Take care with preparation. A poorly prepared job always catches up with you; durability is compromised and in the worst case the finished substrate is not good enough for further processing. But first and foremost, before you start your work you should perform an inspection to check that the substrate corresponds with the industry standard. If you are applying filler to a plaster substrate, follow recommendations in accordance with EN 13963.
Different substrates require different preparation. Always follow the manufacturer’s recommendations to achieve the best substrate for continued processing.
These are the general guidelines:
- Start by protecting doors and windows with plastic, sheets of cardboard or masonite panels. Protect the floor with protective paper, for example.
- Sand off any “flashes” and significant unevenness on concrete, plaster and light concrete using a steel filling knife, “bark spud”, sanding block or sanding machine.
- Cut off damaged cardboard on plasterboard. Repair any major damage using low shrinkage filler or gypsum-based powder filler.
- Wipe down smooth painted surfaces that are to be filled using paint cleaner.
- Apply primer to untreated steel, wood and fibreboard panels in order to counteract raised fibres and seepage of resins, rust, etc.
- Scrape, sand and dust down painted wood.
- Remove any loose wallpaper or fabric. In most cases, it is a requirement that you use a protective primer so that the wallpaper does not blister.
- Clean any dirty or greasy areas. Basically, before filling work starts, the substrate must be firm, clean and dry. Also make sure you choose the right application method, the right filler for the substrate and method, and the right tool. .