Painting over dark textured paint can be an extremely difficult task if it is not done properly. Whenever a dark color is to be covered up a solid coat of primer has to be applied, sometimes two coats depending on the color that was present. Then a beginning coat of white needs to be applied followed by two coats of the color that you are changing it to. The other issue that may present a problem is that since the dark paint is textured, a coarse roller should be used, rather than a medium or fine one. Just remember to complete one stage at a time, and make sure that work as fast as you can without being sloppy or missing sections of the area.
Step 1 - Clean the Area
Before attempting to cover up the dark textured paint clean the entire area with hot soapy water and a rag, and then rinse it down with a warm washcloth to remove any soap or stains that are left. Fill in any holes with putty, and if any windows or corners need to be caulked, do so before continuing to the next step. Remember that every good paint job begins and ends with the quality of the preparation work that is done.
Step 2 - Apply Primer
After the walls are repaired and dried begin applying a thick coat of primer to cover up the dark textured paint. Use an angled paint brush to cut in all the corners and around any doors and windows, and then use the coarse roller to complete the area. If you are not very steady make sure to tape off any areas that will not be painted, and make sure to drape the drop clothes over the floor and any furniture or appliances that are present. Repeat this process with another coat if the dark textured paint is still showing through. There is never a need to add more than 2 coats of primer though, so do not waste the time or effort doing it. Allow this coat to dry before moving on.
Step 3 - Paint a White Coat
Follow the steps that you used when applying the primer and coat the entire area with white. Use the angled brush to cut in and another coarse roller to finish it off. Be sure that the paint is uniform and that the brush and roller are wet, not dripping, with paint as you work. Allow this coat to dry before moving on.
Step 4 - Apply Colored Paint
The final step in painting over dark textured paint is to apply two coats of the color that you wish the area to be. Once again use the angled brush to cut in and then a coarse roller to finish it off. Work in sections and work from side to side, making sure that the next row is rolled on before the previous row dries, otherwise lines will appear. Repeat these steps for the second coat after the first has dried.