Common Defects in Painting – Civil Engineer explains

Painting protects the structure against the various aggression actions like corrosion, decaying, weathering, etc. The paint is select on many factors like surface, type of environment, and many more. Or else, the defects occur in painting. 

The common defects are as follow:

1.Peeling and Blistering

Peeling means the swelling in the paint film occurs. The swelling occurs because of the presence of moisture, oil or grease matter. It happens due to moisture then it is known as peeling and if it is done by oil and grease then it is known as blistering. This happens due to the imperfect seasoning of timber, imprisoned gases between the paint coats or by the usage of excess oil in the final coat. These defects can remove by using porous paints instead of using paints like oil paints, enamel paints, etc. 


Fading means the mark on the paint surface. This happens due to the atmosphere agencies like sunlight, moisture, etc. To prevent fading, in paint the weathering resistant pigments should be used.


If there is visibility in the background due to the insufficient obscurity of the paint, the final coat is known as grinning. The paint should be non-transparent to cover the background surface. 


Chalking happens due to insufficient oil in the primer. Chalking is the formation of the powder on the surface. It can be prevent by using the oil in the primer, and by applying the paint at the recommend spreading rate. 

5. Running

The thin layer of the paint is the coating on the glossy and the smooth surface of the paint can run back and many times the small area of the surface is uncovered is known as Running.  


Sagging means the surface in which is paint with the thick layer may run downwards and then will form the sagging in the paint.



The detachment of the paint film on the surface is known as flaking. It occurs when the bond of the surface and the paint is poor. While applying the paint the surface should be clean and rub which the paper before applying the paint. 


Blooming happens due to improper weathering, ventilation, defective paint, etc. Dull patches are seen on the paint surface. 


The paint gets shrinks and develops the crawls on the surface is known as Wrinkling. That occurs when a thick layer of the paint is a coat on the surface. This can prevent only by allowing the undercoat of the dry before the final coat application.  


Flashing means the glossy patches on the surface. This happens due to the poor quality of paint, weathering action, poor workmanship, etc. 


Saponification means the soap patches form on the paint surface, the paint film gets the peel off from the surface. Saponification occurs when the paint surface is expose by chemicals. 


Alligatoring means the pattern cracking similar scales of an alligator. It occurs when the hard coat of the paint is apply over the soft coat of the paint. The high-quality oil-based primer employs as the primer coat to prevent. 


Checking is similar to Alligatoring but here the cracks are very limit are in a small area. It happens due to the paint applied while very cold weather or it can be due to the application of paint before dry the undercoat. 


Mildew is a fungus in which grows well in warm, dark places and moist. It affects the bond between the paint coats. It can prevent while keeping the surface dry and clean before applying the paint on it. If there is mildew then wash the surface with the solution of bleach. 


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