Removing old paint from a wall can be a time-consuming but immensely rewarding task. Stripping away the old paint is essential before you repaint the wall. If you don't bother, the paint will not stick properly, and it will soon begin to flake off. Taking the time to perform the procedure correctly will assure a good-looking, permanent new paint job.
Lay plastic sheeting on the floor. This will protect the floor and act as a catch-all for the paint scrapings.
Spray a thorough coat of a water-based chemical stripper on the walls with the old paint. Use an airless sprayer (the type used to spray weed killer or bug spray). Apply the chemical stripper in the afternoon and let it remain on the walls overnight. Clean the sprayer thoroughly with hot water.
Scrape the layers of paint from the walls the next day, using the putty knife. The wider blade will allow you to cover more area with less work.
Spray another coat of chemical stripper on the walls and scrape the walls again to remove any remaining bits of paint.
Sand the walls with 80-grit sandpaper. This makes the walls rather rough, which is necessary for the paint to adhere properly. Skipping the sanding will result in flaking or peeling paint later on.
Apply a layer of interior primer with the paint roller. Cover the entire area. Allow the primer to dry completely, which should take about two hours.
Paint the walls with the interior paint colour of your choice, using the paint roller. Make sure that your paint roller has a good, thick nap on it, so it will hold plenty of paint. This will help eliminate bare spots. Allow the paint to dry for about three hours and apply a second coat of paint. Although the paint will dry in a few hours, wait at least two days before hanging anything on the walls.