Valance Face Width (Rod/Board Face Width) should extend at least 2" on each side (total 4") of drapery rod for adequate clearance.
Standard Returns are 5 1/2" per side (total 11"). This gives you the needed 2" clearance for mounting over a single window treatment. For every additional layer of treatments, add at least 2" to the return size.
Decide where your valance will be installed on the window (top of frame, above under drapery, or at ceiling). Take ALL length measurements from this point.
• Measurement of product from end to end.
• Projection from the wall. This determines the location of the first panel on pleated styles.
• Add together the total of face width + left return + right return.
• The actual flat length of the valance including options.