratify it to the specified thickness according to the design requirements. When the thickness of the gray cake is reached at the last pass, it is scraped with a scraping ruler and smoothed with a wooden trowel so that the flatness and verticality meet the requirements of the acceptance specification.
3.4 Construction of Anti-crack Mortar
1) The preparation of anti-crack mortar is the same as that of thermal insulation mortar. Commercial dry mortar can be added directly to the site and stirred with water. 2) After the heat-insulating layer is solidified (press the stationary surface with the palm of the hand), wipe the first pass of anti-crack mortar, and control the thickness to 2mm~3mm. 3) Laying the alkali-resistant glass fiber mesh cloth, laying the grid cloth immediately after the first pass of the anti-cracking mortar, and pressing the mesh cloth with a wooden trowel to flatten and compact the mesh cloth in advance according to the wall size. Planning cut, overlap 100mm. 4) The remaining 2mm~3mm anti-crack mortar shall be used for surface mortar construction after the grid cloth is compacted and smoothed. The surface layer must be compacted and light surfaced. 5) After the plaster is cured for 24 hours, it is cured with a sprayer, and it is usually cured for at least 7 days.
3.5 Polymer cement-based waterproof coating construction
1) Waterproof construction time selection, until the natural drying of the anti-crack mortar maintenance period can be completed after the waterproof coating construction. 2) The construction of polymer waterproof coating is strictly in accordance with the normal waterproof construction process. First brush the primary treatment agent once again, brushing must be uniform, not leaking the bottom, and then brush the first time waterproof coating, brushing the direction of the horizontal, until the first time the coating is not sticky after the second brushing, The direction of vertical brushing, so repeatedly until the thickness of the coating reaches the design requirements. 3) The amount of material used for each pass should be basically the same, must not be too much or too little, so as not to cause uneven film thickness and affect the quality.
3.6 Exterior Putty and Exterior Wall Coating Construction
The exterior wall putty and exterior wall coating construction can be carried out after the acceptance of the exterior wall waterproof coating film. The operation process can be in strict accordance with the exterior wall coating construction process.
3.7 Precautions
1) The raw materials for insulation mortar, anti-crack mortar and water-proof coating are all semi-finished goods. When it is stored on site, it must be waterproof and moisture-proof. The storage time should not exceed 3 months. The stirring slurry must be used with stirring to prevent The failure of raw materials resulted in empty drums, cracks and other defects that caused the external wall to leak. 2) When the external scaffolding pull-node is reserved for the empty hole, a waterproof reinforced layer shall be formed within a range of 100 mm beyond the periphery of the hollow after the outer frame cut-off hole is sealed. 3) After the construction of exterior wall paint is completed, the drilling site of pipe supports such as external wall risers and gas pipes must be sealed with a weather-resistant structural sealant to prevent rainwater from penetrating through the bracket holes. 4) During the entire external wall construction schedule, it is necessary to fully consider the time difference between the connection of various processes and make reasonable arrangements, and fully reserve the maintenance time of thermal insulation mortar and anti-crack mortar. 5) Construction of insulation mortar and anti-crack mortar is strictly prohibited in rainy weather.
4 Conclusion
The project has been completed and delivered since its construction in December 2008. It has so far undergone many typhoon storms. There has been no case of complaints about the leakage of external walls so far. The quality of exterior wall construction was well received by the expert group and it was successfully rated as a quality project in the city, which has provided good social benefits for our company's development and construction business.
Fenghua Jade Motor Co., Ltd. , http://www.nsoutdoorproducts.com