Walls can be covered in dust and dirt unless they’re cleaned regularly. Although most modern paints are made to adhere to nearly any surface, they’ll stick best to smooth, clean surfaces. If the surface is dirty, oily or greasy, you risk paint peeling or bubbling when it’s dry. If walls are dusty when you apply paint, surfaces may look mottled or bumpy instead of smooth.
We all know painting over the cracks isn’t a good idea. Why? A fresh coat of paint accentuates any cracks or imperfections, making the wall look messy and unfinished. Watch out for cracks, tiny holes from nails and screws, or dents from door handles or furniture.
If there are large or small gaps around skirtings, cornices and walls, filling them means you’ll get a clean, crisp painted line between your wall and the wooden trim. Caulking/filling these gaps also gives you a smooth barrier, so gaps don’t get filled with dust, dirt or even insects. A flexible filler such as Selleys No More Gaps copes with building movement, so it won’t crack.
Unless you’re painting a brand new wall, chances are it has bumps, imperfections and old roller lint from previous paint jobs. Sanding before you paint gets rid of any rough spots, leaving your paint surface smooth for a great-looking finish. Sanding also adds adhesion to walls; the sandpaper creates small, rough ridges that mean the paint sticks well to the wall, and is less likely to flake.
Painting straight over flaky paint is a quick route to an uneven finish that peels or bubbles. Peeling paint can also mean there’s a lack of adhesion between the wall and paint. Painting over it simply masks the problem, instead of fixing it.
Much like interior walls, exterior weatherboard needs to be cleaned, sanded and have any gaps filled before re-painting. Maintaining weatherboards means getting rid of rough areas and old flaky paint. This will help new paint last much longer as it will have a clean surface to adhere to.