Q：Why the wall application is divided into primer and top coat?
A：The new or old wall may suffer from alkalization due to the heavy moisture, especially in humid environment, which is the root cause of affecting the quality of the paint. Applying a layer of alkali-resistant primer before top coat application can not only save the decoration cost, but also effectively resist the penetration of alkaline substance on the wall, prevent the precipitation of water soluble salt and the wall efflorescence. Meanwhile, the good adhesion of primer enables the wall surface to be smoother and the top coat can be applied more easily, as well as reduces the usage of top coat. Therefore, the wall avoids the paint defects and is beneficial to maintain of painting effect for a long time.
Q：What preparations should be made before the decorative construction of wall?
A：① Check whether the environment, temperature, relative humidity, ventilation, cleanliness and other conditions are suitable or not;
② Cover the parts that do not need to be coated;
③ Prepare the application tools and clean them;
④ Add water and mix evenly according to the product description.
Q：What is the working procedure for the construction of wall paint?
A：Actually, the construction of wall paint is simple. Except for the scraping of putty, the consumers can roll or brush the wall paint by themselves. The spray coating should be performed by professionals. The working procedure of the wall application are as follows: substrate processing → putty leveling (generally two times ) → putty polishing (360# sandpaper) → brushing one coat of primer (light polishing with 600# sandpaper) → brush two coats of top coat
Q：What are the precautions for wall decoration?
A：① The putty is used to level the wall, and the thick scraping should be avoided as far as possible. The 360# or above sandpaper is used for polishing and cleaning the wall after drying. It is required to avoid the sand mark and sand hole during polishing;
② The application of the primer should be even without missing. The light polishing is adopted if the primer polishing is necessary. Don’t wear out the primer;
③The interval of each top coat application should be more than 4 hours. The recoat time should be extended accordingly in the condition of low temperature or high humidity. The second application should be performed when the upper layer of paint film is dry.
Q：The first of seven wall problems: low opacity.
A：The causes include the insufficient brushing layers, thin coating or strong colors contrast between the priming coat and top coat. The following methods may be used in such case:
① Perform brushing according to the suggested layers;
② Remember to fully stir the print before brushing, and mix the paint according to the dilution rate as shown on the can. Don’t over dilute;
③ Brush one or two times when the primer and the top coat have strong color contrast, which enables the top coat cover the primer fully.
Q：The second of seven wall problems: low mould stain.
A：The wet home environment is the reason. The mould stain (if any) should be cleaned with diluted bleaching water (bleaching water/water = 1:10). In order to prevent the reappearance of stains, try to select the paint with sound anti-mold property. Meanwhile, avoid performing under humid environment (especially when the relative humidity is higher than 85%).
Q：The third of seven wall problems: sweeping profile.
A：The problem may be caused by application of another layer of paint when the priming coat is not completely dry, or the viscosity of paint is too high during application. The following methods may be selected in such case:
① During the application, the paint should be brushed gently, the force should be even and the directions should be uniform. The second layer can be applied when the first layer of paint has been completely dry.
② Dilute appropriately according to the instructions.
Q：The fourth of seven wall problems: sagging.
A：The causes of this problem include too thick coat, excessively thinned paint, uneven painting on the large surface or fail to connect the “wet edge” in time. The solutions are as follows:
① The coat should not be too thick. Can brush more layers if necessary;
② The paint should be mixed according to the dilution rate as shown on the can before application. Don’t dilute it excessively;
③ The connection part between the areas should be swept vertically when painting different areas;
④ After the paint film is completely dry, use a dry or wet sandpaper with the warm water containing a small amount of detergent to remove the sagged paint and polish the paint film. Then wash thoroughly with clean water and reapply when it is completely dry.
Q：The fifth of seven wall problems: chalking.
A：The causes of this problem include the paint ageing, the salt-shaped paint film due to the erosion of alkaline substance or mistake interior wall paint for exterior wall. The following methods may be adopted in such cases:
① Remove and clean the affected part, and re-brush the wall when it is completely dry;
② The primer with strong alkali resistance should be applied before painting when the wall is suffered from the erosion effect of alkaline substance.
Q：The sixth of seven wall problems: flaking.
A：The problem may be caused by painting on the surface with dust, grease or previous glossy paint, or the incompatibility between the selected top coat and the primer which reduces adhesion. If it is a small-area of flaking, remove the loose paint at this point and surrounding areas, and then apply the primer and top coat. If it is a large-area of flaking, polish the whole painted surface thoroughly before the reapplication of primer and top coat. In addition, please carefully read the instructions on the paint can and select compatible primer and top coat before application.
