Troubleshooting

Interior plaster Surfaces

BLISTERING OF ENAMEL PAINT

Description 

Loss of paint adhesion resulting in bubbling and flaking of the coating. In this particular example, there is a bathroom shower on the opposite side of the wall which was not adequately sealed.

Possible diagnosis

  • Excessive moisture ingress at the back of paint film. 
  • Painting too soon before the masonry structure has dried.
  • Poor structural design aspect related to moisture barriers.

Remedy

  • Remove all loose and flaking paint. 
  •  Establish cause of moisture ingress and rectify.
  • Allow structure to dry out before repainting.

FLAKING 

Description
Topcoat flaking with friable powdery undercoat.

Possible diagnosis

  • Painting on powdery substrate ie.
    old chalking paint, powder-like skim plaster, gypsum etc.

Remedy

  • Remove all loose and flaking paint. 
  • Remove friable residue from a substrate and apply a coat of NEO Bonding Liquid before recoating.

POOR STAIN RESISTANCE

Description
Stains and dirt being absorbed by the coating make cleaning difficult.

Possible diagnosis

  • Incorrect type of coating used for areas prone to dirt contamination. High sheen and water-based enamels such as NEO Gloss Acrylic are better suited for kitchens, playrooms, work areas and other surface areas which are likely to get soiled. Alternatively, use hardwearing NEO Teflacryl.
  • Low-quality paints that are porous in nature will be more inclined to staining.

Remedy

  • Use stain-resistant coatings such as NEO Teflacryl or NEO Dur (SABS Grade 1) in areas that are prone to soiling.
  • Good quality water-based emulsion sheen paints should be adequate for most applications. More specialized coating might be required for more aggressive contaminants.

TINTER DEVELOPMENT/RUB UP

Description
The non-uniform colour that appears after a surface was painted with a roller and smaller areas (edges) were finished with a brush,(generally not associated with untinted paint). 

Possible diagnosis

  • The paint base and tinter are not compatible. The application pressure/ shear are different for roller and brush application. A roller has a higher shear rate compared to brushing and will thus help to wet out and disperse the colourant better compared to brushing.
  • Colours might also vary from tin to tin depending on the method of agitation/mixing. More intense mixing should result in better colour development.

Remedy

  • Ensure that the tinter development properties are similar for roller and brush. Test both application methods side by side on a small area before commencing with a project.

CRACKING

Description
Hairline cracking of the paint film which can later progress in to chip flaking.

Possible diagnosis

  • Generally associated with paints which are highly filled and applied too thickly. Typically found in runs, puddles, and overlaps. 
  • Rapid drying of water-based dispersions as a result of painting over the porous and powdery substrate.
  • Rapid drying due to extremely hot or windy conditions.
  • Low-quality paint with poor adhesion and flexibility.
  • Over thinning.
  • Applying the paint too thinly.

Remedy

  • Remove loose and lifting paint. 
  • Porous substrates should be sealed with NEO Acrylic Primer.
  • Loose, powdery crack filler surfaces should be sealed with NEO Bonding Liquid prior to over coating.

 MARRING OR BURNISHING

Description
Marking of paint surface due to rubbing and scrubbing. Generally associated with dark, matt paint used in high traffic areas.

Possible diagnosis

  • Use of a very matt paint in high traffic areas. 
  • Use of a poor quality matt paint with low scrub resistance.
  • Excessive scrubbing or spot cleaning.
  • Frequent contact of painted surface to objects such as furniture.

Remedy

  • Gloss, sheen or semi-matte finishes are recommended in areas that might require frequent cleaning or traffic, such as NEO Dur High Gloss (SABS Grade 1), NEO Teflacryl or NEO Dur (SABS Grade 1).
  • Avoid abrasive means to clean paint surfaces.

POOR PRINT RESISTANCE

Description
Imprint marking of the paint film.

Possible diagnosis

  • Surface contact to paint film before it has properly dried. Note: Touch dry does not imply hard dry.
  • Use of low-quality paint with excessive drying time.
  • Painting in humid or cold conditions which interferes with the drying and curing of the paint.

Remedy

  • Allow defect to dry thoroughly. Sand back and recoat.

WRINKLING, LIFTING OR PULLING UP

Description
Wrinkling and pulling up of the paint film due to swelling.

Possible diagnosis

  • A coating with a strong solvent has been applied on top of alkyd paint. Make sure that the solvents of top coating are compatible with the existing underlying coating.
  • There has been prolonged contact with solvent spillage.
  • Accidental contact of coating surface with a paint remover.

Remedy

  • Remove loose and lifting paint. Repaint as per manufacturers instructions.

 CRATERING, PINHOLE AND PORES

Description
Cratering is used to describe small bowl-shaped depressions in the paint film.

Possible diagnosis

  • Coatings which are too thickly applied could result in air being trapped. The gas bubbles rise to the surface and burst, forming small craters in the wet paint film, which fail to flow out before the paint has set.
  • Incorrectly formulated water-based paint i.e. defoamer additive related.
  • Excessive shaking by the retailer of the in store tinting machines.

Remedy

  • Sand defect away and recoat.

POOR HIDING

Description
The paint coating does not obliterate the underlying surface which it is meant to cover, resulting in uneven color consistency.

Possible diagnosis

  • Insufficient layers of paint are applied. 
  • Not all pigment colours provide the same degree of hiding. Bright yellow and red pigments are notorious for poor hiding and thus it is to be expected that more coats will be required.
  • Increased contrast between the background colour and the new paint colour can contribute to hiding difficulty.
  • Low cost and low-quality paints can be expected to require additional coats as they may have poor leveling/flow properties and or pigment selection. 
  • Spreading the paint out more than is recommended, either by thinning, diluting, excessive rolling or using low-quality tools and/or roller cover.

Remedy

  • Apply additional coats carefully using the correct equipment and technique.
  • Consider factors such as paint colour/ pigment selection, cost, quality, substrate and background colour or consult a NEO Paints technical expert for advice.

SPATTER

Description
Paint droplet spatter produced during roller brush application.

Possible diagnosis

  • Low quality emulsion paints are more prone to spatter.
  • Incorrect paint type or application equipment.
  • Poor roller application technique.

Remedy

  • Use high-quality paints with low spatter rheologies such as NEO Dur (SABS Grade 1), NEO Multi Dur (SABS Grade 2) or NEO Aurora (SABS Grade 3).
  • Do not overload roller with paint. Work in 1m2 sectors utilizing W or M patterns, using controlled medium speed movements.