A professional painter can take 5 to 6 hours to paint the walls and the ceiling of a standard 12 feet by 12 feet room assuming that the condition of the walls is fine, and that it needs an application of two coats of flat paint. Two to 3 more hours may be needed for painting the door, baseboards and windows.
An experienced painter will require about 8 hours or one work day to paint the ceiling and walls in two rooms. However, the exact time required to paint a room is determined by a number of factors, some of which include the type of paint and the number of colors to be used, the size of the room and the available manpower.
A standard paint work is usually assumed to be the application of two coats of a particular colored paint on the walls, and one coat of a standard white paint on the ceiling. Therefore, painting different walls within a room in different colors or applying different colors of paint on a particular wall to create a unique design will increase the time needed to complete the whole project. On the other hand, dark colors, such as red, need to be applied three to four times on the wall, significantly increasing the time needed to complete the painting project.