Q：The last of seven wall problems: wrinkling.
A：The problem of wrinkling may be caused by the drying speed of coating surface is higher than that of bottom layer due to the thick coat and exposure to direct sunlight or too high temperature during application. To solve this problem, can use a dry or wet sandpaper and warm water to remove the wrinkled part completely, clean it with clean water thoroughly, and reapply the same paint after it is completely dry. Dilute the paint according to the instructions on the can during application. Do not apply paint film excessively. The painting times may be increased if necessary.
Pinhole: There are needle holes or traces of cracked bubble on the waterproof layer.
A：Causes: ① The substrate is too dry and the high water absorption is high;
② The substrate is too rough and uneven;
③ The waterproof materials are mixed without defoaming after vigorous stirring.
Prevention and solutions:
① Fully wet the base surface in advance, but no obvious water is allowed;
② Level the base surface if the problem is caused due to the roughness of the base surface;
③ Mix and stand still for 5 minutes. Perform the application after the disappearance of bubble.
Q：Chalking: The strength of the surface is low after the waterproof layer is dried and maintained. The hand rubbing may lead to the chalking or damage.
A：Causes: ① Application under too low or too high temperature;
② The ambient humidity of application is high, and the waterproof layer has not been completely cured;
③ The substrate absorbs too much water and the moistening is insufficient, or the waterproof layer is directly used on the calcium silicate board, light brick or other substrates;
④ Add too much water during the use of waterproof material.
Prevention and solutions:
①The application should be performed when the temperatures is 5℃ -40℃. The electric lamp can be used for heating, and the air conditioner or other equipment can be used for cooling;
② The ambient humidity of application should not higher than 85%. The fan or other equipment can be used to accelerate the ventilation;
③ The substrate with high water absorption should do the sealing treatment before the application of waterproof material;
④ The amount of water adjusted by the viscosity of waterproof material should be within 5% of the liquor. It is forbidden to add a large amount of water.
Q：Delamination and flaking: There are delamination and flaking on the substrate, in the waterproof layer or between the second and the first waterproof layer.
A：Causes: ① The strength of substrate is insufficient, there is dust, oil stain and other dirts;
② The waterproof layer is directly made on the asphalt waterproof material, polyurethane, coil and other materials, or the rigid waterproof layer is made on the flexible waterproof layer;
③ There is obvious water on the base surface during application;
④ The closed water test is performed when the waterproof layer application has not passed the 48-hour maintenance period.
⑤ The waterproof processing of the downstream face should use the flexible waterproof paint.
Prevention and solutions:
① The substrate must be cleaned before application until it is neat and free of oil stain, dust or other dirt;
② For the substrate with asphalt waterproof material, polyurethane, coil and other materials, the original waterproof layer must be removed first to the cement base surface;
③ The base surface is wetted without obvious water before the application;
④ The waterproof layer should be maintained for at least 48 hours after the application of waterproof layer is completed, and then the closed water test should be conducted;
⑤ The waterproof processing of the downstream face should use the rigid waterproof materials;
⑥ The cement mortar substrate must be maintained for more than 7 days, and the concrete structure must be maintained for more than 28 days. If the strength of the substrate is insufficient, the loose material should be removed, and the cement mortar layer should be re-scraped for sealing treatment.
Q：Cracking: There is crack on the waterproof layer, especially the hairline crack at the wall corner.
A：Causes: ① The thickness of the single-channel waterproof layer is too large, which leads to the shrinkage crack;
② The stockpile is too thick at the internal and external corners;
③ Select the improper waterproof materials;
④ The waterproof overlapping layer is wrong. The rigid waterproof layer is constructed on the flexible waterproof layer.
⑤ Add too much water when using the waterproof material.
Prevention and solutions
① The thickness of single coating should not exceed 1.5mm. The coating should be performed with thin layer and printed for many times;
② The arc processing should be performed at the internal and external corners. The coating should be performed with thin layer and printed for many times;
③ The structure of application should be understood before application. The rigid waterproof material should not be used at the deformable area, such as the waterproof processing of roofing;
④ The waterproof layer should follow the waterproof lap joint; the rigid waterproof paint should cover the flexible waterproof paint;
⑤ The amount of water adjusted by the viscosity of the waterproof material should be within 5% of the liquor. It is forbidden to add a large amount of water.
Q：Efforescence: There are the white signs on the surface and there is the white powder when the hand touches it.
A：Causes: ① There is obvious water on the substrate during application;
② The water is splashed on the surface after application;
③ The closed water test is conducted too early.
