After pairing a new valance with a curtain board, check with the panel’s fall length as a guide to assist you dress the windows. A shorter valance complements a shorter panel; a lengthier valance complements a more panel. The header style and the valance shape are different factors which can affect the fall length. For instance, a fuller pinch-pleat valance needs to have a minimum fall of 8 inches; a slimmer pencil-pleat may have a minimum fall of 6 inches as a window topper.
As a guideline, a straight valance has a drop measuring 1/6 the curtain fall. Match a 12-inch valance fall up to a 72-inch curtain fall; a 15-inch valance with a 72- to 90-inch curtain fall; and an 18-inch valance with a 90-inch and more extended curtain fall.
A shaped valance has a minimum inside completed fall and a maximum outside completed fall, like the vertical measure at the side borders — for instance, a crescent-shaped or arched valance with a short center and 2 long sides. Both of these dimensions may have a difference of 5 to 7 inches between minimum and maximum drop dimensions. The valance’s shorter thickness should measure approximately 1/6 to 1/5 the curtain fall. A shaped valance fall ranging from 10 to 15 inches matches up to a 72-inch curtain fall; a 12- to 18-inch valance fall with a 72-inch into 90-inch curtain fall; and a 14-inch into 21-inch valance with a 90-inch and more curtain fall.