A cornice board is basically an enhancement to your window, and adding curtains is practically a must. It is a good idea to include a cornice board as a window treatment because it adds a beautiful and elegant touch to the room. It is rather easy to build one yourself, and you do not have to be an expert carpenter to do it. The most important thing is to match it with the color scheme of the room. You can either paint your cornice board to match the color of the walls, or else you could opt to cover it with fabric that matches the curtains' fabric. Also, make sure that there is enough depth to accommodate curtains and the rod underneath the cornice board.