Most paint problems arise from plastered surfaces not being sound, dry and clean before the coating is applied. These three factors are part of Plascon’s key requirements for aesthetically appealing and long-lasting surfaces.  

Sound plaster 

A sound surface is one prepared with plaster mixed in the right ratios, using high-quality ingredients, and then professionally applied and properly cured. 

Cracks are often caused by plaster surfaces drying out too quickly before they can form cohesive strength. These cracks, even hairline ones that are not clearly visible to the naked eye, expand and contract with the surface and can ultimately crack the paint.  

Ensure the plaster remains hydrated by wetting newly plastered surfaces. 

Plascon Professional Elastoshield, a highly elastic coating that can withstand repeated contraction and expansion over fine cracks, is ideal for use on plaster surfaces that are prone to cracking. 

Plaster Disbonding

Wet plaster 

Painting over damp plaster or water ingress through cracks, results in water migrating through the cementitious substrate carrying high-pH lime particles to the surface. This appears in white, salty-like layers, called efflorescence, and spotty discolouration of the paint, called alkaline burn. 

High humidity levels in the air can lead to surfactant leaching. Surfactants are compounds added to paint to promote stability and even spreading. They usually either dry off as the paint cures or seal into the paint. However, when drying conditions are especially cold, steamy or damp, or when plastered surfaces aren’t allowed to dry completely, the compounds leach to the paint’s surface in an uneven film that can look oily or sticky. 

Ensure the plaster is completely dry before applying a primer, such as Plascon Professional Alkali Resistant Plaster Primer. 

Issue: How to ensure the best results when painting. 
Solution: Preparation is key to most applications. Plastered surfaces should be sound, dry and clean before applying paint. 

Uneven plaster 

Poor, aesthetically unappealing plaster finishes require high-cost coating systems to be applied by skilled painters to improve the appearance. 

Coating systems such as the Plascon Professional Bridging Compound and Professional Marroca Coarse Texture help protect and improve the appearance of uneven plastered surfaces. 


Regular maintenance assessments are important, to identify and address problems so that they can be resolved before major damage occurs. This not only helps manage maintenance costs but will also extend the life of the coating system. 

For more information, contact Plascon:
Tel: +27 0860204060

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