Painting Defects

Efflorescence

  • One of the most common problems faced on masonry substrates is efflorescence. It is caused by humidity in the substrate due to insufficient drying of the substrate or water leakage. White salty crystals is deposited on the wall surface after water seeping from hairline cracks and dried out.
  • To prevent efflorescence, it is important to repair cracks with appropriate putty, and allow fresh masonry to dry completely before painting. A high quality, efflorescence resistant wall sealer (e.g. KCC Wall Sealer 500) is recommended before applying subsequent top coats.

Chalking

  • Chalking is the formation of loose, chalky particles on the surface of the paint. It is caused by disintegration of paint due to weathering or environmental chemical attack. While paint films will inherently chalk when they reached an advanced age, wrong usage or paint, such as use of incorrect paint system (e.g. using interior paint for exterior wall) or inferior paint could accelerate the chalking of paint film.
  • It is important to apply a suitable and quality paint system to prevent chalking. In the case of heavy chalking, it is recommended to remove the paint film completely with high pressure water jet, allow dry and apply a coat of wall sealer (e.g. KCC Koresil 450), followed by high quality finishing coats (e.g. KCC Korevon Silk).

Discolouration

  • Discolouration is the phenomenon where the original colour changes in hue (e.g. violet changes to blue) or loses its intensity and turns lighter in shade. Certain sensitive pigments deteriorate and changes colour on exposure to sunlight or unsuitable chemical environment. Discolouration is usually brought about by the use of paint or colour unsuitable to adverse environmental conditions.
  • If an unsuitable colour undergoes discolouration, remove the paint film, clean and repaint with the correct choice of colour as well as correct type of paint (e.g. use weather resistant paint such as KCC Korever for external walls).

Flaking and Peeling

  • Flaking or peeling occurs when the paint film is lifted and peeled from the substrate surface due to poor adhesion from inadequate surface preparation, or usage of low quality wall sealer.
  • If flaking or peeling occurs, it is essential to remove the loose paint completely, clean the surface, and repaint with high quality wall sealer (e.g. KCC Wall Sealer 500) and adequate paint.

Blistering

  • Blistering is the formation of hollow projections from underneath the paint film. Blistering of paint of wood or masonry surfaces is caused by moisture entrapment beneath the surface coating.
  • When isolated blistering has occurred, sand down the paint film, clean and repaint. If blistering is severe, it is recommended to remove the whole paint film and repaint after the substrate is sufficiently dry.

Algae and Fungi Growth

  • Algae and fungi grow almost exclusively outdoors as they both require sufficient moisture, and algae require sunlight to grow. In our harsh tropical climate of high humidity, rainfall, and abundant sunshine, our buildings are especially prone to proliferation of algae and fungi.
  • Algae and fungi can be removed by high pressure water jetting and manual scrubbing. The wall surface should be treated with KCC fungicidal solution. Moisture source and cracks should be repaired before repainting.