Preparing your walls basically consists of two parts: cleaning the wall and making any necessary repairs. Cleaning the wall is essential because paint will not bond to dirt, grease, dust, or to a shiny surface. Additionally, there may be existing glossy paint or wallpaper that needs to be dealt with.
Repairs are done mainly for aesthetic purposes, to ensure that the wall appears flawless before you begin your paint job. This can take a little time, but it is worth it in order to achieve a fully professional result. If you are creating a highly textural finish, such as dry brushing, it is less important to complete every single repair exhaustively, because this technique hides imperfections very effectively.
Cleaning Dust and Dirt: To clean walls of dust and loose dirt, you can vacuum the wall gently with a vacuum cleaner or use a soft cloth or brush.
Cleaning Grease: If the walls are greasy, wipe them down with a damp cloth and a mild cleaning agent. Our favorite recipe for such a cleaning agent is to mix a bit of ammonia with dishwashing detergent and then add about two tablespoons to a quart of warm water. Be sure to go over the walls again with another clean cloth, this time using only plain water.
Do not wash raw wood or unpainted plaster. Continue reading for instructions for preparing these surfaces.