To paint over unprimed wallboard, sandpaper the surface to make it rough, wash the wall, tape the trim and paint the wall. Without primer, use self-priming paint or an extra coat of regular paint.
- Sandpaper the surface
If the wallboard is covered with vinyl, roughen it up by running some sandpaper wrapped in a block of wood over it by hand.
- Wash the surface
New wallboard is dusty, and old wallboard has dirt, stains, grease, film, dust and cobwebs. Wash the surface to be painted with household cleaner or warm water and dish soap. Wipe it down afterwards with pure water. Let it dry completely before you paint.
- Protect the trim, furniture and floor
Apply painter's tape around the edges of any trim, baseboards and casements. Put a drop cloth on the floor under the wall. Cover any furniture remaining in the room with plastic.
- Paint the wall
Primer seals the pores in the wall, making the paint adhere better and spread smoothly. In the absence of primer, use self-priming paint, which has the same binding power as primer. Alternatively, apply three coats of paint instead of two, so the top coat is smooth and even. Use quality rollers and brushes. Paint borders and corners with a brush, and use a roller for the main portions. Allow the paint to dry thoroughly between each coat.