Surfaces must be sound, clean, dry and free from grease, wax or any loose material that prevents good adhesion. Rub down using a suitable abrasive paper and dust off.
For masonry surface, the relative humidity should be under 17% according to Protimeter or let the substrate dry from 21-28 days in normal conditions (average temperature 30°C, humidity of environment is about 80%)
Previously Painted Surface
Remove all loose and flaking paint by scraping or sanding previously painted areas and sand smooth. Surface must be free of any loose material that prevents good adhesion. If mould is present, treat with suitable fungicidal wash or diluted bleach and rinse with clean water. Allow to dry before painting.
For Galvanised Steel Surface
Degrease new galvanised steel and abrade structural galv to remove chemical treatments to ensure maximum adhesion.