What is the construction method of exterior wall coating in Shenzhen?

The substrate of exterior wall coating requires the most basic requirements of the coating surface of architectural coating-dryness, firmness and cleanliness. 1. drying: the cement wall shall be maintained for at least 1 month (7 weeks in winter), with the humidity below 6% and the wood surface humidity below10%; There are no structural problems such as water seepage and wall cracking. 2. Firm: no pulverization and looseness, and no loose paint on the old wall. 3. Cleanliness: no oil, grease, mold, algae and other adhesions. The substrate does not meet the requirements, which will seriously affect the performance of the paint film. The high humidity of the wall surface may cause the paint film to bubble, peel and fall off, the wall surface is infiltrated with alkali, the paint film loses its luster and even becomes moldy; Loose substrate and dirt adhesion will affect the adhesion of paint film, leading to peeling and peeling. If there is mold growth, it will cause the paint film to be moldy. Exterior wall coating substrate treatment 1. New wall. Maintenance 1 month or more, humidity < 6% (can be tested by hygrometer), removal of floating ash stains and alkali leakage. 2. Old wall. Rinse with high-pressure water or mechanical polishing to remove dust and bacteria and algae that may breed, clean and dry, brush mildew-proof liquid (prepared with bleaching powder 10% solution) if necessary, and then rinse with water; The old coating is intact, and can be directly recoated after cleaning the surface; The old coating has the phenomena of pulverization, foaming, cracking and peeling, so it is necessary to remove the old coating and repaint the primer and topcoat. 3. wallpaper wall. You can tear off the wallpaper, wash away the glue, dry it, do appropriate treatment according to the wall conditions, and then brush the paint. 4. Glass fiber surface. Can be directly coated with topcoat. 5. wood. Remove or replace the worn and rotten parts of the surface, clean and repair the surface, and repair the joints between doors and windows and walls with elastic fillers. 6. Metal surface. Iron: the rust spots on the surface should be removed first, and the corresponding antirust primer should be painted immediately after cleaning; Coloring: remove the oil stain and oxide layer on the surface, apply primer, and increase the adhesion accordingly. Exterior wall coating wall treatment 1. If the wall is flat, it is recommended not to use putty. 2. If putty is used, it is easy to brush it thinly instead of thickly. 3. The requirements for putty should not only be easy to batch and polish, but also have good strength and durability. For exterior walls, kitchens and bathrooms, putty should have good cohesiveness, durability and water resistance. 4. Treatment methods of possible problems on the wall: dust and powder-high-pressure water can be used for washing outdoors and wet cloth can be used for wiping indoors; Grease-clean with neutral detergent; Mortar-Remove with shovel, scraper, etc. Mould-outdoor high-pressure washing, indoor brushing with bleach for a few minutes, rinsing with clear water to dry. Construction conditions of exterior wall coating Latex paint is a kind of water-based coating, which requires high construction and maintenance conditions. The construction and maintenance temperature is higher than 5℃ and the ambient humidity is lower than 85% to ensure good film formation. Low temperature will cause problems such as powdering and cracking of latex paint film, and environmental humidity will make the paint film dry for a long time, which will eventually lead to poor film formation. Weather factors must be considered in the construction of external walls. Before coating latex paint, it can't rain for 12 hours to ensure the substrate is dry. It can't rain for 24 hours after painting to avoid the paint film being washed away by rain. Exterior wall paint coating system Generally, exterior wall building paint coating system is divided into three layers: primer, intermediate paint and topcoat. 1. Primer. Primer seals the alkalinity of the wall, improves the adhesion of the top coat, and has a great influence on the coating performance and surface effect. If the primer is not used, the adhesion of the paint film will be weakened, and the alkalinity of the wall will have a great impact on the performance of the topcoat. In particular, the use of the bottom surface of white cement putty may cause problems such as powdering, yellowing and alkali penetration of the paint film, destroy the performance of the top coat and affect the service life of the paint film. 2. Medium paint. The main function of medium coat is to improve adhesion and hiding power, provide three-dimensional patterns, increase fullness, and correspondingly reduce the amount of topcoat. 3. Top coat. Topcoat is the last coating in the system, which has decorative effect and resists environmental damage. Considering the different requirements of users, we can recommend different exterior wall facing products. Skilled operation level is needed to achieve good painting effect, but the construction of latex paint is not very difficult. First of all, the requirements for the substrate should be clean, dry and firm, and the coating conditions should be suitable and the dilution ratio should be accurate according to the instructions. Excessive dilution will make the coating unable to cover the bottom and powder, and the shiny coating will lose its luster and appear different colors. Secondly, good construction equipment is also necessary. 1. Exterior walls shall be painted from top to bottom, from roofs, gutters, columns, beams and rafters to walls, doors, windows and floors. Each part should be brushed from top to bottom in turn. When drawing every part, you can't give up halfway. If you have to stop, you should also choose the original connection parts of the building structure, such as the connection between the wall and the window frame. This will avoid unsightly seams. There are two steps to brush the cornice: first brush the bottom of the cornice, and then brush the sunny part. When brushing several cornices at the same time, move the ladder and move with the wall in turn, move quickly during the brushing process, and brush back and forth several times in the dry-wet joint from time to time to avoid leaving overlapping or seams. 2. Windows: Hinged sliding windows should be painted open. The order is top, edge and bottom first, then cross bar, window frame, top line plate and window sill. 3. Flat door: This door is painted the same as the wall. Draw the border first and then fill it, brush it from top to bottom, and stop at the joint between the door and the wall. Another method is to use the roller first, and then gently pat it in the vertical direction with a brush to remove the stripe marks of the roller. 4. Fancy wooden door: The paint of this kind of door should start from the concave and convex part at the top, and each piece should be filled after brushing the edges. Finally, the rest of the door, the door frame and its connection with the wall should be painted. After the post-treatment construction of exterior wall paint is completed, it is necessary to clean the tools immediately, otherwise the tools will be damaged after the paint is dried; The remaining paint should be kept clean and sealed. Brush coating is a construction process of roller coating with special napping roller, and the paint film has a certain three-dimensional effect. The products usually used for napping are mainly elastic coatings with high solid content and high viscosity. Among them, by adjusting the viscosity of the product, two different effects can be drawn: sharp, smooth and full. Because the special drum is porous, some air will be mixed in the construction process, resulting in some small bubbles. When the viscosity of the product is too low, bubbles are more likely to occur, so it is forbidden to add water during construction. You can also use slurry relief paint to nap and then coat. The cost of this technology is slightly lower, but the surface texture is poor, and flat coating is a common construction technology. According to local requirements, batch putty scraping (such as Northeast China) or full putty scraping (such as Beijing) is not required during construction. This method requires the wall to be flat, and a flat coating can be formed after brushing, and the flatness of the large surface is enough to be used as the key index of the flat coating process.