Paint master advises… 8 Things to remember when painting a previously painted wall
01 August 2014
1. Do a wipe test with your hand to see if any white powder is sticking to your hand. Some walls that are more exposed to sunlight has the tendency to have a white residue. It means that the paint has aged and it is chalking.
2. Wash off any dirt and remove any algae with a water and JIK solution.
3. Remove any white efflorescence with a water and spirit of salts solution.
4. Flaking paint needs to be removed by hand or with a high pressure wash system. If the plaster is very bristle it could mean the pressure wash can damage the plaster work and that the plaster then needs to be repaired. You don’t want to paint over plaster that is powdery and damaged.
5. Use a proper exterior filler / stopping, not one designed for interior use. All the areas that are filled should then be sanded and primed with bonding liquid.
6. Check the waterproofing on top of any boundary walls, windowsills, loose standing walls and parapet walls. Apply 2-3 coats of Paint master Umbrella Waterproofing on top of these surfaces. Make sure not to stretch the application since you need to have a maximum film thickness. It also helps to apply the coats with a brush and not with a roller. Use a criss-cross coating system.
7. Prime the walls with bonding liquid if necessary. The paint will not stick properly on a powdery chalking surface. Rather be safe than sorry. Apply one coat of bonding liquid to ensure good adhesion.
8. Apply 2 coats of Paint master Sheen, Texture 7 or Ultra Matt. All of these products are designed to last 7 years and has an excellent spreading rate. Rather apply 2 coats than 1 coat to get the minimum required micron film thickness.