The formation of white patches on a newly painted wall can be attributed to a few different factors. Here are some possible reasons:
Efflorescence: Efflorescence occurs when water-soluble salts, such as calcium carbonate or sulfates, migrate to the surface of the wall through the paint film. As the water evaporates, it leaves behind the white powdery deposits. This is commonly seen in areas with high moisture levels or when there is water intrusion from the exterior of the wall.
Moisture or water damage: If the wall had excessive moisture or water damage before being painted, it can cause the paint to blister or peel off, leading to white patches. This could be due to leaks, condensation, or inadequate drying of the wall surface before painting.
Inadequate priming: Proper priming is essential before painting to ensure good adhesion and uniform coverage. If the wall was not adequately primed or if a low-quality primer was used, it can result in white patches or uneven paint absorption.
Residue or contaminants: If there were residues, dirt, or contaminants on the wall surface before painting, they can affect the adhesion of the paint and cause white patches. It is important to thoroughly clean and prepare the surface before applying paint.
Insufficient paint coverage: In some cases, white patches may be visible if the paint was not applied evenly or if there was inadequate coverage. This can happen if the paint is too thin, the roller or brush strokes were inconsistent, or if multiple coats were not applied properly.
To address the issue of white patches on newly painted walls, it is advisable to identify and rectify the underlying cause. This may involve addressing moisture problems, repairing any wall damage, ensuring proper surface preparation, using high-quality primers and paints, and applying the paint evenly and with adequate coverage. If the issue persists or if you are unsure about the cause, consulting a professional painter or contractor can provide further guidance and assistance.