Problem solving - Concrete

Flaws in painting could crop up due to reasons not really obvious. It could range from poor preparation of a surface to unsuitable weather conditions, from wrong choice of a paint product to inadequate knowledge of application techniques. Here are a few step-by-step instructions to trouble-shoot most of your anxieties on the painting zone.

 

Flaking / Peeling

Flaking or peeling paintwork is similar to blistering. This condition is caused by the presence of moisture under the painted surface.

Reasons:

• Poor preparation of the surface.
• Painting in damp conditions.
• Too many previous coats of paint.
• Use of the wrong primers.

As paint will not adhere to a flaky surface, we suggest the following treatment:

Remedy:

 

 

 

Moisture Penetration

via foundation

This is caused by rising damp, and water evaporation.

Reason:

• The paint film is pushed by the infiltration of moisture from below the surface.

Remedy:

• Isolate the area, using a barrier of waterproof material.
• Move fresh plants away from the walls.

 

 

 

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Efflorescence

Formation of white crystals on the painted surface.

Reason:

• Dampness in the area.
• Salt content in its surface.

Remedy:

• Clean surface with a stiff bristle and remove all the particles.
• Washing the surface with fresh water is recommended.
• Apply a suitable primer on a dry and clean surface.

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Blistering

This results from poor adhesion of the paint to the surface due to rapid drying of the film, and subsequent vaporising of the trapped solvents. Consequently, the topcoat is pressurised, causing blistering of the surface.

Reason:

• Dampness in the timber.
• Moisture in the atmosphere.

Remedy:

• Ensure that the paint penetrates thoroughly into the surface.
• Remove all defective paint.
• Allow every coat to harden completely between coats

 

 

 

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Major Cracks

Strong structural movements cause major cracks on the surface.

Reason:

• Inadequate or fast curing of plaster.

Remedy:

• Ensure that the area is dry.
• Open up the cracks in a ‘V’ shape.
• Clean the surface well and apply appropriate crack filler in layers.
• Ensure that each layer dries thoroughly.

Use a good quality primer to seal the surface.

 

 

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Minor Cracks

Any structural movement causes minor cracks to appear.

Reason:

• Inadequate or fast curing of paint.

Remedy:

• Ensure that the area is dry.
• Use an appropriate primer followed by a filler to fill the cracks.

 

 

 

 

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Chalking

Loose white powder comes off onto the hand when the surface is rubbed.

Reason:

• Poor UV resistance of the paint.

Remedy:

• Sand the surface properly in order to remove as much of the loose white powder as possible.
• Wash the surface with fresh water.
• Use recommended coat of sealer prior to painting. In this case, up to two coats of a good quality primer may be necessary

 

 

 

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Fading

The paint, used on external surfaces (especially in hot countries such as those in the Middle East, and Africa), fades or discolours after prolonged exposure to ultra-violet rays.

Reason:

• The paint used on the external surface contains synthetic or organic pigments.

Remedy:

• Be sure to check out with the manufacturer that the paint has been formulated with only inorganic or natural pigments (UV stable).

 

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Intercoat Adhesion Failure

• Primarily due to the usage of incompatible paint systems.

Remedy:

• Ensure complete removal of the existing paint.
• Use the appropriate/recommended paint system.

 

 

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Slow Drying

Reason:

• Inadequate surface preparation.
• Painting in cold and damp conditions.

Remedy:

• Use cloth soaked in white spirit or any paint remover to remove the paint.
• Wash the surface with warm, soapy water before drying.

• Apply a good quality primer to seal the surface.

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