Things You'll Need
Roller with extension
Whether you've been painting your walls and accidentally streaked your ceiling, or you've been painting your ceiling and find it looks streaked instead of smooth, there's no quick fix for painting errors. You can't remove your mistakes; you're going to have to paint over them. Luckily, while it takes a little time, it's a pretty easy process.
Fix Streaks of a Different Color Than Your Ceiling
Wait for the paint on your walls and ceiling to dry completely.
If you don't have any paint that is the same color as your ceiling, you'll have to buy new paint. In fact, even if you have some of the original paint you used, the ceiling may have faded to another color, and you will have to match that. If possible, bring a paint chip to the home improvement or hardware store when you buy your paint so you can match it precisely. If the streaks are very close in color to your ceiling color, you may be able to get away without using primer. In most cases, however, you will need to cover the streaks with primer to cover the new color before you paint the matching color.
Move your furniture to the center of the room and cover it with a drop cloth. Place plastic tarps over the floor.
Set up the ladder. Put painter's tape along the edge of the walls. Again, make sure the paint on the wall is perfectly dry before you do this.
Climb up the ladder with an open can of primer. Brush a layer of primer over the streaks on the ceiling. Depending on the size of the streaks, you may be able to get away with just a few strokes to cover your error. The primer should cover the paint completely without bleeding through.
Wait for the primer to dry completely. Then brush a layer of matching colored paint over the primer. Try to make strokes at different angles so it covers without making obvious lines.
Wait for the paint to dry completely. If the color you used to paint over the streaks stands out too much from your original paint color, you may have to repaint the entire ceiling.
Fix Same-Color Streaks on a Ceiling Paint Job
Gather the painting supplies. Move your furniture to the center of the room and cover it with a drop cloth. Place plastic tarps over the floor.
Take a roller with extension, dip it lightly in paint, and roll it back and forth on the ribbed paint tray, removing as much excess paint as possible.
Go up your ladder, and roll the paint onto the ceiling at an angled stroke up to the left and back. Then, at an angle, stroke up to the right and back, all against the original angle of the stroke. The criss-crossed strokes should cover the streaks.
Wait for the paint to dry. If the job still looks streaked and/or irregular, chances are you will have to put another coat of paint on the entire ceiling. Often, if you can still see paint strokes, you simply haven't applied enough paint uniformly across the entire surface.