It seems really rewarding whenever we paint our house. However, contentment quickly evolves to dissatisfaction within a year or two. Painting defects are to blame for this.
Unfortunately, there is no common cause for these painting defects, and there is also no specific defect. Distinct regions have different defects, which are largely determined by climate conditions.
However, the selection and application of paint to the damp surface is the primary cause of these defects. We’ve covered a variety of defects in painting, their causes, and how to fix them in the sections below.
Different Types of Painting Defects
Painting defects are a typical faults on painted surfaces that develop over time. This defects can occur for a variety of causes, and there is no single cause for it. The most prevalent painting defects are described below.
- Peeling and Blistering
- Cracking
- Checking
- Flaking
- Chalking
- Alligatoring
- Wrinkling
- Running and Sagging
- Mildew
- Blooming
- Flashing
- Grinning
Peeling and Blistering
Swelling of paint occurs when the adhesion between one or more paint layers, or between primer and the wall surface, is lost.
Blistering refers to the swelling generated by any oil or grease on the surface, whereas peeling refers to the swelling caused by moisture.
Non-porous coatings, such as oil-based paints and enamels, are prone to this type of defect.
For heated surfaces like radiators, a special heat-resistant paint should be applied.
Causes
Moisture in the air, oil and greasy surfaces, and trapped gases lodged between the painted surface and the paint film, which expand anytime under the influence of heat, are the main causes of blistering and peeling defects.
Cure
To avoid such painting defects, use emulsion paints, which have a porous coating that allows moisture to pass through.
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Cracking
Cracking is a form of coating defect defined by the chipping away of the applied paint film in tiny portions or completely. The cracks run throughout the entire paint system, all the way down to the original surface. Cracks in the plaster or brickwork prevent the paint from adhering to the surface.
Causes
- Painting on an already glossy surface is a common cause of cracking.
- When painting on a wood surface, if the object is not properly seasoned, the paint may crack.
- These defect can also be caused by applying the top coat over the prior coat without allowing it to dry.
Cure
To correct these defect, the underlying causes of cracking must be addressed.
Checking
Checking is a type of cracking that isn’t as severe as cracking defect. When hair cracks form around a tiny area these are termed as crazing and when this enclosed area is huge it is called as crocodiling.
Causes
It occurs when the paint film loses tensile strength and develops when paint is put in extremely cold weather or when the undercoat is not properly dried.
Cure
The top layer is smoothed with emery or sand paper and a fresh coat of paint is applied when cracks are extremely minor and do not expand with time.
Flaking
Flaking is a type of paint failure that occurs when the paint lifts up and peels away from the substrate due to a lack of adherence. In layman’s terms, it’s the separation of the paint film from the surface.
Causes
- Paints used were of poor quality, with poor adherence and elasticity.
- Moisture seeps through the pores in the coatings, causing the link between the surface and the paint film to break down.
- Paint coating applied in a very thin layer.
Cure
- Plastic emulsion paints are used.
- Before applying a new coat, the surface should be wiped with sand or emery paper.
- Prior to painting, any dirt or dust on the surface should be removed.
Chalking
The formation of chalky white powder on the surface of a paint coat is referred to as a chalking defect. Due to a lack of oil in the primer, the paint film becomes powdery.
Causes
- When a painted surface is exposed to direct sunlight for an extended period of time, the chalking effect may occur.
- Darker colours absorb more heat and UV rays than lighter colours, making them more susceptible to this defect.
- Paint that has been too thinned or spread too thinly.
Cure
Before repainting with an authorised UV resistant coating system, the entire surface will need to be pressure washed or scrubbed with a non-metallic scouring pad to remove all surface impurities and chalking.
Alligatoring
Alligatoring occurs when a paint film generates patterned cracks that resemble alligator skin. Cracks usually only form on the outside surface or coat. It is also called as chip cracking.
Causes
- Due to ageing and severe weathering effects, these defects are most commonly noticed on oil-based paints.
- This defect can also be caused by applying too much paint in a single layer.
- Furthermore, alligatoring can be caused by applying a second coat too quickly without allowing the prior coat to dry properly.
Cure
The easiest way to get rid of alligatoring is to scrape off all of the paint from the affected area, even if it hasn’t cracked everywhere, and repaint the entire building or segment of the building.
Wrinkling
Wrinkling or crawling occurs when the paint coating is too thick or there is too much oil in the paint. Due to the larger thickness of the paint layer, which decreases over time as it dries, the lower area of the paint does not dry.
Causes
Painting in hot weather might result in this defect because the top layer of paint dries faster than the base layer.
Cure
Allow the damaged area to dry completely before sanding it down to a well-cured coat and applying a new finish. Remove the paint layer completely and repaint if there is serious wrinkling.
Running and Sagging
When the paint does not stick to a smooth, shiny surface and flows back or towards the unpainted region, it is referred to as sagging and running. Before painting, the surface to be painted should be scraped with emery paper.
Causes
- This defect can be caused by improper mixing of various paint components.
- The painted object or building was too cold when the paint was applied.
Cure
Using a regular rubbing motion to smooth up the sagging areas.
Mildew
Mildew is a fungus that grows on many external painted surfaces, as well as inside bathroom walls and other damp or poorly ventilated interior places. Mildew grows best in warm, wet, and gloomy environments.
Causes
- In the case of wood, this fault might occur if the wood is not properly primed.
- If there are mildew traces beneath the existing coat on the painted surface.
- This appearance can also be caused by humidity and moisture issues.
Cure
To control its growth, zinc oxide and phenol mercury oleate are highly effective.
Blooming
It appears as dull spots on the finished, polished, or painted surface as a result of a paint defect or inadequate ventilation.
Causes
- To speed up solvent release, fan compressed air onto the film may cause this defect.
- Usage of poor quality thinner.
Cure
If there is minor blooming, it can be eliminated by rubbing with a polishing chemical. If the problem is serious, it is recommended that the surface be repainted.
Flashing
The emergence of certain glossy spots on the painted surface indicates this defect.
Causes
Weathering actions, the use of cheap paint, and poor construction are all blamed for this defect.
Cure
If this flaw is discovered, another coat of paint can be applied.
Grinning
The grinning is caused by the paint film’s uneven opacity, even after the final layer. In this scenario, the background and its flaws may be readily seen. Grinning can also be referred to as grinning through or partial concealment.
Causes
- This flaw can be caused by a thin coating layer on the surface.
- Workmanship that isn’t up to par.
- This flaw will occur if bright colors are used for priming or undercoats.
Cure
If this problem is discovered, the affected region should be treated by applying a matching coat.