Prevention and solutions:
The treatment of the shortage is mainly focus on prevention. It cannot have obvious water on the substrate before application. The waterproof layer should be well protected after application. In addition, the cement-based product itself cannot eliminate the problem of efforescence.
With the general thickness of 0.5-5mm, floor paint is a high polymer layer only covered the concrete ground even in its highest strength.Eventually the real force is focus on the concrete ground. The self strength, density, surface state and other factors of cement substrate surface will affect the coating effect of floor directly. Therefore, the substrate processing is the top priority during the coating of floor paint.
Coating of floor paint for cement substrate surface
Requirements of substrate
Cement substrate should be hard without any sand or chalking.
① The high-quality cement (the cement grade is 425 or above);
② The new cement mortar layer should be maintained well.
The cement substrate should be flat without unevenness, voids and pits, lumps other defects. . The coating of floor paint is relatively thin. The flatness of the substrate will directly affect the final effect.
Requirements for flatness: No gap longer than 2mm when placing a 2-meter-long scale on the substrate surface.
Generally, the surface of the new concrete substrate contains moisture. The moisture content of the base surface must be lower than 4% before processing; otherwise, there will be bubbles and convexity in the coating surfac. In severe conditions, there will be flaking and other quality defects. The new concrete substrate surface should be maintained for more than 28 days after the application is completed;
The strength of concrete must be above C25. It may cause the hollowing, peeling and other defects, as well as reduce the service life of floor paint if the strength is not enough. The strength of substrate is tested by rubbing the surface back and forth with the steel brush or tapping the surface with the small steel hammer. The test is failed if there is any fragment or peeling;
Alkalinity requirements of substrate surface: The PH value is should be less than 9;
If the application substrate surface is under the ground or on the first floor, a waterproof layer must be made.
Substrate surface processing
Processing of new substrate surface
① Substrate test: Check the substrate whether solid, sanded, hollow, shelled or not, and is there any points to be repaired;
② Repairing: Knock off the hollow and shelled parts and refill with cement mortar;
③ Gap filling: Fill the crack and expansion joint with middle coating mortar;
④ Polishing: Fully polish the substrate surface with a polishing machine to remove the floating sand or other loose material on the surface;
⑤ Dedusting: Thoroughly dedust with dust collector, feather duster or other toolss.
Treatment of oil stains on the substrate surface
If the substrate surface is polluted by the oil stains, the pores of concrete at this point have been fully filled with oil stains. The epoxy primer cannot penetrate into the concrete, which may affect the adhesion of primer and substrate, and even cause the shrinkage cavity and other shortages sometimes. If the substrate surface is polluted by the oil stains, please adopt the following methods for processing:
① The less oil stains on the surface can be cleaned with scrub brush dipped with detergent or solvent and operated for many times until there is no oil stains;
② For the heavily polluted substrate, it is recommended to remove the oil stains by the burning of gasoline or alcohol;
③ Remove the polluted concrete layer with grinding machine.
If the methods mentioned above are not effective in removing the oil of the substrate surface, it is recommended to make a concrete again.
Treatment of substrate surface efflorescence
The substrate surface with high alkalinity, particularly serious efflorescence, is required to be neutralized with oxalic acid diluents and rinsed with clean water to neutral. The rinsed ground should be fully dried.
Treatment of crack
Cut the cutting joint into “V” shape, clean off the gallets, sundries and other thing, level with the suitable materials, and polish smooth after drying.
The application should be suspended if the temperature is higher than 35℃ or lower than 5℃, or the humidity is higher than 85% or lower than 35%. The application should be avoided in high winds, heavy rain or hot weather;
The substrate surface which will be applied should keep clean and rough to a certain degree;
Mixing should be performed strictly in accordance with the stipulated proportion and then mix evenly with the electric mixer. The epoxy coating should be cured for about 5 minutes, and the application should be performed after it cures fully. Note: It is recommended to use the mixed paint up within the service life;
The roll coating should be performed according to a certain direction and sequence when applied with a roller. The whole coating should achieve uniform thickness. Special attention should be paid to the connections between roll coating, and check while rolling;
To strictly comply with the time interval between two application of the paint;
No smoking on the application site. The paint should be stored in the shade place to avoid the direct sunlight.
The floor paint products should be used carefully. The safety notes on the package label should be noticed before and during application. The related safety regulations of the state or local government should be followed;
Swallowing is harmful or fatal. Please seek the medical advice immediately if swallowed;
Avoid to breath in the vapor or moist of the paint. Skin and eyes cannot contact with this product. This product should only be used under the well-ventilated circumstances. If it is used in narrow or poorly ventilated places, the powerful ventilation measures must be taken;
Precaution should be taken all the time against fire and explosion.